preliminary book of abstracts

Transcription

june
wednesday-thursday
2014
4
th
early stage researchers
workshop
in nanoscience
instituto imdea nanociencia
c/ faraday, 9 · campus cantoblanco
MOLESCO
w w w . n a n o s c i e n c e . i m d e a . o r g
25-26
25-26
june
wednesday-thursday
2014
4
th
workshop
in nanoscience
instituto imdea nanociencia · c/ faraday, 9 · campus cantoblanco
Organizing committee
Dr. Cristina Flors
Dr. Borja Ibarra
Dr. Alfonso Latorre
Dr. Teresa González
Dr. Álvaro Somoza
Dr. María Jesús Villa
Ms. Patricia López
Scientific committee
Dr. Aitziber L. Cortajarena
Dr. Juan Luis Delgado
Dr. David Écija
Dr. Daniel Granados
Dr. Daniel Ortega
Dr. Ana Pizarro
Dr. Emilio Pérez
Dr. Juan Rojo
Dr. Begoña Sot
PROGRAMME
Chair: Teresa González
15:15-15:30 O6
Ana
Martín-Lasanta
(IMDEA
Nanociencia)
Studying the electrical properties of
nanosized objects
15:30-15:45 O7
Ana Zuzuarregui (CIC nanoGUNE)
Highly reflective polymeric substrates
functionalized utilizing ALD
15:45-16:00 O8
Longfei Wu (IMDEA Nanociencia)
Highly efficient solid state emission of
regio-regular
polythiophene
upon
dilution in a conjugated polymer matrix
11:00-11:30 Coffee Break & Photo
16:00-16:30 Coffee Break
Session 1. Chair: David Écija
Session 3. Chair: Ana Pizarro
11:30-11:45 O1
Ramón Bernardo (IMDEA Nanociencia)
E-beam assisted etching and patterning
of few-layer molybdenum disulfide
11:45-12:00 O2
Jorge Quereda (UAM)
MoS2 roughness and friction quenching
by interaction with atomically flat
substrates
12:00-12:15 O3
Huayu Feng (IMDEA Nanociencia)
Magnetoplasmonic nanorings as novel
architectures with tunable magnetooptical activity in wide wavelength
ranges
12:15-12:30 O4
Juan
Jesús
Navarro
(IMDEA
Nanociencia)
Spatial variation of a Giant Spin-Orbit
effect induces electron confinement in
graphene on Pb islands
16:30-16:45 O9
Antonio García (UAM)
Immunosensors based on the Fano
resonance of Ga nanodroplets
16:45-17:00 O10
B.
Macarena
Cobaleda
(CIC
biomaGUNE)
Iron Oxide Nanoparticles Carrying
dsRNA and Targeting Lymph Nodes for
Immunotherapy
17:00-17:15 O11
David Cabrera (IMDEA Nanociencia)
Influence of biological matrix on
nanomagnetism
of
Iron
Oxide
Nanoparticles
17:15-17:30 O12
Rahman Shokri (CNB-CSIC)
Transfection
of
T
cells
with
nanoparticle-conjugated antisense to
p21 led to an increased T activation
pattern
17:30-17:45 O13
Emmanuel Ruggiero (CIC biomaGUNE)
Near Infrared Activation of Metal-Based
Anticancer Agents by Upconverting
Nanoparticles
17:45-18:00 O14
Javier Hernández-Gil (CICbiomaGUNE)
Magnetic nanoparticles combined with
Pt(IV) prodrugs and immunostimulatory
dsRNA for theranostic applications
Wednesday, 25 June
9:00-9:45 Registration
9:45 Opening:
Miranda
Prof.
Rodolfo
10:00-11:00 Invited Lecture:
Dr. José Luis Pau (UAM)
Nanowire photodetectors and imagers
fabricated
by
dielectrophoretic
assembly: review and prospects
12:30-13:30 Poster session 1
13:30-15:00 Lunch
Session 2. Chair: Paolo Perna
15:00-15:15 O5
Marta Mroz (IFN-CNR, Politecnico di
Milano)
Amplified spontaneous emission in
conjugated polyrotaxanes under quasicw excitation
Thursday, 26 June
10:00-11:00 Invited Lecture:
Dr. Marta Mas-Torrent
(Institut de Ciència de Materials de
Barcelona)
Organic
Molecules
as
Active
Components in Electronic Devices.
Chair: Emilio Pérez
11:00-11:30 Coffee Break & Photo
Session
Delgado
4.
Chair:
Juan
Luis
15:30-15:45 O21
Alberto Sanz (ICTP-CSIC)
Control of composition by self-assembly
of amphiphilic copolymers inside
micropores combining the breath
figures technique and the coffee stain
phenomenon
15:45-16:00 O22
Javier López (UCM)
Repeat protein scaffolds: a template for
ordering electroactive molecules in
solution and solid state
16:00-16:30 Coffee Break
Session 6. Chair: Pierre Couleaud
11:30-11:45 O15
María Acebrón (IMDEA Nanociencia)
Surface composition controls the optical
properties of alloyed QDs encapsulated
in silica shells
11:45-12:00 O16
Emiliano Martínez (UAM)
A dinuclear thiocarboxylate paddlewheel Ni(II) complex as unusual
precursor
of
electrochemically
generated Ni(OH)2 nanoparticle
12:00-12:15 O17
Olga Trukhina (UAM)
Switchable Electron Transfer Reactivity
in Phthalocyanine - Sc3N@C80
Supramolecular Ensembles
12:15-12:30 O18
Alberto de Juan (IMDEA Nanociencia)
Mechanically Interlocked Single-Wall
Carbon Nanotubes
12:30-13:30 Poster session 2
13:30-15:00 Lunch
Session 5. Chair: Alfonso Latorre
15:00-15:15 O19
Nina Gómez (CIC biomaGUNE)
Nanosized
materials
based
on
dinuclear Gd(III) complexes as novel
theranostic carriers
15:15-15:30 O20
Iria Bravo (UAM)
Synthesis
of
gold
nanoparticles
assisted by capping ligands playing a
three-in-one role
16:30-16:45 O23
Sara Hernández (IMDEA Nanociencia)
Functional nanostructure by designed
protein self-assembly
16:45-17:00 O24
Unai Carmona (CIC nanoGUNE)
Tuning, Inhibiting and Restoring the
Enzyme Mimetic Activities of PtApoferritin
17:00-17:15 O25
Irene Gutiérrez (IMDEA Nanociencia)
Mechanochemistry of G-Quadruplexes
studied by single-molecule force
spectroscopy
17:15-17:30 O26
Aitor Monserrate (IMDEA Nanociencia)
Combinig super-resolution fluorescence
microscopy and AFM for advance DNA
imaging
17:30-17:45 O27
Jose
Alberto
Morín
(IMDEA
Nanociencia)
Single-molecule
mechanical
characterization of the HmtSSB binding
properties to ssDNA.
17:45-18:00 O28
Marta Palacios (ICTP-CSIC)
Tailored functional protein platforms
18:00-18:15 Awards & Closing
Remarks: Nazario Martín
18:15-19:30 Refreshments
Poster Session 1 (25 June)
P1 The Impact of Photo-oxidation on Charge Carrier Dynamics in P3HT:PCBM Solar
Cells. Safakath Karuthedath (IMDEA)
P2 On the growth mechanisms of GaAs nanowires synthesized by Ga-assisted
chemical beam epitaxy. Carlos García Nuñez (UAM)
P3 A Landau–Squire nanojet: measuring picolitre flows with Optical Tweezers.
Benjamin Gollnick (CNB-CSIC)
P4 High coercive isotropic CoFe2O4 powders obtained by ultrafast-milling for
permanent magnet applications. Karol Marek Golasinski (IMDEA)
P5 Nanoscale ripple patterns as a playground for AFM lithography and manipulation
experiments. Patricia Pedraz (IMDEA)
P6 An outer-sphere coordination chemistry approach for platinum based anticancer
drug delivery. Amaia Garaikoetxea (CIC biomaGUNE)
P7 Inorganic superparamagnetic iron oxide nanoparticles for the delivery of innate
immune response agonists. Ana Isabel Bocanegra (CIC biomaGUNE)
P8 Development of novel theranostic agents based on transion metal complexes and
upconversion nanoparticles. Silvia Alonso (CIC biomaGUNE)
P9 Experimental set-up of an optically accesible STM. Alberto Martín (IMDEA)
P10 Elastic-Plastic Switch of Tomato Bushy Stunt Virus Particles. Aida Llauró (UAM)
P11 Electrical properties of thin Pd-ZrO2 granular films prepared by Radio Frequency
Magnetron Sputtering. Hicham Bakkali (U. Cádiz)
P12 Epitaxial magnetite films with four-fold anistropy and RT <100> easy axis grown by
PLD. Javier Pedrosa (IMDEA)
P13 Pressurization of human adenovirus particles during maturation. Álvaro Ortega
(UAM)
P14 Aggregation-Induced Enhanced Emission - Intra- and Intermolecular Structural
Factors. Junqing Shi (IMDEA)
P15 Magnetic nanoparticles as doxorubicin delivery system for targeting breast cancer
cells. Ana Lazaro-Carrillo (UAM)
P16 Long-lived photoexcited states in SWNT-PFO blends. Abasi Abudulimu (IMDEA)
Poster Session 2 (26 June)
P17 Fine tuning of size and polydispersity of carbon spheres to obtain carbon opals.
Luz Karime Gil (ICMM-CSIC)
P18 Non covalent interactions between graphene/exTTF. Marina Garrido (UCM)
P19 Size, shape and capping ligand dependence of cyclic voltammetry studies on
CdSe nanocrystals. Julio J. Conde (UAM)
P20 New fullerene-based materials for organic photovoltaics. Inés García (IMDEA)
P21 2D Nanostructures Based in Modified Oligonucletides. Romina Lorca (IMDEA)
P22 New fullerene derivatives for photovoltaics. Rafael Sandoval (IMDEA)
P23 Single molecule characterization of the DNA unwinding mechanism of the T7
helicase. Fernando Cerrón (IMDEA)
P24 Mechano-selective bacteria surface adhesion. Felipe Viela (IMDEA)
P25 Fluorescent gold nanoclusters stabilized by repeat portein scaffolds. Sergio Adan
(IMDEA)
P26 Naphthalene bisimides for the synthesis of Mechanically Interlocked Derivatives of
Carbon Nanotubes. Sofia Leret (IMDEA)
P27 Synthesis of PEGylated gold nanorods dimers using molecular linkers. Guillermo
González (UCM)
P28 Synthesis of Extended Graphdiyne Wires by Vicinal Surface Templating. Borja
Cirera (IMDEA)
P29 Nanotubular Systems Self-assembled through Orthogonal Supramolecular
Interactions. Violeta Vazquez (UAM)
P30 Supramolecular synthesis of discrete p-conjugated cyclic tetramers. Carlos
Montoro (UAM)
P31 Synthesis of Graphene Sheets for Device Fabrication. Andrés Black (IMDEA)
P32 2D lanthanide-based molecular architectures on surfaces. Jose Ignacio Urgel (TU
München)
P33 Permanent magnets: From nanostructured thin films to powder-like systems with
GPU-based micromagnetics. Gabriel Rodríguez (IMDEA)
ABSTRACTS
I-1 Nanowire photodetectors and imagers fabricated by
dielectrophoretic assembly: review and prospects
J. L. Pau, C. García Núñez, A. García Marín, J. Piqueras
Electronics and Semiconductors Group, Applied Physics Department, Facultad de Ciencias,
Universidad Autónoma de Madrid
Light sensors based on nanomaterials have demonstrated promising capabilities to
outperform the sensitivity of some of the current detector technologies. Internal
mechanisms in nanowires (NWs), nanotubes and graphene raise the responsivity
levels well above those found in bulk devices as the surface-to-volume ratio becomes
larger. In the NW case, gain values up to 108 have been measured surpassing the gain
levels of many avalanche photodiodes and photomultiplier tubes. Although the high
response is often accompanied by long response times and persistent effects, the gainbandwidth product is, in many materials, superior to that found in bulk devices. These
mechanisms, thoroughly studied in ultraviolet ZnO NW detectors, can involve gas
adsorption-desorption processes on the nanomaterial surface that are also responsible
of slow transients. In the infrared region, superconducting NWs have reached optimal
operation for single photon counting at very low temperatures, showing high detection
efficiencies and low dark count rates. Despite these promising characteristics, the
high-level integration of single NWs in two-dimensional arrays for imaging applications
is rarely encountered due to the technical challenge that the fast, reliable, and
reproducible assembly of NWs represents.
The dielectrophoresis (DEP) term describes the movement of suspensoid particles
relative to that of the solvent in non-uniform electric fields. The dielectrophoretic force
induced in the particles can be used to attract them to specific sites defined by pairs of
electrodes separated by a few micron gaps. Last results obtained on the development
of NW photodetectors fabricated by DEP will be presented in this talk with special focus
on the optimization of the conditions for the effective alignment of NWs. The
preparation methods of the NW dispersions in the transfer process from the growth
substrate to the receptor surface prior to the DEP alignment will be reviewed. These
studies have led to the development of single NW devices, fully-transparent NW
detectors and different types of photodetector structures, namely, photoconductors, np-n heterojuntions, and metal-oxide-semiconductor diodes. The effects of the NW
diameters, the contact characteristics between the NWs and the electrodes, the
dielectric passivation or the surface silanization for bio-functionalization purposes will
be discussed.
R. Gurwitz, R. Cohen, and I. Shalish, “Interaction of light with the ZnO surface: Photon induced oxygen
"breathing," oxygen vacancies, persistent photoconductivity, and persistent photovoltage”, J. Appl.
Phys. 115, 033701 (2014).
V. B. Verma, F. Marsili, S. Harrington, A. E. Lita, R. P. Mirin, and S. W. Nam, “A three-dimensional,
polarization-insensitive superconducting nanowire avalanche photodetector”, Appl. Phys. Lett. 101,
251114 (2012).
C. García Núñez, A. García Marín, P. Nanterne, J. Piqueras, P. Kung, and J. L. Pau, “Conducting properties
of nearly depleted ZnO nanowire UV sensors fabricated by dielectrophoresis”, Nanotechnology 24,
415702 (2013).
A. García Marín, C. García Núñez, E. Ruiz, J. Piqueras, and J. L. Pau, “Fast response ZnO:Al/CuO
nanowire/ZnO:Al heterostructure light sensors fabricated by dielectrophoresis”, Appl. Phys.
Lett. 102, 232105 (2013).
I-2 Organic Molecules as Active Components in
Electronic Devices
Marta Mas-Torrent
Institut de Ciència de Materials de Barcelona.
Nowadays, most data storage devices are based on binary logic bit cells which
are reaching the highest possible density storage capability due to the sizeresolution limitations of lithographic techniques. Molecular electronics, which
aims at employing molecules as active electronic components, offers an
alternative approach to the downscaling of the devices: a bit of data storage
information could in principle be as small as an individual molecule. In this
direction, we show that the immobilization of electroactive molecules on
surfaces offers a promising platform to fabricate switches in which an electrical
input can be transduced into different optical and magnetic outputs. These
hybrid materials permit hence to write, store and read information, which is very
promising for developing molecular non-volatile memory devices, of great
interest in Molecular Electronics.
Figure 1. Left. Self-assembled monolayer of an electroactive organic PTM radical on ITO that
behaves as an electrochemical switch with optical and magnetic outputs. Right. Fluorescence
image of a patterned SAM of a PTM radical prepared by microcontact printing.
O-1 E-beam assisted etching and patterning of few-layer
molybdenum disulfide
Ramón Bernardo Gavito,*a,b Rodolfo Mirandaa,b,c and Daniel Granadosb
a
Dpto. de Física de la Materia Condensada, Universidad Autónoma de Madrid, Facultad de ciencias, 28049, Madrid, Spain;
IMDEA Nanociencia, Faraday 9, 28049, Madrid, Spain;
c
Instituto de Ciencia de Materiales “Nicolás Cabrera”, Universidad Autónoma de Madrid, Fac. Ciencias, 28049, Madrid, Spain;
E-mail: [email protected]
b
Transition metal dichalcogenides have attracted a huge interest since the isolation of graphene. This interest is
based in the fact that these materials develop different properties when their thickness is reduced down to the
monolayer or few-layer regime [1]. Among all of them, molybdenum disulfide (MoS2) is especially interesting
because as a bulk it is a semiconductor with an indirect band-gap in the near-infrared region of the spectrum, and
this band-gap blue-shifts when reducing the number of layers, resulting in a direct band-gap semiconductor which
emits in the visible (1.85eV) when its thickness is reduced to a single layer [1, 2, 3].
During the last years, many different techniques for fabricating MoS2 single layers have been developed, such as
mechanical exfoliation [2, 3], XeF2 plasma etching [4] and many others [5, 6].
In this work we use mechanical exfoliation to deposit MoS2 flakes on a SiO2/Si substrate and use an electron
beam with a XeF2 flow to locally etch specific regions of the flake (Fig. 1) without using masks or electron beam
lithography resists.
We also created point defects using a focused ion beam and visualized on-line the growth of hexagonal holes (Fig.
2) while using the SEM while keeping the XeF2 flow. This is consistent with the results obtained in [4] using a XeF2
plasma and graphene as a masking layer.
Using this method we are able to pattern the exfoliated MoS2 and to selectively etch the material with arbitrary
shapes and a good lateral resolution. This will allow us to design complex structures with controlled thicknesses,
giving us the possibility to fabricate different kinds of devices such as photonic crystals, quantum dots or
transistors.
FIGURE: Cascaded MoS2 flake of ifferent thicknesses patterned using the proposed technique.
Notes and References.
1
2
3
4
5
6
Qing Hua Wang, Kourosh Kalantar-Zadeh, Andras Kis, Jonathan N. Coleman, Michael S. Strano. Nature Nanotechnology 2012, 7,
699.
Kin Fai Mak, Changgu Lee, James Hone, Jie Shan, and Tony F. Heinz. Phys. Rev. Lett. 2010, 105, 136805.
A Castellanos-Gomez, N Agraït, G Rubio-Bollinger. App. Phys. Lett. 2010, 96, 213116
Yuan Huang, Jing Wu, Xiangfan Xu, Yuda Ho, Guangxin Ni, Qiang Zou, Gavin Kok Wai Koon, Weijie Zhao, A. H. Castro Neto, Goki
Eda, Chengmin Shen, and Barbaros Özyilmaz. Nano Research 2013, 6, 200.
Xiao Huang, Zhiyuan Zeng and Hua Zhang. Chem. Soc. Rev. 2013, 42, 1934.
Xin Lu, Muhammad Iqbal Bakti Utama, Jun Zhang, Yanyuan Zhao, Qihua Xiong. Nanoscale 2013, 5, 8904.
O-2 MoS2 roughness and friction quenching by interaction
with atomically flat substrates
Jorge Quereda1, Nicolás Agräit1,2,3, Andres Castellanos-Gomez4 and Gabino RubioBollinger1,3*.
1
Departamento de Física de la Materia Condensada. Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid,
Spain.
2
Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia. E-28049 Madrid (Spain).
3
Instituto Nicolás Cabrera, Campus de Cantoblanco, 28049 Madrid, Spain.
4
Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
e-mail: [email protected]
Two-dimensional materials have attracted great interest in the last years due to their promising applicability in
nanoelectronics [1, 2]. Although graphene is the most widely studied two-dimensional material, its lack of bandgap
has limited its technological applicability in the development of semiconducting devices. To overcome this issue
two different strategies have been applied: inducing a bandgap in graphene or replacing graphene for another two dimensional material with a high intrinsic bandgap. Atomically thin MoS 2, a transition metal dichalcogenide, is being
widely investigated as an alternative to graphene for semiconducting ap plications due both to its intrinsic 1.8 eV
2 -1 -1
bandgap and high mobility μ > 200 cm V s . Due to their inherent large surface-to-volume ratio, the chemical,
optical, mechanical and electrical properties of atomically thin materials can be strongly modified by their
interaction with the substrate where they are deposited [3, 4]. In fact, we find that the roughness of the MoS 2
monolayers is dominated by the roughness of the substrate and therefore amorphous SiO 2 substrates induce a
much larger corrugation in the MoS 2 monolayers than atomically flat substrates. Specifically, MoS2 monolayers
transferred onto mica or hexagonal boron nitride substrates present a roughness about 50% lower than on SiO 2.
Furthermore, we find a good correlation between the substrate-induced roughness and the friction in MoS 2 layers,
indicating that the friction in atomically thin MoS 2 layers might be strongly modified by the MoS 2/substrate
interaction.
FIGURE. Statistical analisis of atomic force microscope (AFM) topography and friction measurements. (a) Heigh
histograms of monolayer MoS2 surfaces deposited on mica, hexagonal boron nitride and SiO 2 (b) AFM friction
measurements as a function of MoS2 flake’s thickness. (c) Comparison between measured flake’s friction and
roughness.
Notes and References
1.
2.
3.
4.
Novoselov, K., et al., Two-dimensional atomic crystals. Proceedings of the National Academy of Sciences of the United States
of America, 2005. 102(30): p. 10451-10453.
Castellanos-Gomez, A., et al., Fast and reliable identification of atomically thin layers of TaSe2 crystals. Nano Research,
2013. 6(3): p. 191-199.
Lee, C., et al., Frictional characteristics of atomically thin sheets. Science, 2010. 328(5974): p. 76-80.
Jorge Quereda, A.C.-G., Nicolás Agräit and Gabino Rubio-Bollinger, MoS2 roughness and friction quenching by interaction
with atomically flat substrates. (On preparation), 2014.
O-3 Magnetoplasmonic nanorings as novel architectures with
tunable magneto-optical activity in wide wavelength ranges
Hua Yu Fenga, Feng Luo*a, Renata Kekesib, Daniel Granadosb, David Meneses Rodríguezb,
Jorge M. Garcíab, Antonio Garcia Martínb, Gaspar Armellesb, and Alfonso Cebollada*b
a
b
IMDEA Nanoscience, Faraday 9, Ciudad Universitaria de Cantoblanco, 28049, Madrid, Spain Tel: 912998764;
IMM-Instituto de Microelectrónica de Madrid (CNM-CSIC), Isaac Newton 8, PTM, E-28760 Tres Cantos, Madrid, Spain Tel:653958587
A novel magnetoplasmonic system constituted by Au/Co/Au nanorings fabricated by hole mask colloidal
lithography is presented. They exhibit a bimodal resonant behavior in the optical and, more noticeably, in the
magneto-optical (MO) properties. We demonstrate that fine control and enhancement of the MO activity can be
achieved by modifying ring’s structural dimensions such the apex-to-apex distance, and/or the inner and outer ring
diameter. This way, large MO activity with moderate optical losses can be achieved in the visible range.
