Le Courrier - Club Nano

Le Courrier
N°46
N°47
Octobre 2010
EDITO En cette période de grandes incertitudes où apparaissent des nouvelles menaces perçues au niveau des changements climatiques, des risques industriels ou des effets de la globalisation de l’économie, les Nanotechnologies joueront‐
elles le rôle moteur de progrès, comme beaucoup attendent, ou doivent‐elles être considérées comme une de ces nouvelles menaces ? Le Club NanoMicroTechnologie a, une fois encore, d’apporter un éclairage sur ces deux aspects : par les essayé Journées Nanoscience et Industrie, qui se sont tenues les 25 et 26 mars 2010, à Ecully, dans l’agglomération lyonnaise, et journées NanoBiotechnologie, NanoToxicologie et par les Nano et Société qui sont programmées les 2 et 3 décembre 2010, à Orsay, en région parisienne. Ainsi, les journées Nanosciences et industrie, organisées conjointement par l’Ecole Centrale de Lyon, l’INSA de Lyon, l’INL, l’Ecole nationale supérieure des mines de Saint‐Etienne et le Club NanoMicroTechnologie ont tout d’abord essayées de montrer le dynamisme des nanotechnologies, remarquable tant par la diversité des sujets que par les avancées des recherches en cours. Ces journées ont plus particulièrement ciblé les nanomatériaux et les couches nanométriques pour leurs propriétés physico‐
chimiques, électroniques et biologiques à l’origine de nombreuses applications au service de l’optique, de la santé, de l’aéronautique, du spatial et de l’instrumentation industrielle. A cette occasion, les implications sociétales ont également été abordées. Le succès indéniable de ces journées, qui ont accueilli plus de 130 personnes, a été rendu possible grâce à la qualité des présentations faites à la fois par des industriels et des académiques. L’accueil et l’organisation des responsables de l’Ecole Centrale de Lyon ont été certainement pour beaucoup dans la réussite de cette organisation. Les Nanotechnologies ont ainsi pu confirmer leur transversalité. La propriété motrice des Nanotechnologies est de créer des passerelles entre les atomes et la matière condensée ce qui permet de faire apparaître de nouvelles propriétés physiques, chimiques et mécaniques. Les nano‐
particules et les nano‐objets sont notamment attendus dans des applications comme les capteurs et autres MEMS,
du fait des nouvelles propriétés qu’ils apporteront (matériaux piézoélectriques, thermoélastiques, semi‐
conducteurs, et surtout les nouveaux matériaux biocompatibles…) Un des secteurs plus particulièrement abordé, au cours des ces journées, fut celui des biotechnologies où les avancées et les potentiels sont nombreux, aussi bien, dans la détection et le traitement des maladies, que dans la réalisation de BioMEMS, ou encore, le développement rapide de la bioélectronique pour l’élaboration de prothèses artificielles… Notre Club souhaite maintenant approfondir les sujets qui font encore débat, en vous invitant à nous joindre, les 2 et 3 décembre 2010, pour les journées NanoBiotechnologie, NanoToxicologie et Nano et Société organisées avec la participation de Nanoinnov et de l’UniverSud, et qui se tiendront dans l’amphithéâtre Lehmann d’Orsay‐Paris‐
Sud. Ce sera aussi l’occasion de fêter ensemble les 20 ans du Club NanoMicroTechnologie et la parution du 4ème ouvrage, intitulé NANOTOXICOLOGIE et NANOETHIQUE, volume qui clôture la série d’ouvrages dédiés à l'enseignement des nanosciences. Stéphane Renard Président du Club NanoMicroTechnologie René Fillit Auditeur Secrétariat
Edito
p.1
Actualités
p.2-3
Portrait d’un membre : ENSM-SE Gardanne
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Electrochemical transistors with ionic liquids
for enzymatic sensing
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Journées Nanosciences et Industrie :
Posters
p.8-14
1 CONFERENCES Journées NanoBiotechnologie NanoToxicologie Nano et Société 2 et 3 Décembre 2010 Amphithéâtre LEHMANN Campus d'Orsay‐Paris Sud L'évènement dédié au PHOTON et à ses applications 26‐29 octobre 2010 Paris Parc Floral http://www.pri‐event.org/index.php Ces journées coïncident avec les 20 ans du Club NanoMicroTechnologie. Le Club NanoMicroTechnologie, organise, avec la http://www2.minatec.com/Draft‐Nanosystems‐Workshop‐
Nov2010.pdf Colloque franco/japonais sur la nanophotonique
4‐5 novembre 2010 Villetaneuse France http://www.cnanoidf.org/spip.php?article205 participation de NanoInnov et le soutien de Universud Paris, les "JOURNEES NANOBIOTECHNOLOGIE, NANOTOXICOLOGIE, NANO et SOCIETE". En complément de présentations d'avancées techniques dans les domaines scientifiques cités ci‐
