issue 3 - Diamond Hard Surfaces

ISSUE NINE DECEMBER 2008
€5.00 / £3.50 ISSN 1757-2517
THE MAGAZINE FOR SMALL SCIENCE
Gear up
for Gold
Nano is changing
the sports arena
Bendy chips
Flexible, stretchable circuits
To the Extremes
Nano to withstand the harshest environments
Christoph Gerber
Microscopy pioneer’s visions for the future
Small country, Big ideas
Switzerland’s nanotech environment
Plasma
New treatments for functionalised textiles
Nanosensors
Big benefit or big brother
What’s new in nano
Keep up with the latest news
PLUS: FINE TUNING OPTICAL TECHNIQUES FOR SELECTIVE FLUORESCENCE
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F R E E O N L I N E S U B S C R I P T I O N : w w w. n a n o m a g a z i n e . c o . u k
In the next issue - Due out 1st February 2009: Energy and the Environment.
Nanotechnology for environmental benefit, clean water, land remediation,
nano-construction. Plus, Nanoparticle toxicology, ink-jet printing and molecular
manufacturing, what’s new in nano, nanomedicine, ethics… and lots more
002
◊nano
nano
Issue 9 December 2008
Editor:
Advertising:
Elaine Mulcahy
[email protected]
elaine.mulcahy@
nanomagazine.co.uk
Subscriptions
[email protected]
+44 (0)1786 447520
Design: Different Voice: www.differentvoice.co.uk
Contributors
David Tolfree, MANCEF. Aurelio Fassi, Mextex. Speedo.
Adidas. Larry Katz, University of Calgary. John Rogers,
UIUC. Christian Schönenberger, NCCR Nanoscale
Science, University of Basel. Christoph Gerber, NCCR
Nanoscale Science, University of Basel. David Evans,
John Innes Centre. Chris Walker, Diamond Hard Surfaces.
N Vigneshwaran, Central Institute for Research on Cotton
Technology. Gail McConnell, University of Strathclyde.
Richard Moore, Institute of Nanotechnology. Shirley Coyle
and Dermot Diamond, CLARITY.
©2008 ION Publishing Ltd
6 The Alpha Centre
Stirling University Innovation Park
Stirling
FK9 4NF
Scotland
Disclaimer: Article contributions to NANO magazine come from a range of sources
and while we always strive to ensure accuracy in reporting, NANO accepts no
responsibility for inaccuracies that may arise. The views of contributors do not
necessarily reflect the views of NANO magazine or IoN Publishing Ltd.
014
FEATURES
Nano helps win gold ...........................014
Clothing to equipment: Nanotech is
changing the sports arena
Bendy Chips .........................................018
Flexible, stretchable circuits fit all sorts
of shapes and sizes
013
038
COMMENT
Nanosensors.........................................038
To the Extremes ...................................030
Nano to withstand the harshest environments
Fine tuning............................................034
Laser microscopes and new avenues
for optical imaging
Big benefit or big brother
018
Commercialising Nanotechnologies ..042
Challenges, opportunities, issues
INTERVIEW
Christoph Gerber ................................026
COUNTRY PROFILE
Ottilia Saxl speaks to Professor Christoph
Small country, big ideas.....................023
Switzerland’s nanotech environment
and fulfilling his lifetime’s ambition.
Gerber about chemical sensors of the future
030
REGULARS
Editorial.................................................004
Events ....................................................006
What’s new in nano .............................008
026
034
Nanomedicine ......................................036
Nanoart..................................................041
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Nanotechnology
and textiles
Elaine Mulcahy PhD, Editor
s nanotechnology techniques and
applications become more
sophisticated, we are likely to see a
whole new variety of textiles with integrated
electronics, special self-cleaning abilities,
resistance to fire, protection from ultraviolet
light, and a range of other features. There is
currently a huge amount of research and
development being conducted across the
globe from universities to global corporations
to design and create the next generation
textiles. Venture Development Corporation
(VDC) estimates that consumption in the
smart and interactive textiles market is
today worth about US$720 million.
A
Novel nanotech textiles are already being
integrated into leading-edge applications
for a range of industries including
aerospace, automotives, construction and
sportswear. They also hold significant
promise for the healthcare industry in selfcleaning surfaces, smart surgical gloves,
implants and prosthetics and round-theclock patient monitors.
Examples of industries where nanotechenhanced textiles are already seeing some
application include the sporting industry,
skincare, space technology and clothing
and material technologies for better
protection in extreme environments.
Perhaps the most widely recognized
application today is in the shark-skin suit
worn by world-record breaking Olympic
swimming champion Michael Phelps.
The suit, which includes a plasma layer
004
Textiles are changing thanks to
nanotechnology. Better healthcare
systems, protective clothing and
integrated electronics are just some of
the applications. But could such
technologies be exploited to steal
information or cheat in sporting events?
enhanced by nanotechnology to repel water
molecules, is designed to help the swimmer
glide through the water and has become a
common feature of major swimming events
as all competitors attempt to enhance their
chances of winning.
textiles in fire, space, war and intense uv
light. In this regard, the application of
nanotechnology on textile materials could
lead to the addition of several functional
properties. Silver nanoparticles, for
example, provide antibacterial properties
while platinum and palladium decompose
harmful gases or toxic chemicals.
Running shoes, tennis racquets, golf balls,
skin creams, and a range other sporting
goods have also been enhanced by
nanotechnology. In the article on nanotech
in sport in this issue, we provide some
examples, but also ask – is a shark-skin
swimsuit a form of cheating? If all athletes
do not have access to the most high tech,
expensive clothing and equipment on the
market, does it provide those that do with an
unfair advantage? And how can or should
the use of clothing, equipment and props
be regulated?
Anti-corrosive pipes for the oil and gas
industry, which could help save billions
of dollars, spacesuits that monitor the
astronaut’s vital signs and hospital gowns
that resist hospital super-bugs are some
of the applications discussed. UV-blocking
textiles enhanced with zinc oxide nanoparticles and extremely strong, wearresistant surface coatings are two approaches
likely to have application in the military,
aerospace and other civilian products.
Staying with nano-enhanced textiles,
in the article on nanotech in extreme
environments we explore some uses of
As well as developing textiles to withstand
extreme environments, scientists have
looked to naturally existing viral
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nanoparticles that live in some of the
harshest environments on earth, for new
building blocks for nanotechnology.
Researchers at John Innes Centre describe
the use of a virus extracted from extremely
hot, acidic volcanic springs in Iceland as a
building block for materials scientists. Not
only did the viral nanoparticles stand up to
the extreme laboratory tests the scientists
put it through, it also proved to be a very
useful labeling molecule for various
biological applications. The team describe
their finding as the discovery of a new,
extremely stable and unique nano-building
block. Perhaps extreme environments on
Earth hold many more, as yet undiscovered,
of these novel nanoparticles.
Garments that sense their surroundings and
interact with the wearer is an area of
considerable interest. As technology
advances and new technologies are more
easily integrated into textiles, smart clothing
with sensing abilities could one day hit the
market. Such textile-based nanosensors
could provide a personalized healthcare
system, monitoring your vital signs as you
run up a hill or responding to changes in
the weather. In the home, a network of
intelligent devices could respond to your
every move, which may be a bit too much
for many people, but has potential use for
providing more independence for people
suffering from dementia or other
psychological problems.
Are sensors in clothes going a step too far?
In our article on Nanosensors – Big benefit
or big brother, the authors say it depends
how the information is being used. Personal
data circulated within a communications
network would need to be encrypted with
the proper security measures in place. Such
measures must be developed before these
products hit the market. Vital health
statistics and a monitor of our every move is
not the sort of information we would like to
fall into the wrong hands.
In the past number of months, a team of
researchers led by John Rogers at the
University of Illinois, Urbana-Champaign,
have published a range of articles in
Nature, Science, Proceedings of the
National Academy of Sciences, on the
development of electronic circuits that
bend and stretch.
This issue includes a feature on
development of these bendy chips, which
display some amazing properties.
Nanoribbons form the basis for the chips
which are so bendy they can wrap around
the edge of a microscope coverslip and so
Ó
NOVEL NANOTECH TEXTILES ARE ALREADY
BEING INTEGRATED INTO LEADING-EDGE
APPLICATIONS FOR A RANGE OF INDUSTRIES
INCLUDING AEROSPACE, AUTOMOTIVES,
CONSTRUCTION AND SPORTSWEAR.
stretchable they can be twisted into a
corkscrew. The researchers are focusing
applications development in the healthcare
industry and believe these tiny, flexible
electronic sheets could one day be used to
line the brain to monitor activity in patients
at risk of epilepsy or be integrated into
surgical gloves to monitor a patient’s vital
signs during surgery.
Switzerland is the profiled country in this
issue and we are delighted to include a
detailed and informative interview with one
of Switzerland’s best known scientists,
Professor Christoph Gerber. Professor
Gerber made a major contribution to the
invention of the scanning probe microscope
and the atomic force microscope. He is also
a co-inventor of biochemical sensors based
on AFM technology and speaks of his vision
for the future in the field of chemical
sensing, providing a mini tutorial along
the way.
Professor Gerber is currently based at
Switzerland’s National Competence Center
(NCCR) for Nanoscience, the country’s
leading network in nanotech research and
development. In our profile piece we
explore some of the work at the NCCR
Nanoscience and gain an insight from one
of the leaders of research, Professor
Christian Schönenberger, on the wide range
of applications, networks and collaborations
at the research centre.
This issue also includes all our usual
regular sections including news and events,
and our regular features on nanomedicine
and tools and instruments.
Nanomedicine, in this issue, focuses on
plasma technologies that may be used to
add functionalities to modern textiles and
may, in turn, provide a range of applications
in nanomedicine from anti-fouling coatings
to wear resistance. New techniques in
optical microscopy that are enabling
scientists to view cells and tissues in three
dimensions provide our tools and
instruments feature.
This is the final issue of NANO for the year.
We look forward to providing more
interesting news and features from the
nano-world in the new year.
Letters
We have plans to introduce a letters
page to the magazine.
If you would like to send a letter
to the editor, please email
[email protected]
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Events Calendar
EVERY MONTH WE HIGHLIGHT THE KEY CONFERENCES AND SUMMITS
WHERE INDUSTRY EXPERTS, ACADEMICS AND POLICY MAKERS CONVENE
December 1-5
MRS Fall meeting, USA
The 2008 MRS Fall Meeting will feature
45 technical symposia, an international
exhibition highlighting products and
services of interest to the materials
community, and much more.
www.mrs.org
December 3-5
Nanotechnology International
Forum, Russia
An opportunity to share the valuable
experiences of well-known business people
and leaders of major corporations, learn
about the latest advancements of some of
the world’s leading scientists and establish
new contacts in the world of business
and science.
www.rusnanoforum.ru
December 4-5
Aachen-Dresden International
Textile Conference, Germany
Topics discussed at this meeting include
polymer technologies for advanced
textiles, functional materials, lightweight
and innovative concepts for highly
dynamic textile machinery and innovative
protective textiles.
www.aachen-dresden-itc.de
December 9-12
SPIE Smart Materials,
Nano+Micro-Smart Systems,
Australia
SPIE Smart Materials, Nano- and MicroSmart Systems symposium is an
international, multidisciplinary event that
will cover the extensive use of micro- and
nanofabrication technologies in our world.
http://spie.org
December 12-14
Bangalore Nano 2008, India
Bangalore is recognized as the knowledge
capital of India and has emerged as the
most preferred destination for frontier
technologies like Information Technology
and Biotechnology. Bangalore IT and
006
Bangalore Bio are now recognized as
India's leading events in their fields.
www.bangalorenano.in
January 21-24
Nanobiophysics & Chemistry
Conference 2009, Antigua and Barbuda
This conference will address progress and
prospects in Nanobiophysics & Chemistry
including nano and microfluidics, single
molecule techniques, biomimetics and
sensing, biomolecules in confined
environments, in vivo imaging, forces in
biomolecular systems, manipulation of
biomaterials, spectroscopy of biomaterials,
nanoparticles in biological environments,
force microscopies, simulation of
biomolecules and biomolecular assemblies
at the atomic and coarse grained scales.