Additionally, sizeable MO activity spectrally spans from the visible to the near IR, extending the spectral range over
which current magnetoplasmonic structures exhibit MO activity.
FIGURE
1 G. Armelles; A. Cebollada; A. García-Martín; M. U. González. Adv. Optical Mater. 2013, 1, 10
2 G. Armelles; A. Cebollada; A. García-Martín; J. M. García-Martín; M.U. González; J. B. González-Díaz; E Ferreiro-Vila; J. F.
Torrado. J. Opt. A: Pure Appl. Opt. 2009,11, 114023.
O-4 Spatial variation of a Giant Spin-Orbit effect induces
electron confinement in graphene on Pb islands
F. Calleja a, J.J. Navarro*a,b, M. Garnicaa,b, A.L Vázquez de Pargaa,b and R. Mirandaa,b
a
IMDEA Nanociencia, Madrid, Spain.
Departamento de Física de la Materia Condensada , Universidad Autónoma de Madrid, Spain.
b
Graphene´s set of extraordinary electronic, mechanical or optical properties does not include strong spin-orbit
interaction. By growing epitaxially graphene on single crystal metal surfaces under Ultra High Vacuum (UHV) conditions
[1] and intercalating heavy atoms below it, we show how to add a giant spin-orbit interaction.
We discuss the intercalation of an ordered array of Pb atoms below graphene, which results in the appearance of a
series of equally spaced, sharp peaks in the differential conductance, as revealed by laterally resolved Tunnelling
Spectroscopy at 4.6 K. The vicinity of Pb enhances the, usually negligible, spin-orbit interaction of graphene. The spatial
variation of the spin-orbit coupling when going from graphene intercalated with Pb to graphene directly deposited on
Ir(111) creates a pseudo-magnetic field that originates pseudo-Landau levels [2].
1
2
A.L. Vázquez de Parga et al, Phys. Rev. Lett. 2008, 100, 056807
F. Calleja et al, submitted
O-5 Ampliefied spontaneus emission in conjugated
polyrotaxanes under quasi-cw excitation
Marta M. Mroz,a,e* Giuseppe Sforazzini,b Yongchun Zhong,c Kam Sing Wong,c Harry L.
Anderson,b Guglielmo Lanzanid and Juan Cabanillas-Gonzaleza
a
Instituto Madrileño de Estudios Avanzados, (IMDEA-Nanociencia), Madrid, Spain, previous address
Department of Chemistry University of Oxford Chemistry Research Laboratory, Oxford, UK. tel. 44 (0) 1865 275704
c
Department of Physics Hong Kong University of Science and Technology, Hong Kong, China. tel. (852) 2358-7475
d
Center for Nano Science and Technology@Polimi Istituto, Italiano di Tecnologia, Milan, Italy. tel. 039 02 23999872
e
Istituto di Fotonica e nanotecnologie (IFN)-CNR, Milan, Italy tel. 039 0223996582
b
We present a combined time resolved spectroscopy study on a rotaxinated conjugated polymer together with
amplified spontaneous emission characterization and detailed analysis. We show that optical amplification over a
bandwidth of more than 30 nm and amplified spontaneous emission under quasi-cw laser pumping (1 ms pulse
width) can be achieved in supramoleculary encapsulated polymer film [1]. We have recently shown that
supramolecular encapsulation of conjugated polymers is an effective means to suppress intermolecular
interactions, which leads to enhanced spectral properties such as higher luminescence quantum yield and blue
shifted emission [2]. Ultrafast spectroscopy and cw-PIA results show that supramolecular threading reduces the
generation of long-lived states, thus broadening the gain bandwidth and enabling quasicontinuous wave optical
pumping for optical amplification.
FIGURE. ASE output under quasi-CW pump at 10.5, 29, 124 and 509 W/cm2 (from bottom to top, solid lines)
together with ASE action under fs-pump (open circle); inset: pumping scheme
1
2
Mróz MM, Sforazzini G, Zhong Y, Wong KS, Anderson HL, Lanzani G, Cabanillas-Gonzalez J. Adv Mater. 2013, 25(31), 4347-51
Mróz MM, Lanzani G., Virgili T., McDonnell SO, Frampton MJ, Anderson HL, Phys. Rev. B 2009 , 80 , 045111
O-6 Studying the electrical properties of nanosized objects
Ana Martín-Lasanta a,b Delia Miguel,b Sara P. Morcillo,b Luis Álvarez de Cienfuegos,b Linda
A. Zotti,c Edmund Leary,a,c Rocío Jurado, b Diego J. Cárdenas,d G. Rubio-Bollinger,c,e Sara H.
Mejias, a Pierre Couleaud, a Aitziber L. Cortajarena,a José M. Abada,f,Juan M. Cuerva,b
Nicolás Agrait,a,c,e M. Teresa Gonzáleza
a
Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Campus UAM ,Cantoblanco, 28049, Madrid, Spain;
Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Granada, C. U. Fuentenueva s/n, 18071 Granada, Spain;
Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain;
d
mica Orgánica, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain;
e
Instituto Universitario de Ciencia de Materiales
C b
’’, Universidad Autónoma de Madrid, 28049 Madrid, Spain;
f
Departamento de Química
,
,C
b
,
,
b
c
Using a home-built STM under ambient conditions, we study the electrical properties of nanosized objects as
organic molecules and nanoparticles.
Organic molecules such as oligo(phenyleneethynylene) (OPE) derivatives have been widely studied in
mechanically controlled break junction experiments (BJ-STM) because they are highly conjugated, rigid molecules
whose functional properties can be systematically tuned by chemical synthesis. OPEs basic components are benzene
rings connected by triple bonds but beyond benzene, an enormous amount of aromatic heterocycles exists. Recently we
have studied a new family of thiomethyl OPE3 and OPE4 derivatives in which one inner benzene ring has been replaced
by nitrogen heterocycles in order to investigate how the presence of nitrogen atoms affect the molecular conductance in
comparison with their all-carbonated analogs. Transport studies through longer derivatives OPE4 allowed us to study the
correlation of conductance with molecular length. Terminal 4-pyridyl units have been used as anchor molecules and they
1
exhibits excellent anchoring performance with high conductance and percentage of molecular junctions formed. For this
reason, another interesting issue to face was if the presence of the nitrogen basic electron pairs could act as a second
2
anchoring group thus yielding to two distinct conductance states.
On the other hand, we are also conducting single-molecule experiments by combining STM-imaging (recorded
3
in constant-current mode) with conductance and I/V measurements on isolated 1.6 nm-size gold nanoparticles (AuNPs)
4
and AuNPs bioconjugated to a CTPR (consensus tetratricopeptide repeat) helix-turn-helix motif protein backbone. In
this experiments we are seeking on single-ET features for clear quantized charge signatures and their variation with the
capping of the nanoparticles. The tunneling spectroscopy is performed by positioning the Au tip over an isolated object
by disabling the feedback control and measuring I-V characteristics.
References
1
Hong, W.; Manrique, D. Z.; Moreno-García, P.; Gulcur, M.; Mishchenko, A.; Lambert, C. J.; Bryce, M. R.; Wandlowski, T. J. Am.
Chem. Soc. 2011, 134, 2292−2304.
2
Su, T. A.; Widawsky, J. R.; Li, H.; Klausen, R. S.; Leighton, J. L.; Steigerwald, M. L.; Venkataraman, L.; Nuckols, C. J. Am. Chem.
Soc. 2013, 135, 18331-18334.
3 Jensen, P. S.; Chi, Q.; Grumsen, F. B:; Abad, J. M.; Horsewell, A.; Schiffrin, D. J.; Ulstrup, J. J. Phys. Chem. C 2007, 111, 61246132.
4 Cheng, C. Y.; Jarymowycz, V. A.; Cortajarena, A. L.; Regan, L.; Stone, M. J. Biochemistry 2006, 45, 12175-12183.
5 Chaki,N. K.; Singh,P.; Dharmadhikari,C. V.; Vijayamohanan, K. P. Langmuir 2004, 20, 10208-10217.
O-7 Highly reflective polymeric substrates functionalized
utilizing ALD
Ana Zuzuarregui,*a Borja Cotob, Jorge Rodríguezc and Mato Knez a,d
a
CIC nanoGUNE Consolider, 20018 Donostia-San Sebastián, Spain. Tel: 943574000;
IK4 Tekniker, Eibar, Spain. Tel: 943206744;
c
Torresol Energy (SENER Group), Las Arenas, Spain. Tel: 944818142;
d
IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain. Tel: 944052660
b
In Termosolar Plants reflective surfaces are one of the key elements of solar fields to concentrate energy in the
receivers. The reflexion index is proportional to the amount of solar energy that can be concentrated. Glass mirrors
are most commonly introduced in industrial plants due to their good performances however they also have all the
drawbacks glass brings about (high cost, high weight, mechanical sensibility). Therefore , polymeric substrates are
being considered as alternative to glass.
In this work, highly reflective surfaces on polymer substrates have been fabricated using atomic layer deposition
(ALD). ALD is a thin-film coating technique that enables the modification of surfaces of materials with nanoscale
films. This technology is based on the sequential delivery of precursors from the gas phase and self -saturating
surface reaction that leads to a perfectly controlled and conformal growth of the coating. Figure 1a shows a
scheme of the operating principle of the ALD technique. ALD has great potential to be utilized for numerous
emerging applications, including fabrication of sensing and energy devices, the corrosion protection and sensitive
material encapsulation, flexible electronics, etc.
In our particular approach, we have used FEP (fluorinated ethylene propylene) as the polymeric substrate for its
physico-chemical properties, and TiO2 was applied as the coating material for the same reason. The deposition of
the nanometric layers has been carried out sequentially introducing the precursors into the ALD chamber at a
processing temperature of 120 ºC. The growth rate of TiO2 was 0,065 nm/cycle. In order to characterize the quality
of the coatings and the adherence of the TiO2 to the polymeric substrate, optical and SEM microscopy, AFM
topographic analysis and adherence Scotch tape tests have been carried out. Figure 1b shows a representative
example of the characterization performed.
The optimization of different parameters involved in the deposition process , including the nature of the precursors,
the thickness of the ceramic layer and the pre-treatment and post-treatment of the samples, resulted in surfaces
with a reflection index of 97%, an improved value if compared to commercial references such as Miro Alanod
(90%) and RefleTech (93-94%) [2], [3]. The data obtained from the optical characterization as well as the
micrographies and adherence test show that the surfaces obtained with ALD are a real, affordable and robust
alternative to glass mirrors in solar fields.
Figure 1. a) Scheme of the ALD process. b) Optical micrographies of the TiO3 coated polymeric substrates, b1:
first attempt, b2: optimized samples
References
1
M. Knez, K. Nielsch, and L. Niinistö, “Synthesis and Surface Engineering of Complex Nanostructures by Atomic Layer
Deposition,” Adv. Mater., vol. 19, no. 21, pp. 3425–3438, Nov. 2007.
2
C. E. Kennedy, “Advances in Concentrating Solar Power Collectors : Mirrors and Solar Selective Coatings,” 2007, vol. 6103.
3
ReflecTech Inc, “ReflecTech Plus Mirror film.” 2011.
O-8 Highly Efficient Solid State Emission of Regio-Regular
Polythiophene upon Dilution in a Conjugated Polymer Matrix
Longfei Wua, Santiago Casadoa, Larry Lüera, Ruidong Xiab, Feng Luoa and
Juan Cabanillas-Gonzaleza
a
b
IMDEA Nanociencia, Calle Faraday 9, Ciudad Universitaria de Cantoblanco, Madrid 28049 Spain.
Key Laboratory for Organic Electronics & Information Displays (KLOEID), Institute of Advanced Materials (IAM)
Nanjing University of Posts & Telecommunications, Nanjing 210046, China
Regio-regular polythiophene (P3HT) is a prototype of p-type conjugated polymer in organic bulk heterojunction
[1]
solar cells. In the solid state, P3HT chains arrange into self-organized 2D p-stacked lamellar structures, favouring
[2]
charge transport along and across the lamellae. This positive effect in transport has however its counter-part on
[3]
poor emissive properties associated to H-aggregates. These characteristics are preserved to a certain extent even
upon dilution in inert matrices such as PMMA or polystyrene. In this work we demonstrate how the use of a
conjugated polymer host matrix, (Poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4,8-diyl) also named
F8BT), leads to efficient emission and optical gain properties in the former as demonstrated by Amplified
Spontaneous Emission (ASE) measurements. Furthermore, a very efficient Fӧrster resonant energy transfer (FRET)
is established between F8BT and P3HT. We report a combined spectroscopic characterization of the blends in order
to unravel the role that polymer chain conformation and FRET has on ASE.
Figure. (a)The typical ASE spectrum of RR-P3HT/F8BT film, (b) The dependence of the output intensity (integrated area) and FWHM on
the input fluence, and the polymer chemical structures: (c) RR-P3HT and (d) F8BT.
References
1 Y. Kim, S. Cook, S. M. Tuladhar, S. Choulis, J. Nelson, J. R. Durrant, D. D. C. Bradley, M. Giles, I. McCulloch, C. S. Ha, M.
Ree, “A strong regioregularity effect in self-organizing conjugatedd polymer films and high efficiency polythiophene:fullerene
solar cells”, Nat. Mater. 5, 197 (2006).
2 H. Sirringhaus, P. J. Brown, R. H. Friend, M. M. Nielsen, K. Bechgaard, B. M. W. Langevel d-Voss, A. J. H. Spiering, R. A. J.
Janssen, E. W. Meijer, P. Herwig, D. M. de Leeuw, “Two-dimensional charge transport in self-organized, high-mobility
conjugated polymers”, Nature 401, 6 (1999).
3 J. Clark, J. F. Chang, F. C. Spano, R. H. Friend, C. Silva, “Determining exciton bandwidth and film structure in polythiophene
films using linear absorption spectroscopy”, Appl. Phys. Lett. 94, 163306 (2009 ).
O-9 Immunosensors based on the Fano resonance of Ga
nanodroplets
A. García Marín,*a M. J. Hernández,a E. Ruiz,a José M. Abad,b E. Lorenzo,b J. L. Pau,a
J. Piquerasa
a
Grupo de Electrónica y Semiconductores (ELySE), Dpto. Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid, Spain. Tel:
91 497 8607;
b
noma de Madrid, 28049 Madrid, Spain. Tel: 91 497 4488
In the field of refractive index sensing, many research groups have focussed on plasmon line shape tuning in
order to narrow down the line widths, which results in a higher figure-of-merit (FOM = (dλ/dn)/fwhm), which makes
1
it possible to reach lower detection limits. One path to reach this goal is to look at Fano interference, a
characteristic asymmetric line shape observed under certain conditions in scattering, transmission and reflection
spectra. In periodic arrays of localized plasmon resonators, the origin of this interference is atributed to the
coupling of different plasmonic modes which have been applied successfully for refractive index sensing
applications.
In the present work, we investigate a Fano resonance in self-assembled Ga nanodroplets (GaNDs) by
spectroscopic ellipsometry. The nanostructures are deposited by thermal evaporation on Si(100) substrates. This
nanodroplets present strong localized surface plamon resonance in reflectance spectra with two characteristic
2
oscillation modes whose energy position depends on the diameter droplet. For Ga nanodroplet diameters of 240280 nm (Figure 1A for SEM images), we observe strong Fano interference between different plasmon modes,
whose intensity is strongly dependent on the incident angle (Figure 1B).
The resonance is employed to develop an immunosensor capable of detecting small molecules, such as
glutathione (GSH) in external reflection ellipsometry. The GaND surface is functionalized immersing the sample in
a 3,3′-dithiodipropionic acid di(N-hydroxysuccinimide ester) (DTSP) in dimethyl sulfoxide (DMSO) solution. The
self-assembled monolayer formed yields the possibility of immobilizing antibodies (in this work, anti-glutathione)
through the formation of amide bonds. The sensing characteristics of this architecture are demonstrated in
immunoassays performed under increasing concentrations of L-reduced GSH (analyte). From the technical
viewpoint, the results are very promising because the optical coupling in the proposed sensing scheme is less
3
complex than that required in plasmonic sensors based on a Kretschmann configuration.
Figure 1: (A) Ga nanodroplets deposited on the Si(100) substrate; (B) Ellipsometric spectra of the GaNDs at
different incident angles.
1
2
3
Lodewijks, K.; Ryken, J.; Roy, W.V.; Borghs, G.; Lagae, L.; Dorpe, P.V. Plasmonics 2013, 8, 1379–1385
Hernández, M.J.; Cervera, M.; Ruiz, E.; Pau, J.L.; Piqueras, J.; Avella, M.; Jiménez, J. Nanotechnology 2010, 21, 455602
García-Marín, A.; Abad, J.M.; Ruiz, E.; Lorenzo, E.; Piqueras, J.; Pau, J.L.; Analytical Chemistry 2014, 86, 4969−4976
O-10 Iron Oxide Nanoparticles Carrying dsRNA and Targeting
Lymph Nodes for Immunotherapy
B. Macarena Cobaleda-Siles*, M. Henriksen-Lacey, A. Ruiz de Angulo, and J.C. MarequeRivas
CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia - San Sebastian, Spain. Tel: +34 943 005323;
Email: [email protected]
Delivery of ligands, which induce the activation of antigen presenting cells (APCs) through the engagement of
Toll Like Receptors (TLRs), to lymph nodes (LNs) has become a primary goal for the research and development of
(1)
vaccines against infectious diseases and cancer. The synthetic molecule poly (I:C) mimics viral double-stranted
(2)
RNA (dsRNA) and is recognized by TLR3, which plays a key role in antiviral immunity. The ability of poly (I:C) to
trigger intracellular signalling cascades upon binding to TLR3 makes it an immuno and chemotherapeutic agent of
(3)
significant clinical interest.
(4)
We show here, how hydrophobic IONPs combined with PEGylated phospholipids to form water soluble micelles
are decorated with poly (I:C) by a simple self-assembly approach to promote potent activation of APCs. By
fluorescently labelling these IONP-filled micelles and using LysoTracker (a late endosomal/lysosomal marker) and
anti-TLR3 antibodies, we find that this nanocarrier delivers poly (I:C) to endosomal TLR3. Radiolabelling of the poly
99m
(I:C)-IONP micelles with
Tc tricarbonyl for SPECT imaging and using the MRI capabilities of the IONPs we show
that this system is capable of migrating from the site of injection to LNs through the lymphatic system, depending
on the site and route of administration. We will discuss that effective lymphatic trafficking is most likely due to the
optimum size of the poly (I:C)-IONP micelles (< 80 nm). In vitro and in vivo studies showed that using this nanocarrier
(6)
the immunostimulatory activity of poly (I:C) is greatly enhanced.
In summary, we describe a new biocompatible nanocarrier which can be tracked using three different synergistic
molecular imaging techniques (fluorescence microscopy, MRI and SPECT/CT) to effectively deliver the poly (I:C) to
lymph nodes and endosomal compartments in cells of the immune system. Effective delivery is related to the
significantly enhanced immunostimulatory activity.
The work was supported by the MINECO (grants CTQ2001-22723) and PRI-PIBIN-2011-0812) and the Departments of Industry
(grant ETORTEK), Education, Universities and Research of the Basque Country (grant PI -2012-33).
1 S.T. Reddy, A.J. van der Vlies, E. Simeoni, V. Angeli, G.J. Randolph, C.P. O´Neil, L.K. Lee, M.A. Swartz, J. A. Hubbell, Nat.
Biotechnol., 2007, 25, 1159.
2 L. Alexopoulou, A.C. Holt, R. Medzhitov, R.A. Flavell, Nature, 2001, 413, 732.
3 H. Kanzler, F.J. Barrat, E.M. Hessel, R.L. Coffman, Nat. Med., 2007, 13,552.
4 N.Gómez Blanco, M.Jauregui-Osoro, M. Cobaleda-Siles, Carmen R. Maldonado, M.Henriksen-Lacey, D. Padró, S. Clark and Juan
C. Mareque-Rivas, Chem. Comm.,2012, 48, 4211.
5 M. Cobaleda-Siles, Juan C. Mareque-Rivas et al. (submitted).
O-11 Influence of biological matrix on nanomagnetism of Iron
Oxide Nanoparticles
D. Cabreraa, G. Salasa, S.M. Ocampoa, J. Camareroa,b and F.J. Terana,c
a
b
c
IMDEA Nanociencia, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain ;
Dpto. Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain;
Unidad Asociada de Nanobiotecnología, CNB-CSIC & IMDEA Nanociencia, 28049 Madrid, Spain;
Iron oxide nanoparticles (IONP) are finding a rapidly increasing number of biomedical applications due to their
structural, colloidal and magnetic properties. The controllable IONP size and tailored chemical features favors their
internalization into cancer cells without cytotoxicity drawbacks. Thus, the nanoscale and magnetic properties of
IONP crystals allow them to act as contrast agent, drug-delivery nanocarriers, and/or intracellular hyperthermia
mediators.
IONP heat dissipation power and magnetic properties are modulated by different mechanisms which may be
influenced by dipolar interactions, viscosity and aggregation. The nanoparticle internalization into cells and/or
tissues lead to large aggregation of particles which reduces heating efficiency 1 and degrades their magnetic
properties. In general, the internalization in biological matrix (cells or tissues) favours dipolar interactions which
negatively influence the effectiveness of the diagnostic and therapeutic approach for which IONP would be
designed. For that reason, understanding the role of dipolar interactions is of great importance towards the use of
IONP as efficient hyperthermia mediators and contrast agents.
My PhD work aims to understand the influence of biological matrix on the nanomagnetism of IONP by looking at
heat dissipation power (crucial for controlling heat exposure in treatments) and magnetization cycles of IONP
subjected to alternating magnetic fields. In my first year, we have started by studying the influence of particle
concentration and viscosity on the heat dissipation power of IONP. Figure 1 reveals that interacting phenomena
lead to an increase of specific absorption rate (SAR) values in water while SAR values in agar are maintained
constant. That reveals that interparticle interaction may be influenced by viscosity.
Figure 1. SAR values of IONP of 20nm for iron concentrations up to 15 gFe/L at 105 kHz and 50 mT, in water
and agar (5%) dispersions.