dessus, une attention particulière sera apportée aux considérations d'enseignement d'éthique, liées à de société l'émergence et des nanotechnologies. NanoSAFE November 16‐18, 2010 Maison MINATEC® Parvis Louis Néel 38054 Grenoble, FRANCE http://www.clubnano.asso.fr/ http://www.nanosafe.org 4èmes Journées Franco‐espagnoles IBERNAM ‐ CMC2 Microsystèmes / Microsistemas November 25, 26th 2010 Residència d’Investigadors C/Hospital 64, Barcelona (Spain) http://www.ibernam.net/taxonomy/term/6 ElecMol’10
5th international meeting on molecular electronics Dec. 6‐10, 2010 http://elecmol10.grenoble.cnrs.fr/ 2
APPEL A POSTERS PUBLICATIONS Dernière publication du Club en librairie depuis le 2 septembre 2010 Journées NanoBiotechnologie NanoToxicologie Nano et Société 2 et 3 Décembre 2010 Amphithéâtre LEHMANN Campus d'Orsay‐Paris Sud Contact : marcel.lahmani@univ‐evry.fr Date limite d’envoi des propositions : 15 Novembre 2010 "Les nanosciences Nanoéthique" L’objectif de ces journées est de présenter certaines des Tome 4: Nanotoxicologie et avancées scientifiques en matière de nanobiotechnologie, de nanotoxicologie et de méthodes de prévention des risques depuis les aspects théoriques jusqu’aux applications. Les évolutions induites par ces progrès feront également l’objet d’exposés illustrant la diversité de leurs potentialités. Une attention particulière sera apportée aux considérations éthiques et sociales liées au développement de nouvelles technologies ainsi que Enseignement des Nanosciences sous la direction de M. Lahmani et P. Houdy certaines actions concernant les aspects sociétaux et de formation proposées par NanoInnov. http://www.clubnano.asso.fr/ Le livre "Les Nanosciences ‐ Nanomatériaux et Nanochimie" a reçu le prix Roberval 2008 dans la catégorie Enseignement Supérieur http://www.vigotmaloine.com/index.php/Medecine/Explo
rations‐fonctionnelles/Biologie‐clinique/LAHMANI‐M./‐Les‐
nanosciences‐3.‐Nanobiotechnologies‐et‐
nanobiologie/9782701144702.html 3
Department of Bioelectronics Interfacing electronics with life sciences ÉCOLE NATIONALE SUPÉRIEURE DES MINES DE SAINT‐ÉTIENNE Centre Microélectronique de Provence Georges Charpak 880, route de Mimet 13541 GARDANNE ‐ France http://www.emse.fr/spip/‐Departement‐bioelectronique‐.html Bioelectronics deals with the coupling of the worlds of Key to these new technologies is a fundamental electronics and biology, and this coupling can go both understanding of the interface between electronic ways. The natural ability for “recognition” in the materials and biology. Organic electronics – an biological world, such as between two complimentary emerging technology that relies on carbon‐based DNA strands, can be combined with the awesome semiconductors and promises to deliver devices with power of microelectronics to process signals to build unique properties – seems to be ideally suited for the powerful new biosensors. At the same time, electronic interface with biology. The “soft” nature of organic devices can help “guide” biological events, for materials offers better mechanical compatibility with example cell growth, thereby creating new tools for tissue than traditional electronic materials, while their biomedical research. This cross‐fertilization between natural compatibility with mechanically flexible the two disciplines improves our understanding of life substrates suits the non‐planar form factors often processes and forms the basis for advanced disease required for biomedical implants. More importantly, detection and treatment. Tools generated in this their ability to conduct ions in addition to electrons arena, such as medical diagnostics and bioelectronic and holes opens up a new communication channel implants, will dominate the future of healthcare and with biology. Our Department combines expertise in help increase the span and quality of our lives. They organic electronics and biology. Our research aims to will also play a dominant role in modernizing elucidate the fundamentals of the electronic agriculture and in protecting animal health, our food materials/biology interface and to launch new supply, and the environment. bioelectronic technologies. George Malliaras
Head of Department of Bioelectronics 4