The conference will also provide an
overview of the latest developments in
bionano physics and chemistry.
www.zingconferences.com
January 25-29
Nanomedicine Conference 2009,
Antigua & Barbuda
This conference will address progress
and prospects for nanomedicine and
nanotoxicology including drug delivery,
imaging and diagnostics, cancer, tissue
engineering, interactions of nanomaterials
with living tissue and nanotoxicology.
www.zingconferences.com
February 1-4
NanoAfrica 2009, South Africa
The third NanoAfrica Conference will be
held at the CSIR International Convention
Centre. This follows on from two
conferences in 2004 and 2006 in Cape
Town. NanoAfrica 2009 is jointly organised
by the South African Nanotechnology
Initiative (SANi) and the National Centre
for Nano-Structured Materials (NCNSM)
in association with the Department of
Science and Technology.
www.nanoafrica.co.za
February 18-20
Nanotech 2009, Japan
International nanotechnology exhibition
and conference
www.nanotechexpo.jp
February 23-27
European training action on
ceramic nanocomposites, Spain
Experts of the Consortium of the Integrated
Project NANOKER will give answers to
questions related to the world of ceramic
nanomaterials such as: Which are the
technological and scientific barriers to
overcome in order to obtain added-value
products? And, What synthesis, processing
and up-scaling technologies are available
right now and in the near future?
www.nanoker-society.org
February 27
Nanotoxicology: Health and
Environmental Impacts, UK
This meeting has CPD accreditation
This symposium is aimed at bringing
together eminent scientists at the forefront of
the nanotoxicology field to present their
current research findings and discuss the
potential impact of nanomaterials on human
health and the environment. This event will
therefore present an ideal opportunity for
toxicologists, nanotechnologists, industrial
members and governmental regulatory
agencies to interact and discuss the latest
developments in this controversial field
www.regonline.co.uk
February 28-March 4
Trends in NanoScience 2009,
Germany
The 3rd International Symposium
“Trends in Nanoscience 2009” will bring
together scientists from both chemistry and
physics, addressing experimental as well as
theoretical issues. The meeting aims at
promoting understanding of the
organization, interactions and control
schemes of complex nanosystems and,
by trying to relate structure and function,
will advance knowledge leading ultimately
to new technologies.
www.uni-ulm.de
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March 2-9
Graphene week, Austria
This conference will be devoted to the rapidly progressing science
and technology of graphene (atomically thin graphitic films): advances
in its growth and manufacturing graphene-based devices, investigation
of physical properties of graphene using a broad range of
characterization methods, and emerging applications of this new
material. Topical sessions will address graphene synthesis and its
ARPES and STM studies; manufacturing of graphene p-n junctions,
nanoribbons and quantum dots and their transport studies, heat
transfer in graphene-based structures and hybrid circuits; optical
properties of graphene and its applications in optoelectronics.
www.esf.org
March 10-12
5th annual Smart Fabrics 2009, Italy
This well-established IntertechPira’s two day event and half day
workshop will analyse the latest business, design and science
developments of the smart textiles field. At the conference, leading
integrators and renowned retailers, brand owners and
manufacturers will give their honest opinion on how the industry
needs to move forward to meet market requirements. Delegates will
have the chance to learn about emerging applications on the
boundaries of what is possible in Smart Textiles. Exploring the
newest trends faced by home health care, industrial clothing, sport
clothing, cosmetics and other markets, IntertechPira’s 5th annual
Smart Fabrics 2009 is an event not to be missed!
www.smartfabricsconference.com
March 11-12
This conference at The Royal Society in London is bringing
Nanofibers for the 3rd millennium, Nano For Life,
together multiple disciplines and various technologies and
Czech Republic
developments in the textiles arena. The conference will explore
Exchange ideas with corporate executives and academic leaders
textile developments that can be used by various industries, as
that drive nanofiber innovation for tomorrow‘s products.
well as keeping the audience up to date on the latest technologies
www.nano3millenium.com
and their applications.
www.nano.org.uk
March 11-13
Nano and Photonics, Austria
This event is an informal meeting for those interested in photonic
applications of modern nanotechnology. One goal is to create an
March 22-27
International Advanced Course: Public
Communication & Applied Ethics in Nanotechnology, UK
Austrian wide discussion platform for state of the art work in basic
This course is intended for all those working in nanotechnology
reasearch done at various universities as well as industrial based
with an interest in its public communication and ethical
research and development.
implications. The intensive, highly diverse programme is delivered
www.nanoandphotonics.at
by leading experts in public policy, science communication, ethics,
risk assessment and regulatory affairs in the nanotechnology field.
March 18-19
Participants will be trained in writing, speaking, debating and
Innovations in Textiles 2009 - Smart, Nano and
carrying out practical communication exercises.
Technical Textiles for Medical, Industrial and Clothing
www.nanotechia.org
Applications, UK
The Institute of Nanotechnology has previously organised three
international conferences on textiles, providing an international
platform where a diverse community of professionals from industry,
To advertise your event here, please contact the
editor [email protected]
academia and fashion can come together to share information,
research findings and practical experiences – ranging from
nano to smart textiles.
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When a molecule of resazurin dye (on top of
the particle) binds to the gold nanoparticle it
is changed to highly fluorescent resorufin (in
front of the particle) by removal of an oxygen
atom (moving away to the right). Resorufin
glows under ultraviolet light. A graph of the
time it spends before releasing from the gold
surface reveals details about how the reaction
takes place. (Image by Aleksandr Kalininskiy)
All nanoparticles
are not created equal
A novel microscopic technique developed at Cornell has shown that all nanoparticles
are not created equal: some carry out their reactions in different ways than others.
he new method enables the
researchers to observe the behaviour
of single nano-particles of a catalyst,
right down to the resolution of single catalytic
events. The Cornell team have also directly
observed that every nanoparticle changes
the speed of its catalytic reaction over time,
and they have measured the time scale.
T
There is intense interest in nanocatalysts for
such applications as fuel cells and pollutant
removal, because nanoparticles provide a
larger surface area to speed reactions, and
in some cases, materials that are not
catalytic in bulk become so at the nanoscale.
“Understanding the fundamental principles
that govern the catalyst activity can help us
to design new catalysts,” said Peng Chen,
Cornell assistant professor of chemistry
and chemical biology. “Nanoparticles are
dynamic entities. Maybe we can think about
designing smart catalysts that can adapt to
different conditions.”
008
The research by Chen and colleagues is
described in Nature Materials.
The researchers immobilized spherical
gold nanoparticles about 6 nanometers in
diameter on a glass surface and flowed a
solution of a dye over them. The gold
catalyst changes molecules of the dye into
a new fluorescent form. Using a
microscope that focuses on a very thin
plane, the researchers made a “movie” with
one frame every 30 milliseconds.
A dye molecule briefly binds to the surface of
the gold, where an oxygen atom is removed.
The new molecule fluoresces, and a blip of
light appears in the microscope image,
remaining until the molecule releases from
the catalyst. The researchers were able to
isolate the blips from individual nanoparticles
and identify single catalytic events.
They saw two slightly different reaction
patterns: On some nanoparticles the dye
molecule binds to the surface, is changed
and then releases. On others, after the
change the molecule moves to a new
position before it releases. And on some
nanoparticles, both types of reaction occur.
The nanoparticles, Chen explained, are not
perfectly spherical, and different parts of
the gold crystal are exposed at different
places on the surface; this may account for
the different reaction patterns.
Reactions at the same sites also varied
in their timing. The time a fluorescent
molecule remains at a given site might
be short, then longer, then short again.
The explanation, the researchers said,
is that the catalytic reaction also causes
a restructuring of the surface of the gold,
and this causes the subsequent reactions
to take place faster or slower. Later, the
gold surface recovers to its original
structure, and the reaction returns to
its original timing.
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Nano
Stars
Another step towards quantum computing was taken when a team of scientists processed
information in the electron spin (blue) and stored it in the nuclear spin (yellow) of phosphorus
atoms through a combination of microwave and radio-frequency pulses. (Image: Flavio Robles,
Berkeley Lab Public Affairs)
Atomic memory for qubits
n international team of scientists have shown, for the first time, how a single
atomic nucleus could be used as a quantum computational memory –
bringing quantum computing a step closer.
A
The researchers from Oxford and Princeton Universities and Berkeley Lab may have
solved one of the major obstacles to quantum computing – memory. The findings
were published in Nature.
Researchers at the National Institute
of Standards and Technology (NIST)
in the US have found that gold
nanostars exhibit optical qualities
that make them superior for chemical
and biological sensing and imaging.
The star-shaped nanoparticles could
one day be used in a range of
applications from disease diagnostics
to contraband identification.
The scientists used a technique called
surface-enhanced Raman spectroscopy
(SERS) to view the nanoparticles. SERS
relies on metallic nanoparticles, typically
gold and silver, to amplify signals from
molecules present in trace quantities. The
researchers found the signal from various
molecules was much stronger when
enhanced by nanostars, compared to
nanospheres, which are commonly used for
Raman enhancement.
The NIST scientists have perfected the
process for making the gold nanostars from
the bottom-up using surface alterations to
manipulate their growth and control their
shape. They were also able to guide the
nanostars to gather together in a solution
creating “hot spots” where molecular
enhancement is even greater.
In classic computing, information is processed and stored based on the charge of an
electron, and represented in a binary digit or ‘bit’, which carries a value of 0 or 1.
Quantum computing utilizes an intrinsic quantum property called "spin," in which
certain particles can act as if they were tiny bar magnets. Spin is assigned a
directional state of either "up" or "down," which can be used to encode data in 0s and
1s. However, unlike charge in classical computing, which is either present or not, spin
can be up, down or both, thanks to a quantum effect called "superposition."
www.nist.gov
Superpositioning exponentially expands the storage capabilities of a quantum data bit
or "qubit." Whereas a byte of classical data, made up of three bits, can represent only
one of the eight possible combinations of 0s and 1s, a quantum equivalent (sometimes
called a qubyte) can represent all eight combinations at once. Furthermore, thanks to
another quantum property called "entanglement," operations on all eight combinations
can be performed simultaneously.
NIST scientists found that gold and silver
nanostars improved the sensitivity of Surface
Enhanced Raman Spectroscopy 10 to 100,000
times that of other commonly used nanoparticles.
These uniquely shaped nanoparticles may one
day be used in a range of applications from
disease diagnostics to contraband identification.
Colour added for clarity (Image: NIST)
Of the many challenges facing quantum computing, one of the biggest has been
finding a way to preserve the integrity of data while it is stored. Although the spin of
electrons has proven well-suited for data processing, it is too fragile to be used as
memory – the data quickly becomes corrupted by the influence of other electrons. To
overcome this obstacle, the co-authors of this experiment turned to the more protected
environs of the atomic nucleus and successfully transferred a state created in electron
spin to nuclear spin.
Lead author John Morton (Oxford University) said: “The electron acts as a middle-man
between the nucleus and the outside world. It gives us a way to have our cake and eat
it – fast processing speeds from the electron and long memory times from the nucleus.”
If the quantum computing dream is one day realised, these machines will be able
to perform calculations billions of times faster than the most powerful supercomputers today.
www.lbl.gov
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A schematic representation to show the
nanomechanical detection of antibiotic-peptide
interactions on multiple cantilever arrays. The
blue and white structures show chemical binding
interaction between vancomycin and the
bacterial mucopeptide analogue, DAla. The red
line represents the mechanical connectivity of
the chemically reacted regions on the cantilever.