1
Di Corato, R. et Al. . Biomaterials 2014, Available online 9 May 2014
O-12 Transfection of T cells with nanoparticle-conjugated
antisense to p21 led to an increased T activation pattern
Rahman Shokria , Siamak Javanib, Alfonso Latorreb, Ana Latorreb, Álvaro Somozab and
Dimitrios Balomeno*a
a
Immunology & Oncology department, CNB,CSIC, Madrid, Spain
Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia), & CNB-CSIC-IMDEA Nanociencia Associated Unit
"Unidad de Nanobiotecnología“ Cantoblanco, 28049 Madrid, Spain
[email protected]
b
p21 can act as a cell cycle inhibitor, cellular senescence mediator or control DNA damage repair. Previous
studies from our lab showed that p21 regulates T cell responses and it was assumed that this was associated to
the effect of p21 in inhibiting cell cycle. Our latest data with p21 -/- T cells revealed a novel p21 function, showing
that p21 can act as a negative regulator of the activation machinery in repeatedly stimulated T cells. To understand
and clarify this p21 function, we considered essential to examine the effect of induced reduction in p21 expression
after T cell activation.
In this study, a p21 antisense was synthesized with chemical modifications and conjugated to gold nanoparticles
(AuNPs) and used for T cell transfection. As a control, T cells were transfected with the p21 antisense by the
Amaxa kit.
Mouse T CD4 positive cells were extracted from spleen and after purification were Con-A stimulated for 1 day
and cultured at 37 °C in RPMI medium and IL-2 for 5 days. Transfection was carried out at the end of the 5-day
expansion using AuNPs or the Amaxa kit. A nonsense sequence (PolyT) was also used as control in the wild type
and p21 knockout T cells. Four hours after transfection, the cells were stimulated again with Con-A and plated.
Transfection efficiency was checked by Flow cytometry and p21 expression evaluated by Western-blot in these
time points.
Results showed that transfection efficiency mediated by AuNPs was 33% after 24 hours, while using the Amaxa
kit the equivalent efficiency rate was 49%. Importantly, using AuNPs, we observed a decrease in p21 expression
as early as 1 hour after secondary stimulation (Fig 1, top). On the other hand, using of the Amaxa kit the drop of
p21 expression became evident as late as 14h after restimulation. Lowering of p21 levels lead to a notable
increase of elements involved in the T cell activation pathway, such as p -AKT (Fig 1, top), which is an early
indicator of activation. Furthermore we detected the increase in protein expression, which form part of the more
advanced signaling for activation of the NF-kB pathway such as CARMA1 and BCL10 (Fig 1, bottom).
Introducing gene regulatory elements can be accomplished using viral, nonviral, or electroporation methods.
Liposomes and chitosan exhibit low transfection efficiency and transfection based on viral vectors is time
consuming and not always effective. Electroporation methods (like the Amaxa kit) are often accompanied by
substantial cell death. Our data show that use of nanoparticles to deliver RNA, apart from the fact that induces
minimal death, leads to a very early reduction of the target protein. This property of nanoparticl e-conjugated
antisense delivery is important for systems where manipulation of a target protein should be rapid. This is the case
for activation of T cells, which occurs within the first hour after their stimulation.
Figure1: Western Blot results for Tcell Transfection by AuNPs-p21 antisense.
O-13 Near Infrared Activation of Metal-based Anticancer
Agents by Upconverting Nanoparticles
E. Ruggiero,*a A. Habtemariama,b,c and L. Salassaa
a
CIC biomaGUNE, Paseo Miramón 182, 20009, Donostia, Spain Tel: +34 943 00 53 00 - ext. 309;
IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain;
c
Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
b
Photodynamic therapy (PDT) is emerging in the clinics as an alternative therapeutic protocol to traditional cancer
treatments. PDT kills cancer cells by generating reactive species upon light excitation of a prodrug (i.e.
photosensitizer). Light activation allows to control spatially and tempo rally the effects of the treatment, decreasing
systemic toxicity of anticancer agents and limiting unwanted side effects [1].
On the bases of the success of Pt(II) and Pt(IV) anticancer agents, several photoactivatable Pt(IV) anticancer
agents have been developed for PDT in the last few years. However, such photoactive systems all suffer from the
need of high-energy UV or visible light for activation [2], which is not ideal for in vivo applications since low tissue
penetration is achieved at such wavelengths and cellular damage can be induced.
Coupling photoactivatable anticancer complexes with upconverting nanoparticles (UCNPs) is a promising strategy
to overcome such challenging limitation.
UCNPs can convert NIR light into UV-visible light, meeting metal complexes' demand for high-energy light
excitation. Recently, we have demonstrated the photoactivation of Ru polypyridyls by UCNPs [3] and we are
currently extending the strategy to light-sensitive Pt(IV) anticancer complexes.
In this contribution we will discuss our advances in the design of hybrid systems which combine biocompatible
UCNPs with Pt(IV) prodrugs. Our efforts are ultimately aimed at developping theranostic nanoplatforms that are
capable of releasing cytotoxic platinum species under NIR activation and that allow visualization via multimodal
imaging methods.
1 Farrer, N. J.; Salassa, L.; Sadler, P. J. Dalton Trans., 2009, 10690.
2 Garaikoetxea Arguinzoniz, A.; Ruggiero, E.; Habtemarian, A.; Hernández-Gil, J.; Salassa, L.; Mareque-Rivas, J. C. Part. Part. Syst.
Charact., 2014, 1, 46.
3 Ruggiero, E.; Habtemariam, A.; Yate, L.; Mareque-Rivas, J. C.; Salassa, L. Chem. Commun., 2014, 50, 1715.
O-14 Magnetic nanoparticles combined with Pt(IV) prodrugs
and immunostimulatory dsRNA for theranostic applications
Javier Hernández-Gil,*a Macarena Cobaleda-Siles,a Ane Ruiz de Anguloa and Juan C.
Mareque-Rivasa
a
Cooperative Centre for Research in Biomaterials (CIC biomaGUNE), 2009 San Sebastián, Spain. Tel: +34 943 00 53 23
The integration of nanotechnology and cancer research offers extraordinary opportunities to yield advances in
1
the diagnosis and treatment of cancer. To achieve these goals, inorganic nanoparticles (iNPs) have attracted
2
considerable interest due to their unique and versatile electronic, optical, plasmonic and magnetic properties.
Nowadays, it seems clear that modern iNPs can be more than just “imaging” or “therapeutic” probes, and combine
2
both features to enable detection and treatment of disease in a single procedure (“theranostic” agents). However,
these iNP-based systems still need to tackle issues such as insufficient sensitivity, limited spatial and temporal
resolution, efficient tumor targeting, undesirable off-target activities and, simple preparation/purification before
3
being candidates for clinical translation. Through a “multimodal imaging” approach, nanoparticles can help to
overcome the intrinsic limitations of each imaging modality towards diagnosing/staging the disease. On the other
hand, through “multimodal therapy” design, nanoparticles can exhibit a synergistic cancer cell killing effect by
exploiting different complementary drug payloads, cellular targets and “off-target” effects. In this context, I will
present here a “theranostic” agent designed to offer the possibility of cancer diagnosis/staging through multimodal
imaging and therapy by combining chemotherapy and immunotherapy mechanisms.
This oral presentation will focus on our recent efforts to combine in a single construct iron oxide nanocrystals as
MRI contrast platforms, a novel inactive Pt(IV) cisplatin prodrug as a chemotherapeutic agent, and polyinosinic polycytidyl acid (poly (I:C) dsRNA) as an immunostimulatory agent. The nanosystem can also be easily
99m
4
functionalized with a
Tc tricarbonyl complex, offering the opportunity of tumor detection and in vivo tracking by
combining complementary imaging modalities (SPECT and MRI). This nanocronstruct potentially possesses the
ability to direct a multiple attack against tumors by combining the effects of the targeted Pt -based anticancer drugs
5
with activation of immune cells by the “off-target” iNPs. First, I will describe the simple two-step strategy to obtain
this iNP-based theranostic agent: (i) formation and isolation of water soluble micelles with encapsulated iNPs
inside by self-assembling of Pt(IV)-modified phospholipid(s) and, (ii) attachment of poly (I:C) dsRNA to the Pt(IV)iNP-filled micelles. Then, I will discuss different in vitro experiments which confirm the ability of this nanosystem to
kill cancer cells of various origins and also to activate cells of the immune system. Finally, I will show by SPECT
and MRI studies how this nanosystem is effectively delivered in vivo.
‡
1
2
3
4
5
This work was supported by the MINECO (grants CTQ2001-22723) and PRI-PIBIN-2011-0812) and the Departments of Industry
(grant ETORTEK), Education, Universities and Research of the Basque Country (grant PI-2012-33).
Ferrari, M. Nat. Rev. Cancer 2005, 5, 161–71.
(a) Maldonado, C. R.; Salassa, L.; Gómez-Blanco, N.; Mareque-Rivas, J. C. Coord. Chem. Rev. 2013, 257, 2668-2688; (b) Cheon,
J.; Lee, J.-H. Acc. Chem. Res. 2008, 41, 1630-1640.
Cheng, Z.; Zaki, A.; Hui, J. Z.; Muzykantov, V. R.; Tsourkas, A. Science 2012, 338, 903-910.
Gomez Blanco, N.; Jauregui-Osoro, M.; Cobaleda-Siles, M.; Maldonado, C. R.; Henriksen-Lacey, M.; Padro, D.; Clark, S and
Mareque-Rivas, J. C. Chem. Commun. 2012, 48, 4211-4213.
Mellman, I.; Coukos, G.; Dranoff, G. Nature 2011, 480, 481-489.
O-15 Surface composition controls the optical properties of
alloyed QDs encapsulated in silica shells
a
b
a
María Acebrón,* Juan Galisteo, D. Granado, J. M. Gallego,
a,c
Beatriz H. Juarez
a,b
R. Otero,a,c Cefe López b and
a
Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanoscience), Canto blanco 28049, Madrid, Spain.
Instituto de Ciencias de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, 28049 Canto blanco, Madrid, Spain.
c
Departamento de Física-Química Aplicada. Universidad Autónoma de Madrid, 28049 Cantoblanco, Madrid, Spain.
b
Encapsulation of nanomaterials is a common strategy for several aims: it may reduce the toxicity of quantum dots (QDs),
prevent from degradation of a nanomaterial, help the diffusion in a particular medium, etc. In most cases encapsulation
of Cd-based QDs with SiO2 by microemulsion methods yields a concomitant decrease in quantum yield either upon
coverage or with time [1-5].
In this work, we explain several factors influencing the coverage reaction and provide a methodology to cover QDs with
SiO2 preserving or even increasing the luminescent quantum yield. Two different alloyed QDs containing Cd, Se, Zn, S
have been used. In this work we give some hints to understand the mechanism of this coverage reaction, following it by
Nuclear Magnetic Resonance (NMR). Especial empasis is given to the role of ligands directly anchored to the QDs
surfaces or non-anchored but intercalated in between them, as represented in scheme 1. Furthermore Synchrotron XRay Photoelectron Spectroscopy (XPS) characterization has been employed to understand differences on the QD
surfaces. Finally, the samples have also been characterized by time resolved spectroscopy to probe its decay dynamics
during each step of the covering process.
Scheme 1. Silica growth using microemulsion method. a) TEM image of QDs encapsulated into a silica shell b) Steady state characterization of QDs before silica coating (black)
and coating (grey) c) Distribution of decay rates of QDs (black) and QDs silica coated (grey) d)Decay dynamics of QDs before and after silica encapsulation, black and grey
respectively.
References
1
2
3
4
5
F. Pietra, R. J.A. van Dijk - Moes, X. Ke, S. Bals, G. Van Tendeloo, C. Donega, D. Vanmaekelbergh Chem. Mater., 2013, 25 (17),
pp 3427–3434.
R. Koole, M. M. van Schooneveld, J. Hilhorst, C. Donegá, D. C. ʼt Hart, A. van Blaaderen, D. Vanmaekelbergh, A. Meijerink Chem.
Mater., 2008, 20 (7), 2503-2512
D. Gerion, F. Pinaud, S. C. Williams, W. J. Parak, D. Zanchet, S. Weiss, A. P. Alivisatos, J. Phys. Chem. B, 2001, 105 (37), 88618871
Z. Zhelev, H.Ohba, R Bakalova, J.Am. Chem. Soc. 2006, 128, 6324-6325
P.Yang, N. Murase, M. Suzuki, C. Hosokawa, K. Kawasaki, T. Kato, T. Taguchi, Chem. Commun., 2010, 46, 4595-4597
O-16 A dinuclear thiocarboxylate paddle-wheel Ni(II) complex
as unusual precursor of electrochemically generated Ni(OH)2
nanoparticles for oxidative electrocatalysis
E. Martinez-Periñan*a, M. Gennarib, M. Revenga-Parraa, J. M. Abada,d, E. Mateo-Martíc, F.
Parientea, R.Mas-Ballestéb, F. Zamorab,d, E. Lorenzoa,d
a
Departamento Química Analítica y Análisis Instrumental, Universidad Autónoma de Madrid, Madrid, Spain, 914972523,
Departamento Química Inorgánica, Universidad Autónoma de Madrid, Madrid, Spain.
Centro de Astrobiología, CSIC-INTA, Torrejón de Ardoz, Madrid, Spain.
d
IMDEA Nanociencia, Madrid, Spain.
b
c
The search of electrocatalytic materials is the subject of intense study in a wide variety of research areas, such
as chemical synthesis, fuel cell catalysis, energy storage and electrochemical sensors. Among many possible
electrocatalytic materials, nickel hydroxide has received increasing attention. Although different routes have been
1, 2
described for the formation of nickel hydroxide on surfaces, these methods typically result in thin film structures . The
direct in situ formation of nickel based structures on electrodes that changes to nickel hydroxide in alkaline medium
represents a simpler alternative to the routes already employed. We report here the electrochemically generation of
microstructures from an unusual precursor: tetrakis(thioacetate)dinickel(II) complex. The dimetal complex (NiNi) exhibits
a dinuclear asymmetric paddle-wheel structure depicted in Figure 1A. NiNi can be electrodeposited as microbars onto
gold, glassy carbon and high ordered pyrolytic graphite electrodes as can be seen in FE-SEM images (Figure 1B). When
these microstructures modified electrodes are immersed in alkaline medium (NaOH 0.1M), microstructures are
transformed to Ni (OH)2 nanostructures (30 nm aprox) randomly disperse onto the electrode surface (Figure 1C). The
high specific area of nanoparticles as well as the great amount of nickel hydroxide recovering the electrode surface (Γ=
-9
2
4.52·10 mol/cm ) benefits the electrocatalytic process. Ni(OH)2 nanoparticles modified electrodes have been employed
for electrocatalytic oxidation of sugars (glucose, fructose, maltose, sucrose and lactose) and alcohols (methanol, ethanol,
1-propanol, 2-propanol, cyclopenthanol and cyclohexanol). In the case of sugars the best catalytics behaviour was
5 -1
observed with monosacarides and in the case of alcohols with primary alcohols. A catalytic rate constant of 5.36×10 s
was determined for glucose (Figure 1D). This high value confirms the great catalytic efficiency of the material. Thus, the
resulting modified electrodes can be very useful as sensors for the determination of sugars and alcohols.
Figure 1:
150
B
Electrochemical
Oxidation
C
0.1M NaOH
Application:
Electrocatalytic
oxidation
D
without D-Glucose
0.5mM D-Glucose
100
I(A)
A
50
0
0.0
0.1
0.2
0.3
0.4
0.5
0.6
E(V)
‡
Figure 1:
A. Structure of tetrakis(thioacetate)dinickel(II) complex.
B. FE-SEM image of microstructure generated on an Au electrode immersed in a solution of 0.1mM tetrakis (thioacetate) dinickel
(II) in 0.1MTBAP/CHCl3 after 150s applying 1.15V. (NiNi modified electrode).
C. FE-SEM image of Ni(OH)2 nanostructure generated after immersing a NiNi modified electrode in 0.1M NaOH.
D. Cyclic voltammograms of a GC NiNi modified electrode in 0.1 M NaOH solution at 0.010 V s −1 in the absence (black line) or in
presence (red line) of 0.5 mM glucose.
1.
2.
Vidotti, M.; Córdoba de Torresi, S. I. Electrochem. Acta 2009, 54, 2800-2084
Sawaby, A.; Selim, M. S.; Marzouk, S. Y.; Mostafa, M. A.; Hosny, A. Phys. B 2010, 405, 3412-3420
O-17 Switchable Electron Transfer Reactivity in
Phthalocyanine – Sc3N@C80 Supramolecular Ensembles
Olga Trukhina,a,b Marc Rudolf,c Giovanni Bottari,a,b Dirk M. Guldic, Luis Echegoyend and
Tomas Torresa,b
a
Department of Organic Chemistry, Autonoma University of Madrid, Cantoblanco, 28049 Madrid, Spain;
IMDEA Nanociencia, Cantoblanco, 28049 Madrid, Spain;
c
Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg, 91058 Erlangen, Germany;
d
Department of Chemistry, University of Texas at El Paso, El Paso, TX 79968, USA
b
Phthalocyanines (Pcs) are planar, two-dimensional aromatic pophyrinoids which possess outstanding structural,
optical and electrical properties as well as stability that render them perfect building blocks for the incorporation
into multifunctional materials [1]. Similarly, Ih-Sc 3N@C80 fullerene – the most abundant member of the fullerenes
family after C60 and C70 – in addition to have excellent electron-accepting properties, provides conditions for an
extra stabilization of charge-separated states due to the presence of the internal Sc3N species [2]. This makes
Ih -Sc 3N@C80 an ideal molecular partner for photo- and electroactive molecular systems such as Pcs.
Although several reports have appeared on the preparation of covalent Sc3N@I h-C80 ensembles [3], there is no use
of Ih-Sc 3N@C80 for the preparation of non-covalent assemblies. In this context, plenty of supramolecular systems
arranged via coordination interactions have been successfully demonstrated for Pc-C60 supramolecular dimers and
trimers [4]. Low accessability of non-covalent supramolecular systems with Ih-Sc3N@C80 is mainly caused by the
more sophisticated synthesis and purification of the corresponding fullerene derivatives.
Herein, we report a novel example of donor-acceptor Pc/Ih -Sc3N@C80 supramolecular dimers assembled via metalligand coordination interactions between Zn(II)Pcs (1 or 2) and pyridil-substituted Ih-Sc3N@C80 (4) or C60 fullerene
(3) (Figure 1). Photophysical (ground- and excited state) and electrochemical studies on these ensembles showed
that depending on the electron-donor (1) or electron-acceptor (2) character of the ZnPcs, a switchable electron
transfer reactivity occurs in the case of the Ih-Sc3N@C80 supramolecular systems 1/4 and 2/4, revealing the ability
for this endohedral metallofullerene to behave either as electron donor or electron acceptor unit.
Figure 1. Molecular structures of Zn(II)Pcs 1, 2, pyridyl-substituted fullerenes 3, 4 and Zn(II)Pc/pyridyl-fullerene
supramolecular complexes 1/3, 2/3, 1/4, and 2/4.
References
1
2
3
4
a) Bottari, G.; Urbani, M.; Torres, T. in Organic Nanomaterials: Synthesis, Characterization, and Device Applications, Torres,
T.; Bottari, G. (Eds.) John Wiley & Sons, Inc., Hoboken, New Jersey, 2013, 163 – 187; b) de la Torre, G.; Bottari, G.; Sekita,
M.; Hausmann, A.; Guldi, D.M. and Torres, T. Chem. Soc. Rev. 2013, 42, 8049 – 8105 c) Bottari, G.; de la Torre, G.; Guldi,
D.M. and Torres, T. Chem. Rev. 2010, 110, 6768 – 6816
a) Wang, T. and Wang, C. Acc. Chem. Res. 2014 47, 450 – 458 b) 8. Rudolf, M.; Wolfrum, S.; Guldi, D. M.; Feng, L.;
Tsuchiya, T.; Akasaka, T.; Echegoyen, L. Chem. Eur. J. 2012, 18, 5136 – 5148 c) Olmstead, M.M.; Balch, A.L.; Pinzon, J.R.;
Echegoyen, L.; Gibson, H.W.; Dorn, H.C. in Chemistry of Nanocarbons, Akasaka, T.; Wudl, F.; Nagase, S. (Eds.) John Wiley
& Sons, Ltd. Singapore, 2010, 239 – 259
a) Wolfrum, S.; Pinzon, J.R.; Molina-Ontoria, A.; Gouloumis, A.; Martin, N.; Echegoyen, L.; Guldi, D.M. Chem. Commun.,
2011, 47, 2270 – 2272 b) Pinzon, J.R.; Gasca, D.C.; Sankaranarayanan, S.G.; Bottari, G.; Torres, T.; Guldi, D.M.;
Echegoyen, L. J. Am. Chem. Soc. 2009, 131, 7727 – 7734 c) Pinzon, J.R.; Cardona, C.M.; Herranz, M.A.; PlonskaBrzezinska, M.E.; Palkar, A.; Athans, A.J.; Martin, N.; Rodriguez-Fortea, A.; Poblet, J.M.; Bottari, G.; Torres, T.; Gayathri, S.;
Guldi, D.; Echegoyen, L. Chem. Eur. J. 2009, 15, 864 – 877
Bottari, G.; Trukhina, O.; Ince, M.; Torres, T. Coord. Chem. Rev. 2012, 256, 2453 – 2477
O-18 Mechanically Interlocked Single-Wall Carbon
Nanotubes
Alberto de Juan,aYann Pouillon, b Luisa Ruiz-González,d Almudena Torres-Pardo,d
Santiago Casado, a Nazario Martín,a,c Ángel Rubio,b and Emilio M. Péreza
a
IMDEA Nanoscience, C/ Faraday 9, Ciudad Universitaria de Cantoblanco, 28049, Madrid, Spain. E-mail:
[email protected]
b
EuropeanTheoretical Spectroscopy Facility, Centro Joxe Mari Korta, Avenida de Tolosa, 72, 20018, Donostia-San Sebastian,
Spain.
c
Departamento de Química Orgánica, Fac. C.C. Químicas, Universidad Complutense de Madrid, Av. Complutense s/n, 28040,
Madrid, Spain.
d
Departamento de Qumica Inorgánica, Fac. C.C. Químicas Universidad Complutense de Madrid, Avenida Complutense s/n,
28040 Madrid (Spain)
1
Single wall carbon nanotubes (SWNTs) are one of the most promising carbon nanomaterials . Hence, extensive
research efforts have been devoted to their chemical manipulation. The attachment of molecular fragments
2
through covalent bond formation produces kinetically stable products, but implies the saturation of some of the
3
nanotubes’ C-C double bonds. The supramolecular modification, on the other hand, maintains the structural
integrity of the SWNTs, but yields labile noncovalent associates. Here, we present a strategy to obtain
4
mechanically interlocked derivatives of SWNTs(MINTs) based on a clipping strategy. The introduction of the
mechanical bond as a new tool for the manipulation of SWNTs combines the advantages of the covalent and the
noncovalent approaches, yielding stable associates where the structural integrity of the nanotube is maintained.