Sang Yoon Yang,a Fabio Cicoira,a Robert Byrne,b Fernando Benito‐Lopez,b Dermot Diamond,b Róisín M. Owens c, George G. Malliarasc ÉCOLE NATIONALE SUPÉRIEURE DES MINES DE SAINT‐ÉTIENNE Centre Microélectronique de Provence Georges Charpak 880, route de Mimet13541 GARDANNE ‐ France We report an enzymatic sensor based on an organic electrochemical transistor that uses a room temperature ionic liquid as an integral part of its structure and as an immobilization medium for the enzyme and the mediator. Although conducting polymer electrodes have been used in biosensing and actuation for decades, recent developments in the field of organic electronics have made available a variety of devices that bring unique capabilities at the interface with biology.1‐2 One example is organic electronic ion pumps, which are able to precisely control the flow of ions between two reservoirs, and have been used to pump neurotransmitters and stimulate cochlear cells in the inner ear of a guinea pig.3‐5 Another example is organic electrochemical transistors (OECTs) that are being developed for a variety of biosensing applications, including the detection of ions,6‐8 metabolites (such as glucose9 and lactate10) and antibodies.11 Originally developed by Wrighton in the 80’s,12 OECTs consist of a conducting polymer film (channel of the transistor) in contact with an electrolyte. A gate electrode is immersed in the electrolyte, while source and drain electrodes make contact to the channel and allow a measurement of its conductance.13 A polymer that is commonly used in OECTs is poly(3,4‐ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS). In a typical experiment, a positive potential is applied at the gate electrode, which causes cations from the electrolyte to enter the PEDOT:PSS film and dedope it, causing a decrease in its conductance. This manifests itself as a change in the current that flows between the source and drain electrodes.13 OECTs exhibit a typical feature associated with transistors, namely a small current at the gate electrode can cause a large change in the current that flows in the channel, and as such it has been used to amplify biological signals. The gate electrode, for example, can be used as a “working electrode”, and the current that flows in it as a result of a redox reaction can be amplified by the OECT. This amplification manifests itself by the fact that the sensor’s sensitivity increases with gate voltage,14 and leads to devices that require very simple electronics for signal readout. Zhu et al. took advantage of this fact to demonstrate a simple sensor for glucose in phosphate buffered saline (PBS).9 The sensor consisted of a PEDOT:PSS OECT with a Pt gate electrode and with the redox enzyme glucose oxidase (GOx) dissolved in the electrolyte (PBS). This work was extended to demonstrate sensors that work down to the micromolar concentration range,14 can be made entirely out of polymers by using an appropriate mediator,15 and operate with other redox enzymes, allowing the development of multianalyte sensors.10 In parallel to these developments, room temperature ionic liquids (RTILs ‐ molten salts which are entirely composed of ions and are in the liquid state at ambient conditions16) have been gaining considerable interest in electrochemistry as alternatives to aqueous electrolytes such as PBS.17 Reasons include a large electrochemical window of operation, and a high conductivity, which alleviates the need for a supporting electrolyte. For the particular case of enzymatic sensing, enzymes have been found to retain their selectivity, stability and in some cases even enhance their catalytic activity in a RTIL medium, though this last point is still a matter of debate.16, 18‐22 Consequently, RTILs have been incorporated in amperometric biosensors. (a)
(b)
GOx/Fc in [P1,4,4,4][Tos]
PEDOT:PSS
FOTS treated glass
[P1,4,4,4] cation
Tosylate ([Tos]) anion
G
S
D
(c)
G
S
Channel
Glucose
solution
Gate
electrode
D
Fig. 1: (a) Chemical structure of [P1,4,4,4][Tos]. (b) Layout of the OECT, indicating the area where the RTIL was confined. (c) Photograph of the OECT with a drop of glucose solution added. The balls at the pads are made of silver paste. In this communication, we report an enzymatic sensor based on an OECT that uses a RTIL as an integral part of its structure. The strategy we follow involves patterning the RTIL over the active area of the OECT, and using it as a reservoir for the enzyme and the mediator. When the solution containing the analyte is added to the device, it mixes with the RTIL. The analyte, the enzyme, and the mediator are allowed to interact and the OECT transduces this interaction. According to this strategy, an important requirement for the RTIL is that it wets the PEDOT:PSS film, thus allowing the enzyme and the mediator to be patterned over the active area of the device. Moreover, the RTIL should be miscible with the aqueous solution that carries the analyte (PBS). We found that the RTIL triisobutyl(methyl)‐phosphonium tosylate ([P1,4,4,4][Tos], Fig. 1a, supplied by Cytec Industries) satisfies these requirements, as the Tos anion gives it a rather 5