(Image: UCL)
Hospital superbugs
under nano-detection
The growth in antibiotic-resistant hospital superbugs, such as MRSA, is a
major global health problem, contributing to the deaths of hundreds of people
every year. Researchers at the London Centre for Nanotechnology at UCL
have used a novel nanotechnology approach to look more closely at how
antibiotics work to pave the way for new, more effective drug treatments.
The researchers used cantilever arrays – tiny levers no wider than a human hair – to
examine the process that normally takes place in the body when the antibiotic
vancomycin binds itself to the surface of the bacteria. They covered the cantilever in
mucopeptides from the bacteria and found that when the antibiotic attached itself it
stressed the bacteria to a point which would likely lead to its breakdown.
When they looked at non-resistant and resistant strains of bacteria, they found it was
about 1000 times harder for the antibiotic to attach itself to the drug-resistant bugs,
rendering it therapeutically ineffective.
The team believe that by further investigating the binding and mechanical influences of
antibiotics on the bacterial cells, more powerful and effective antibiotics may be
developed. The work also demonstrates the effectiveness of silicon-based cantilevers
for drug screening applications.
www.ucl.ac.uk
Fountain pen
writes nano-arrays
Researchers at Northwestern
University have created a nanoscale
fountain pen, the nanofountain probe
(NFP) to write nanoscale protein
arrays, which may have application
across a range of areas including
genomics, proteomics, drug
screening and disease detection.
Horacio Espinosa, head of the research
team and professor of mechanical
engineering in the McCormick
School of Engineering and Applied
Science at Northwestern.
The research was published in the
Proceedings of the National Academy of
Science (PNAS).
Each nanofountain probe chip has a set of
ink reservoirs that hold the solution to be
patterned. Like a fountain pen, the ink is
transported to sharp writing probes
through a series of microchannels and
deposited on the substrate in liquid form.
"The NFP works much like a fountain pen,
only on a much smaller scale, and in this
case, the ink is the protein solution," said
The researchers say that by maintaining
the sensitive proteins in a liquid buffer, it
helps to protect their biological function
and also means they can write for
extended periods over large areas
without replenishing the ink.
The use of an electrical field added
another degree of control over the
deposition of the protein on the substrate
and the scientists claim they were able to
create dot and line arrays with a
combination of speed and resolution not
possible using other techniques.
www.northwestern.edu
010
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Nanowires as
disease detectors
Yale scientists have created
nanowire sensors coupled with
simple microprocessor electronics
that are both sensitive and specific
enough to be used for point-of-care
disease detection, according to a
report in Nano Letters.
Gecko feet take
another step
The ability of gecko lizards to scurry up walls and cling to the ceiling by their
toes have been of interest to scientists for years and many have attempted to
mimic or re-create the microscopic branched elastic hairs that enable geckos
to stand upside-down. The tiny hairs take advantage of atomic-scale attractive
forces to grip surfaces, which enable them to support heavy loads. Many
research groups have attempted to mimic these hairs using structures made
from carbon nanotubes.
A team of researchers from the University
of Dayton, the Georgia Institute of
Technology, the Air Force Research
Laboratory and the University of Akron,
have now created a carbon nanotube-based
material with a gripping ability nearly three
times the previous record – and ten times
better than a real gecko at resisting
perpendicular shear forces.
The researchers say the material could
have many technological applications,
including connecting electronic devices
and substituting for conventional adhesives
in the dry vacuum of space. The nanotube
material is able to tightly grip vertical surfaces
but can be easily lifted off when desired.
The key to the new material is the use of
rationally-designed multi-walled carbon
nanotubes formed into arrays with "curly
entangled tops," said Zhong Lin Wang, a
Regents' Professor in the Georgia Tech
School of Materials Science and
Engineering. The tops, which Wang
compared to spaghetti or a jungle of vines,
mimic the hierarchical structure of real
gecko feet, which include branching hairs
of different diameters.
The research was published in Science.
www.gatech.edu
Immune cells are activated by the
presence of highly specific antigens on
the surface of cells that signal the
presence of bacteria, viruses or cancers.
In these experiments, T-cell (a type of
immune cell) activation generated a tiny
current in the nanowire electronics,
signaling the presence of a specific
antigen. The Nanowires could identify
activation from a single specific antigen,
even when there was substantial
background “noise” from a general
immune stimulation of other cells.
Tarek Fahmy, Yale assistant professor of
biomedical engineering explained:
“Imagine I am the detector in a room
where thousands of unrelated people are
talking and I whisper “Who knows me?”
I am so sensitive that I can hear even a
few people saying, “I do” above the
crowd noise. In the past we could detect
everyone talking, now we can hear the
few above the many.”
The researchers believe this level of
sensitivity and specificity is
unprecedented in a system that uses
no dyes or radioactivity. It is also
extremely fast, producing results in
seconds, and is compatible with
existing CMOS electronics.
The scientists envisage an iPod-like
device with changeable cards to detect
or diagnose disease in POC diagnostic
centres in both developed and
developing countries.
www.yale.edu
The long and short of
it: buckypaper for
electrical performance
Single-walled carbon nanotubes can act as tiny electrical
conductors, changing a normally insulating polymer into
an electrical conductor, with applications ranging from
transparent electrical shielding materials to futuristic
flexible video displays.
Researchers at the National Institute of Standards and Technology
(NIST) in the US have now made some of the most precise
measurements yet to identify the point at which random two- or
three-dimensional networks of nanotubes become transparent,
conducting sheets.
The team made nanotube mats or “buckypaper” from highly
refined, length-sorted nanotube samples and found that the
threshold at which the buckypaper became conductive became
lower as the tubes got longer. The research illustrates the
importance of using longer, uniform-length nanotubes for making
high performance conducting films.
www.nist.gov
011
S
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Nanowires
come
together
A team of chemists at The Johns
Hopkins University has created
water-soluble electronic materials
that spontaneously assemble
themselves into "wires" 10,000
times smaller than a human hair.
An article about their work was
published in the Journal of the
American Chemical Society.
At upper right, a cadmium sulfide nanosphere before
stress is applied. The hollow sphere is partly
transparent to the electron beam. At lower right, the
sphere after being stressed to the point of failure.
(Image: National Center for Electron Microscopy,
Lawrence Berkeley National Laboratory)
Nanospheres pass
strength test
Nanocrystalline materials hold great
potential for creating strength in
materials. However, they are currently
limited restricted by a limited ability to
withstand large internal strains before
they fail.However, they are currently
limited by a limited ability to withstand
large internal strains before they fail.
Berkeley Lab scientists have now
engineered hollow spherical nanospheres capable of withstanding
extreme stresses and deformities without
losing strength. The results were published
in Nature Materials.
Andrew Minor of the National Center
for Electron Microscopy (NCEM) in
Berkeley Lab’s Materials Sciences Division
said: "Essentially we’re investigating
structural hierarchy, which is known to play
an important role in determining the
strength of many bulk materials – bone, for
example – only here we’re applying it on
the nanoscale. In this case the hierarchy is
the size of the crystal domains, from three
or four nanometers up to 10 nanometers;
the thickness of the shells, from 35 to 70
nanometers; and the diameter of the
spheres, from about 200 to 450 nanometers.
We experimented on dozens of
012
nanospheres with variations in each
of these dimensions."
What they observed as a diamond anvil
slowly bore down on the hollow
nanospheres (made from cadmium
sulfide) was that the spheres gradually
bulged at the sides as they were squashed.
Cadmium sulfide is inherently brittle and
might have been expected to break easily,
but instead the spheres deformed by as
much as 20 percent of their original
diameter before they shattered.
Previous attempts to increase the
deformability of nanomaterials, in order to
reduce their tendency to fail under limited
strains, have also unfortunately reduced
their strength. The new experiments with
hollow nanospheres show that, by
combining strength and deformability, the
hollow spherical geometry confers both
high strength and relatively high strains at
failure. The ability to endure high stress and
strain is a direct result of structural
hierarchy: the small grain size gives high
strength, while the overall shape of the
sphere distributes stress and allows the
structure to withstand high strains.
www.lbl.gov
"What’s exciting about our materials is
that they are of size and scale that cells
can intimately associate with, meaning
that they may have built-in potential for
biomedical applications," said John D.
Tovar , an assistant professor in the
Department of Chemistry in the Zanvyl
Krieger School of Arts and Sciences.
"Can we use these materials to guide
electrical current at the nanoscale?
Can we use them to regulate cell-tocell communication as a prelude to reengineering neural networks or
damaged spinal cords? These are the
kinds of questions we are looking
forward to being able to address and
answer in the coming years."
The team used the self assembly
principles that underlie the formation
of beta-amyloid plaques, which are the
protein deposits often associated with
Alzheimer’s disease, as a model for
their new material. This raises
another possibility: that these new
electronic materials may eventually
prove useful for imaging the
formation of these plaques.
"Of course, much research has been
done and is still being done to
understand how amyloids form and to
prevent or reverse their formation,"
Tovar said. "But the process also
represents a powerful new pathway to
fabricate nanoscale materials."
www.jhu.edu
Atomic Force Microscope image of the
nanostructures (left) and a zoomed in
region to show finer structure (right).
(Image: Stephen Diegelmann)
S
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‘Small Wonder:
Nanotechnology
and Cosmetics’.
IN A REPORT PUBLISHED IN NOVEMBER, WHICH? IDENTIFIES THE
MOST COMMON NANOPARTICLES IN COSMETICS, AND CALLS
FOR TESTING OF THESE PARTICLES TO ENSURE THEIR SAFETY.
hich? asked cosmetics
producers to identify the kinds of
nanoparticles in their products
and to provide details of any safety testing.
Which? discovered that several cosmetic
products do in fact contain soluble or
insoluble nanoparticles which impart
specific properties. The insoluble
nanoparticles may pose a health risk, but
are in the main limited to a very few kinds.
Most companies claim to have extensively
tested their products, but the tests may not
be sufficient to identify all risks.
W
In order to reinforce confidence in the safety
of cosmetic products, Which? has called for
a series of actions. They asked that
companies report their use of manufactured
nano materials; that potentially unsafe and
illegal products to be removed immediately
from sale; that an independent expert group
to be established to advise the Government
on the risks and benefits of nano sunscreens.
They also suggested that the new EU
Cosmetics Regulation should include a
positive list of manufactured nano materials
permitted in cosmetic products, and that
clear information on the use of nano
materials in cosmetics, as well as nanotechnology in general, should be provided.
The Institute of Nanotechnology, a UK
based charity which promotes a better
understanding of nanotechnology and its
applications, broadly agrees with these
recommendations. On its website,
it commented:
“The safety or otherwise of most of the
nanoparticles identified in the Which?
report is already known or could be
established relatively quickly. If a
nanoparticle type presently used in a
cosmetic is deemed likely to pose a threat
to human safety, then the product containing
that particular kind of nanoparticle should
be withdrawn. In the future, safety testing
for each insoluble nanoparticle that the
cosmetics industry wishes to introduce
into its products should be mandatory”.
“The cosmetics industry is far from trivial although it is an industry that is often
overlooked when Governments highlight
organizations which contribute most to the
economic well-being of a country! It has
been said that more money is spent globally
on cosmetics than defence - how much
nicer to be a producer of moisturizing
creams and lipsticks than cluster bombs
and mines!
“From the list of nanoscale ingredients in
the cosmetic products gleaned by Which?,
it is apparent that nanoparticles of titanium
dioxide and zinc oxide are key components
in many cosmetic preparations. Hydroxyapatite
is also mentioned, as is nanosilver. There
are others, some of which have been borrowed
from the pharmaceutical sector, such as
soluble nanoemulsions and lipo-somes,
which have mostly already been subjected
to the rigorous safety testing required of that
industry, and are of less concern.