We employed a bis-alkene terminated molecule decorated with two recognition units for the carbon nanotubes of
adequate size to be closed around the nanotubes through ring closing metathesis (RCM), yielding
pseudorotaxane-type architectures.
The mechanically interlocked nature of the derivatives is probed by analytical, spectroscopic, and microscopic
techniques, as well as by appropriate control experiments. Individual macrocycles were observed by HR STEM to
circumscribe the nanotubes.
References
1.
2.
3.
4.
J. M. Schnorr and T. M. Swager, Chem. Mater., 2011, 23, 646-657.
N. Karousis, N. Tagmatarchis, D. Tasis, Chem. Rev. 2010, 110, 5366-5397.
Y.-L. Zhao, J. F. Stoddart, Acc. Chem. Res. 2009, 42, 1161-1171.
A. de Juan, Y. Pouillon, L. Ruiz, A. Torres, S. Casado, N. Martín, Á. Rubio and E. Pérez, Angew. Chem
Int. Ed. 2014, 53, 5394 –5400.
O-19 Nanosized materials based on dinuclear Gd(III)
complexes as novel theranostic carriers
Nina Gómez-Blanco,*a Martín Regueiro-Figueroa,b Ane Ruiz de Angulo,a Andrés de Blas,b
Teresa Rodríguez-Blas,b and J.C. Mareque-Rivasa
a
CIC biomaGUNE, Paseo de Miramón 182, 20009, Donostia-San Sebastián, Spain. Tel: +34 943005323;
Departamento de Química Fundamental, Universidade da Coruña, Rúa da Fraga 10, 15008, A Coruña, Spain. Tel: +34 981167000
b
Among the approved compounds for clinical use as contrast agents in Magnetic Resonance Imaging
1
(MRI), gadolinium (Gd) complexes are the most commonly used. Currently, there is a considerable interest in
2
developing Gd nanoparticles which provide good MR relaxivities and new in vivo targeting possibilities. Recently,
it has been reported that dinuclear Gd(III) complexes containing two 2,2’,2’’-(1,4,7,10-tetraazacyclododecane1,4,7-triyl) triacetic acid (DO3A) units linked by 4,4’-dimethyl-2,2’-bipyridyl (1) or bispyrazolylpyridyl (2) units form
3
stable nanosized aggregates in aqueous solutions. Our most recent research efforts focus on using these Gd
nanosized materials for new diagnostic applications and for theranostic (therapy + diagnosis) nanomedicine.
Nanoparticles derived from 1 and 2 were prepared and their sizes were determined by Transmission Electron
Microscope (TEM) and Dynamic Light Scattering (DLS) (1: 100 nm; 2: 40 nm), which is an ideal size for lymphatic
trafficking and targeting lymph nodes (LNs). By targeting LNs it may possible to monitor by MRI the invasion status
4
of tumor-draining LNs in tumor staging/preoperative planning applications. Evaluation of the cytotoxicity showed
that these nanosized Gd(III) contrast agents are not toxic. T1-weighted MR images at 7T show a brightening
caused by a reduction in the T 1 relaxation time of water protons at relatively low Gd concentrations, which indicated
their excellent suitability as MR imaging agents.
These Gd-based nanosized materials were also loaded with the anticancer drug, doxorubicin (DOX), and
the construct was characterized by UV-vis and fluorescence spectroscopy. The release of DOX was found to be
slow at pH = 5.3 and pH = 7.4 and 37C. Evaluation of the aniproliferative activity against human prostate cancer
cells (PC3) showed that the Gd-DOX nanoparticle display significant cytotoxicity after 72 h incubation with the PC3
cells (e.g. IC50 = 1.5 M). Currently, we are investigating the cell uptake and the in vivo LN targeting ability of these
Gd-based diagnostic and theranostic nanoparticles.
1
2
3
4
Caravan, P; Ellison, J. J; McMurry, T. J; Lauffer, R. B. Chem. Rev. 1999, 99, 2293-2352
Park, J. Y; Back, M. J; Choi, E.S; Woo, S; Kim, J. H; Kim, T. J; Jung, J. C; Chae, K. S; Chang, Y.; Lee, G. H. ACS Nano. 2009, 3,
3663-3669.
Regueiro-Figueroa, M.; Nonat, A.; Rolla, G. A.; Estebán-Gómez, D.; de Blas, A.; Rodríguez-Blas, T.; Charbonniere, L. J.; Botta, M.,
Platas-Iglesias, C. Chem. Eur. J. 2013, 19, 11696-11706.
Thorek, D. L. J.; Ulmert, D.; Diop, N-F. M.; Lupu, M. E.; Doran, M. G.; Huang, R.; Abou, D. S.; Larson, S. M.; Grimm, J.
Nat.Commun. 2014, 5, 3097.
O-20 Synthesis of gold nanoparticles assisted by capping
ligands playing a three-in-one role
Iria Bravo*a, Mónica Revenga-Parraa, Tania Garcíaa, Encarnación Lorenzoa,b, Félix Parientea
and José María Abada,b
a
Departamento de Química Analítica y Análisis Instrumental, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain. Tel:
914972523;
b
Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Faraday, 9, Campus UAM, Cantoblanco, 28049
Madrid, Spain.
E-mail: [email protected]; [email protected]
Noble metal nanoparticles, in particular gold nanoparticles (Au-NPs), are considered as very attractive materials
due to their unique optical, electronic, magnetic, and catalytic properties that differ from those of bulk metal. Durin g
the last decades, intense research efforts have been devoted to develop new synthetic and functionalizing
strategies. The methods of synthesis of AuNPs are based on chemical reduction of tetrachloroauric acid by
external chemical reductants in the presence of functionalizing agents. However, these methods often produce
undesired sideproducts. To overcome this, different functionalizing agents for Au-NPs have recently been
1
developed displaying a dual role of effective reducing agents of gold salts and of s tabilizers.
In the present work we develop a method for the preparation of functionalized AuNPs going one step further by
using Schiff base ligands playing a triple role as reductant, stabilizer and catalyst. The three-in-one performance of
the capping ligand as a new concept of AuNPs synthesis will be shown.
The synthesized gold nanoparticles possess an average diameter of 30 nm and show a plasmon band at 534nm.
They present electrocatalytic activity towards hydrazine, hydrogen peroxide and oxigen reduction.
40
A
B
30
c
20
Current (A)
Absorbance (u.a.)
2
1
10
b
0
-10
0
-20
300
400
500
600
wavelength (nm)
700
800
a
-0,6
-0,4
-0,2
0,0
0,2
0,4
0,6
Potential (V vs. Ag/AgCl)
A) Absorption spectrum and TEM image of the synthesized gold nanoparticles.
B) Cyclic voltammograms of synthesized gold nanoparticles modified carbon electrodes in 0.1M NaOH in absence
(a) and in presence of hydrazine 0.1mM (b) and 1mM (c).
1
2
3
Zhang, A. Q.; Cai, L. J.; Sui, L.; Qian, D. J.; Chen, M. Polymer Reviews 2013, 53, 240-276
Ganguly, M.; Pal, A.; Pal, T. The Journal of Physical Chemistry C 2011, 115, 22138–22147
Revenga-Parra, M.; Lorenzo, E.; Pariente, F. Sensors and Actuators B 2005, 107 678–687
O-21 Control of composition by self-assembly of amphiphilic
copolymers inside micropores combining the breath figures
technique and the coffee stain phenomenon
Alberto S. de León,a Adolfo del Campo,b Marta Fernández-García,a
Juan Rodríguez-Hernández,a Alexandra Muñoz-Bonillaa,c
a
Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC), C/ Juan de la Cierva 3, 28006-Madrid, Spain.
Instituto de Cerámica y Vidrio (ICV-CSIC), C/ Kelsen 5, 28049-Madrid, Spain.
c
Current Address: Dpto. de Química Física Aplicada, Facultad de Ciencias, UAM, C/ Francisco Tomás y Valiente 7, Cantoblanco, 28049Madrid, Spain.
b
In the last years, self-assembly processes have received more and more attention because its possibility of creating
hierarchically structured materials easily in one single step [1]. Within this context, we have alreary studied the effect
of coffee stain that occurs during the breath figures technique, whenever a water-soluble compound is used [2]. To
gain a better insight of this effect, we have fabricated porous films using blends of polystyrene, that acts as matrix,
and three different amphiphilic additives. On the one hand, two different synthesized block copolymers of
polystyrene-b-poly[poly(ethylene glycol) methyl ether methacrylate] (PS-b-PEGMA) with variable hydrophilic ratio
and on the other hand one commercial non-ionic surfactant, Pluronic F127. The synthesized copolymers present
different length of the blocks, being one of them water-soluble (PS40-b-PEGMA 48) whilst the other remain in the
organic phase (PS45-b-PEGMA 34 ). THF was employed as solvent in all the cases and concentrations were
maintained constant to 30 mg/mL. In order to study the distribution of these amphiphiles inside the micropores,
confocal micro-Raman spectroscopy was used. We observed that the distribution of the amphiphiles inside of the
microholes depended on the hydrophilicity and the surface tension of the condensed water droplets. First, water
nonsoluble PS45-b-PEGMA 34 copolymer was found to be homogeneously distributed along the whole surface of the
pores. On the contrary, water-soluble PS40-b-PEGMA 48 copolymer tends to migrate towards the edge of the pores
showing a ring-like structure. This effect is known as the coffe stain effect and it has be en previously observed in
porous materials by our group [2]. Finally, when Pluronic F127 was used, it was observed that it was specifically
allocated only at the bottom of the holes. This phenomenon is associated to a decrease of the surface tension of the
condensed water droplet when the surfactant is solubilized. Figure 1 depicts an scheme of these three different
possibilites.
WATER INSOLUBLE
AMPHIPHILIC COPOLYMER
WATER SOLUBLE
AMPHIPHILIC COPOLYMER
Figure 1. Schematic illustration of the breath figures and coffee stain processes occurring simultaneously from
polymer blends based on a PS matrix and three different amphiphilic polymers: a water insoluble PS 45-bP(PEGMA300) 34, and two water soluble polymer PS 40-b-P(PEGMA300) 48 (low decrease of surface tension) and
Pluronic F127 (high decrease of surface tension). XZ Raman mappings are also depicted.
The ability of being able to control selectively the coverage of the pores by favoring or reducing the coffee stain
phenomenon with surfactants that have different surface tension properties, can be used for interesting application s
where complex micro or nanoscaled patterns are needed, i.e. sensors, genomics or photonic devices.
References
[1] Whitesides G.M.; Grzybowski B. Science 2002, 295, 2418-2421
[2] De León A.S.; Del Campo A.; Fernández-García M.; Rodríguez-Hernández J.; Muñoz-Bonilla, A. Langmuir 2012,28, 9778-9787
O-22 Repeat protein scaffolds: a template for ordering
electroactive molecules in solution and solid state
Javier López-Andarias, a Sara H. Mejías, b,c Carmen Atienza,a Aitziber L. Cortajarena*b,c and
Nazario Martín*a,b
a
Organic Molecular Materials Group, Complutense University, Madrid 28040, Spain. Tel: 91 394 4332;
IMDEA Nanoscience, Campus de Cantoblanco, Madrid 28049, Spain;
c
CNB-CSIC-IMDEA Nanociencia Associated Unit "Unidad de Nanobiotecnología" 28049-Madrid, Spain.
b
E-mail: [email protected]@ucm.es
Porphyrins have been widely investigated in the field of materials due to their interesting photophysical
properties. In this sense, much effort has been made for constructing ordered porphyrin arrays in the solid state,
searching for a real application of these organic materials. The use of bioinspired approaches has been barely
1
2
developed for this purpose, using peptides and nucleic acids as scaffolds for precisely controlling the position
and face-to-face orientation of porphyrins in solution. Moreover, the main challenge is to maintain the secondary
structure in the solid state for constructing highly ordered materials at the mesoscale since it has never been
explored due to the disruption and unfolding of the structure during the solvent casting process.
In this work, we present the use of consensus tetratricopeptide repeat proteins (CTPR) as scaffolds for
organizing porphyrins in solution and solid state. CTPRs have been previously reported to form films which
3
retain their secondary structure in a macroscopic aligned manner. Slightly modifying the sequence of
aminoacids, by introducing eight cysteine residues in four loops of the protein, and synthetizing two non-charged
water-soluble porphyrins properly functionalized with a maleimide group (1 and 2), result in the construction of a
conjugated macromolecule with an average of seven porphyrins in the structure. This approach highlights the
effectiveness of almost quantitatively connect these dyes to the structure of the CTPR.
A thorough spectroscopic study has been done, noticing a bathochromic shift in the porphyrin Soret band
comparing to the monomer 1 and 2, proving the typical J-aggregation in solution. Interestingly, circular dichroism
(CD) spectra of the conjugates display a bisignate signal in the Soret region, revealing the ability of the protein to
organize the chromophores in a chiral way. Furthermore, the peptide region of the CD spectra in these
conjugates maintains the α-helical fingerprint of the pristine CTPR. Going to the solid state, homogeneous solid
films have been prepared, which maintain all the spectroscopic properties of the material in solution. This fact
evidence that the conjugates do not undergo unfolding when solvent is evaporated.
Figure 1. Porphyrin derivatives 1 and 2 (left), schematic representation of conjugates (top right) and CD spectra
of conjugate with porphyrin 2 in the Soret absorption region (bottom right).
References
1
2
3
a) Kang, B.; Chung, S.; Deok, Y. A.; Lee, J; Seo, J Organic Letters 2013, 1670-1673. b) Dunetz, J. R.; Sandstrom, S.; Young,
E. R.; Baker, P.; Van Name, S. A.; Cathopolous, T.; Fairman, R.; de Paula, J. C.; Akerfeldt, K. S. Organic Letters 2005, 25592561.
Brewe, A.; Siligardi, G.; Neylon, C.; Stulz, E. Org. Biomol. Chem. 2011, 777-782.
Grove, T. Z.; Regan L.; Cortajarena, A. L. Jour. Chem. Soc. Interface 2013, 10, 83.
O-23 Functional nanostructure by designed protein selfassembly
Sara H. Mejíasa,b ,Pierre Couleauda,b Javier Lopezc, Begoña Sota,b, Carmen Atienzac, Teresa
Gonzaleza, Aitziber L. Cortajarenaanda,b
a
Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia) 28049-Madrid, Spain
CNB-CSIC-IMDEA Nanociencia Associated Unit “Unidad de Nanobiotecnología” -28049-Madrid, Spain.
c
Departamento de Química Orgánica, Facultad de C.C. Quimicas, Ciudad Universitaria sn, Madrid, Spain.
b
The development of application-oriented innovative materials requires methods for control of structures along
different size scales. Bottom-up self-assembly that relies on highly specific biomolecular interactions of small defined
1
components, is an attractive approach for biomaterial design and nanostructure templating .
2
In this work, we used modular designed consensus tetratricopeptide repeat proteins (CTPRs) (Figura1A) for
the generation of 3D structures (protein nanotubes) and functional nanostructures. CTPR arrays contain multiple
3,4
identical repeats that interact through a single inter-repeat interface to form elongated superhelix (Figure 1B) .
We present the study and characterization of the generated 3D protein-structures to use them as templates for
the creation of functional materials. We show the characterization of the conjugation of the protein with gold
nanoparticles and the preliminary results of the conjugation of proteins with electroactive organic molecules.
1.
The formation of the nanotubes is achieved by introducing two single point mutations in the protein to create a new
hydrophobic interface in the CTPR superhelix that will interact with identical interface on another CTPR molecule
(Figure 1C). We show the formation of protein nanotubes and characterization of the new 3D structures.
2.
The conjugation of gold nanoparticles to CTPR protein templates aims the organization of nanometric objects with
atomic precision. Specific amino acids for metal coordination and nanoparticles binding are introduced at defined
positions of the repeat sequence of the CTPR. We use high resolution imaging techniques such as atomic force
microscopy (AFM), transmission electron microscopy (TEM) and scanning transmission microscopy (STM) to
characterize the CTPR-AuNps conjugates. (Figure1D).
3.
We propose to use CTPR proteins in order to template donor-acceptor pairs for electroactive materials. In order to
achieve an efficient electron transfer the arrays of molecules need to be ordered at defined distances. We show
preliminary data in which we explore the potential of CTPR protein scaffolds for nanometer-precise arrangement of
the molecules (Figure 1E).
(1)
(2)
(3)
(4)
T.Z Grove, L. Regan and A. L. Cortajarena, J. R. Soc. Interface., 2013, 10, 20130051
Kajander, T.; Cortajarena, A. L.; Regan, L. Methods Mol. Biol. 2006, 340
Kajander, T.; Cortajarena, A. L.; Mochrie, S. G.; Regan, L. Act Crystallographica 2007, D63, 800.
Cortajarena, A. L.; Wang, J.; Regan, L. Febs J 2010, 277, 1058.
O-24 Tuning, Inhibiting and Restoring the Enzyme Mimetic
Activities of Pt-Apoferritin
Unai Carmona,*a Lianbing Zhang,a Le Li,a and Mato Knezab
a
CIC nanoGUNE, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian, Spain. Tel: 943 574 000;
IKERBASQUE, Basque Foundation for Science, Alameda Urquijo 36-5, 48011 Bilbao, Spain. Tel: 944 052 660;
b
Many nanoparticles (NPs) exhibit catalytic properties, sometimes even being key features with special interest
for chemical or biological applications. In some cases, the catalytic properties of NPs can mimic biological
enzymes, but the reaction mechanisms are often different or unclear. In contrast to many artificial catalysts,
biological enzymes have specific reactions, unique substrates and natural inhibitors, which regulate their catalytic
activities. In this work we show that protein-encapsulated Pt NPs can mimic various enzymatic activities, such as
[1]
oxidase, catalase and superoxide dismutase (SOD). The activity of the hybrid components can further be
[2]
controlled with selective inhibition of one of the catalytic activities. For this purpose, the catalase- and SOD-like
enzyme mimetic activities of the bioinorganic Pt-apoferritin (Pt-apo) hybrid compounds were analysed with 3amino-1,2,4-triazole (3AT) or NaN 3 as inhibitors. While one of the inhibitors was able to inhibit both catalytic
reactions, the other one selectively inhibits one activity.
The decreasing peroxide decomposition catalytic activity of the NPs over times of uses is a further factor
considered in this work together with a strategy to recover the diminished activity of the inhibited compound. In this
sense a reducing agent was used to recover the decreased activity. XPS analysis confirmed the successful restore
of the surface chemical properties of the NPs, which shows the potential not only for catalytic use of the NPs.
Figure 1: Reaction specific enzyme mimetic NPs with restorable activity; can be achieved with a selection of
inhibitors for specific reactions and treatment with a reducing agent, can restore the surface chemical properties of
inhibited NPs.
References
1
2
Zhang, L.; Laug, L.; Münchgesang, W.; Pippel, E.; Gösele, U.; Brandsch, M.; Knez, M., Nano Lett., 10, (2010) 219–223.
Carmona, U.; Zhang, L.; Li, L.; Munchgesang, W.; Pippel, E.; Knez, M., Chem. Commun., 50, (2014) 701-703.
O-25 Mechanochemistry of G-Quadruplexes studied by singlemolecule force spectroscopy
Irene Gutiérrez1, Miguel Garavís2,3, Santiago Casado1, Elisa Poyatos1, Sara de Lorenzo1,
Carlos González2, Alfredo Villasante3 and J. Ricardo Arias-González1,4
1
2
.
Instituto Madr
Instituto de Química Física Rocasolano, CSIC, C/Serrano 119, 28006 Madrid, Spain.
3
B
gí
“
O h
”
-UAM, Universidad Autónoma de Madrid, C/Nicolás Cabrera 1, 28049 Madrid,
Spain.
4
CNB-CSIC-
U
“U
gí ”.
E-mail: [email protected]; [email protected]
DNA has the potencial to adopt rare but biologically relevant structures with applications in Nanomedicine. The
last two decades have witnessed a research burst in the G-quadruplex (GQ) conformation, which was discovered
in 1962 [1] and whose significance has been recently fueled by the demostration of its existence in vivo [2]. Found
in guanine-rich regions, the GQ is a four-stranded arrangement consisting of planar arrays of four Hoogsteenbonded guanines – called G-quartets – stabilized by monovalent cations.
Guanine-rich regulation regions in the human genome – as some oncogene promoter regions, telomeres,
ribosomal DNA, G-rich mini-satellites and immunoglobulin switch regions – posess the potential to adopt the GQ
conformation [3,4]. The presence of these sequences, along with the fact that their unique conformation provides
selective recognition sites for small molecules, have enabled GQs as important drug-design targets for the
treatment of various human disorders, such as viral infections or cancer [5]. Furthermore, due to their high
capability to form higher order structures, like G-nanowires, these biological structures are viewed as powerful
platforms for the design and construction of new devices for Nanotechnology [6].
Single-molecule investigations of long
human telomeric RNA (TERRA), a
ribonucleic GQ found at the end of the
telomeres, have been carried out recently
[7,8]. Here, we have synthetised RNA
molecules with different numbers of
TERRA repeats to analyze their relative
stability and mechanical behavior. We
have used AFM to measure their
nanoscale dimensions on a one-by-one
basis and optical tweezers to study single
unfolding events by the application of
mechanical force in the pico-Newton
range.
Our results constitute a necessary step
towards the global understanding of GQ
stability, dynamic processing by motor
proteins and interactions with drugs.
References
1
2
3
4
5
6
7
8
Unfolding of a TERRA GQ by optical tweezers. Right inset, cartoon of the
experiment. Left inset, AFM image and height diagram of a four-repeat TERRA
construction shown with a double-stranded RNA for comparison
Gellert, M.; Lipsett. M.N.; Davies, D.R. Proc.Natl.Acad.Sci.USA 1962, 48, 2013-2018.
Paeschke, K.; Simonsson, T.; Postberg, J.; Rhodes, D.; Lipps, H.J. Nat.Struct.Mol.Biol. 2005, 12 (10), 847-854.
Rawal, P.; Kummarasetti, V.B.R.; Ravindran, J.; Kumar, N., Halder, K.; Sharma, R.; Mukerji, M.; Das, S.K.; Chowdhury, S.
Genome Res. 2006, 16, 288-298.
Parkinson, G.N.; Lee, M.P.H.; Neidle, S. Nature 2002, 417, 876-880.