hydrophilic character. (a)
device and allowing it to be accommodated in the hydrophilic virtual wells. Subsequently, 50 μl of glucose solution in PBS were added to the device and allowed to mix with the RTIL solution. The resulting solution did not spread, but rather formed a neat droplet over the area defined by the hydrophilic virtual wells, as seen in Fig. 1c. It should be noted that we found it critical to create such wells on both the channel and the gate electrode in order to achieve reproducible control over the spread of the solution. Fig. 2a shows the transient response of the drain current of an OECT for different concentrations of glucose solution, upon the application of a 0.4 V pulse at the gate electrode with a duration of 3 minutes. The drain voltage was ‐0.2 V. The data shows the characteristic decrease of drain current upon gating,14 which can be understood on the basis of the reactions shown in Fig. 3. As glucose in the solution is oxidised, the enzyme (GOx) itself is reduced, and cycles back with the help of the Fc/ferricenium ion (Fc+) couple, which shuttles electrons to the gate electrode (Fig. 3a). For example, for 10‐2 M of glucose, this cascade of reactions causes a current of 8×10‐8 A to flow to the gate electrode. At the same time, cations from the solution (M+) enter the PEDOT:PSS channel and dedope it (Fig. 3b),28 thereby decreasing the drain current to a degree that depends on glucose concentration.14 Due to the amplification inherent in the OECT, the change in the drain current is much larger than the gate current itself (for 10‐2 M of glucose the drain current changes by 1.2×10‐5 A, as shown in Fig. 2a). -6
Current (A)
-15x10
-10
-7
-5
-2
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0.8
Response
0.4
2
Time (min)
4
6
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solution
0.6
0.0
-7
10
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GOx/Fc in [P1,4,4,4][Tos]
PEDOT:PSS
FOTS layer
-6
10
-5
10
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10
-3
10
Glucose concentration (M)
0
0.2
10 M
-5
10 M
-3
10 M
-2
10 M
-2
10
Fig. 2: (a) Transient response of the drain current of an OECT upon application of a gate voltage of 0.4 V and duration of 3 min. The drain voltage was ‐0.2 V. (b) Current modulation of the OECT as a function of glucose concentration. Inset shows the concept of device operation, and the arrows indicate the dissolution the RTIL carrying the enzyme and the mediator into the analyte solution.
The layout of the device is shown in Fig. 1b. Details of the fabrication process are given in supplementary information. Two parallel stripes of PEDOT:PSS, with widths of 100 µm and 1 mm, respectively, were patterned on a glass support using photolithography. Contact pads at the end of the stripes allowed facile electrical connection to the source‐measure units. The wide stripe was used as the transistor’s channel and the narrow one as the gate electrode, as it has been shown that for enzymatic sensing the area of the channel must be larger than that of the gate electrode.26 A monolayer of (tridecafluoro‐1,1,2,2‐tetrahydrooctyl) trichlorosilane (FOTS) was patterned on the surface of the device leaving uncovered only a small area of the channel and of the gate electrode. These areas of PEDOT:PSS which were left uncovered by FOTS served as hydrophilic “virtual wells”27 and were shown to be effective in confining the RTIL (and the glucose solution, when it was added) over the centre of the device. The experiments involved placing a small amount (1.43 μl) of [P1,4,4,4][Tos] that included the enzyme glucose oxidase (GOx, 500 unit/ml) and the mediator ferrocene [bis (n5‐
cyclopentandienyl) iron] (Fc, 10 mM) on the centre of the D-glucono-1,5-lactone
GOxred
Fc+
PEDOT+:PSS- + e-
GOx
Fc
PEDOT+:PSS-
(a)
(b)
D-glucose
PEDOT+:PSS- + M+ + e- → PEDOT + M+:PSS-