“Anxieties as to the safety of cosmetics
containing nanoparticles therefore hinge
on the possible health risks of a relatively
few nanoparticle types. Importantly, new
research by nanotoxicologists is every day
adding to our sum of knowledge about
these nanoparticles, as to which are safe
and which may pose a hazard to health,
enabling informed decisions to be made
about products containing them.
“In conclusion, the Institute of
Nanotechnology unequivocally concurs
with the actions recommended by
Which?, and in order to maintain
confidence in this important industry
sector, agrees that Government should
implement these actions now”.
Note: The Institute of Nanotechnology
strongly supports the use of validated,
in-vitro toxicological procedures, and
expects that the safety of nanoparticles
used in cosmetics can be assessed
using these procedures, without
recourse to live animal experiments.
*Which? report Small Wonder: Nanotechnology in
Cosmetics (November 2008)
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◊nano
Nano helps
Win Gold
AMERICAN SWIMMER MICHAEL PHELPS STUNNED THE
WORLD AS HE RACKED UP EIGHT GOLD MEDALS AND
BROKE SEVEN WORLD RECORDS IN JUST EIGHT DAYS AT
THE BEIJING OLYMPICS. AND HE WASN’T THE ONLY ONE
BREAKING RECORDS. ALMOST ALL OF THE 25 SWIMMING
RECORD BREAKERS HAD ONE THING IN COMMON – SKINTIGHT SWIMWEAR THAT HELPED THEM GLIDE THROUGH
THE WATER. ELAINE MULCAHY EXPLORES NANOTECH
ADVANCES THAT ARE HELPING ATHLETES WIN GOLD.
peedo launched its LZR Racer suit weeks before the Olympics and had already broken
records before Phelps hit the pool in Beijing. It is the latest in almost a decade of design
research which has seen the FASTSKIN FSII in 2004 and the FS PRO in 2007.
Development of the new suit involved collaboration between Speedo’s Aqualab, NASA and a
number of international research institutes – the mission: to create a swimsuit that will glide
through the water like sharkskin.
S
The LZR Racer (pronounced Laser Racer) is made from an ultra lightweight, low drag, water
repellent, fast drying fabric called LZR PULSE that incorporates a nano-molecular plasma layer
to repel water and enable the suit to move through the water with minimal friction.
Developed by Italian-based Mectex SpA, the PlasmaMec technology works by repelling water
molecules over a wider surface area so that less water is absorbed by the material. The
treatments are reported to reduce water absorption in the material to only two per cent of fabric
weight, compared to 50 per cent absorption in the previous Fastskin fabrics.
Mectex claim their plasma nanotechnology is also eco-friendly as it doesn’t use any chemicals
or demand high energy in production, and has application across a wide range of textiles – not
just for creating super-fast swim suits.
“This technology could be used in a range of clothing lines. For example, we are already
looking at its use in sweat-free gym wear that repels sweat from the surface of the clothing so
that it doesn’t get wet, no matter how much you sweat,” says Aurelio Fassi, a researcher at
Mectex.
“Fabrics with PlasmaMec treatment may also be used for ski wear, outdoor wear, work wear,
race wear, bike and motorbike wear and medical wear and many other hard sports in which
athletes perspire a lot. Because the fabrics have been treated with PlasmaMec, water
molecules stay on the surface and are not absorbed into the yarns like cotton, wool or linen. ‘
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This means perspiration evaporates very
quickly and the athletes remain dry.”
Nanoplated
The swimmers were not the only athletes in
Beijing trying out ultra-high tech gear to
ensure their best chance of medal success.
Javelins made of aluminium wrapped in
carbon, high-tech bikes and extra-light track
shoes are just some examples of the range
of top-level sporting arenas where nanotech
can be found.
Silver 400m medallist, Jeremy Wariner was
sporting Adidas new track spike at the
Games. The Lone Star spike, which is
named after Wariner’s home state of
Texas, is believed to be one of the most
technologically advanced and lightest
running shoes to ever hit the track.
The shoe has 400mm spikes specifically
positioned to suit Wariner’s gait and
featured the first ever full-length carbon
nanotubes reinforced plate.
Leveraging new innovations from the
plastics industry, Adidas applied materials
only previously used in the automotive and
aerospace industries to design a carbon
nanotubes reinforced full-length plate,
which they dub the “nanoplate”. This
thinner and stronger one piece, full-length
plate reportedly provides Wariner more
stability, comfort, better torsion, safety and
increased flexibility while minimizing the
energy loss.
Mechanical and chemical bonds with the
nanotubes increased the structural integrity
and durability of the plate, allowing Adidas
to build one continual flexible piece as
opposed to the previous three-piece design,
which included metal screw-in spikes and
016
multiple fold points adhered together by
cement. The new full-length plate also
measures about one third the thickness of
Jeremy’s previous spike and weighs 50
percent less, making it the lightest spike
ever created by Adidas.
tennis racquets use a new structure called
Karophite Black, which was created by
bonding carbon black, graphite and SiO2
together at the nano level. The result is a
denser and much stronger racquet – and an
even faster serve.
Adidas claim that with less material
between his foot and the track, the new
plate allows Jeremy’s feet to be closer to the
ground, therefore promoting more natural
movement of the foot. The material’s
defining physical properties result in
increased flexibility, torsion and less energy
loss as Jeremy’s foot comes off the track.
Cycling too has been changed by
nanotechnology as bicycles get lighter and
faster. Canadian-based Easton Sports and
Swiss-based BMC collaborated to create
the first bicycle frame made entirely using
carbon nanotubes, which debuted in the
Tour de France in 2005. The frame was
extremely light, weighing less than 1kg, but
also very strong, providing the perfect
combination of strength and weight to help
the riders climb the French mountains.
“We spent more than two years working
with Jeremy Wariner, the best curve runner
in the world to design the Adidas Lone Star,”
said Mic Lussier, Adidas Innovation Team
Leader at Adidas America.
“We know mid-distance races are won and
lost in the curves so we looked at what he
already does best and from there created
the finest curve running shoes in the world.
The adidas Lone Star allows Jeremy to push
even better in the turn and provides him
with even more physical confidence,
stability and efficiency.”
K Factor
Sports equipment too is starting to become
more sophisticated as nano-engineering
moves into main stream applications. Tennis
racquets, golf clubs, bowling balls, javelins
and bicycles have all been impacted in
some way by nano- technology advances.
In tennis, for example, Wilson’s “[K] Factor”
technology has been used by many of the
world’s top tennis players, including Roger
Federer and the William’s sisters. The
Japanese-based ABS, a bowling products
manufacturer, was the first to launch a nanocoated bowling ball, reported to be scratch
resistant. The Nanodesu range of bowling
balls are coated in nano carbon C60 or
other nanomaterials to give them strength
and durability. The company launched the
original Nanodesu ball in 2004, selling 2000
in the first month.
Golf has also been getting the nano
treatment. American-based Grafalloy has
introduced a golf club shaft featuring
“Nanofuse” technology, which made its
debut at the 2007 PGA Tour. More recently,
Trevor Immelman won the 2008 Masters
using the club. Grafalloy collaborated with
Powermetal Technologies to create the socalled Epic shafts by harnessing the
strength properties of nano-crystalline
metals and fusing them at the molecular
level with a composite polymer substrate.
Vice President of Engineering / R&D for
Grafalloy, Graeme Horwood says, “While
◊nano
Ó
THIS TECHNOLOGY
COULD BE USED IN
A RANGE OF CLOTHING
LINES. FOR EXAMPLE,
WE ARE ALREADY
LOOKING AT ITS USE IN
SWEAT-FREE GYM WEAR
THAT REPELS SWEAT
FROM THE SURFACE OF
THE CLOTHING SO THAT
IT DOESN’T GET WET.
some shaft manufacturers have
incorporated carbon nanotubes into
composite shaft design, that use is only
scratching the surface of the true potential
of nanotechnology.
“Epic represents the first sporting goods
product that’s been truly enabled by recent
advances in utilizing complete
nanotechnology. With Nanofuse, we are
introducing an entirely new material into
golf shaft design that offers the advantages
of both steel and graphite without any of the
inherent limitations associated with each.”
Golf balls have also been nano-treated.
NanoDynamics have created a ball
constructed around a hollow metal core that
results in the ball weight being distributed
to the outside, instead of concentrated in the
centre as in conventional balls.
Body map
Clothing and equipment are not the only
areas where nanotechnology is impacting
sport. Various products on the market from
sunscreens to motion sensors are helping
athletes to improve their game.
Bionova is a skincare manufacturer that
uses a nanotech approach in its products to
enhance self-healing processes. Multiple
targeted products have been developed for
different body parts, including products
specifically customized (weather, court
type, etc.) for tennis players for the Grand
Slams tournaments. The French Open face
cream, for example, uses nanocomplexes to
protect the skin from abrasions from the
court surface, while nanocomplexes of
natural UV Chromophores help to protect
the skin from sun damage.
In Australia, researchers at the CSIRO
have developed wearable body mapping
garments for the Australian Institute of
Sport to assess athletes’ performance.
The technology, which started as a virtual
air guitar, consists of wearable sensors
embedded in clothing with custom
software to map gestures and movements
by the wearer.
The scientists are using the technology to
map the motions of athletes, which are then
used to trigger rhythmic audio responses
that provide feedback to the athlete and
helps them to learn automatic movement
responses. The technology is being tested
by the Australian Netball team.
Nanotechnology has also helped team
psychology and crowd support. Fibre
imprinting nanotechnology developed at the
University of Cantebury in New Zealand has
been used to print the names of 100,000
rugby fans onto a single thread of the Silver
Fern of the All Blacks jersey. The names of
all 1073 past and present All Blacks players
have also been stitched onto the fern.
Current team captain, Richie McCaw said
having the names of fans stitched onto the
jerseys provides the players with a further
reminded of the public support for the team.
The range of areas where nanotechnology will
impact on sport is enormous. From clothing to
equipment to enhancing performance and
team promotion, nanotech is likely to impact
sporting achievement at all levels.
Nano-screen
However, as clothing, equipment and
products get smarter, lighter and better, the
question must be asked – where do we
draw the line? Is wearing a high-tech swim
suit a form of cheating? It certainly gives an
advantage to athletes that have the access
and funds to equip themselves with the
latest high-tech gear on offer.
Professor and Director of the Sport
Technology Research Laboratory at the
University of Calgary in Canada, Larry Katz,
says the use of nanotechnology in
specialized tools, clothing, and nutritional
supplements puts poorer nations and
individual athletes at a great disadvantage
since they may not have access to the latest
and greatest.
“For example, the Canadian Swimming
Association at its major national competition
just prior to the Beijing Olympics ruled that
no swimmer could compete at the National
Championships using the new Speedo
swim suits since not all athletes had access
to the suits and they wanted a level playing
field. However, once the winners were
chosen, all Olympic competitors were given
Speedo suits,” he says.
“On a national level, Canada wanted its best
participants and then they ensured that
athletes had the best resources to succeed
at the International level.
“Since many of these innovations
are proprietary, other countries cannot get
access to them even if subsidies could be
provided. Who guarantees the "level playing
field" at the International level?
“Perhaps we need a “Nanotechnology”
screening system similar to the “Drug
Testing" programs currently in place. The
onus is on the International Associations to
provide a level playing field, since the
National Associations are biased towards a
“win at all costs” mentality.” µ
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Bendy chips
Flexible, stretchable circuits will see
electronics fit all sorts of shapes and sizes
018
◊nano
MORE THAN HALF A CENTURY HAS PASSED SINCE THE
FIRST MICROCHIPS WERE CREATED. IN THAT TIME WE
HAVE SEEN A REVOLUTION IN ELECTRONICS DEVICES –
AS MORE AND MORE COMPONENTS WERE SQUEEZED
ONTO TINY CHIPS, TELEPHONES, COMPUTERS AND
GADGETS GOT SMALLER AND SMALLER.
ut, despite their ever-shrinking size,
microchips retain one small problem –
if you bend them they break. This
single factor limits their use in a range of
potentially limitless applications from
second skins to biomedical implants.