Ou, T.M; Lu, Y.; Tan, J.; Huang, Z.; Wong, K.; Gu, L. Chem. Med.Chem. 2008, 3, 690-713.
Alberti, P.; Bourdoncle, A.; Saccà, B.; Lacroix, L.; Mergny, J.L. Org. Biomol.Chem. 2006, 4, 3383-3391.
Garavís, M.; Bocanegra, R.; Herrero-Galán, E.; González, C.; Villasante, A.; Arias-González, J.R. Chem. Commun. 2013, 49,
6397-6399.
Yangyuoru, P.M.; Zhang, A.Y.Q.; Shi, Z.; Koirala, D.; Balasubmarian, S.; Mao, H. Chem.Bio.Chem. 2013, 14, 1931-1935.
O-26 COMBINING SUPER-RESOLUTION FLUORESCENCE
MICROSCOPY AND AFM FOR ADVANCED DNA IMAGING
Aitor Monserrate,*a Santiago Casadoa and Cristina Florsa
a
IMDEA NANOSCIENCE, Calle Faraday 9, Ciudad Universitaria de Cantoblanco, 28049, Madrid, SPAIN. Tel: 912998765
In many areas of research like biology, medicine, chemistry or materials science, fluorescence microscopy is a
really powerful tool and it has become widely used. But its spatial resolution is limited to 200-300 nm due to
diffraction of light, so finer details become blurred. However, new techniques which allow imaging below the
diffraction limit have been developed [1]. These techniques are known as super-resolution methods and can reach
a spatial resolution of tens of nanometers. A growing number of super-resolution methods are based on the
detection of single photoactivatable fluorescent molecules, and a post-acquisition analysis step to precisely localize
the emission of the molecules with nanometer precision.
Super-resolution techniques are steadily improving, and new fluorescent labelling and post-acquisition
localization analysis methods are being developed. Both labelling and post-processing analysis are prone to
imaging artifacts, and therefore there is a need to provide new tools that allow a robust validation of superresolution localization images. For that reason we have developed a super-resolution microscope that is coupled to
an atomic force microscope (AFM). With this novel correlative microscope we are able to identify the potential
artifacts and we can obtain valuable information for improving current super-resolution methods. We have tested
the capabilities of the correlative microscope with lambda DNA labelled with the intercalating dye YOYO -1 [2], and
we are currently investigating labelled DNA nanostructures. The combination of super -resolution and AFM is not
only a useful tool to improve current nanoscopy methods but also to answer new biological questions.
Figure 1: In situ correlative AFM and super-resolution fluorescence imaging. a) AFM, b)
super-resolution image of stretched -DNA labelled with YOYO-1. The green arrow marks a
DNA section that is visible in AFM but not visible in fluorescence. The yellow arrow shows
two DNA fragments that are close to each other and that can be resolved in the AFM and
super-resolution image but not in the standard fluorescence image. Scale bar is 1 mm.
1
2
S.W. Hell, Nat. Methods 6, 24–32. (2009)
A. Monserrate, S. Casado, C Flors, Chemphyschem 15, 647-650 (2014)
O-27 Single-molecule mechanical characterization of the
HmtSSB binding properties to ssDNA.
José A. Morin,*a Laurie S. Kagunib and Borja Ibarraa
a
Imdea Nanociencia, Faraday, Nº 9 Ciudad Universitaria de Cantoblanco, 28049. Madrid (España) Tel: 034 912998898
Department of Biochemistry and Molecular biology, Michigan State University, 319 Biochemistry Building Michigan State University,
East Lansing, MI 48824-1319, USA.
*E-mail: [email protected]
b
Mitochondrial DNA (mtDNA) encodes for most of the components of the cellular electron transport chain.
Mutations on mtDNA have been associated with respiratory chain dysfunction, which in turn causes rare diseases
in plants and humans. Therefore, faithful replication of mtDNA is essential for the correct f unctioning of the cell.
The human mitochondrial single-stranded DNA binding protein (HmtSSB) plays a critical role at the mtDNA
replication fork, coordinating the interactions between single -stranded DNA (ssDNA), the DNA polymerase γ and
the mtDNA helicase [1]. However, little is known about the real time kinetics of the HmtS SB interaction with the
ssDNA and the structural and mechanical properties of the HmtSSB -coated ssDNA polymer; which is essential
information to understand the role of the HmtSSB on DNA metabolism. Using optical tweezers ([2]) we have
developed a single molecule manipulation assay that addresses these questions (Figure 1). Our data show that the
mechanical properties of ssDNA change dramatically in the presence of HmtSSB and they strongly depend on both
the monovalent salt (0.05 to 0.3 M NaCl) and protein concentrations (5 to 200 nM) suggesting that HmtSSB
interacts with ssDNA in two different modes [3]. Moreover, force pulling experiments designed specifically to test
the stability of the HmtSSB-coated polymer show that HmtSSB units associate with each othe r in a cooperative
fashion, whose strength also depends on ionic conditions and protein concentration. Consistent with this
observation, real time polymerization kinetics exhibit two distinct behaviors, characterized by the apparent
cooperativity, that interchange continuously as the ratio of salt to protein concentration is tuned.
Figure
1:
Experimental
setup.
A:
In
a
typical
experiment a ssDNA molecule
is attached by one end to a
bead trapped in an optical trap
(through
digoxigeninantidigoxigenin
interaction,
green scuare) and by the other
to a bead held at the tip of a
micropipette (through biotinstreptavidin interaction, red
circle). A force feedback loop
imposed to the. optical trap
allows recording in real time
the compaction that suffers the
ssDNA molecule when the HmtSSB is introduced in the experimental chamber, revealing the kinetics of this
interaction. B: Force extension curve of a typical experiment. After opening a hairpin to obtain ssDNA (blue curve)
and recording the interaction (Figure 1 A), the resulting polymer is progressively stretched (inset, red segments)
and relaxed (inset, black segments). Stretching the polymer at increasing pulling forces promotes the unbinding of
the HmtSSB from the DNA, allowing the HmtSSB-ssDNA molecule to extend until the initial extension is achieved
(that of a naked ssDNA molecule, red curve). The effect of increasing the pulling force in subsequent pull and relax
cycles provides a valuable information about the structure of the HmtSSB-ssDNA complex.
References
1
2
3
M. Falkenberg, N. Larsson and C. Gustafsson, “DNA replication and transcription in mammalian mitochondria.”,
Annu Rev Biochem, 76, 679-699, 2007.
S. B. Smith, Y. Cui and C. Bustamante, “Optical-trap force transducer that operates by direct measurement of
light momentum.”, Methods Enzymol, 361, 134-162, 2003.
T. M. Lohman and M. E. Ferrari, “Eschericçhia coli single-stranded DNA-binding protein: multiple DNA-binding
modes and cooperativities.”, Annu Rev Biochem, 63, 527-570, 1994.
O-28 Tailored functional protein platforms
Marta Palacios-Cuesta1, Aitziber López-Cortajarena2, Olga García1 and Juan RodríguezHernández1
1 Department of Chemistry and Properties of Polymers Instituto de Ciencia y Tecnología de Polímeros, (ICTP-CSIC), Juan de la Cierva
3, 28006 Madrid, Spain.
2 Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Cantoblanco, 28049 Madrid, Spain & CNB-CSICIMDEA Nanociencia Associated Unit "Unidad de Nanobiotecnología"
[email protected]
A new procedure focused on the design and preparation of structured and functional polystyrene surfaces by controlling
two chemical reactions occurring simultaneously i.e. photocrosslinking and/or photodegradation is developed. The
elaboration of sub/micrometer size patterned surfaces by UV-light exposure is reported where, in addition, the surface
chemical composition can be controlled by the incorporation to the mixture of a block copolymer having either
hydrophobic or hydrophilic monomer blocks.
By using short irradiation times, polystyrene (PS) can be initially crosslinked whereas an excess of the exposure time
provokes the degradation of the material. As a result of the optimization of time of exposure, the use of an appropriate
cover or the incorporation of an appropriate amount of absorbing active species (photoinitiator) different tailor made
1
surface patterns can be obtained, from boxes to needles (see Figure 1).
Moreover, in addition to the surface pattern we introduced changes on the chemical composition of the PS. Firstly, a
fluorinated copolymer is incorporated in the photopolymerizable mixture and migrated to the surface. Its composition can
be modified depending on such factors as the environmental conditions or the concentration of copolymer within the
blend. Also, the incorporation of an amphiphilic block copolymer PS-b-PGA [polystyrene-block-poly(L-glutamic acid)]
block copolymer that will provide functional surfaces with major advantages. In particular, the presence of carboxylic
functional groups provides a unique opportunity to anchor, for instance polypeptide sequences. We describe the
immobilization of polypeptide sequences in precise surface positions that allows the use of the surfaces for protein
recognition purposes. The immobilization of the fluorescent proteins (see Figure 1) evidences the success of the
recognition and opens a new alternative for protein patterning on surfaces for many biotechnological and biomedical
2
applications .
Figure 1. Evolution of the surface structure as a function of the experimental conditions employed.
References
1 M. Palacios , O. García , and J. Rodríguez-Hernández Langmuir, Constructing Robust and Functional Micropatterns on Polystyrene
Surfaces by Using Deep UV Irradiation. 2013 29, (8), 2756–2763.
2 M. Palacios-Cuesta , A.L. Cortajarena , O. García, and J. Rodríguez-Hernández, Biomacromolecules, Versatile Functional
Microstructured Polystyrene-Based Platforms for Protein Patterning and Recognition, 2013 14 (9), 3147–3154.
P-1 The Impact of Photo-oxidation on Charge Carrier
Dynamics in P3HT:PCBM Solar Cells
Safakath Karuthedath*a,b, Meera Stephenb, Kristijonas Genevičiusb, Gytis Juškab,Tobias
Sauermannc, Hans-J. Egelhaafc, Reinhold Wannemachera, Larry Lüera
a
Optical Spectroscopy and Microscopy of Nanostructured Materials, IMDEA Nanociencia, C/ Faraday, 9, 28049 Cantoblanco (Madrid),
Spain.
b
Department of Solid State Electronics, Vilnius University, Saulėtekio 9 III k., 10222 Vilnius, Lithuania.
c
Belectric OPV GmbH ,Landgrabenstr. 94, 90443 Nürnberg, Germany
Organic solar cells (OSC) are flexible, very thin, semi-transparent and nicely colored. This opens up markets like BIPV
(Building Integrated Photo-Voltaic), where the classical silicon based solar cells cannot compete. But the effect of
chemical degradation of the active layer of OSC on the performance of the devices is still poorly understood. In OSC
based on P3HT:PCBM (poly(3-hexylthiophene)/[6,6]-phenylC61-butyricacidmethylester), oxygen-induced degradation
[1]
causing 2% ground state absorption loss leads to a 70% reduction in the short circuit current . This work therefore
attempts to study how photo-induced oxidation of a model polymer influences charge carrier generation and
recombination in the bulk heterojunction with the most commonly used fullerene. To this end, blend films of P3HT/PCBM
(1:0.8) were degraded under AM 1.5 illumination in dry synthetic air, producing on degradation levels which are relevant
for the operation of solar cells. The extent of degradation was quantified by the UV/vis-absorbance loss of P3HT:PCBM.
The change of the photo induced charge carrier dynamics in the P3HT:PCBM phase during degradation was measured
by µs-transient absorption spectroscopy (TAS) and charge extraction by linearly increasing voltage (CELIV) technique.
The charge carrier dynamics of P3HT:PCBM exhibit pronounced effects of oxygen attack on the films, even at very
early stages of degradation, before any significant absorption loss is induced. From the TAS measurements a
significant retardation of charge recombination dynamics is observed in degraded samples, but on the other hand
photo degradation induces no significant changes on the charge generation rate. Photo-CELIV traces are in good
agreement with TAS results, showing a decreasing in the mobility of the charge carriers and slowing down the
recombination rate upon degradation. We rationalize these effects by invoking oxygen-induced traps that reduce
[2]
the effective mobility and hence the recombination rate of the photo-generated charge carriers
References
[1]. A. Seemann, T. Sauermann, C. Lungenschmied, O. Armbruster, S. Bauer, H.-J. Egelhaaf, J. Hauch, Solar Energy,2010, 85, 1238–
1249.
[2]. S. Karuthedath, T. Sauermann, H-J. Egelhaaf, R. Wannemacher, C. Brabec, L.Lüer, "The Effect of Oxygen Induced Degradation on
Charge Carrier Dynamics in P3HT:PCBM and Si-PCPDTBT:PCBM Thin Films and Solar Cells" To be submitted, 2014.
P-2 On the growth mechanisms of GaAs nanowires
synthesized by Ga-assisted chemical beam epitaxy
C. García Núñez,* A.F. Braña, N. Lopez and B.J. García
a
Grupo de Electrónica y Semiconductores, Dpto. Física Aplicada, Universidad Autónoma de Madrid, C/ Fco. Tomás y Valiente 7, 28049,
Madrid, Spain. Tel: 91 497 8607;
Up to now, there are a few articles in the literature which show the successful growth of GaAs nanowires (NWs)
in chemical beam epitaxy (CBE) systems by vapor-liquid-solid (VLS) method and using Au as catalyst. However,
Au is demonstrated to hinder the electrical properties of the NW by the unintentional incorporation of Au impurities
into the GaAs sublattice. In addition, the low crystalline purity obtained in those NWs is a direct consequence of the
zinc blende (ZB) – wurzite (WZ) polytypes formed mainly due to the existing strain between both Au and Ga
structures. For these reasons, alternative catalysts such as Ga have been proposed as a potential substitute of Au
in molecular beam epitaxy processes due to the good compatibility between Ga and GaAs structures. Theses
promising processes are known as Ga- or auto-assisted VLS and they have not developed for CBE growths yet.
In this work, vertically aligned GaAs NWs are grown by Ga-assisted VLS process in CBE system on Si(111)
substrates and using triethylgallium (TEGa) and tertiarybuthylarsine (TBAs) as organometallic precursors for
elements III and V, respectively. Each growth is monitored in-situ by reflection high energy electron diffraction
(RHEED) technique. The analysis of the RHEED features shows NW characteristic diffraction patterns (see spotty
pattern, left figure below), identifying the formation of different crystalline phases (ZB or WZ), structural defects
such as twins, parasitic nanostructures (tilted NWs, traces and nanocrystals).
The resultant morphology of NWs is analyzed by scanning electron microscope as a function of substrate
preparation and Ga pre-deposition conditions as well as the growth parameters such as substrate temperature (Ts),
gas source pressure, growth time and V/III ratio. The preparation of the Si(111) substrate surface has been
demonstrated to be crucial for a successful growth of NWs. Oxide thickness above 1 nm is observed to inhibit the
NW growth because TEGa is not decomposed in Ga species, reason why the Ga droplets cannot be formed.
Furthermore, it is found that the pre-deposition of Ga droplets is necessary to obtain NWs. Both, pre-deposition
and stabilization times ranged between 0 and 3 min are studied, showing Ga droplets with different sizes. It is
noticeable that below a critical droplet diameter, around 150 nm, NWs growth is not observed which means there is
a time delay (see right figure below) before what NW length is approximately zero. Thereafter the initial delay time
NW length presents a linear tendency with the growth time. The efficiency of the Ga diffusion along the NW facets
allows the catalyst to keep its size during long growth times (> 1 h). In this work, lithographed Si(111) substrates
are also used aiming to reduce the formation of parasitic nanocrystals at the NW base which can act as Ga traps
during long growth processes limiting the maximum NW length because of the Ga droplet extinction.
The study about the growth parameters shows that NWs grow under a V/III ratio of 1. The increase or decrease
of this ratio is demonstrated to hinder the NW aspect ratio. On the other hand, the Ts window is narrow for GaAs
NWs grown by CBE on oxidized Si substrates (560-620 ºC); the decreases of Ts down to 580ºC leads the fastest
growth rate around 5.4 µm/s, which is 10 times faster than that measured for 2D growth of GaAs films using the
same growth conditions. However, the increase of Ts up to 620ºC has an advantage over low temperature
processes; that is the reduction of the surface impurities such as nanocrystals and traces due to the re-evaporation
of Ga and As species.
P-3 A Landau–Squire nanojet ––
measuring picolitre flows with Optical Tweezers
Nadanai Laohakunakorna, Benjamin Gollnickb*, Fernando Moreno-Herrerob, Dirk G. A. L.
Aartsc, Roel P. A. Dullensc, Sandip Ghosald, and Ulrich F. Keysera
a
Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK.
Centro Nacional de Biotecnología, CSIC, Darwin 3, Campus de Cantoblanco, 28049 Madrid, Spain.
c
Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Rd., Oxford OX1 3QZ, UK.
d
Department of Mechanical Engineering and (by courtesy) Engineering Sciences & Applied Mathematics, Northwestern University,
Evanston, Illinois 60208, USA.
*E-mail: [email protected]
b
Fluid jets are found in nature at all length scales – from microscopic to cosmological. At the small end, recent
progress in micro- and nanofluidics has contributed a variety of new sensing devices for biological systems [1].
Here, we report on an electroosmotically driven jet from a single glass nanopore about 75 nm in radius with a
maximum flow rate of ∼15 pL/s [2]. A novel anemometry technique allows us to map out the vorticity and velocity
fields that show excellent agreement with the classical Landau−Squire solution of the Navier−Stokes equations for
a point jet. We observe a phenomenon that we call flow rectification: an asymmetry in the flow rate with respect to
voltage reversal. Such a nanojet could potentially find applications in micromanipulation, nanopatterning, and as a
diode in microfluidic circuits.
[1] J. Hong, J. B. Edel, and A. J. deMello, Drug Discovery Today 2009, 14 (3-4), 134-146.
[2] N. Laohakunakorn*, B. Gollnick*, F. Moreno-Herrero, D. G. A. L. Aarts, R. P. A. Dullens, S. Ghosal, and U. F. Keyser, Nano Letters
2013, 13, 5141−5146 (*equal contribution).
P-4 High coercive isotropic CoFe2O4 powders obtained by
ultrafast-milling for permanent magnet applications
K.M. Golasiński *(1), F.J. Pedrosa (1), D. Granados (1), A. Quesada (2),
F. Rubio-Marcos (2), M.N. Guzik (3), S. Deledda (3), J.F. Fernández (2), J. Camarero
(1,4), and A. Bollero *(1)
(1)
(2)
(3)
(4)
IMDEA Nanoscience, Madrid, Spain
Electroceramic Department, Instituto de Cerámica y Vidrio, CSIC, Madrid, Spain
Institute for Energy Technology, 2027 Kjeller, Norway
Dep. Física Materia Condensada, Instituto Nicolás Cabrera, UAM, Madrid, Spain
∗E-mail: [email protected]; [email protected]
Rare earth-based permanent magnets (RE-PM) are used in a large number of nowadays technological
applications. The rapidly increasing market of emerging technologies (wind turbines, electric vehicles, etc.)
demands increased amounts of this type of magnets. This demand in combination with the strategic geographical
distribution of RE (especially critical for heavy RE elements) requires an efficient use of RE-PM, and the search of
alternatives for specific applications. Ferrites-based magnets, with improved properties respect to traditional
ferrites,
are
considered
a
good
alternative
in
the
performance
range
of
-3
(BH)max = 35-100 kJm (currently covered by low grade RE-PM) [1]. Cobalt ferrite (CoFe2O4) is a promising
ferrimagnetic oxide for magnetic recording, biotechnological, and hard magnetic applications. This is mainly due
to its high Curie temperature (790 K for bulk material), large magnetocrystalline anisotropy, and excellent
chemical stability.
In this work, authors show the possibility of obtaining a fourfold increase in coercivity for isotropic cobalt
ferrite (CoFe2O4) powders with a mean grain size in the range of a few tenths of nanometers. This has been
achieved by using high energy ball milling with milling times as short as 1.5 – 6 minutes in contrast with previous
studies [2].
CoFe2O4 powders have been prepared by sol-gel followed by heat treatment at 900ºC in air. X-ray
diffraction showed the presence of exclusively spinel CoFe2O4 phase. This powder has been used as a starting
material for milling experiments following two different routes: dry milling in air, and milling with oleic acid as
surfactant medium (followed by removal of the surfactant). Coercivity as high as 4 kOe, and an outstanding
3
energy product (BH)max above 17 kJ/m have been obtained through ultrafast milling. This is explained by the
small grain sizes achieved, the stress anisotropy, and pinning effects induced on them during the milling process.
References
[1] http://nanopyme-project.eu/
[2] B.H. Liu and J. Ding, Appl. Phys. Lett. 88, 042506 (2006).
Acknowledgements
This research was supported by the EU-FP7 NANOPYME Project (No. 310516).
P-5 Nanoscale ripple patterns as a playground for AFM
lithography and manipulation experiments
Patricia Pedraz*a, Pawel Nitaa, Santiago Casadoa, Carlos Pimentelb, Francesco Buatier de
Mongeotc, Enrico Gneccoa
a
IMDEA Nanociencia, Campus Universitario de Cantoblanco, Calle Faraday, 9, 28049, Madrid, Spain. Tel: 34 912998746;
Departamento de Cristalografía y Mineralogía, Universidad Complutense de Madrid, 28040 Madrid, Spain. Tel: 34 913944959;
c
Dipartimento di Fisica, Università di Genova and CNISM, Via Dodecaneso 33, 16146 Genova, Italy. Tel: 39 0103536324;
b
Anisotropic surface structures with characteristic length scales in the range of 10-100 nm are important for a
better understanding of fundamental friction and wear processes. In our contribution we will focus on two kinds of
nanoscale ripple patterns on polymer and glass surfaces.
First, we will discuss the formation of these structures on polystyrene (PS) caused by a silicon tip repeatedly
scanned at room temperature on the originally flat substrate [1]. The ripple growth process will be interpreted in the
framework of the Prandtl-Tomlinson model, which is commonly used to explain stick-slip at atomic scale. Different
corrugations and periodicities are expected and measured, depending on the applied load, scan velocity, contact
stiffness and tip width.
Second, we will present preliminary results on the manipulation of gold nanospheres on a rippled glass surface,
which was fabricated by ion-beam sputtering. The nanoparticles are "channeled" along the ripples, almost
independently of the scan direction. However, when a bottleneck or other nano-defects are encountered, the
spheres may either stop their motion or jump transversally to the ripples. We will also show how the lateral force
signal acquired when the particles are pushed or pushed by the probing tip can be used as a source of information
on the nanomanipulation process.
Figure 1. AFM topography (left) and corresponding lateral force (right) pattern of ripples made on a solvent-enriched polystyrene
(PS) surface (F N = 530 nN and v = 10 µm/s).