Fig. 3: Reactions at the gate electrode (a) and at the channel (b) of the OECT. Fig. 2b shows the response of the OECT, in terms of change in drain current (ΔI/I), to glucose concentration. The detection range is shown to be at least from 10‐7 to 10‐2 M, and covers the clinical glucose level in human saliva (0.008 ~ 0.21 mM), suggesting that this device could be used as a glucose detector for monitoring glucose both in blood (2~30 mM) and in saliva.29 It is important to note that, contrary to Fc, which dissolved in [P1,4,4,4][Tos], GOx was present in a dispersed state in [P1,4,4,4][Tos], and it dissolved only when the glucose solution was added to the OECT. It is well known that the dissolution of enzymes in a RTIL can result in a change of the secondary and higher enzyme structure and causes the loss of enzyme activity.30 Therefore, a heterogeneous state in which GOx is dispersed in the RTIL can protect it from denaturation and help maintain its activity. In the same context, dispersion rather than dissolution can be used as a way to enhance the long‐term stability of biosensors. Although we did not investigate this matter in any depth, we tested an OECT stored at ambient temperature 30 days after its fabrication. When a 10‐2 M glucose solution was added the response was the same (~0.8) as that of a freshly fabricated device. 6
In summary, we demonstrated the integration of an organic electrochemical transistor with a room temperature ionic liquid to yield an enzymatic sensor. The ionic liquid was confined on the surface of the transistor using a photolithographically patterned hydrophobic monolayer, which defined hydrophilic virtual wells. An enzyme and a mediator were immobilized in the ionic liquid and, when the aqueous solution which carried the analyte was added, they dissolved in it. The enzyme was in a dispersed state in the ionic liquid, which may prove to be a good strategy for improving long‐term storage. Using the glucose/glucose oxidase pair as a model, we demonstrated analyte detection in the 10‐7 to 10‐2 M concentration range. Notes and references a
Materials Science and Engineering, Cornell University, Ithaca, NY 14853, USA. Fax: +1‐607‐255‐2365; Tel:1‐607‐255‐1956 b
Centre for Sensor Web Technologies, National Centre for Sensor Research, Dublin City University, Dublin 9, Ireland. Tel: +353‐1‐
7005404 c
Centre Microelectronique de Provence, Ecole Nationale Superieure des Mines de Saint Etienne, 880, route de Mimet, 13541 Gardanne, France. Fax: +33‐4‐42‐61‐65‐97; Tel: +33‐4‐42‐61‐66‐44; E‐mail: [email protected] † Electronic Supplementary Information (ESI) available: [device fabrication procedure]. See DOI: 10.1039/b000000x/ [1] M. Berggren, A. Richter‐Dahlfors, Advanced Materials 2007, 19, 3201. [2] R. M. Owens, G. G. Malliaras, Mrs Bull 2010, 35, 449. [3] J. Isaksson, P. Kjall, D. Nilsson, N. D. Robinson, M. Berggren, A. Richter‐Dahlfors, Nature Materials 2007, 6, 673. [4] K. Tybrandt, K. C. Larsson, S. Kurup, D. T. Simon, P. Kjall, J. Isaksson, M. Sandberg, E. W. H. Jager, A. Richter‐Dahlfors, M. Berggren, Advanced Materials 2009, 21, 4442. [5] D. T. Simon, S. Kurup, K. C. Larsson, R. Hori, K. Tybrandt, M. Goiny, E. H. Jager, M. Berggren, B. Canlon, A. Richter‐Dahlfors, Nature Materials 2009, 8, 742. [6] J. T. Mabeck, J. A. DeFranco, D. A. Bernards, G. G. Malliaras, S. Hocde, C. J. Chase, Applied Physics Letters 2005, 87, 013503. [7] D. A. Bernards, G. G. Malliaras, G. E. S. Toombes, S. M. Gruner, Applied Physics Letters 2006, 89. [8] P. Lin, F. Yan, H. L. W. Chan, ACS Applied Materials & Interfaces 2010, 2, 1637. [9] Z. T. Zhu, J. T. Mabeck, C. C. Zhu, N. C. Cady, C. A. Batt, G. G. Malliaras, Chemical Communications 2004, 1556. [10] S. Y. Yang, J. A. DeFranco, Y. A. Sylvester, T. J. Gobert, D. J. Macaya, R. M. Owens, G. G. Malliaras, Lab on a Chip 2009, 9, 704. [11] D.‐J. Kim, N.‐E. Lee, J.‐S. Park, I.‐J. Park, J.‐G. Kim, H. J. Cho, Biosensors and Bioelectronics 2010, 25, 2477. [12] H. S. White, G. P. Kittlesen, M. S. Wrighton, Journal of the American Chemical Society 1984, 106, 5375. [13] D. A. Bernards, G. G. Malliaras, Advanced Functional Materials 2007, 17, 3538. [14] D. A. Bernards, D. J. Macaya, M. Nikolou, J. A. DeFranco, S. Takamatsu, G. G. Malliaras, Journal of Materials Chemistry 2008, 18, 116. [15] N. Y. Shim, D. A. Bernards, D. J. Macaya, J. A. DeFranco, M. Nikolou, R. M. Owens, G. G. Malliaras, Sensors‐Basel 2009, 9, 9896. [16] M. Armand, F. Endres, D. R. MacFarlane, H. Ohno, B. Scrosati, Nature Materials 2009, 8, 621. [17] M. C. Buzzeo, R. G. Evans, R. G. Compton, Chemphyschem 2004, 5, 1106. [18] K. Fujita, D. R. MacFarlane, M. Forsyth, Chemical Communications 2005, 4804. [19] K. Fujita, D. R. MacFarlane, M. Forsyth, M. Yoshizawa‐Fujita, K. Murata, N. Nakamura, H. Ohno, Biomacromolecules 2007, 8, 2080. [20] S. Park, R. J. Kazlauskas, Curr Opin Biotech 2003, 14, 432. [21] H. Zhao, O. Olubajo, Z. Y. Song, A. L. Sims, T. E. Person, R. A. Lawal, L. A. Holley, Bioorg Chem 2006, 34, 15. [22] Z. Yang, J Biotechnol 2009, 144, 12. [23] Y. Liu, L. Liu, S. J. Dong, Electroanalysis 