B
Elaine Mulcahy spoke to John Rogers about
a new type of chip that can bend around
corners and stretch like an elastic band,
which could change the way we think about
and use electronics.
“Lightweight, foldable and stretchable
electronics with performance that matches
traditional, rigid semiconductor wafers
would enable many new applications,”
Rogers says.
Bendable chips
To make the ultrathin, foldable circuits,
Rogers and his colleagues printed n- and pdoped silicon nanoribbons onto a thin sheet
of plastic, which was in turn glued to a
fixed, inflexible substrate. The nanoribbons
were organised and the chips fabricated to
yield fully integrated Si-CMOS circuits,
equivalent to the type of circuit used to
manufacture about 99 per cent of all
electronic devices. Once the circuits had
been created, the underlying substrate layer
was dissolved leaving only the circuit
stamped onto the thin, flexible plastic sheet.
from external forces caused by bending
and work just as well as those on a solid,
inflexible wafer.”
“Some examples include wearable, or even
implantable, health monitoring systems,
smart surgical gloves with integrated
electronics and futuristic electronic eye
cameras with human-scale field of vision.
The possibilities are enormous.”
Professor Rogers holds the Flory-Founder
Chair in Engineering, as a Professor in the
Department of Materials Science and
Engineering at the University of Illinois at
Urbana-Champaign where they have been
developing a new generation of such
flexible, stretchable electronics.
Circuits printed onto plastic or foil with
varying degrees of flexibility have been
developed before. However, evidence
suggests their flexibility has come at the
cost of performance and they lag behind
conventional chips in their functionality.
Also, they do not offer the type of stretchability
that would be required for integration on a
complex curvilinear surface, such as an
organ in the human body.
Using new techniques for printing nand p-doped silicon nanoribbons onto
ultrathin sheets of plastic, Rogers and his
colleagues have built a new type of
integrated circuit technology with similar
performance characteristics and
components to conventional chips but
with the added benefit of being reversibly
foldable and stretchable.
Stretch and flex
Such foldable, bendable chips marked a
significant step forward in the design up
flexible circuitry. However, while good at
bending like a sheet of paper, they were not
stretchable, like a rubber band.
The technique was first described in
Science in April this year.
“The ultrathin circuits exhibit extreme levels
of bendability, without compromising the
electronic properties,” Rogers says.
“There are two reasons for this. Firstly,
there’s the basic mechanics. The entire
thickness is just 1.5 microns. That includes
the plastic substrate, metallization, silicon,
dielectrics – everything. A circuit that thin is
naturally bendable, just by the mechanics.
“A second and more subtle feature of
our chips, is our ability to place the most
fragile parts of the circuit into the “neutral
mechanical plane”. That is the part of the
chip that experiences zero strain during
bending or twisting.
“By placing the fragile components into
these low-strain pockets, they are protected
In order to overcome this limitation, Rogers
and his colleagues came up with a simple
solution. Immediately after releasing the thin
circuit sheet from the inflexible substrate,
they bonded it to a prestretched piece of
rubber. Allowing the rubber to snap back to
its original state cause the formation of
small waves, or mechanical buckling, in the
circuit sheet.
“Circuits in this geometry offer fully
reversible, stretchability without substantial
strains in the circuit materials themselves.
The physics is similar to the workings of an
accordion bellows,” Rogers explains.
This type of circuit technology developed
by Rogers and his team offer new
possibilities for integrating electronics with
biological systems, medical prostheses and
monitoring devices, lightweight packaging
and a range of various other applications.‘
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THE STRATEGIES WE HAVE DEVELOPED ARE IMPORTANT NOT ONLY
FOR THE SI-CMOS CIRCUITS THAT THEY ENABLE BUT ALSO FOR THEIR
STRAIGHTFORWARD SCALABILITY TO MUCH MORE HIGHLY INTEGRATED
SYSTEMS WITH OTHER DIVERSE CLASSES OF ELECTRONIC MATERIALS WHOSE
INTRINSIC BRITTLE, FRAGILE MECHANICAL PROPERTIES WOULD OTHERWISE
PRECLUDE THEIR USE IN SUCH APPLICATIONS.
Eye camera
Already, the team has explored and
developed the use of their stretchable
circuits in the design of an electronic eye
camera with a wide field of view, published
in Nature in August.
“The human eye is an extremely efficient
system, capable of taking a panoramic
image of the field of view. We cannot only
see what is straight in front of us, we can
also see what is left and right of our direct
field of vision. They accomplish this
performance even with very simple, single
component imaging lenses, by using
hemispherical detector arrays (i.e. the
retina).” Rogers says.
“In contrast, cameras on the market today
use planar detector arrays and
comparatively more complex optics that
add cost, weight and size to the system.
Even in these cases, for wider fields of view,
distortions, poor focusing and aberrations
can occur in the image at the edges.
“Tackling this problem by attempting to
create a camera that more closely mimics
the working of a natural eye presented a
good test for a practical application of our
approaches to stretchable electronics.”
Eyes are hollow spheres. Along the inside
wall of the back of the eyeball lies a layer of
detector cells, the retina, which process
information from the light that passes
through the lens near the front of the eye.
This hemispherical detector helps the eye
to achieve its wide field of view and is
extremely difficult to match using conventional,
planar optoelectronics technologies.
“Technologies developed until now have
only been useful on surfaces of rigid,
020
components adopted a slight bend, taking
the strain off the electronics in the system.
The circuit was then transferred to a hollow
hemispherical glass lens substrate and the
electronics were connected to an external
recording device. A hemispherical glass
cap containing an imaging lens was fixed to
the top of the system to complete the eye.
semiconductor wafers or glass plates and,
in more recent work, flat plastic sheets and
slabs of rubber. None are suitable for the
eye-camera application contemplated here
because of the mechanical strains needed
to accomplish the hemispherical geometry
are too large. They just would not be able to
bend into shape without fracturing the
circuit materials,” Rogers says. “Fully
stretchable electronics, on the other hand.”
Using techniques similar to those described
above for bendable circuits, Rogers and his
colleagues have created an eye camera
with a hemispherical detector system that
mimics the human retina.
To create the eye, a thin, hemispherical
elastomeric element was stretched into a
flat ‘drumhead’ shape. Separately, a silicon
wafer consisting of photo-detectors and
diodes with metal interconnects was
created. The circuit was then laid onto the
pre-stretched elastomer before it was
allowed to relax back into its initial,
hemispherical shape, forcing the
circuitry to also take on the hemispherical
configuration. As it did this, the tiny
interconnects between the electronic
Images taken with the camera proved it did
work and that the optical effects were consistent
with expectation, as verified by modeling.
As more pixels (electronic components) are
added, the resolution could potentially
match conventional cameras and offer
enhanced features for biomedical and
photographic imaging techniques.
“The ability to place electronic systems on
unconventional, non-planar surfaces has
application far beyond hemispherical
camera or even other classes of bioinspired device designs, to include
biological monitoring devices, implants,
prosthetics, and so on,” Rogers says.
Corkscrew twist
The eye camera has already inspired
Rogers to investigate the potentials for even
◊nano
greater stretchability in electronic design.
He predicts electronic circuits capable of
twisting into corkscrew shapes or stretching
like an elastic band.
This design led to electronic properties that
were largely independent of strain, even in
extreme configurations such as a corkscrew
twist or elastic stretched to twice its length.
“We have already demonstrated in a range
of circuit examples, a form of stretchable
electronics that matches conventional chips
in performance but can also accommodate
nearly any type of mechanical deformation
to high levels of strain,” he says.
“We have created new design rules for
circuits that provide both excellent
electrical performance and capacities
to be elastically deformed in diverse
configurations to high levels of strain.
The same ideas can, in many cases, be
used to advantage in other conventionally
rigid, planar technologies such as
photovoltaics, sensor networks, photonics,
and so on,” Rogers says.
The technique was recently published in
the Proceedings of the National Academy
of Sciences.
To create these circuits, the researchers
firstly fabricated the Si-CMOS circuits on
ultrathin plastic substrates, as described
above. Small regions between the individual
components of the system were then
removed to leave a segmented mesh with
active electronic islands connected by thin
metal bridges. The plastic substrate was
then dissolved to leave only the patterned
circuit sheet.
This sheet was then transferred to a
pre-stretched plastic substrate, in much
the same manner as the stretchable
circuits described above. However,
in this case, when the plastic was
allowed to relax back into shape,
rather than the wavy characteristic
of the first stretchable circuits, the
interconnecting lines between the electronic
components on the new circuits were able
to raise from the surface to form arched
bridges between the components.
In this format, the system could be
stretched or compressed to high levels
of strain – up to 100 per cent in some
cases – in any direction or combination
of directions.
“The strategies we have developed are
important not only for the Si-CMOS circuits
that they enable but also for their
straightforward scalability to much more
highly integrated systems with other diverse
classes of electronic materials whose
intrinsic brittle, fragile mechanical
properties would otherwise preclude their
use in such applications.”
Medical monitors
One potential application of such
technology could be in the development of
a sheet of electronics that could sit on the
brain and monitor activity in patients at risk
of epilepsy, for example. Another technology
being considered is an electronic latex
glove that would enable a surgeon to monitor
the patient’s vital signs during surgery.
Rogers says, “We are building lots of
different things – stretchable solar ‘skins’ for
integration with wide ranging classes of
structures and surfaces, stretchable display
systems, and so on.
Our main interest is in biomedical.We now
have, in our collaborations with Professor
Brian Litt at the University of Pennsylvania,
working electrical monitors that wrap the
surface of the brain (successful
demonstrations in rats) and pacing
devices that wrap the heart (successful
demonstrations in pigs). We are pushing
into other similar types of possibilities,
and increasing the sophistication and
capabilities of the brain and heart systems.”
So is this technology likely to mark a
revolution in electronic design?
“We feel that the rigid, planar nature of
existing technologies impose design
constrains that limit application
possibilities. Bringing the power of
state-of-the-art electronics, sensors,
displays, and photovoltaics to places
where they couldn’t go before should have
considerable value. We have a seed effort,
funded by a prominent venture capital firm
in Boston, to explore market sizes
associated with the most promising
application possibilities. We also have
many interactions with large companies
who are interested in these types of
systems,” Rogers says.
The message: watch this space. µ
All images courtesy of John Rogers, UIUC
021
Study nanoscience at
the Swiss Nanoscience
Institute, Basel.
Students are invited to apply to study for a BSc in Nanoscience, or for a
Masters degree by thesis. PhD positions are also available to young
researchers who want to work at the frontiers of nanoscience and
nanotechnology in the internationally renowned Swiss Nanoscience Institute.
In Basel, we combine basic science
with application-orientated research.
Research projects can focus on
nanoscale structures with the aim of
providing new approaches to life
sciences, the sustainable use of
resources, and to the information
and communication disciplines.
The University of Basel also
coordinates the Swiss NCCR network
of universities, federal research
institutes, industrial partners and
the Argovia-network (financed by the
Swiss Canton of Aargau). Through
these and other activities, the
University continues to reinforce
its internationally acknowledged
position as a centre of excellence in
nanoscale sciences.
See: www.nanoscience.ch, or contact Dr Katrein Spieler, [email protected]
for further information on our nanosciences courses, and how to apply.
LD
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Small country
Big ideas
SWITZERLAND’S NANOTECH ENVIRONMENT
anoparticles for new vaccines,
N
Nanoscale science is one of these areas.
nanostructures on credit cards,
exploration that might lead to the
development of quantum computers, the
microscopy and spins are just
The NCCR Nanoscale Science receives
application of cantilever systems in
some of the range of research projects
annual funding of about 16 million Swiss
genomics, proteomics and diagnostics, or
currently underway at institutions
Francs (10.5M euro) which comes from the
the use of single molecules as electronic
across Switzerland.