1
Napolitano, S.; D’Acunto, M.; Bachieri, P.; Gnecco, E.; Pingue, P., C. Nanotechnology 2012, 23, 475301
P-6 An outer-sphere
sphere coordination chemistry approach for
platinum based anticancer drug delivery
Amaia Garaikoetxea Arguinzoniz,
Arguinzoniz a Nina Gómez Blancoa and Juan C. Mareque Rivasab
a
Cooperative Centre for Research in Biomaterials,
Biomater
(CICbiomaGUNE), 20009, San Sebastián, Spain. Tel: 0034 943 005323.
005323
Ikerbasque, Basque Foundation for Science, 48011, Bilbao, Spain.
b
Platinum complexes e.g. cisplatin are among the most well-known chemotherapeutic agents and are currently
1
used for the treatment of a variety of tumours.
tumour
However these anticancer drugs still present several
seve
limitations
such as the poor solubility and the undesired side effects. To overcome these limitations a new generation of Pt(IV)
prodrugs have gained a great interest over
ov the last few years. The Pt(IV) prodrug approach helps to address some
of the main drawbacks of these drugss, allowing the delivery of the complex in an inert form to later generate the
2
cytotoxic Pt(II) species through intracellular reduction mechanisms.
mechanisms
In order to improve the intracellular delivery of these prodrugs, different strategies have been used, including
3
polymeric nanoparticless where the drug can be encapsulated or nanoparticles with different coatings where the
4
prodrug can be attached. Synthetic polymers like the well-known
well known polyethyleneimine (PEI) can also facilitate the
5
cellular uptake thanks to their cationic nature; in fact PEI is widely used as a transfection agent. However high
molecular weight (MW) PEI commonly used for transfection, also has a high toxicity.
toxicity
Here we describe the possibility of using outer-sphere
outer
coordination chemistry as strategy for the delivery of an
anionic cisplatin prodrug. This Pt(IV)
(IV) complex forms outer-sphere
sphere coordination interactions with non-toxic LMW
PEI. The high positive charge density provided by the polymeric matrix facilitates its cellular uptake,
upta
and promotes
the intracellular reduction of the prodrug to generate the cytotoxic Pt(II) drug and therefore an enhanced toxicity
compared to the prodrug itself. The
he versatility of this system relies on the possibility of incorporating PEI as a
coating ligand in many different types of nanoparticles, thus the chance of developing combinatorial and
multimodal therapy systems to achieve much better cure rates.
rates
1
2
3
4
5
Graf, N.; Lippard, S.J. Adv. Drug Delivery Rev. 2012, 64, 993-1004.
Hall, M. D.; Hambley, T. W. Coord. Chem. Rev. 2002, 232, 49-67.
Dhar, S.; Gu, F. X.; Langer, R.; Farokhzad, O. C.; Lippard, S. J. Proc. Nat. Acad. Sci. 2008, 105,
105 17356-17361.
Min, Y.; Mao, C.; Xu, D.; Wang, J.; Liu, Y. Chem. Commun. 2010, 46, 8424-8426.
Xia, T.; Kovochich, M.; Liong, M.; Meng. H.; Kabehie, S.; George, S.; Zink, J. I.; Nel, A. E. ACS Nano,
Nano 2009, 3, 3273-3286.
P-7 Superparamagnetic iron oxide nanoparticles for the
delivery of a Toll-like receptor 7 agonist
Ana Isabel Bocanegra Gondana, B.Macarena Cobaleda-Silesa and Juan C. Mareque-Rivasa
a
CIC biomaGUNE, Paseo Miramón, 182, 20019, Donostia-San Sebastián (Guipúzcoa), España. Tel: +34 943 005 300;
In most biomedical applications of nanomaterials, surveillance by the immune system is
considered an obstacle. A recent paradigm shift is to engineer nanomaterials which work with the
immune system (i.e. activate the body´s defense mechanisms against diseases caused by foreign
pathogens and endogenous malignant cells). To achieve this goal one of our research targets is to
direct TLR ligands to the lymph nodes to trigger stronger and safer immune response for
immunotherapy applications. Here we describe the development and characterisation of a novel
system based on superparamagnetic iron oxide nanoparticles (SPIONs) designed to carry and
deliver the synthetic Toll-like receptor 7 (TLR7) agonist Imiquimod – a molecule with proven
utility in treating skin cancers and viral infections.
Two SPIONs of around 5 nm in diameter were solubilised and stabilised in water with
PEGylated phospholipids to afford micelles with a hydrodynamic diameter of ca. 45 nm. One of
SPIONs was doped with Zn2+ ions at the outside surface to enhance its magnetic properties for
magnetic resonance imaging (MRI).1 We have seen that this modification significantly improves
also the binding affinity of imiquimod by the nanoparticles. We, therefore, hypothesize that
imiquimod attaches to the surface of the SPIONs through a coordination bond, forming a chelate
with the metal ions. The immunostimulatory activity of the SPION-imiquimod system was studied
in J774 cells (a murine macrophage cell line). According to our results of IL-6 induction in vitro by
J774 cells imiquimod retains its immunostimulatory properties.
It has been shown that the combination of two TLR agonists can lead to a synergistic
activation of the immune response.2-5 We show here that we can carry together on the same
nanoparticle a specially active combination of two TLR ligands, imiquimod and poly(I:C), a
synthetic double-stranded RNA TLR3 agonist, and that this leads to a potent activation of the J774
cells with much lower concentrations of the TLR agonists.
References
1
2
3
4
5
Chen, F.; Bu, W.; Lu, C.; Chen, G.; Chen, M.; Shen, X.; Liu, R.; Shi, J.; J. Nanosci. Nanotechnol 2011, 11 (12), 10438-43
Warger, T.; Osterloh, P.; Rechtsteiner, G.; Fassbender, M.; Heib, V.; Schmid, B.; Schmitt, E.; Schild, H.; Radsak, M.P.; Blood
2006, 108 (2), 544-50.
Napolitani, G.; Rinaldi, A.; Bertoni, F.; Sallusto, F.; Lanzavecchia, A.; Nat Immunol 2005, 6 (8), 769-76.
Suet Ting tan, R.; Lin, B.; Liu, Q.; Tucker-Kellogg, L.; Ho, B.; Leung, B.P.; Ling Ding, J.; Immunol Cell Biol 2013, 91 (5), 37787.
Krummen, M.; Balkow, S.; Shen, L.; Heinz, S.; Loquai, C.; Probst, H.C.; Grabbe, S.; J Leukoc Biol 2010, 88 (1), 189-99.
P-8 Development of novel theranostic agents based on
transition metal complexes and upconversion nanoparticles
S. Alonso,*a and L. Salassaa
a
CIC biomaGUNE, Paseo Miramón 182, 20009, Donostia, Spain. Tel: +34 943 00 53 00 - ext. 309
Transition metal complexes have unique photophysical and photochemical properties which have been explored
for many applications including medicinal chemistry and biology. Several metal complexes displaying light1
triggered biological activity have been recently reported and show potential as agents for photodynamic therapy.
Nevertheless, metal complexes are typically characterized by low extinction coefficients in the 600–1000 nm
region, posing a major limitation for their development as practical clinical tools.
Optically active nanoparticles can be employed as an effective tool to extend the range of excitation wavelengths
2
for metal complexes and overcome such fundamental drawback.
Our recent research focuses on the use of upconversion nanoparticles (UCNPs) for the photoactivation of
anticancer complexes (e.g. Pt, Ru). UCNPs based of a NaYF4 lattice doped with lanthanides ions (e.g. Yb, Er, Tm)
can efficiently convert 980-nm light to higher energies in the ultraviolet and visible region, hence allowing to trigger
3
the photochemistry of metal complexes and potentially their biological effects. Such approach is promising not
only because the NIR light used to excite UCNPs penetrates deeper into tissues, but also because UCNPs have
outstanding features as multimodal imaging tools.
In this contribution we will show our work plan and preliminary results in this new and promising field.
1
2
3
Farrer, N. J.; Salassa, L.; Sadler, P. J. Dalton Trans., 2009, 10690.
Garaikoetxea Arguinzoniz, A.; Ruggiero, E.; Habtemarian, A.; Hernández-Gil, J.; Salassa, L.; Mareque-Rivas, J. C. Part. Part.
Syst. Charact., 2014, 1, 46.
Ruggiero, E.; Habtemariam, A.; Yate, L.; Mareque-Rivas, J. C.; Salassa, L. Chem. Commun., 2014, 50, 1715.
P-9 Experimental set-up
set up of an optically accesible STM
A. Martín Jiménez,*a,b K. Lauwaeta ,D. Écijaa , J. M. Gallegoa,c, D. Granadosa,
R. Oteroa,b, R. Mirandaa,b.
a
Instituto
nstituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia),
(I
Madrid;
Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid;
Madrid
c
Instituto de Ciencia de Materiales, CSIC, Madrid.
b
One of the most powerful techniques for studying the structural and electronic properties
pro
of surfaces
at the atomic scale is the Scanning Tunneling Micropsocpe (STM). In an STM a tip with a curvature of
several tens of nm and a tip apex consisting of a few atoms is used as a mobile electrode employed
to study materials on the atomic scale.
sca Topography images as well as dI/dV curves and maps,
maps which
give information about the electronic Density of States (DOS),
(DOS) can be obtained.
obtained A further great
advantage of STM is the possibility to
t locally excite luminescence.. Inelastic processes induced by the
tunneling electrons can lead to light emission from tip-induced
tip induced surface plasmons of the metal as well
as intrinsic molecular fluoresecence.
fluoresecence
This poster presents the design
desig and the first results of an experimental set-up
up that allows for the
collection of light induced by the tunnel junction of an optically accessible STM at IMDEANanoscience. This STM operates in an Ultra High Vacuum (UHV) environment as well as at low
temperatures (≈4 K). There is the possiblity to clean and prepare various surfaces, as well as the
option of growing interesting optical systems by means of Molecular Beam Epitaxy (MBE).
Furthermore it is possible to perform additional meaturements in-situ, such as Low Energy Electron
difraction (LEED) and Auger Electron Spectroscopy (AES).
(AES)
P-10 Elastic-Plastic Switch of Tomato Bushy Stunt Virus
Particles
A. Llauróa, E. Copparib, F. Imperatoric, A.R. Bizzarrib , L. Santic, S. Cannistrarob and P. J. de
Pabloa
a
Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049. Madrid, Spain
Biophysics and Nanoscience Centre, CNISM-DEB, Università della Tuscia, 01100. Viterbo, Italy;
Department of Agriculture, Forests, Nature and Energy (DAFNE), Università della Tuscia, Via San Camillo de Lellis snc, 01100
Viterbo, Italy.
2
3
The study of virus protein shells mechanics in the elastic regime has provided insights into the virus strength and
structure, such as the rigidity of the shells or the precursors of the disassembly. However, there is a lack of
information about the plasticity of viral cages, including their molecular and structural determinants, which results in
the permanent deformation of particles without breakage. Here we investigate the effects of pH and ions
sequestration on the mechanics of individual Tomato Bushy Stunt Virus nanoparticles (TBSV-NPs) by using Atomic
Force Microscopy (AFM). Our experiments show that the depletion of calcium ions from the intra-capsid binding
sites reduces the stiffness of TBSV-NPs and induces an elastic-plastic transition on the mechanical response of
these shells. Interestingly, we found that this plastic transition could be triggered by mechanical deformation, a fact
that was also supported by a careful analysis of the virus adsorption geometries on the surface. All these results
indicate that, apart from act as structural stabilizer of the capsids, calcium ions may be inextricably linked to the
molecular determinants of plasticity in TBSV-NPs. Finally, we suggest that the capsid plasticity of TBSV-NPs may
not only have implications during the infection of plant cells, but may also increase the stability of these cages for
cargo transportation at the nanoscale.
P-11 Electrical properties of granular Pd-ZrO2 thin films
prepared by Radio Frequency Magnetron Sputtering
Hicham Bakkali and Manuel Domínguez
Departamento de Física de la Materia Condensada, Universidad de Cádiz - 11510 Puerto Real (Cádiz) Spain. Tel: 956016317
Nanostructures have been often studied in recent times in order to determine the unique properties
displayed at nanoscale regime. The behavior of single grains in granular systems was analyzed and there
are some theoretical models which give us an idea of such behavior, but the properties of a series of
grains is rather complex. In particular, we have measured the dc tunneling differential conductance G (V,T)
of granular Pd-ZrO2 thin films prepared by a RF magnetron co-sputtering deposition technique. We found
that temperature dependence of G (V,T) at zero bias reveals the presence of thermally assisted tunneling
showing the form . The dependence of G (V,T) on applied voltage shows a parabolic background (Fig. (a))
which reveals the presence of elastic tunneling at the high temperature range (265-286K). Moreover,
below T ~ 234K a dip, superimposed to the parabolic background, develops and the increase of G(V) at
low voltage is caused by the Coulomb blockade of tunneling. Thus, the conductance can be described by
the universal scaling expression [1]. On the other hand, the ac electrical properties of granular thin films of
Pd-ZrO2 have been studied. We found that, at room temperature (290 K), throughout the full frequency
range, the ac response of the samples is dominated by a set of identical parallel paths with direct tunneling
resistance and a constant phase element (CPE), associated with the smaller particles (~ 2 nm in size). In
contrast, at low temperature and at intermediate frequencies, the contribution of the smaller particles can
be neglected and the ac response is completed by the additional contribution related to the capacitor
effects between the larger particles (~ 5nm in size), which are further apart and do not contribute, initially,
to the direct tunneling mechanism. The shortcut processes between the smaller particles, due to their
capacitive properties, reduce the high tunnel barriers between the larger particles and allow them to
connect by a tunneling-assisted conduction path, thus leading to the appearance of a Constant Phase
Angle regime (CPAR). Therefore, the ac response was well modeled by a equivalent circuit which involved
two distributed elements as shown in Fig. (b).
FIGURE
(a) DC electrical response: current-voltage characteristics, differential conductance and normalized
1/2
1/2
differential conductance, G(V, T) − G(0,T)/T , as a function of the parameter (e|V |/KBT) for the
temperature range 38–286 K. (b) AC electrical behaviour: complex modulus plots of Pd-ZrO2 films
measured at different temperatures. At the temperature range 30-160 K, two semicircles are clearly shown
while, at room temperature, only one semicircle is observed. The solid lines show experimental curve
fitting to the equivalent circuit model proposed.
1.
Bakkali, H and Dominguez, M. Europhys. Lett. 104, 17007 (2013).
P-12 Epitaxial magnetite films with four-fold anistropy and RT
<100> easy axis grown by PLD
F.J. Pedrosa,*a J.L.F. Cuñado,a,b J. Camarero,a,b M. Sanz,c M. Oujja,c E. Rebollar,c J.F. Marco,c
J. de la Figuera,c M. Monti,c M. Castillejo,c M. García-Hernandez,d F. Mompeand and
A. Bolleroa
a
IMDEA Nanociencia, 28049 Madrid, Spain
Departamento Física de la Materia Condensada, Instituto Nicolás Cabrera, 28049 Madrid, Spain
c
Instituto Química Fisica Rocasolano, CSIC, 28006 Madrid, Spain
d
Instituto Ciencias Materiales de Madrid, CSIC, 28049 Madrid, Spain
b
Magnetite (Fe 3O4), a well known magnetic material, is attracting much interest in the last years due to its robust
ferrimagnetism down to nanometer thickness, good electrical conductivity and presumed half-metal character. Thin
films can be considered as ideal cases for the design of improved bulk magnets [1].
In this study, high quality stoichiometric magnetite thin films with a tickness between 50 – 150nm have been grown
by ablation from a self-prepared sintered hematite target using a nanosecond infrared (IR) laser at 1064nm [2] and
a substrate temperature of 750K. Single crystal substrates of SrTiO3:Nb, MgAl 2O4 and MgO have been used in the
preparation of Fe3O4 epitaxial films. By comparison, polycristalline Fe 3O4 films were grown on Al 2O3 and Si
substrates. The films were characterized using X-ray diffraction (XRD), atomic force microscopy (AFM), Raman
and Mösbauer spectroscopy, vectorial magneto-optical Kerr effect microscopy (v-MOKE), superconducting
quantum interference device (SQUID) magnetometry and ferromagnetic resonance (FMR).
All fims consisted of stochiometric magnetite and presented Verwey transition at 115-118K. Room temperature
coercivitiy values (35 – 45 mT) agree well with values reported in the literature for magnetite films in this thickness
range. In-plane hysteresis loops were measured by v-MOKE in dependence of the orientation of the applied
magnetic field in the 0-360º range with an angular step of 4.5º. For all epitaxial films under study, the highest
coercivity is found at 0, 90, 180 and 270º, thus orthogonal to each other, while the lowest coercivity is found
between those. This well-defined four-fold symmetry is indicative of biaxial magnetic anisotropy, highlighting the
high quality of the films grown by IR-PLD.
Moreover, these angular studies show that the maxima of the remanence and coercivity are along in-plane <100>
film directions [3] while most of studies dealing with bulk and magnetite thin film systems show room temperature
(RT) in-plane <110> magnetic easy axis. In order to verify this result, ferromagnetic resonance (FMR) experiments
have been carried out at 9.4 GHz frequency. Figure 2 shows the angular dependence of the in-plane resonance
field at room temperature for the Fe3O4 layer grown on SrTiO3. This result proves that the easy axes are indeed
the in-plane <100> directions in this film.
Figure 1: (Left) Polar representation of the angular evolution of
coercivity for a magnetite film grown on SrTiO3:Nb. (Right) In-plane
hysteresis loops acquired at 0º and 45º.
Figure 2. Angular dependence of the inplane resonance field at room temperature
of Fe3O4/SrTiO3 film obtained from FMR
experiments.
References:
[1] http://nanopyme-project.eu/
[2] M. Sanz et al. , Applied Surface Science 282, 642 (2013).
[3] M. Monti et al. , J. Appl. Phys. 114, 223902 (2013).
Acknowledgements
This research was supported by the EU-FP7 NANOPYME Project (No. 310516).
P-13 Pressurization of human adenovirus particles
during maturation
Alvaro Ortega-Esteban,*a Gabriela Condezo,b Ana J. Pérez-Berná,b S. Jane Flint,c
Carmen San Martinb and Pedro J. de Pabloa
a
Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain;
Department of Macromolecular Structure, Centro Nacional de Biotecnología (CNB-CSIC). Darwin 3, 28049 Madrid, Spain;
c
Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA;
b
Viruses infect target cells in a specific way. Bacteriophages insert their genome through a tail from the outer part of
the bacteria wall, leaving the shell outside. In this case the DNA storages elastic energy inside of the viral cage
1
that generates internal pressure, which plays a central role in the first step of infection. On the other hand,
eukaryotic viruses enter via endocytosis and disassemble to release the genome, such as human adenovirus.
Some of the determinants which trigger the disassembly process remains unknown. Different biophysical
techniques that allow characterizing capsid disruption in vitro, show that immature adenovirus are more stable than
the mature ones under a variety of stress conditions and that maturation primes adenovirus for highly cooperative
2
DNA release. Mechanical disruption of individual mature viral particles shows that DNA core is less condensed
3
than in immature ones. Based on these results, and in new measurements of the rigidity of the core, we
hypothesize that changes in core compaction during maturation may increase capsid internal pressure to trigger
proper uncoating of adenovirus.
1 Hernando-Pérez, M. et al., Small 2012 8, 2365
2 Pérez-Berná, A.J. et al., J. Biol. Chem. 2012 287, 37
3 Ortega-Esteban, A. et al., Sci. Rep. 2013 3, 1434
P-14 Aggregation-Induced Enhanced Emission - Intraand Intermolecular Structural Factors
Junqing Shi,1,2 Yongqiang Dong,2 Xiaoliang Luo,2 Seong-Jun Yoon,3 Sang Kyu
Park,3 Soo Young Park,3 Shinto Varghese,1 Begoña Milián-Medina,1 Johannes
Gierschner1
1
Madrid Institute for Advanced Studies - IMDEA Nanoscience, Madrid, Spain
Tel: +34 912998765 E-mail: [email protected]
2
Department of Chemistry, Beijing Normal University, Beijing, China
Center for Supramolecular Optoelectronic Materials, Department of Materials
Science and Engineering, Seoul National University, Seoul, South Korea
3
Materials with aggregation-induced enhanced emission (AIEE) have become an active field of
research during the past 15 years due to the application as active components in sensing and
photoluminescence (PL) imaging. In particular, reversible switching between non-/luminescent
[1]
phases has found special interest. However, AIEE is a complex synergetic phenomenon relying on
2a]
both intra- and intermolecular conditions,[ i.e. PL quenching in solution (or amorphous phase), and
[2b
proper intermolecular alignment (as well as morphology) in the crystalline phase. ] The mechanism
might significantly differ among different systems. To gain a deeper understanding, we have followed
[3]
two different strategies, (i) stepwise locking of phenyl rings of tetraphenylethenes (TPE; Fig. 1), and
[4]
structural modification of cyano-substituted distyrylbenzenes (DCS; Fig. 2). Large variations of
solution PL quantum yields and lifetimes for the TPE and DCS series allow for a systematic
understanding of the PL quenching mechanism in solution, further supported by quantum-chemistry.
Correlation of solid state PL rates and intermolecular arrangements gives direct insight into the
[2a, 4]
intermolecular factors promoting AIEE,
and stresses the importance of the understanding of the
synergetic contributions.
-CN
-OR
-CF3
-OR
-NR2
Fig. 1: Stepwise locked TPEs
Fig. 2: Structural variation of DCS
[1] (a) S.-J. Yoon et al, J. Am. Chem. Soc. 132 (2010) 13675. (b) X. Luo et al, J. Phys. Chem. C 116 (2012) 21967.
[2] (a) J. Gierschner, S. Y. Park, J. Mater. Chem. C 1 (2013) 5818. (b) J. Gierschner et al, J. Phys. Chem. Lett. 4 (2013)
2686.
[3] J. Shi et al, Chem. Comm. 48 (2012) 10675.
[4] J. Shi et al, in preparation.
P-15 Magnetic nanoparticles as doxorubicin delivery system
for targeting breast cancer cells
Ana Lazaro-Carrillo,*1,2 Macarena Calero,1,2 Pierre Couleaud,2 Antonio Aires,2 Alfonso
Latorre,2 Álvaro Somoza,2 Aitziber L. Cortajarena2 and Angeles Villanueva1,2
1
2
Universidad Autónoma de Madrid, Departamento de Biología, Darwin 2, 28049 Madrid, Spain. Tel: 34 914978235;
Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia), Faraday 9, 28049 Madrid, Spain.