2007, 19, 55. [24] X. Shangguan, H. F. Zhang, J. B. Zheng, Electrochemistry Communications 2008, 10, 1140. [25] X. M. Wu, B. Zhao, P. Wu, H. Zhang, C. X. Cai, Journal of Physical Chemistry B 2009, 113, 13365. [26] F. Cicoira, M. Sessolo, O. Yaghmazadeh, J. A. DeFranco, S. Y. Yang, G. G. Malliaras, Advanced Materials 2010, 22, 1012. [27] B. Zhao, J. S. Moore, D. J. Beebe, Science 2001, 291, 1023. [28] D. Nilsson, T. Kugler, P. O. Svensson, M. Berggren, Sensors and Actuators B‐Chemical 2002, 86, 193. [29] M. Yamaguchi, M. Mitsumori, Y. Kano, Ieee Eng Med Biol 1998, 17, 59. [30] R. M. Lau, M. J. Sorgedrager, G. Carrea, F. van Rantwijk, F. Secundo, R. A. Sheldon, Green Chem 2004, 6, 483. 7
Nous publions ci‐après les posters présentés lors des Journées Nanosciences et Industrie 2010. En remerciant les auteurs de nous avoir autorisés à les publier. SANTE M. Moussaoui, R. Saoudi, S. Palle Laboratoire Hubert Curien Université de Lyon Université Jean Monnet CNRS UMR5516 18 Rue du Professeur Benoît Lauras 42000 Saint‐Etienne France Contact: saoudi@univ‐st‐etienne.fr http://clubnanomicro.asso.fr/documents/posters_2010/poster_moussaoui_2.pdf Cubic‐type ZnS nanoparticles (NP) were prepared by an easy and economic chemical method at 100 ◦C without any surface‐active agent. The nanopowders were characterized X‐ray powder diffraction (XRD), UV‐vis absorption, fluorescence confocal microscopy and Scanning Electron Microscopy (SEM). The average diameter of the nanoparticles was less than 10 nm. Strong and stable red and green emissions from the samples were observed under UV excitation. We use the emission property of ZnS NP to study the intracellular imaging. The experiments demonstrate the ZnS NP internalization without alteration of cells. Hence, the ZnS NP can be used as biomarkers for medical applications. We have performed a study to examine the ZnS NP uptake in cultured tobacco cells to investigate the cellular imaging. Key words: ZnS nanoparticles, bio‐labeling applications. 8
Ning SUI, Virginie MONNIER, Yurij ZAKHARKO, Yann CHEVOLOT, Olivier MARTY, Vladimir LYSENKO, Magali PHANER‐GOUTORBE, Jean‐Marie BLUET, Eliane SOUTEYRAND* Institut Lavoisier UMR 8180 Université de Versailles Saint‐Quentin en Yvelines 45 Av des Etats‐Unis Contact: Virginie Monnier, Ecole Centrale de Lyon, CNRS‐INL. virginie.monnier@ec‐lyon.fr http://clubnanomicro.asso.fr/documents/posters_2010/poster_monnier.pdf Fluorescent labeling is an efficient approach for biological imaging of living cells and is widely used now. Organic dyes are usually adopted due to their high fluorescence quantum yield and their reproducible optical and chemical properties [1]. But most of them are toxic to tissues and organs and also highly sensitive to photobleaching. Here, we chose inorganic silicon carbide (SiC) nanoparticles to perform fluorescent labeling. These nanoparticles are synthesized by electrochemical anodization of a bulk SiC polycrystalline wafer in a HF/ethanol electrolyte. With its chemical passivity, thermal stability and weak toxicity, SiC is a well adapted material for fluorescent labeling. Recently, SiC nanoparticles were used successfully for the fluorescent imaging of living fibroblast cells [2]. However, to obtain a visible fluorescent labeling, concentrations of SiC nanoparticles higher than 1g/L have to be used. At this concentration, the accumulation of nanoparticles leads to undesirable physiological changes in cells, which is not acceptable for a marker that should not be seen by cells. In our work, we designed a hybrid nanoprobe containing gold and SiC nanoparticles for plasmon‐fluorescence coupling. The aim is to strongly enhance the fluorescence of SiC nanoparticles in order to reduce the concentration of SiC nanoparticles that must be injected in biological media. These nanoprobes include a silica shell which is biocompatible and suitable for further biological functionalization. The Au@SiO2 core‐shell beads were prepared using the direct Stöber sol‐gel synthesis [3]. Then, SiC nanoparticles are adsorbed on the with SiC colloids. They were observed using scanning surface of silica beads by simply mixing silica beads electron microscopy (SEM), transmission electron microscopy (TEM). Atomic force microscopy (AFM) and dynamic light scattering in solution showed that SiC nanoparticles formed a layer at the surface of silica beads. First photoluminescence results are presented. [1] U. Resch‐Genger, M. Grabolle, S. Cavaliere‐Jaricot, R. Nitschke, T. Nann, Nature Methods, 2008, 5, 763‐775. [2] J. Botsoa, V. Lysenko, A. Gelöen, O. Marty, J. M. Bluet, G. Guillot, Appl. Phys. Lett., 2008, 92, 173902. [3] W. Stöber, A. Fink, E. Bohn, J. Coll. Interf. Sci., 1968, 26, 62‐69. 9