University of Basel, where the SNI is based,
switches are just some examples of the
the Federal Government, network partners
wide range of applications that nano-
Nanotechnology research in the country is
and other third parties. Another 5 million
science will bring,” Professor
primarily coordinated by the Swiss
Swiss Francs (3.2M euro) is provided by the
Schönenberger said.
Nanoscience Institute (SNI) under the
Swiss Canton Aargau.
umbrella of the National Centers of
However, the potential risk and ethical
Competence in Research (NCCR)
Professors Christian Schönenberger and
implications associated with these new
Nanoscale Science.
Daniel Loss, both from the Department of
technologies is not lost in the ambition for
The NCCR Nanoscale Science is one
Physics at the University of Basel, lead the
new discovery, and assessing risk is a
research program.
consistent focus of the SNI.
Potential
“While the potential of nanotechnology is
of 20 current national centres funded
by the Swiss National Science Foundation,
Switzerland’s leading provider of
“Nanoscale science reaches far beyond
almost mind-boggling, for scientists at the
scientific research funding, with an annual
the development of new nanomaterials. The
SNI it is unquestionable that any risks
budget of about 500 million Swiss Francs
development of more powerful microscopes
associated with new materials must be
supporting 7000 researchers.
to discover and analyse the nanoworld, the
explored in detail and that approval for use
investigation of biological systems,
needs to be regulated.” ‘
The NCCRs are centres of research
excellence set up to promote long-term
research projects in areas considered to be
of vital strategic importance for the
development of science in Switzerland.
Ó
NEW TECHNIQUES IN ATOMIC FORCE MICROSCOPY WILL
HELP TO UNRAVEL A WIDE RANGE OF QUESTIONS ON THE
STRUCTURE AND FUNCTION OF THE COMPONENTS OF A CELL.
023
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Collaboration
Focus
chip to provide a fast and sensitive
About 200 scientists including physicists,
The six focus research areas are:
instrument for future medical diagnostics.”
physicians, computer scientists and
Nanobiology
Quantum Computing and
engineers, are employed at the SNI
Led by: Professor Andreas Engel
Quantum Coherence
conducting research in any of the six key
(University of Basel) and Professor
Led by: Professor Daniel Loss (University
subject areas that are the focus of the
Ueli Aebi (University of Basel)
pharmacologists, biologists, chemists,
institute (see below).
of Basel) and Professor Klaus Ensslin
(ETH Zurich)
The development and application of new
The research effort is a coordinated
tools for medicine and biology are the main
This focus area is involved in researching
and collaborative approach that spans
focus of research in Nanobiology. This
the manipulation of single spins,
institutions across the country.
The key networks involved are:
includes major topics concerned with the
decoherence of spin-qubits and the study of
imaging of cantilever array sensors for
entanglement in nanostructures.
genomics, proteomics and diagnostics,
• The University of Basel (including the
departments of Physics, Chemistry,
Pharmaceutical Sciences, Biozentrum,
Kantonsspital)
• Swiss Federal Institute of Technology
Zurich (ETHZ)
and the application of nano-optics for
Here, researchers develop new concepts
observing and manipulating molecular
and build novel nanostructures in semi-
processes in living cells.
conductors, and sometimes also in new
material systems such as graphene, to store
New techniques in atomic force microscopy
single electrons and to manipulate the spin
will help to unravel a wide range of
degree of freedom in a controlled manner.
questions on the structure and function of
In addition to electrical measurements and
• University of Zurich
the components of a cell. A fast developing
control, another important topic is the
• Swiss Federal Institute of Technology
Lausanne (EPFL)
area, for example, is related to the
optical control and detection of spin-qubits,
fragmentary understanding of regulatory
which offers promising alternatives to
networks within and between the cells of an
electronic transport.
• University of Neuchatel
organism which dictate how the cell
• University of Fribourg and the Adolph
Merkle Institute (AMI)
responds to external stimuli.
An important research avenue is involved
• Swiss Center for Electronics and
Microtechnology Neuchatel (CSEM)
“The quantitative assessment of the nucleic
of decoherence of single-qubits, which will
acids involved and the proteins expressed
be important for quantum computing, and
• Paul Scherrer Institute Villigen (PSI)
in gaining better theoretical understanding
is a difficult endeavour,” Professor
the concept of entanglement in
Schönenberger said.
semiconducting dots and wires and in
• EMPA
• Fachhochschule Nordwetschweiz
(FHNW)
• IBM Research Laboratory Ruschlikon
024
superconductors.
“Our cantilever technology is an ideal
platform for such analyses because it is
Atomic and Molecular Nanosystems
sensitive and allows label-free detection of
Led by: Professor Ernst Meyer (University
specific nucleic acids or proteins. This
of Basel) and Professor Hans-Josef Hug
technology will be integrated as lab-on-a-
(EMPA/University of Basel)
◊nano
Nanomechanics and nanomagnetism are
the main focus areas in the atomic and
molecular nanosystems research area.
This includes investigations of magnetic
nanostrucures by magnetic force
microscopy and magnetic resonance force
microscopy to ultimately provide
information about single electron and
nuclear spins.
A question being addressed by the
researchers is whether it is possible to
excite resonances of nanometer-sized
objects by alternating electrical fields, and
how these affect their frictional and motional
characteristics. These experiments are
accompanied by theoretical simulations to
understand friction and to investigate the
energetics of molecules in traps.
The nanostencil is an example of a novel
tool that has been developed by
researchers at IBM Zurich. It enables the
creation of 40nm structures and atomic
manipulations that will help to answer
questions about molecular systems at the
nano and atomic scale.
Molecular electronics
Led by: Professor Christian Schönenberger
(University of Basel) and Dr Thomas Jung
(Paul Scherrer Institute)
By studying single supramolecular
structures and the way they conduct
current, researchers hope to reveal new
information about the way electrons flow
through molecules. The design and
preparation of molecular nanosystems are a
major challenge of modern synthetic
chemistry today and tailored molecules are
used in a range of studies at NCCR. This
work has implication for energy harvesting
and storage in future energy efficient
organic materials through a better insight
into the understanding of electron transfer
governing photosynthesis in nature.
Functional Materials
Module leaders: Professor François
Diederich (ETH Zurich) and Professor
Wolfgang Meier (University of Basel)
New, functional nanomolecules and materials
that allow a high level of communication
with biological systems are a focus of
research in the area of functional materials.
Research in nanotechnology and
applications covers a range of
topics including:
• Biophysical and pharmacokinetic
analysis of peptide nano-particles
The assessment of functionalized and
self-assembled nanoparticles for use in
vaccine design and diagnostics.
This includes the design, preparation and
evaluation of new, technically relevant
materials and molecular systems to develop
smart materials that fulfill specific chemical,
physical and biological functions.
• Polymer substrates for waveguide
based analysis of DNA/ Protein Arrays
Research to replace glass plates used
for manufacturing optical chips with less
expensive, nanostructured substrates.
“A particular challenge of this module is the
attempt to mimic the highly complex and
beautiful molecular architectures that are
ubiquitous in nature where they fulfil
important functions and processes of life,”
Professor Schönenberger said.
• Investigation of adhesion and
corrosion on interfaces
Aims to enhance understanding of
adhesion characteristics of different
materials on the nanometre scale to
prevent corrosion in areas such as
medical technology, satellites and
electronic components.
“Since the NCCR has a strong biological
and biomedical component, one major goal
will be the development of new, functional
nanomolecules and materials that allow a
high level of communication with biological
systems. Crucial to reach this communication
is the invention of suitable interfaces
between synthetic and living matter. It is
expected that this will have considerable
impact on the development of new
generations of implant materials, drug
delivery systems, gene vectors, or
diagnostic tools.
• Security characteristics on plastic
cards This research aims to integrate
nanostructures that can be read by
machines to enhance security on credit
cards, identification documents and
driving licences.
More information:
Institute of Physics, University of Basel
“Another focus will be on using selfassembled architectures as templates or
scaffolds for the growth of organic and
inorganic structures, particles, wires or tubes.
These nano-patterned materials and arrays
promise exceptional optical, mechanical,
electronic or magnetic properties.”
Nanotechnology and Applications
Led by: Professor Jens Gobrecht (FHNW,
PSI) and Professor Uwe Pieles (FHNW)
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Christoph
Gerber
From chemical
sensors to fulfilling a
lifetime’s ambition
CHRISTOPH GERBER IS A PIONEER IN SCANNING
PROBE MICROSCOPY. HE MADE MAJOR
CONTRIBUTIONS TO THE INVENTION OF BOTH
THE SCANNING TUNNELLING MICROSCOPE AND
THE ATOMIC FORCE MICROSCOPE AND IS A
CO-INVENTOR OF BIOCHEMICAL SENSORS
BASED ON AFM TECHNOLOGY.
Professor Gerber spoke to Ottilia Saxl
about microscopy, chemical sensors,
the future for smart materials and
improving his golf swing.
OS: Professor Gerber. Thank you for talking
to NANO magazine.
Looking at your very wide ranging CV, it
is hard to know where to begin - and if two
or three pages in NANO magazine are
enough to adequately represent your
interests and achievements!
But let’s make a start on your present
interests, which cover a very exciting
spectrum of leading edge fields indeed.
Can you tell our readers a little bit more
about each, why you are interested in these
areas and where your work is leading?
Firstly, please tell us about your work on
biochemical sensors based on AFM
Technology – and how that ties in / differs
026
from your other interest in chemical surface
identification on the nanometer scale also
using AFM technology.
CG: Ever since we developed the
AFM I stayed in the field because
I am simply fascinated by mechanical
systems and devices. What seemed to
be a science area of the past dramatically
changed with the emergence of the AFM,
starting the new field of nanomechanics.
It has opened up the door to characterize
conducting as well as non-conducting
surfaces with unprecedented resolution.
In many ways the AFM has surpassed its
predecessor the STM. It has been applied
as a universal tool from fundamental
science to diverse disciplines such as
spintronic/quantum computing all the way
to life sciences. Furthermore industry is also
using it in many different applications such
as quality control and beyond.
My personal interest tended towards
applications in chemistry, biology and
medicine. I was intrigued with a long
standing idea to develop a chemical AFM
enabling simultaneous characterization,
topography and chemical identification of
surfaces on the nanometer scale. While
contemplating how to realize such a device
we noticed the possibility to use the surface
of a free-standing cantilever per se as a
chemical sensor. So for the last fifteen years
we pioneered various applications in
chemical sensing.
We distinguish between various modes
of operation. For example, driving the
cantilever at its resonance frequency in
the dynamic mode. Whenever a chemical
reaction occurs it will shift the frequency,
which in turn gives you a direct indication of
the mass changes involved in the reaction.
A Nano balance device so to speak. People
can do this with zeptogramme (10-21 )
sensitivity, at least in UHV.
◊nano
Pushing the absolute limits in device
fabrication, the Zettl Group in Berkeley
report an atomic resolution nanomechanical
mass sensor operating a carbon nanotube
as a cantilever with a detection limit of a few
atoms. This might pave the way to a new
kind of mass spectroscopy.
Running the device in the so called static
mode, molecules are adsorbed on one side
of the cantilever in a self-assembled
manner, creating a closed packed
monolayer, and due to the internal
molecular stress the cantilever bends. The
displacement can be recorded by means of
beam deflection of a laser similarly as in
AFM. Another read out mechanism employs
a piezo-resistive way and allows
miniaturization to such an extent that the
device basically ends up in a lab on a chip
configuration with integrated microfluidics.
Arranged in an array of cantilevers with
integrated reference sensors allowing
differential measurements and instant
calibration, indeed the device has
developed into a very sensitive and
powerful tool that has led to a wide variety
of applications. For example, in a chemical
nose that enables non-invasive diagnostics
in breath analysis of patients suffering from
different illnesses. Measurements of
antibody-antigen interactions with nanomolar sensitivity puts the device on an
equal footing with SPR (Surface Plasmon
Resonance). Extension to a fast detection
method for antibiotics resistant 'superbugs'
is another application. Moreover, DNA
hybridization resulting in a label free
detection of mRNA biomarkers in cancer
progression in a complex background
enables the technology to be used as a tool
in personalized medical diagnostics.