In the last decade there has been a spectacular development of magnetic nanoparticles (MNPs) for biomedical
applications, such as magnetic carriers for drug delivery aided by external magnetic fields, magnetic resonance
imaging contrast agents or cancer therapy compounds for hyperthermia, among others.
More recently, new multifunctional magnetic nanoparticles capable of carrying out simultaneously a dual function,
cancer diagnosis and therapy, are under investigation. This promising new strategy in cancer treatment has been
called theranostics.
The most suitable nano-carrier for drug delivery and cancer chemotherapy should have the following properties:
(i) stability without altering the pharmacological activity of the drug, (ii) to prevent premature metabolic degradation
of the drug in the systemic circulation such that it arrives in a proper state at the specific target, (iii) drug release at
tumour, and (iv) to exhibit similar or lower toxicity than drug non-nano.
In this work we have used biocompatible magnetic nanoparticles (MNPs) coated with dimercaptosuccinic acid
1
(DMSA) . Anti-neoplastic drug doxorubicin (DOX) has been immobilized onto DMSA coating by electrostatic
interactions. Indeed, in ultrapure water at physiological pH, positively charged DOX can be immobilized giving rise
to a funcitonalized MNPs (MNP-DOX) with 40 µmol of DOX /g Fe. The release of DOX from MNP-DOX have been
studied in different media. No significant release were observed in ultra-pure water whereas releases of 78% and
64% were observed after 48h, in PBS buffer and cell culture medium, respectively.
After 24 h incubation MNP-DOX were efficiently
internalized by human breast cancer cells (MDAMB-231). This fact was confirmed by fluorescence
microscopy and Prussian blue staining. Up to 72 h
after MNP-DOX incubation, apoptosis and mitotic
catastrophe cell death were triggered. We
confirmed
these
results
by
α-tubulin
immunofluorescence
(see Fig. 1) and flow
cytometry. In addition Alamar blue assay was
carried out to evaluate cytotoxicty of this
formulation.
In
summary,
doxorubicin
functionalized
magnetic nanoparticles seems a promising tool as
therapeutic agent, due their ability to produce
efficient drug release and cancer cells inactivation.
24 h
72 h
50.0 µm
MF66
MF66-DOX
Figure 1. Immunofluorescence for α-tubulin (green) and DNA counterstained with
Hoechst-33258 in MDA-MB-231 cells. Left image: cells incubated with MF66 without
functionalization. Right image: cells incubated with MF66-DOX at the same
magnification, where doxorubicin induced increased cell size.
1
Calero, M.; Gutiérrez, L.; Salas, G.; Luengo, Y.; Lázaro, A.; Acedo, P.; Morales, MP.; Miranda, R.; Villanueva, A. Nanomedicine
2014, 10, 733-43
* This work was supported by grant from EU-FP7 MULTIFUN project (nº 262943).
P-16 Long-lived photoexcited states in SWNT-PFO blends
Abasi Abudulimu1, Imge Namal2, Florian Späth2, Larry Lüer, 1 and Tobias Hertel2
1
IMDEA nanociencia, Madrid (Spain);
Universität Würzburg (Germany)
2
[email protected]
Abstract
SWNT-PFO blends are developed with the goal to become efficient active materials in photovoltaic (PV)
devices. Since the typical charge extraction times in PV devices, involving organic materials with low charge
mobilities, are in the lower microseconds regime, the photophysics of the system, and its components, must be
studied in detail on this time scale. In this work, we performed transient absorption (TA) spectroscopy on a time
scale from femtoseconds to microseconds, on (6,5) SWNT in PFO-Bpy Matrix in comparison with the (6,5)
SWNT:PFO-BPy Network. Using global analysis of the TA spectra, we have obtained the optical probes for long
lived photoexcited states such as triplet states and trapped charges, and have found out that the life time of longlived states in Matrix sample is much longer (300us) than in Network (1 us). A Redshift of excitonic
photobleaching (PB) was occurred in both samples which we assigned to the Stark Effect caused by electric field
of trapped charges. Global fitting result also showed a slow energy transfer to (7,5) tube around 1.75eV in
Network sample but not in Matrix, which means the SWNTs are very well isolated in PFO-BPy matrix. However,
we didn’t find any sign of charge transfer between SWNT and PFO-BPy.
Photophysical model
Photoexcited states in PFO-Bpy and SWNT, an excitation scenario, where CT is interfacial charge transport
states, “f.c.(11)” and “f.c.(22)” are the free carrier continua and P1 is the polaronic state of PFO. The Right
figure is the complete pump-probe spectrum of the SWNT:BPy Network sample.
P-17 Fine tuning of size and polydispersity of carbon
spheres to obtain carbon opals
a
a
Luz Karime Gil Herrera,
Herrera Alvaro Blanco, Beatriz H. Juárez,
b,c
Cefe Lopez
Lope
a
a
Instituto de Ciencia de Materiales de Madrid, Consejo Superior de InvestigacionesCientíficas (CSIC),
C/Sor Juana Inés de la Cruz 3, 28049Madrid (Spain).
b
IMDEA Nanociencia, Fco. Tomás y Valiente 7, Campus de Cantoblanco, 28049 Madrid (Spain).
c Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco, 28049,
Madrid, Spain
Due to their morphology, low density and high surface area hollow carbon spheres have attracted
much attention in several fields for applications in catalysts, energy storage‐media,
storage
or drug
delivery.
elivery. Furthermore, their use as building blocks to produce high ordered structures is also an
appealing feature in photonics. [1, 2]
In this work, we have synthesized monodisperse carbon spheres by a Hydrothermal Carbonization
treatment using polystyrene beads as seeds and glucose as carbon precursor [3].
[ The experimental
parameters were optimized, mainly diameter of the seed, time and temperature reaction.
The concentration of polystyrene beads, size, polystyrene/glucose ratio, hydrothermal and
carbonization
arbonization temperatures as well as reaction time allow for
or a fine tuning of the size (100‐1000
(100
nm) and monodispersity (<4%) of the final carbon shell structures (PS@C).
Finally we achieved a silicon inverse opal from carbon spheres arranged in opaline structure as
starting material.
Fig. 1a SEM image of hollow carbon
sphere after heat-treatment
treatment at 600 ºC.
Fig. 1b SEM image of empty core from the
carbon sphere after heat-treatment
treatment at 600
ºC.
1) T. Zhang, Q. Zhang, J. Ge, J. Goebl, M. Sun, Y. Yan, Y. Liu, C. Chang, J. Guo, and Y. Yin, J. Phys. Chem. C.,
C 2009, 113,
3168.
2) M. Goodman, K. Arpin, A. Mihi, N.. Tatsuda, K. Yano, and P. Braun, Adv. Optical Mater. 2013, 1,
1 300.
3) R. White, K. Tauer, M. Antonietti, and M. Titirici, J. Am. Chem. Soc., 2010, 132, 17360.
4) Q. Wang, H. Li, L. Chen, X. Huang,
Huang Carbon, 2001, 39, 2211.
P-18 Non covalent interactions between graphene/exTTF
Marina Garrido, a Laura Rodríguez-Pérez,a Mª Ángeles Herranza and Nazario Martín*a,b
a
Organic Molecular Materials Group, Complutense University, Madrid, Madrid 28040, Spain. Tel: 91 394 4227;
IMDEA Nanoscience, Madrid, Madrid 28049, Spain.
b
Since the discovery of graphene in 2004, it has become the most studied nanomaterial due to its unique
mechanical, thermal and electronic properties. However, graphene has a zero bandgap and thus behaves like a
metal, which for many electronic applications could be a severe limitation. To open this band-gap, several
1
approaches have been investigated, such as to modify the electronic structure (electrostatic field tuning ), the
2
3
geometry of the graphene (heteroatom doping ) or both at the same time (chemical modification ). In addition,
graphene has a strong tendency to aggregate due to the strong π-π interactions between individual sheets
hindering manipulation and devices fabrication.
Band-gap opening and exfoliation of graphene, can be both achieved by chemical modification. In this sense,
covalent or non-covalent methods have turned out a powerful methodology to modulate the electronic properties
2
of graphene. The covalent modification provides stable materials, but implies the saturation of some of the sp
4
carbon atoms, while the non-covalent modification of graphene enables conservation of the structure .
In this contribution, we will present different approaches to the non-covalent functionalization of graphene with πextended analogues of the electron-donor tetrathialfulvalene (exTTF), in the search of electroactive materials for
functional structures.
Figure 1: Non-covalent functionalization of graphene with π-extended tetrathialfulvalene.
1
2
3
4
Ohta, T.; Bostwick, A.; Seyller, T.; Horn, K.; Rotenberg, E. Science 2006, 313, 951
Müeller, M. L.; Yan, X.; Dragnea, B.; Li, L. S. Nano Lett. 2011, 11, 56
Special issues devoted to Graphene Chemistry, Properties and Application on Acc. Chem. Res., 2013, 46, 1 (pp. 1-190) and
10 (pp. 2191-2340).
Rodríguez-Pérez, L.; Herranz, M.A.; Martín, N. Chem. Commun., 2013, 49, 3721
P-19 Size, shape and capping ligand dependence of cyclic
voltammetry studies on CdSe nanocrystals
Julio J. Conde*a, Leonor de la Cuevab, Concepción Alonsoa and Beatriz H. Juáreza,b
a
Dpto. de Química Física Aplicada, Universidad Autónoma de Madrid, 28049, Madrid, Spain.
b
IMDEA Nanociencia, Campus de Cantoblanco, 28049, Madrid, Spain.
* E-mail: [email protected]
Colloidal quantum dots, also known as semiconductor nanocrystals (NCs) have been widely investigated in the
recent years due to quantum confinement effects, by which the light emission (and absorption) can be tuned
through changes in the NCs size. Electrochemical techniques combined with optical spectroscopy have been used
to measure the semiconductor band gap [1] and/or to induce changes in the photoluminescence emission or
conductivity [2] of the NCs.
The objective of this work is to investigate changes undergone in the physicochemical properties of NCs using
cyclic voltammetry. The effects of several scans on the position and intensity of reduction/oxidation peaks have
been recorded, as well as the effect for NCs with different sizes. To these aims, NCs obtained by two types of
syntheses have been performed and properly compared (Fig.1): octadecylphosphonic acid (ODPA) capped CdSe,
with rod shape, and chloride and ODPA capped CdSe, with pyramidal shape. Optical characterization was
performed using steady-state optical spectroscopy (absorption and UV/vis) and morphological characterization
using transmission electron microscopy (TEM).
Preliminary results point out to a clear relation between the oxidation and reduction products depending on the
scan direction and a different behaviour of the peaks depending on the organic ligands capping the NCs surface
[1]. Furthermore, a permanent photoluminescence improvement, after performing a cathodic potential scan has
been recorded, what may due to a feasible electron injection on the surface defects of the NCs.
Fig. 1. TEM images of (a) rod shape and (b) pyramidal shape CdSe NCs used for this work
ACKNOWLEDGMENTS: The author acknowledges Fundación Iberdrola for his scholarship.
1. Kuçur, E.; Riegler, J.; Urban, G.A.; Nann, T.; J. Chem. Phys. 2003, 119, 2333-2337.
2. Guyot-Sionnest, P.; Microchim. Acta 2008, 160, 309-314.
3. de la Cueva, L.; Lawaet, K.; Otero, R.; Gallego, J.M.: Alonso, C.; Juarez, B.H.; J. Phys. Chem. C 2014, 118, 4998-5004.
P-20 New [C60] fullerene-based materials for organic
photovoltaics.
Inés García Benito,*a Juan Luis Delgadoa and Nazario Martínb
a
IMDEA-Nanociencia, C/ Faraday, 9, 28049 Madrid, Spain;
b
Facultad de Química, Universidad Complutense de Madrid, 28030, Madrid, Spain;
Photovoltaic (PV) solar cells are currently a hot topic in science as they are able to transform sun light into
electricity.
[1]
Organic solar cell (OSC) devices
are attracting considerable attention, especially after a recent report of a
[2]
device with a power conversion efficiency (PCE) exceeding 10 %.
In OSCs, for which organic fullerene derivatives
have proved to be by far the best electron-accepting n-type materials, the PCE is dependent on open-circuit voltage
(Voc), short-circuit current density (Jsc), and fill factor (FF). The Voc can be increased by raising the LUMO level of the
[3]
fullerene derivative through bis-addition of organic addends.
Therefore, we suggest the synthesis of different C60-derivatives which could theoretically increase the power
conversion efficiency of the device.
Figura 1. Schematic illustration of a polymer–fullerene BHJ solar cell, with a magnified area showing the bicontinuous morphology of the active layer.[4]
(ITO is indium tin oxide and PEDOT-PSS is poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate)
[1] a) Tang, C. W., Appl. Phys. Lett. 1986, 48, 183-185; b) Yu, G.; Gao, J.; Hummelen, J. C.; Wudl, F.; Heeger, A. J., Science 1995,
270, 1789-1791.
[2] a) Green, M. A.; Emery, K.; Hishikawa, Y.; Warta, W.; Dunlop, E. D., Prog. Photovolt. Res. Appl. 2012, 20, 12-20; b) Service, R. F.,
Science 2011, 332, 555-559.
[3] Matsuo, Y.; Kawai, J.; Inada, H.; Nakagawa, T.; Ota, H.; Otsubo, S.; Nakamura, E., Adv. Mater. 2013, 25, 6266-6269.
[4] Fréchet, J. M. J.; Thompson, B. C., Angew. Chem. Int.Ed. 2008, 47, 58-77.
P-21 2D Nanostructures Based in Modified Oligonucletides
Romina Lorca,a,b Alfonso Latorre,a Felíx Zamora,* a,b and Álvaro Somoza* a
a
Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia), & CNB-CSIC-IMDEA Nanociencia Associated Unit
"Unidad de Nanobiotecnología“ Cantoblanco, 28049 Madrid, España. Tel: +34-912998856;
b
Universidad Autónoma de Madrid, Departamento de Química Inorgánica. 28049, Madrid, España. Tel: +34-914973962;
Oligonucleotides have shown great versatility in nanotechnology due to their ability to form stable duplexes
between complementary strands and their nanometric size. The specific interaction between complementary bases
leads to the assembly of DNA strands in a controlled manner, allowing the formation of nanostructures in one, two
or three dimensions.
.
th
This area of research was initiated by N. C. Seeman in the 90 . His main approach is based on the preparation of
[1]
units (tiles) composed of DNA, which are able to assemble with other tiles leading to large 2D structures. In 2006
Rothemund described a new approach known as DNA origami. In this case, a long circular DNA is employed,
[2]
which is "folded" using hundreds of short oligonucleotides into a great variety of shapes . DNA has also been
used to obtain 3D structures composed exclusively of DNA. One remarkable example is the preparation of a box
[3]
with a lid described by Kjems and colleagues . Regarding construction of nanostructures in one dimension using
DNA the aim is the development of molecular nanowires. In this case, the use of modified oligonucleotides have
[4]
recently shown promising results as conductors and semiconductors materials .
Related with this area of research, we are developing a strategy to obtain 2D DNA nanostructures based on the
connection of oligonucleotides with a benzene derivative, which fix the spatial horientation of the oligonucleotides.
Particularly, we are exploring two different approaches; the first one is based on the assembly of complementary
oligonucleotides as depicted in the Scheme 1. In this case, three oligonucleotides are attached at alternative
positions of a bencene ring, which are able to hybridize with a partner structucture bearing the complementary
sequence. The second strategy is based on the polimerization of modified oligonucleotides, using benzene ring
derivatives as cross-linkers. Oligonucleotides have been synthetized bearing two functional groups at 3’ and 5’
ends, which are able to react orthogonally with the functional groups presented in the organic benzene core. The
results obtained using both approaches will be presented in this work.
Scheme 1
Acknowledgements
Spanish Ministry of Science and Innovation (Grants: SAF2010-15440, ACI2009-0969, MAT2011-15219-E and
MAT2010-20843-C02-01) Chilean Ministry of Education CONICYT (PhD Scholarship: BECA CHILE) and IMDEA
Nanociencia are acknowledged for financial support.
1
2
3
4
Seeman, N. C. Annu. Rev. Biochem. Nanomaterials Based on DNA 2010, 79, 65–87
Rothemund, P. W. K.. Nature Scaffolder DNA origami for anoscale shapes and patterns. 2006, 440, 297–302
Andersen ES, Dong M, Nielsen MM, Jahn K, Subramani R, Mamdouh W, Golas M.N, Sander B, Stark H, Oliveira CL,
Pedersen JS, Besenbacher F, Gothelf KV, Kjems J. Nature. Self–assembly of a nanoscale box with a controllable lid. 2009,
459, 73–76
S. D. Watson, A. R. Pike, J. Pate, A. Houlton and B. R. Horrocks, Nanoscale. DNA-templated nanowires: morphology
andelectrical conductivity. 2014, 6, 4027- 4037
P-22 New Fullerene Derivatives for Photovoltaics
R. Sandoval,a J.L. Delgadoa and N. Martína,b
a
IMDEA-Nanociencia, C/ Faraday, 9, 28049 Madrid.
Facultad de Química, Universidad Complutense de Madrid, 28030, Madrid
b
The Sun, represents the most powerful source of energy available in our solar system. Its use with the
1
development of photovoltaic devices is one of the most important challenges today.
Although in the use of solar energy the prevailing technology are photovoltaic devices based on inorganic
materials (silicon), the development of photovoltaic devices based on organic materials and their combination
with inorganic materials “hybrid solar cell” have progressed recently.
It has been recently described the preparation of all organic solar cells based on mixing of fullerene derivates
2
and low band-gap polymers that reach power conversion efficiency of 8%, and also, hybrid solar cells based on
3
perovskite wih organic charge-transport layers that reach power conversion efficiency of 12%.
In this communication we will address the progress carried out by our research group in the field of photovoltaic
devices, with special emphasis on the synthesis of new derivatives of Fullerene for the preparation of
4
photovoltaic devices.
Figure 1. Basic components of organic photovoltaic device (OPV)
1
J.L. Delgado, P-A. Bouit, S. Filippone, M.A. Herranz, N.Martín, Chem. Commun, 2010, 46, 4853-4865.
M. A. Green, K. Emery, Y. Hishikawa, and W. Warta, Prog. Photovolt. 2009, 17, 85. (b) I.W. Hwang, D. M., and A. J. Heeger, J. Phys.
Chem. C 2008, 112, 4350.
3
O. Malinkiewicz, A .Yella, Y. H. Lee, G. M. Espallargas, M. Graertzel, M. K. Nazeeruddin, H. J. Bolink, Nature Photonics, 2014, 8, 128132
4
(a) J. L. Delgado, E. Espildora, M. Liedtke, A. Sperlich, D. Rauh, A. Baumann, C.Deibel, V. Dyakonov, N. Martin, Chem. Eur. J. 2009,
15, 13474. (b) C. Villegas, E. Krokos, P.-A. Bouit, J. L. Delgado, D. M. Guldi and N. Martin, Energy Environ. Sci., 2011, 4, 679.
2
P-23 Single molecule characterization of the DNA unwinding
mechanism of the T7 helicase
Fernando Cerróna, Francisco Caob and Borja Ibarraa
a
Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Cantoblanco, 28049, Madrid, Spain;
b
Departamento de física atómica, molecular y nuclear, Universidad Complutense de Madrid, 28040, Madrid, Spain;
Helicases are motor proteins that use the chemical energy of NTP hydrolysis to drive mechanical processes
such as translocation and nucleic acid separation. The bacteriophage T7 helicase is a good model system for
understanding ring-shaped hexameric helicases and in particular the mechanism used by these proteins to open
1
2
the dsDNA , a question which is still under debate. To shed light on this question we have used optical tweezers
to study the real time kinetics of individual T7 helicase molecules as they unwound dsDNA and translocate on
ssDNA. Our data show that the unwinding velocity decreased with the GC content of the sequence and increased
(~10-fold) when a destabilizing force on the DNA junction was increased. The observed force-velocity and
sequence dependence of the unwinding rate are consistent with a model in which the helicase translocates along
the DNA with 2-4 bp steps and actively destabilize the dsDNA fork with a ∆G=1.15kT. A theoretical model to
precisely define the step size is also proposed.
1
2
The unwinding mechanism of the ring helicase of bacteriophage T7. Yong-Joo Jeong, Mikhail K. Levin, and Smita S. Patel.
Proc. Natl. Acad. Sci. (2004). 101, 19: 7264-7269.
Optical trap force transducer that operates by direct measurement of light momentum. Smith SB, Ciu Y, Bustamante C.
Methods enzymol. 2003. 361, 132-162
P-24 Mechano-selective bacteria surface adhesion
Felipe Viela1, Manuel Rodriguez1, Santiago Casado1, Aitziber Lopez Cortajarena1,2 and Isabel
Rodriguez1
1
Madrid Institute for Advanced Studies in Nanoscience (IMDEA Nanoscience), C/Faraday 9, Ciudad Universitaria de
Cantoblanco, Madrid 28049, Spain.
2
Most bacteria live attached to surfaces as means of survival. Once bacteria attach on to a surface, they
proliferate and form a sessile community of bacteria called biofilm in which the microorganisms are shielded in a selfproduced matrix. Biofilms are notoriously resistant to antibiotic treatment and to immune defenses and as such, they are
either impossible or very difficult to eliminate. Accordingly, the most effective means to avoid bacterial infection is by
preventing the early stages of bacteria attachment and biofilm formation.
To this end, our approach to develop antibacterial surfaces is based on using strictly physical means to affect
bacteria attachment exploiting the response of bacteria to the nanomechanical surface characteristics such as stiffness
[1,2 ].
We fabricate selective surfaces based on dense high aspect ratio high density pillar structures in
polymers. This topography reduces the effective stiffness and alongside, it reduces the effective contacting area of
the bacteria with the substrate. The effective stiffness of a surface can be determined by the structure design with
specific dimensions in terms of pillar diameter, height and array pitch (center to center distance).
The mechano-selective topographies are fabricated via polymer replication using nanoimprinting. Initially,
molds containing the negative geometry of pillars are fabricated in silicon by micromachining techniques. The
molds are then imprinted on to thermoplastic substrates like polycarbonate and polypropylene.
The effective stiffness of the textured substrates is calculated from the force–distance (f-d) curves of indentation
experiments. Applying Oliver and Pharr analysis [3], the effective stiffness of the topography is defined as the slope of
the unloading f-d curve linear fit.