MATERIAUX M. Moussaoui, R. Saoudi Université de Lyon Université Jean Monnet Contact: saoudi@univ‐st‐etienne.fr Laboratoire Hubert Curien CNRS UMR5516 18 Rue du Professeur Benoît Lauras 42000 Saint‐Etienne France http://clubnanomicro.asso.fr/documents/posters_2010/poster_moussaoui_1.pdf In this contribution, we present the formation of ZnO nanoparticles in the glassy matrix and study of their ZnO in the host medium was prepared using the optical properties. The nanocomposite incorporating melting process from a mixture of the raw materials. We have prepared various glass samples with 0% to 4% ZnO concentrations which were heat treated at different temperatures (100 to 600°C). The samples were characterized by UV–Vis absorption, photoluminescence spectroscopy and Raman measurements. The UV–Vis absorption spectra of samples show blue shift in absorption band with respect confinement effect and demonstrates clearly the to bulk ZnO behaviour. This shift is due to quantum formation and growth of ZnO nanoparticles in the glassy matrix. The as prepared nanoparticles exhibit strong and stable green emission under UV excitation at room temperature. This suggests the possibility to use our ZnO nanoparticles doped glass for potential optoelectronical applications such as solar cells, panel display, optical switches, … Keywords: ZnO nanoparticles; glass; melting process; optical characterizations. 10
J. Butet, J. Duboisset, G. Bachelier, I. Russier‐Antoine, E. Benichou, Ch. Jonin, P. F. Brevet Equipe Optique Non Linéaire et Interfaces Laboratoire de Spectrométrie Ionique et Moléculaire, UMR CNRS 5579 et Université Claude Bernard Lyon 1 Contact: [email protected]‐lyon1.fr http://clubnanomicro.asso.fr/documents/posters_2010/poster_butet.pdf Contrairement aux processus optiques linéaires, la Génération de Second Harmonique (acronyme usuel anglais SHG), processus optique non linéaire quadratique, est interdite dans les systèmes centro‐symétriques. Ce processus est donc sensible à la géométrie des nanoparticules et est complémentaire des spectroscopies d’absorption. L’étude de la Génération de Second Harmonique par les nanoparticules métalliques est généralement effectuée pour des particules en solution [1]. Cependant, la taille et la forme de ces nanoparticules diffèrent fortement de l’une à l’autre, ce qui limite l’information obtenue. Par ailleurs, ce processus SHG est non seulement sensible à la symétrie des nanoparticules mais également à leur environnement. Dans le cas de nanoparticules déposées sur un substrat, l’environnement n’est plus homogène et la symétrie globale est brisée, ce qui empêche la détermination des propriétés intrinsèques de la réponse des nanoparticules. Nous avons donc développé une technique permettant des mesures de SHG sur des particules uniques figées dans une matrice de gélatine dans le but de s’affranchir des effets d’élargissement inhomogène de la réponse provenant des distributions de tailles et de formes des nanoparticules étudiées. Cette méthode nous a permis de mesurer pour la première fois l’hyperpolarisabilité, c’est‐à‐dire la section efficace pour le processus SHG, d’une nanoparticule d’or d’un diamètre de 150 nm ainsi que la dépendance du signal SHG avec la polarisation du faisceau incident. Fig. 1 : Imagerie de second harmonique d’une distribution de nanoparticules dans une matrice de gélatine . Fig 2..Etude résolue en polarisation du signal de Second Harmonique d’une matrice de gélatine a) en absence et b) en présence d’une particule unique. La contribution de la nanoparticule seule est obtenue par soustraction c). Le résultat obtenu pour une mesure d’ensemble est montré en d). Références 1. I. Russier‐Antoine, E. Benichou, G. Bachelier, Ch. Jonin and P.F. Brevet, J. Phys. Chem. C, 111, (2007) 9044‐9048 2. J. Duboisset, I.Russier‐Antoine, G. Bachelier, E. Benichou, Ch. Jonin and P.F. Brevet, J. Phys. Chem. C, 113, (2009), 13477‐13481 11
Thomas Barois Laboratoire de Physique de la Matière Condensée et Nanostructures Contact: [email protected]‐lyon1.fr
http://www.clubnano.asso.fr/documents/posters_2010/poster_barois.pdf Dans le domaine des NEMS (Nano ElectroMechanical Systems) les nanotubes de carbone (CNT) ont été mis à profit pour réaliser des résonateurs mécaniques à haute sensibilité aux conditions de l'environnement proche [1]. Dans cette optique, il été montré qu'un CNT en émission de champ électronique était suffisamment sensible pour capter et démoduler un signal radio par couplages électromécaniques [2]. Nous présenterons les résultats expérimentaux obtenus à partir de dispositifs contenant des CNTs mono‐