Applying this kind of MEMS device has
recently become increasingly popular and
manifests itself currently with about 300
annual publications worldwide.
heading? Does it tie in with your other
stated interest in self-organization and selfassembly at the nanometer scale? Or is that
an entirely separate theme?
CG: Well, Nanotechnology is still
dominated to a certain extent by the top
down approach where miniaturization plays
a crucial role. However, there is a
worldwide effort to emulate the bottom-up
approach of self-assembly and selforganisation that has been so successfully
implemented in the natural world. We are
trying to unravel nature’s secrets on a
nanometer scale to create a new generation
of materials, devices and systems that will
spectacularly outperform those we have
today in information technology, medicine,
environmental technologies, the energy
industry and beyond.
As we understand better how nature is
doing 'things' on a fundamental level,
achievements like clean chemistry or
clean processing will emerge along with it
how to handle waste and not pollute the
environment. New smart materials, hybrid
or hetero-structured, as well as carbon
nanotubes, a variety of nanowires or
graphene could be ingredients for novel
energy saving devices. In order to
understand the whole functionality of a
cell, Systems Biology Institutes have been
established with the hope of artificially
synthesizing a cell in a bottom-up approach.
New kinds of drug delivery systems based
on peptides or block co-polymer
nanocontainers are investigated as possible
carrier groups within the NCCR and
elsewhere in institutions involved in this
research. Biology is driven by chemistry
however the scaffold, the gears, the nuts
and bolts, for example, in cell membranes,
is pure nanomechanics, a template
orchestrated by nature which is worthwhile
trying to copy and artificially use for a
variety of functionalities. How to build and
test such devices are also pursued within
the NCCR.
As it so often happens in science you end
up with something different to what was
originally planned as in the above case of
cantilever sensors. However, we have
recently also completed the initially
planned chemical AFM.
OS: You also mention you are undertaking
Atomic Force Microscopy research on
insulators. Please explain what makes
insulators so worthy of research, and what
your research is uncovering.
OS: Secondly, you mention the area of
nanomechanics, nanorobotics, and
molecular devices at the ultimate limits of
measurement and fabrication. That sounds
very futuristic indeed. How is that work
being accomplished, and where is it
CG: The underlying sole idea of the AFM
was to develop a microscope that is able to
characterize non-conducting insulating
surfaces on the molecular and atomic scale.
This was not that easy for a variety of
reasons. Unlike with the STM, where the
tunnel current operates between a single
atom on the tip and surface respectively, the
AFM requires a very sharp tip to keep a
conglomerate of different forces at bay in
order to get atomic resolution.
Gradually people have overcome these
problems and are nowadays able to
operate the AFM with atomic resolution
on insulators in a routine fashion. This is
particularly interesting since it allows
you to investigate a variety of materials,
for example, oxygen atoms on TiO2
surfaces, in order to get a more
comprehensive understanding of the
surface on the atomic scale. This is
simply a unique feature of the AFM.
The same is true if we talk about
characterization of hybrid nanostructures.
Another example is characterization of
molecular nanowires self-assembled on
insulators: important, if one thinks of future
nano circuits. The recent discovery that
diamond might be an ideal material in order
to pursue single-spin level quantum
information at room temperature brings
AFM right in to the heart of investigation, for
example in the study of artificially
manufactured diamond thin films. So
insulating materials play an important role
in any device fabrication on the nanometer
scale, which of course is also true for all soft
matter investigations on surfaces.
OS: Finally, on your list of current interests
is ‘Single Spin Magnetic Resonance Force
Microscopy (MRFM)’! I see that it will be
used to determine the structure of proteins.
Perhaps you could tell our readers more of
what this area of microscopy is about, and
where it is going in terms of application –
and implication!
CG: I have to admit although highly
interested I only occasionally make
contributions to this field. This basically is
the research of colleagues of mine at IBM
Almaden Research in Dan Rugar’s and John
Mamin’s group, as well as Ernst Meyer and
Simon Rast here at the NCCR in Basel.
However, here is what it is all about.
Magnetic Resonance Imaging (MRI) is a
powerful imaging technique, however, it is
still operating in the millimeter and
micrometer resolution range. In a new
approach called MRFM (Magnetic
Resonance Force Microscopy) people can
scale down the device without losing
sensitivity. The heart of the device is a
magnetic tip on a cantilever with a low ‘
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spring constant, oscillating above the
sample (or vice versa) where an external
RF coil is used to excite the spin. Operating
the device in a magnetic field, the forces
between the tip and the resonant region can
be determined by measuring the oscillation
of the cantilever monitoring the change of
the resonance frequency. The forces to be
detected are very small, in the range of atto
Newtons (10-18 N) and the associated
frequency shift is also very small. Gradually
the groups in Almaden and in Basel have
improved the device sensitivity by twelve
orders of magnitude over the years and the
group in Almaden reached in very recent
work a spatial resolution of below 10
nanometers, which allows the detection
of 35 nuclear spins. So the goal to reach
single nuclear spin detection seems
to be achievable within the foreseeable
future. This certainly would have
tremendous implications in structural
biology and beyond.
OS: Now, regarding your own very varied
career. When I looked in detail at your CV,
I was struck by the ‘internationality’ of it!
You have been a visiting scientist in Spain,
the States and Japan; you have also worked
in Sweden, Switzerland, the States and
Germany. Can you explain what this major
international dimension has brought to your
028
work? How has it changed your work? Do
you think you would be the scientist you are
without exposure to so many new cultures
and experiences?
CG: Yes indeed I was very fortunate to
experience living in all these different
places. This cultural diversity greatly
influences you in becoming a global citizen.
It tremendously broadens your horizons and
has an impact on how to challenge and
solve certain problems in a much more
‘all inclusive’ way. In other words, it makes
it easier to view things from a global
perspective. However, on the other hand,
individuality will remain as the major
creative driving force for progress.
OS: To move on to your current position.
Would you be so kind as to tell me about
your responsibilities at NCCR, and what
plans you have for the future of that
organization? Switzerland is often cited as a
leading small country in nanotechnology.
How does NCCR fit into the Swiss strategy
for nanotechnology as a whole? In the past
in Switzerland there was a much-envied
initiative called Top Nano that was focused
on industrial applications. What are your
views about its outcomes, and where do
you think Switzerland see its nano future
lie, now? In science and technology, or
science or technology?
CG: The NCCR is the National
Competence Center for Nanoscience and
the University of Basel is the leading house.
On a project level, six other institutions are
set up in a network. It is a fundamental
research program mainly funded by the
federal government and the University of
Basel. I am one of the founding members
and act on the management board. The
NCCR was up and running already in
2001 to make it one of the first of this
magnitude worldwide and indeed has
turned out to be very successful. This has
not gone unnoticed and additional financial
contributions from other sources are now
available. These new funds, however,
particularly support application-driven
research projects where industrial partners
have to be involved. All these efforts in
Basel are now set up under the umbrella
of the recently founded Swiss Nano
Institute (SNI).
Ever since the window to the nanoworld
has been pushed wide open with the
emergence of SPM, Switzerland has
launched a series of smaller Nano
programs including the above mentioned
Top Nano initiative. All these efforts
provided a platform, enabling cutting edge
science that helped to create a critical pool
of knowledge leading to a series of start-up
◊nano
companies. We have already see that
the technical consequences of this
penetrating industry.
Ó
A new initiative called Nano Tera will
commence by the end of this year with the
goal to linking up nano systems and
devices in big networks. In a new focal
point ETH and IBM Research have teamed
up, building a new Nanocenter on IBM
premises in Zürich to provide a get-together
environment under one roof in a
collaborative and beneficial effort for
both institutions. An annual established
exhibition in St. Gallen called Nanofair
gives industry a platform to show their nano
products and is understood to be the
European counterpart to the big Japanese
and American product shows.
OS: Finally, you seem to have had an
exciting and productive life so far – what
would you still like to achieve?
Within this context education of course
plays a crucial role. Initiated by the NCCR,
in 2002 the University of Basel had already
established a Nano curriculum for Bachelor
and Master courses and beyond (first nano
curriculum worldwide). The first students
finishing these courses have now taken up
their PhD work. We strongly believe that the
interdisciplinary structure of Nano requires
a new breed of scientists and engineers
educated in all science disciplines with no
'language’ barriers, ready to make an
impact on all the global challenges ahead
where Nanotechnology can be applied.
THIS IS AS CLOSE UP AND PERSONAL AS IS
GETS IN STUDYING THE PROPERTIES OF THE
FUNDAMENTAL BUILDING BLOCKS OF MATTER.
CG: The excitement still goes on, in
particular following the newest
developments in non-conductive AFM
where people have recently pushed the
technology to the very limits of
measurements. By introducing damping
non-conductive Dynamic Force Microscopy,
it basically allows you to visualize molecules
beneath the surface in a non-invasive
manner, e.g. in carbon nanotubes. This is
comparable to the ultrasonic method
applied in medicine today, however, in this
case it exhibits molecular resolution.
In another recent development with a
similar method, people can exert a tiny
additional force to the vibrating cantilever
which enables them to kick out strongly
bonded atoms from their existing position
on surfaces at room temperature and
creating a new set of atomic patterns on the
surface, which in turn can be chemically
identified with a new, so-called atom
tracking spectroscopy on the atomic scale.
However the icing on the cake is another
newly established three dimensional
spectroscopy that allows you to position the
vibrating tip of the cantilever in very close
proximity to an atom at any given point on
its surface and examine the atom from a
kind of a ' bird’s eye view '. This is as close
up and personal as is gets in studying the
properties of the fundamental building
blocks of matter.
What I really would like to achieve is to
improve my game of golf to bring it up to a
level where shooting an ace... a hole in one
... becomes more probable. This certainly
would lift my game up to the level of that of
the late much admired John Bardeen, so far
the only scientist to win the Nobel prize in
physics twice. He was known to be a very
keen golfer and apparently stated once :
‘that his hole in one in golf meant as much
to him if not more than the Nobel prizes’ µ
Professor Gerber is currently the
Director for Scientific Communication
of the NCCR (National Center of
Competence in Research Nanoscale
Science) at the Department of Physics,
University of Basel, Switzerland, and is a
founding member of the NCCR. For the
past 25 years, his research has been
focused on Nanoscale Science.
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TO THE
Extremes
SCIENTISTS HAVE BEEN EXPLORING THE EXTREME
ENVIRONMENTS OF ICELANDIC VOLCANOES FOR
NANOSCOPIC VIRUSES THAT COULD BE USED
AS BUILDING BLOCKS FOR NANOTECHNOLOGY.
ELAINE MULCAHY SPOKE TO DAVID EVANS
ABOUT THE UNIQUE CHARACTERISTICS OF
EXTREME VIRUSES AND THEIR POTENTIAL
AS NANO-BUILDING BLOCKS.
030
◊nano
aterials and devices built on the nanoscale have significant
potential applications across a range of technologies, such as
biomedical and electronic devices. Much progress has been
made in fabricating synthetic nanomaterials, such as nanodots and
nanocrystals, which are possible to manipulate on the nanoscale and have
been used in applications ranging from solar panels to medical imaging.
M
However, synthetic nanomaterials have limitations, the most important
being the difficulty to precisely tune and control their behaviour under
harsh laboratory conditions. They may be fragile to acids and high
temperatures required by some fabrication processes and come in a
broad range of sizes and shapes, making a uniform treatment across the
board difficult to achieve.
Rather than attempting to mimic nature to create nanomaterials from the
bottom-up, scientists have more recently begun investigating the use of
naturally occurring ready-made nanoparticles as building blocks for
nanotechnology.