In contrast to a flat surface, preliminary experiments of adhesion of Staphylococcus aureus onto 500
nm pillared surfaces indicate that the topography disrupts the formation of a continuous biofilm (Fig 1A) and the S.
aureus attaches individually within the 500 nm pillar gaps where the spacing allows the coccus to reach the bottom of
the substrate (Fig. 1B). On the other hand, the adhesion of S aureus on to 200 nm dense pillared surfaces is much
reduced. On one hand, the pillar interspacing of this topography does not permit the bacteria to reach the bottom of the
substrate, and only a few bacteria adhere onto the top of the pillars. In addition, nanoindetation tests show that the
effective stiffness of this substrate is significantly reduced compared to the stiffness of the pristine polymer substrate.
A
B
Figure 1. A) Comparison of bateria attachment onto flat and a 500 nm pillared surface after 24 hours of incubation.
B) S. aureus attached over 500 nm pillars
[1]
[2]
[3]
A.I. Hochbaum, J. Aizenberg. Bacteria pattern spontaneously on periodic nanostructure arrays. Nano Lett., vol 10, pp 3717–3721
(2010)
E.P. Ivanova, J. Hasan, H.K. Webb, V.K. Truong, G.S. Watson, J.A. Watson, V.A. Baulin , S. Pogodin, J.Y. Wang, M.J. Tobin, C.
Löbbe, R.J. Crawford. Natural bactericidal surfaces: mechanical rupture of pseudomonas aeruginosa cells by cicada wings. Small
vol 8, pp 2489–2494 (2012)
W.C. Oliver, G.M. Pharr. Measurement of hardness and elastic modulus by instrumented indentation: Advances in understanding
and refinements to methodology. J. Mater Res, vol 19, pp 3-20 (2004)
P-25 Fluorescent gold nanoclusters stabilized by repeat
portein scaffolds
Sergio Adan,*a Pierre Couleauda,b , Sara H. Mejias, a,b Begoña Sot, a,b Alvaro Somoza, a,b and
Aitziber L. Cortajarena a,b
a
Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia) 28049-Madrid, Spain.
b
Gold nanoclusters (AuNCs) have shown a great potential in sensing and biolabeling because of their
1
fluorescent properties . These structures are composed of few atoms of gold and are stabilized by different molecules
2
such as, DNA , dendrimers, Good´s buffer, and proteins. Nevertheless, AuNCs stabilized by proteins, offer unique
properties including the fact that they can be obtained under mild conditions and the structures obtained are stable under
a wide range of pH and ionic force, making them ideal for biological applications. Different proteins have been employed
3
in the preparation of AuNCs such as bovine serum albumin (BSA) , human transferrin, trypsin, pepsin, horseradish
peroxidase, insulin, and lysozyme.
Repeat proteins have gained much interest and have become an attractive target for nanotechnology
4
applications due to their modularity . In this work we have used the repeat module tetratricopeptide repeat (TPR), which
is formed by 34 amino acids and gives rise to a helix-turn-helix motif (Figure 1). These types of proteins have not been
employed before in the preparation of AuNCs and due to their structural properties they could be an ideal substrate for
the stabilization of AuNCs. Particularly, we have studied TPR proteins with different number of tandem repeats (3, 6, 8
and 20) as well as different conditions in the preparation of AuNCs.
Protein-AuNCs were obtained under numerous experimental conditions. The best results were obtained when
ascorbic acid was employed as reducing agent. Importantly, in this case the structure of the protein was retained and
fluorescent AuNCs where stabilized within the protein scaffold. Using the procedure reported herein the function of the
protein was also maintained, as it was demonstrated through binding assays using its cognate ligand, the Hsp90 peptide.
Figure 1. Schematic representation of AuNCs formation using TPR proteins.
The results obtained highlight the potential of AuNCs stabilized by proteins in the preparation of biosensors.
1 J.M. Slocik, J. T. Moore and D. W. Wright, Nano Lett., 2002, 2, 169–173.
2 G. Liu, Y. Shao, F. Wu, S. Xu, J. Peng and L. Liu, Nanotechnology, 2013, 24, 015503.
3 Y. Bao, H. et al., Phys. Chem. C, 2010, 114, 15879–15882.
4 Tommi Kajander, Aitziber L. Cortajarena,a Simon Mochrieb, and Lynne Regan, Acta Cryst. 2007. D63, 800–811.
P-26 Mechanically Interlocking
Interlocking vs Polymer Wrapping of
SWNTs
Sofía Leret García, Emilio M. Pérez
IMDEA
MDEA Nanoscience, C/ Faraday 9, Ciudad Universitaria de Cantoblanco, 28049, Madrid, Spain.
E-mail:[email protected]
Carbon Nanotubes and their derivatives have drawn much attention over the last decade
because of their inherent electronics and mechanical properties.
properties Currently two methods for
the chemical modification of carbon nanotubes (CNTs) have been explored: covalent1 and
supramolecular2. Here, we present a strategy to obtain mechanically interlocked derivatives of
SWNTs (MINTs) based on a clipping strategy.
strategy We have recently introduced the mechanical
bond as a new tooll for the modification of CNTs which combines the advantages of both the
covalent and supramolecular approaches: stability and preservation of the CNT, respectively.
respectively 3
In this work we have utilized naphthalene bisimides as the recognition motif for SWNTs. The
mechanically interlocked nature of the derivatives is probed by analytical and
and spectroscopic
spec
techniques (TGA, NMR, UV-vis
vis-NIR
NIR and Raman) and adequate control experiments.
Remarkably, individual macrocycles can be seen around the nanotubes under TEM scrutiny.
O
O
O
N
n
O
N
O
O
N
N
O
O
n
O
O
References
1.
2.
N. Karousis, N. Tagmatarchis, D. Tasis, Chem. Rev. 2010, 110, 5366-5397.
Y.-L.
L. Zhao, J. F. Stoddart, Acc. Chem. Res. 2009, 42, 1161-1171.
3.
A de Juan, Y Pouillon, L Ruiz-González,
Ruiz
A Torres-Pardo,
Pardo, S Casado, N Martín, A Rubio, and E M Pérez, ,
Angew. Chem. Int. Ed.,
Ed. 2014, 53, 5394-5400.
P-27 Synthesis of PEGylated gold nanorods dimers
using molecular linkers
Guillermo Gonzá
ález*, Gloria Tardajos, Andrés Guerrero-Martínez.
Martínez.
Physical Chemistry Department I, Universidad Complutense de Madrid,
Campus Moncloa 28040-Madrid, Spain.
[email protected]
Abstract
The optical properties of gold metal nanoparticles are characterized by the strongly localized
electromagnetic near and far-field
far field enhancement at the particle surface, phenomenon that is
associated with the coherent oscillation of the conduction band
band electrons coupled to
electromagnetic fields, also called Localized Surface Plasmon Resonance. If two gold
nanoparticles are closed in proximity at the nanoscale, the near field on one nanoparticle interacts
strongly with that on the adjacent particle, leading to a new plasmon resonance mode that
produces large field enhancements at the particle gap, denominated hot spots [1, 2]. Actually, this
phenomenon is the basis of molecule ultradetection in different spectroscopy techniques such as
metal-enhanced fluorescence (SEF) and surface enhanced Raman scattering (SERS) [2].
In this context, spherical gold nanoparticles lack a geometrical preference toward site-specific
site
functionalization, thus limiting their potential applications to form plasmonic dimers. In contrast, one
of the most appealing advantages of anisotropic gold nanorods, as compared with their spherical
counterparts, is their versatility toward chemical functionalization at the nanoparticle tips. Gold
nanorods can be functionalized at the tips with
with functionalized molecules of different lengths and
flexibilities, building up plasmonic dimers and polymers through tip-to-tip
tip
tip bonds [3]. We propose a
new synthetic methodology to obtain stable and monodisperse gold nanorod dimers in solution, in
which the interparticle distance is precisely controlled by means of the length of the molecule
selected to link the individual particles (figure 1).. This new approach opens up the access to new
enhanced plasmonic systems with potential applications in nanoplasmonics
nanoplasmonics by introducing
fluorescent and SERS surface active molecules at such nanoparticle gaps [4].
[
Figure 1. TEM image of gold nanorods dimers.
dimers
References
1. Aizpurua J, Hillenbrand R. Springer
ringer Series in Optical Sciences,167, 2012, pp 151-176.
2. Willets KA, Van Duyne RP. Annu. Rev. Phys. Chem.
Chem 2007; 58(1):267-97.
3.. Vigderman L, Khanal BP, Zubarev ER. Adv. Mater. 2012; 24(36):4811-41.
4. A. Guerrero-Martínez,
Martínez, M. Grzelczak, L.M. Liz-Marzán.
Liz
ACS Nano. 2012, 6, 3655-3662
Acknowledgements
This work was funded by the Spanish MINECO (CTQ2010-18564).
(CTQ2010
A.G.-M.
M. acknowledges receipt of a Ramón y Cajal
Fellowship from the Spanish MINECO.
P-28 Synthesis of Extended Graphdiyne Wires by Vicinal
Surface Templating
a
b
c
d
d
B. Cirera , Y.-Q. Zhang , J. Björk , S. Klyatskaya , Z. Chen , M. Ruben
d,e
b
, J. V. Barth and F. Klappenberger
b
a
Instituto Madrileño de Estudios Avanzados en Nanociencia, 28049 Madrid, Spain
b
Physik Department E20, Technische Universität München, 85748 Garching, Germany
c
Department of Physics, Chemistry and Biology (IFM), Linköping University, 58183 Linköping, Sweden
d
Institute of Nanotechnology (INT), Karlsruhe Insitute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany
e
IPCMS-CNRS, Université de Strasbourg, 23 rue de Loess 67034 Strasbourg, France
Recently, surface-assisted covalent synthesis has emerged as a promising alternative to
nanofabricate carbon allotropes and carbon-rich scaffolds. Following this strategy, the homocoupling of
[1]
terminal alkynes has been studied by us to investigate graphdyine-like architectures on flat metal surfaces.
Under these conditions, inherent side-reactions between ethyne-functionalized monomers decrease the
chemoselectivity of the targeted homocoupling, hence resulting in branched polymeric networks. To
[2]
overcome this problem, we present a novel protocol implementing the vicinal surface Ag(877) , which allows
us to template exclusively the C-C coupling of terminal acetylenic compounds. First, a careful coveragecontrol permits us to confine the absorption of the 4”-diethynyl-1,1’:4’,1”terphenyl (TPDE) linear monomer
uniquely along the step-edges. This one-dimensional (1D) steering favors the later homocoupling through
thermal excitation, thus increasing drastically the chemoselectivity of the linear reaction and producing highquality polyphenyl-butadyine chains. These 1D structures can be classified inside the family of the extendedgraphdyine nanowires, whose electronic band structure is first characterized by means of the density
functional theory (DFT), showing promising applications as a low-dimensional direct band gap
semiconductor. We envision that this general templating approach could be applicable to different reaction
schemes on a large variety of substrates, offering the possibility to synthesize novel materials within the
bottom-up approach.
1 a) Y.-Q. Zhang, N. Kepčija, M. Kleinschrodt, K. Diller, S. Fischer, A. C. Papageorgiou, F. Allegretti, J. Björk, S. Klyatskaya, F.
Klappenberger, M. Ruben, J. V. Barth, Nat. Commun. 2012, 3, 1286. b) Cirera, Y.-Q. Zhang, S. Klyatskaya, M. Ruben, F. Klappenberger,
J. V. Barth, Chemcatchem 2013. 10.1002/cctc.20130029. c) J. Björk, F. Klappenberger, Y.-Q. Zhang, J. V. Barth, S. Stafström, JPCC
2014 118, 3181–3187.
2 B. Cirera, Y.-Q. Zhang, J. Björk, S. Klyatskaya, Z. Chen, M. Ruben, J. V. Barth and F. Klappenberger, Nanoletters. 2014 14 (4), 18911897
P-29 Nanotubular Systems Self-assembled through Orthogonal
Supramolecular Interactions
Violeta Vázquez-González,a R. Chamorro-Mendiluce,a M. José Mayoral,a M. Teresa Aranda,a
N. Bilbao,a C. Montoro-García,a J. Camacho-García,a A. López-Péreza and D. GonzálezRodríguez*a
a
Departamento de Química Orgánica, Universidad Autónoma de Madrid, 28049-Madrid, Spain. Tel: +34-91-4973758.
Our project aims at the preparation of macrocyclic self-assembled systems with a fine control on their size,
1-4
shape and chemical functionality, which will constitute the section of self-assembled nanotubes. To this purpose we
have designed two different linear and planar molecules bearing hydrogen-bonding moieties (perpendicular directors)
and peripheral amide wedges (parallel directors). These monomers are expected to self-assemble into nanotubes
through - interactions and hydrogen bonding of the amide groups.
The role of perpendicular and parallel directors to generate self-assembled nanotubes will be study in detail in
the global process. The former provide a highly stable -conjugated macrocyclic trough hydrogen bonding between
complementary nucleobases (figure 1a), while the parallel directors induce the supramolecular polymerization process of
the macrocyclic self-assembled system (figure 1b).
The supramolecular equilibrium has been studied by UV-Vis Spectrocopy, Fluorescence Spectrocopy, Circular
Dichroism and Nuclear Magnetic Resonance in solution, as well as visualized by imaging techniques (Transmision
Electron Spectroscopy, Scanning Electron Spectrocopy and Atomic Force Microscopy).
FIGURE 1. Supramolecular polymerization process
1.
2.
3.
4.
Special issue on self-assembly at the beginning of the XXI century: Science 2002, 295.
Lehn, J. M., Angew. Chem. Int. Ed., 1990, 29, 1304-1319.
Stoddart, J. F., Acc. Chem. Res., 2005, 38, 723–732.
Anderson H. L., Nature, 2011, 469, 72–75.
P-30 Supramolecular synthesis of discrete π-conjugated
cyclic tetramers
Carlos Montoro García,*a Ana López Pérez,a Jorge Camacho,a Nerea Bilbaoa and
David González Rodrígueza
a
Nanostructured Molecular Systems and Materials group (MSMn), Departamento de Química Orgánica, Universidad
Autónoma de Madrid, 28049, Madrid, Spain
In the present communication we will show how we can “program” π-conjugated monomers with
the required information to self-assemble into cyclic tetramers. The main driving force for tetramer
stabilization is the formation of selective hydrogen bonded pairs between suitable moieties (nucleobases: G,
C, U, A, iG and iC) situated at both ends of the π-conjugated central blocks (Fig. 1).
[1]
The nucleobase moieties
bear bulky side groups that avoid further aggregation processes, limiting the growth to discrete cyclic
tetramers. The self-association process between monomeric units and the characterization of the
hydrogen-bonded ensembles, have been studied by NMR, mass spectrometry, as well as absorption,
fluorescence and circular dichroism spectroscopic techniques in solution. The results show a high stability of
the systems toward temperature or concentration changes in solvents of moderate polarity due to the
formation of Watson-Crick pairs of self-complementary hydrogen bonds between the corresponding
nucleobases (G-C, A-U, iG-iC) which contain most of the information for the self-assembly process.
G-C
iG-iC
A-U
Figure 1: Self-assembled π-conjugated cyclic tetramers.
1
González-Rodríguez, D.; Janssen, P. G. A.; Martín-Rapún, R.; De Cat, I.; De Feyter, S.; Schenning, A. P. H. J.; Meijer, E. W.
J. Am. Chem. Soc. 2010, 132, 4710.
P-31 Synthesis of Graphene Sheets for Device Fabrication
Andrés Black,*a,b Ramon Bernardoa,b, Emilio Pereza, Daniel Granadosa, Amadeo L. Vázquez
de Pargaa,b,
a
IMDEA Nanoscience, C/ Faraday 9, Cantoblanco, Madrid, Spain.
Dep. Física de la Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain.
b
The discovery of graphene has opened the door to the possibility of creating novel devices taking advantage of
graphene’s unique properties, with potential applications in microelectronics, optics, chemical and biological
sensing and spintronics, among others. In order to create such devices, graphene sheets must be isolated and
and transferred onto an appropriate substrate, upon which various microfabrication processes can be carried
out to produce the final device. With this goal in mind, a standard procedure has been developed and optimized
for growing large area graphene and transferring onto a Si/SiO2 substrate. The synthesis of graphene has been
carried out in a high temperature chemical vapor deposition (CVD) furnace, using copper foils as a catalyst for
graphene growth and methane gas as the carbon source precursor. The process parameters, including
temperature, pressure and precursor concentration have been optimized in order to synthesize large area
monolayer graphene sheets. Wet chemical etching techniques are then used to dissolve the copper foil, leaving
only the graphene sheet, which can then be transferred to the substrate of choice. This transfer procedure
involves a series of steps which have been optimized, including the application of a polymer coating to preserve
the graphene sheet during wet etching, and various heating, cooling, and cleaning procedures to ensure the
proper adhesion of the graphene to the desired substrate. Various characterization techniques including Raman
spectroscopy and basic electrical measurements have been employed to confirm the presence of graphene
upon Si/SiO2 substrate.
FIGURE 1: (A) Optical image of monolayer graphene sheet transferred onto Si/SiO2 substrate (20x magnification).
(B) Raman spectroscopy measurements of graphene sheet in (A). Measurements were carried out several
milimeters apart, and all spectra showing peak intensities I2D/IG > 2, confirming that the sheet is indeed a graphene
2
monolayer over its entire area (about 1cm ). The vanishingly small D peak indicates that very few defects are
present in the sheet.
P-32 2D lanthanide-based molecular architectures on surfaces
José I. Urgel1, David Écija1, Willi Auwärter1, Anthoula C. Papageorgiou1, Saranyan
Vijayaraghavan1, Sushobhan Joshi1, Sybille Fischer1, Joachim Reichert1, Svetlana
Klyatskaya2, Mario Ruben2 and Johannes V. Barth1.
1
Physik Department E20 Technische Universität München 85748 Garching (Germany) Fax: (+49) 89-2891-2608. E-mail:
[email protected]
2
Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT) 76344 Eggenstein-Leopoldshafen (Germany).
Supramolecular chemistry on surfaces has emerged as a versatile paradigm to design surfaceconfined advanced
architectures. We present the formation and characterization by scanning tunneling microscopy of advanced
networks involving a flexible five-fold lanthanide (Cerium or Gadolinium) organic coordination. By employing linear
linkers equipped with terminal carbonitrile functional groups (p-NC-(Ph)n-CN-p (n=3,4)), and by tuning the local
rare-earth to molecule stoichiometry, architectures evidencing high spatial complexity are manifested, including an
unprecedented Archimedean snub square tessellation. Alternatively, the formation of molecular structures is
illustrated by the lateral manipulation with excellent control of selfassembled pentamers via attractive tipsupramolecule interactions. Furthermore, the STM tip is used to perform molecular surgery of the pentamers,
giving rise to tetrameric, nonameric and dodecameric supramolecules. These experiments reveal the potential of
lanthanide coordination chemistry and of lateral manipulation techniques to create unprecedented artificial
molecular nanoarchitectures incorporating lanthanide elements, and thus of relevance for molecular design on
surfaces.
FIGURE
“State of the art” STM image showing a 2D lanthanide-organic network
1.
Urgel, José I.; Ecija, D.; et al., J. Phys. Chem. C 2014 DOI: 10.1021/jp502901z.
2.
Urgel, José I.; Ecija, D.; Auwärter, W.; Barth, J. V., Nano Letters 2014, 14, 1369-1373.
3.
Écija, D.; Urgel, José I., et al., Proc. Natl. Acad. Sci. USA. 2013, 110, 6678-6681.
P-33 Permanent magnets: From nanostructured thin films to
powder-like systems with GPU-based micromagnetics
G. Rodríguez-Rodríguez, K.M. Golasiński, F.J. Pedrosa, E. Céspedes, J. Camarero and A. Bollero
Instituto Madrileño de Estudios Avanzados (IMDEA) Nanociencia. Campus de Cantoblanco, 28049, Madrid.
Micromagnetic calculations of magnetic materials are crucial in order to achieve better understanding of how
magnetic systems behave under certain conditions of external fields, temperature and spin currents. In particular,
magnetization reversal nucleation and propagation processes in nanostructures have been broadly studied in order
to get magnetic nanodevices. For this kind of systems, micromagnetic calculations work quite well because of the
usual small size (or even low dimensionality) and well known parameters of the system.
Amorphous and/or bulk–like magnetic material are very complicated unless they have really well defined
magnetic parameters, constrained volumes or, at least, certain periodicity. Therefore bulk-scale micromagnetic
calculations are usually out of the map because of memory and CPU time usage except for uniform and/or periodic
systems.
With using GPU-based code we are able to perform bigger micromagnetic simulations fast enough to optimize
soft and hard ferrite-based (Strontium and Cobalt ferrites, SFO and CFO) powders intended to be the raw
material for permanent magnets fabrication [www.nanopyme-project.eu].
In order to optimize the magnetic properties of final magnets we study individual elements of the powder and
granular-like (polycrystalline) thin films in order to get a model for magnetic parameters dependence of size, shape
and exchange-coupling interaction. Particles size and magnetocrystalline axis orientation distributions are key
parameters in order to get comparable results because the intrinsic stochastic nature of powder-prepared samples.
Multilayered systems are also used as a model to study exchange-coupling mechanism between soft and hard
phases in such kind of novel ferrite-based permanent magnets.
CFO
FO
Interlayer exchange
FIGURE 1
(Top): CFO (Cobalt ferrite, average grain
size 160nm; thickness: 20nm), FO (Ferrite;
average grain size 20nm; thickness: 20nm)
and interlayer exchange map (hotspots
shows a dispersion of 2% over the average
10% interlayer exchange coupling) of
simulated polycrystalline layers.
(Mid): Magnetization during soft (FO)
magnetic layer reversal in perpendicular and
parallel magnetocrystalline arrangements.
(Bottom): Hysteresis loops for several
interlayer
exchange
coupling
and
magnetocrystalline
axis
dispersion
in
perpendiculary arranged layers.
•
•
Perp. layers
Parallel layers
•
http://www.nanopyme-project.eu/
OOMMF User's Guide, Version 1.0; M.J.
Donahue and D.G. Porter; Interagency
Report NISTIR 6376,
NIST,
Gaithersburg, D (Sept 1999)
https://mumax.github.io/
june
wednesday-thursday
2014
4
th
workshop
in nanoscience
instituto imdea nanociencia
c/ faraday, 9 · campus cantoblanco
MOLESCO
w w w . n a n o s c i e n c e . i m d e a . o r g
25-26
25-26
june
wednesday-thursday
2014
4
th
workshop
in nanoscience
instituto imdea nanociencia · c/ faraday, 9 · campus cantoblanco

preliminary book of abstracts

Transcription

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