feuillets suspendus entre deux électrodes métalliques lithographiées (configuration transistor à effet de champ). Pour cette géométrie, nous proposons d'utiliser un signal d'excitation modulé en fréquence (FM) autour d'une fréquence de résonance mécanique d'un CNT. L'originalité de cette technique est qu'elle nous permet de détecter sélectivement les mouvements d'ordre nanométriques d'un seul CNT. Nous disposons ainsi d'un dispositif compact, pouvant être produit en grandes quantités et avec des tensions d'excitation raisonnables dans un cadre d'application entant que nanoradio. Nous présenterons également un modèle électromécanique simple permettant de rendre compte des mesures obtenues [3]. [1] Sazonova et al., Nature [2] Jensen et al., Nanoletters [3] Gouttenoire et al., Small 12
DISPOSITIFS
Guillaume Gomard,a,b, Xianqin Menga,b, Ounsi El Daifa,b, Emmanuel Drouarda, Anne Kaminskib, Alain Faveb, Mustapha Lemitib, Enric Garcia‐Caurelc, Pere Roca i Cabarrocasc and Christian Seassala a Université de Lyon, Institut des Nanotechnologies de Lyon‐INL, UMR CNRS 5270 Ecole Centrale de Lyon, F‐69134 Ecully, France b Université de Lyon, Institut des Nanotechnologies de Lyon‐INL, UMR CNRS 5270 INSA Lyon, F‐69621, Villeurbanne, France c LPICM, CNRS UMR 7647, Ecole Polytechnique, Palaiseau, France http://www.clubnano.asso.fr/documents/posters_2010/poster_gomard.pdf In this communication, we report a cost‐effective way to increase the absorption efficiency of thin film photovoltaic cells, by periodically patterning the absorbing layer as a planar photonic crystal (PC). Concepts will be introduced by focusing on amorphous silicon (a‐Si:H) as the absorbing medium.
Previous theoretical studies conducted on single 1D‐PC membranes made of a‐Si:H predicted an absorption efficiency of nearly 44% between 300 and 750nm, against only 33% for a non‐patterned layer of the same thickness. This enhancement was then experimentally confirmed by performing absorption measurements on samples patterned by laser holography and reactive ion etching. These experiments revealed the effect of this sole patterning on the absorption spectrum, with a good agreement with optical simulations. More recently, we investigated the absorption properties of 2D‐PC membranes with a square symmetry. A relative increase of 25% for the absorption efficiency occurs when passing from a 1D to a 2D‐PC, together with a less polarization dependent behaviour. Thus, we propose to take profit of these unique features in a real photovoltaic cell, as depicted on Figure 1. Given this photonized stack, an integrated absorption of 70% is expected between 300nm and 720nm in the active a‐Si:H layer, which should be then compared to the 54% reached in the case of a similar but non‐patterned stack. Moreover, the high efficiency of the photogenerated carrier collection due to the high field in the thin P‐i‐N stack should lead to an equivalent increase of the conversion yield. Figure 1: Schematic view of a 2D photonized
solar cell with the collection path of the charge
carriers
13
OPTIQUE
M. Moussaoui, R. Saoudi Université de Lyon Laboratoire Hubert Curien Université Jean Monnet CNRS UMR5516 18 Rue du Professeur Benoît Lauras 42000 Saint‐Etienne France Contact: saoudi@univ‐st‐etienne.fr http://www.clubnano.asso.fr/documents/posters_2010/poster_moussaoui_3.pdf In this paper we report the synthesis of mesoporous silica thin films by sol‐gel process. The samples were prepared on quartz substrates by a dip‐coating technique using F127 co‐polymer as the structure directing agent. For the synthesis of ZnS nanoparticles (NP), zinc acetate and thioacetamide are used as starting material. After the reaction was completed ZnS NP optical properties have been carried out. To study the optimal reaction conditions for the synthesis of ZnS NP, samples were heat treated at different temperatures (100° to 700°C). The samples were characterized by UV–Vis absorption and photoluminescence spectroscopies. The UV–Vis absorption spectra of thin films show evident blue shift in absorption band with respect to bulk ZnS behaviour. This shift, due to the quantum confinement effect in the ZnS NP, can be monitored as a function of treatments. Key words: sol‐gel process; thin films; ZnS nanoparticles; optical characterizations. 14 BULLETIN D’ADHESION
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