“Viral nanoparticles, or VNPs, provide a lot of advantages over synthetic
nanoparticles,” says Dr Evans, a researcher at the UK-based John
Innes Centre.
“Firstly, they have been self-assembled with atomic precision by mother
nature and, unlike synthetic nanoparticles, they are all perfectly and
equally shaped and sized. They are also relatively easy to produce in
large quantities and are robust, biocompatible and bioavailable.
“Another important feature of VNPs is that they can be easily modified by
chemical means or genetic engineering.”
If VNPs are to be used in nanotechnology applications, they also need to
be tough. For example, bioconjugation (the process of coupling two
molecules together) may involve non-aqueous solvents and biomedical
applications will expose VNPs to acidic environments, while electronics
applications expose the particles to high temperatures that may break
down some synthetic particles.
Evans and his colleagues, which include researchers from John Innes
Centre, Institut Pasteur in Paris and The Scripps Research Institute in the
US, turned to one of the harshest environments on Earth to find a naturally
occurring nanoparticle capable of withstanding the extremes – the viral
nanoparticle SIRV2.
SIRV2 is a virus that infects Sulfolobus islandicus, a single-celled
microorganism found in hot, acidic springs in volcanic areas of Iceland
that give off sulphurous gases and steam. The springs are extremely hot,
about 88˚C, and acidic, with a pH around 3.
Evans together with his graduate student at the time, Dr Nicole Steinmetz,
and colleagues predicted that a virus capable of withstanding such
extreme heat and resistant to acidic environments could potentially
provide an extremely stable viral nanoparticle that could be used as a
building block for materials scientists.
In order to test their theory, the team put SIRV2 through its paces in
laboratory tests. The findings were recently published in Advanced
Functional Materials.‘
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Nanotechnology in
Extreme Environments:
As well as searching for naturally
occurring nanoparticles in extreme
environments, scientists are using
nanotechnology to develop manmade materials capable of
withstanding the elements on
Earth and in space.
Continued from page 31
Two solvents, DMSO and ethanol, which are
used in many nanoengineering processes
such as bioconjugation techniques and
mineralization reactions were used to test
how well SIRV2 could stand up to harsh
laboratory conditions.
The researchers report the virus
remained intact and infectious in DMSO
concentrations of up to 50% (in water) for at
least six days. SIRV2 exposed to a mixture
of water and ethanol also remained intact
for up to 6 days. At 20% ethanol, SIRV2 also
maintained its ability to infect its host
throughout the testing period.
“Temperature stability and resistance to
extremely low pH values is naturally given
to SIRV2. We have now also shown the
particle’s ability to withstand the harsh
solvent/water mixtures used in nanoengineering processes, which further
supports their potential usefulness for
applications in materials science or
nanotechnology,” Evans says.
“However, being able to withstand
the elements is just one important
feature of viruses as nano-building
blocks. To be potentially useful as a
VNP, the virus must also be open to
modification or decoration with functional
chemical groups. This is where SIRV2
has proven to be truly unique.”
The structure of SIRV2 is indeed unique in
the virus world. All viruses contain proteins
that coat the viral capsule. In SIRV2, two
distinct coat proteins exist – one which
coats the main body of the rod-shaped virus
and another that coats either end.
“The SIRV2 virion presents a unique
particle and no comparable VNP building
block has been studied to date. The unique
structure of the virus opens the potential for
two different attachment sites, allowing
selective chemical modification,” Evans says.
In order to test this theory, the researchers
employed three different chemistries to
assess the usefulness of SIRV2 as a
032
platform for the selective display of a
functional molecule or label, in this case,
the molecule biotin.
Biotin was coupled to carboxylates, carbohydrates and amines present on SIRV2.
When bound to the carboxylates and carbohydrates, the biotin labels were found all
over the SIRV2 particle. However, when
bound to the amines, the labelling
reaction only appeared at the ends of the
viral particles.
“What this suggests is that, depending on
the chemistry used, modifications could be
targeted specifically to the ends of the virus
particle, to its body or both. This sort of
selective modification is unique to SIRV2
and opens up new possibilities,” Evans says.
“For example, in processes where nanobuilding blocks are built up into layers or
arrays, the viral bodies and ends could be
selectively labelled to yield arrays with
different physical properties, for example by
aligning particles body-to-body versus endto-end. This option is not possible with other
rod-shaped VNPs.”
The research proves the potential of
SIRV2 for nanotechnology applications
and the researchers describe their
findings as the discovery of a new,
extremely stable and structurally unique
nano-building block.
“This is only the starting point. Possible
future applications may be found in liquid
crystal assembly, nanoscale templating,
nanoelectronic and biomedical
applications,” Evans says.
It is also likely that many such
nanoparticles, which naturally exist in
extreme environments on Earth, possess a
range of unique, as yet undiscovered
characteristics that will help advance
modern nanotechnology research. µ
David Evans is a research group leader in
the Department of Biological Chemistry,
John Innes Centre.
Dr N Vigneshwaran, a Senior Scientist in
the Chemical and Biochemical
Processing Division of the Central
Institute for Research on Cotton
Technology in Mumbai, India explains:
“Application of nanotechnology on textile
materials could lead to the addition of
several functional properties. For
example, deposition of silver
nanoparticles imparts an antibacterial
property while gold nanoparticles allow
the use of molecular ligands so that the
presence of biological compounds in the
surroundings can be rapidly detected.
“Platinum and Palladium nanoparticles
impart catalytic properties such as
decomposition of harmful gases or toxic
industrial chemicals. More often, these
nanomaterials are impregnated onto
textile materials without significantly
affecting their texture or comfort.
“An additional benefit in the use of metal
nanoparticles is the presence of surface
plasmons. These plasmons are strong
optical extinctions that can be tuned to
different colours by varying their size
and shape. Silver nanoparticles can be
used to create a shiny metallic yellow to
dark pink colour while simultaneously
imparting antibacterial properties to the
textile materials.
“Metal oxide nanoparticles like TiO2,
Al2O3, ZnO and MgO possess
photocatalytic and antibacterial
activity and UV absorption properties.
Textile materials treated with these
nanoparticles are proved to impart
antimicrobial, self-decontaminating and
UV blocking functions for both military
protection gears and civilian health
products.”
Here we provide some examples of
nanoparticles in extreme environments.
Corrosion
Corrosion in pipes, equipment and other
metal surfaces is a major problem that
spans almost all industries. Much
progress has been made in the
development of nano-based coatings to
resist corrosion. US-based Sub-One
Technology, for example recently
announced the development of anticorrosion coatings made from
◊nano
nanometre-sized carbon-based materials
found in petroleum, developed by Chevron
Technology Ventures (CTV). Used with
Sub-One Technology’s “InnerArmour”
deposition, the diamondoid coatings are
reported to extend the life of internal metal
surfaces by providing very high hardness,
low coefficient of friction and strong
protection against corrosion and wear.
The InnerArmor coatings were initially
designed to solve difficult corrosion, wear
and friction reduction challenges in the
interiors of critical liquid and gas handling
equipment and piping and are being tested
in key surface, sub-sea and downhole oil
and gas applications.
“Increased equipment durability is
important to many industries where parts
are continuously exposed to harsh
environments,” says Andrew Tudhope, CEO
of Sub-One Technology.
“Combining the diamondoids developed by
CTV with the durability, rigidity and heat
resistance made possible by the
InnerArmour deposition process creates
protective coatings that can extend part life,
improve flow performance and significantly
reduce operating costs. The diamondoid
technology enables us to offer very thin,
hard coatings which can be cost effectively
deployed across a range of components
spanning multiple industries.”
Such technologies could provide massive
savings for oil and gas companies.
Space
Space exploration is a dangerous mission.
Spacecraft and astronauts are exposed to
extreme high temperatures, radiation and
potential health hazards. Nanotechnology
could play a role in crucial life-support
activities such as carbon dioxide removal
and water purification in space. Carbon
nanotubes are being added to materials
used in thermal protection systems on the
spacecraft coatings to improve
performance. NASA scientists are also
looking for ways to monitor astronauts’
health while on a mission. Ideas currently
being explored include the use of nanosized implants that could monitor vital signs
and relay information back to Earth, and
nanotech approaches for targeted delivery
of medicine.
Hospitals
Hospital infections such as MRSA and C.
difficile have become a major problem
across the world. In Europe, it is estimated
that about three million people a year
develop an infection while in hospital. About
50000 of them will die. Drug-resistant
microbes like MRSA are believed to infect
one in every 10 patients admitted to a
hospital in Europe.
A trans-European research project, led by
the University of Limerick, now hopes to
engineer textiles resistant to MRSA.
The 5 million euro project will involve
nanotechnology techniques to develop selfsterilizing hospital gowns and beddings that
kill bacteria.
Project co-ordinator Dr Tofail Syed says a
significant element of the MRSA problem
arises from the use of conventional textiles
such as hospital gowns, curtains, beddings
and pillow covers. He believes the
development of nanotechnology-derived
textiles will improve hospital sterility and
help in the fight against MRSA.
Military
Extreme environmental conditions are
typical of most defence related applications,
whether they be airborne, seaborne or land
based. Aircraft, tanks, ships and missiles
alike experience harsh extremes of
temperature, pressure and load. In order to
perform reliably in these conditions military
systems need to be designed to be wear
resistant, light weight and durable.
Diamond Hard Surfaces’ ‘Adamant’
material has a unique combination of
extreme properties, physically, electrically
and optically which make it a compelling
proposition for extending the lifetime of
components in missile systems, land based
and water based applications.
The patented CVD process which Diamond
Hard Surfaces Ltd has developed uses
atomized carbon on the nano-scale to
produce a unique form of Diamond-LikeCarbon (DLC). The low process
temperature makes it possible to coat a
wide variety of substrates from plastics such
as polyetheretherketone to ceramics and
sapphire. The coating can be applied in
thicknesses up to 40 microns and beyond,
with an extreme hardness of 3500-4000 Hv
making any surface coated with the material
extremely wear resistant.
Often some of the most extreme conditions
occur in applications operating in desert
environments. Here Adamant’s combination
of hardness and ultra high abrasive resistance
is ideal for applications where extended life
is required when faced with relative
component movement combined with sand.
The materials' extreme hardness combined
with its transparency in the infrared
spectrum range make it ideal for infrared
window applications on tanks. Likewise in
infrared windows for missile applications
where the extreme friction generated by air
passing over the fuselage at speeds of up to
Mach 3 can cause component degradation
through wear.
Other properties of the material also make it
attractive when used in combination with
components needing electrical insulation or
improved high thermal conduction such as
electronic systems.
Further information on Diamond Hard
Surfaces can be found at www.diamond
hardsurfaces.com or by email
[email protected]
Ultra-violet Exposure
Prolonged and repeated exposure to
ultraviolet radiation from sunlight has been
identified as the cause of an increase in the
incidence of skin cancer in humans.
Limiting the skin’s exposure to sunlight,
especially during the hours of maximum
intensity is the best way to reduce risk. For a
person who must work outdoors this is not
feasible, so well-designed clothing made
from UV-blocking textiles is the best
alternative. The transmitted and scattered
light, which is responsible for sunburns, is
the focus of work by Dr N Vigneshwaran.
Here, ZnO nanoparticles score over other
nanoparticles in cost-effectiveness,
whiteness, and UV-blocking property. The
UV-blocking property of a fabric is
enhanced when a dye, pigment, delustrant,
or UV absorber finish is present that
absorbs UV radiation and blocks its
transmission through the fabric to the skin.
Metal oxides like ZnO as a UV-blocker are
more stable when compared to organic UVblocking agents. Hence, the nano-form
ZnO will really enhance the UV-blocking
property due to the increased surface area
and intense absorption in the UV region. Dr
Vigneshwaran’s research has proved the
excellent antibacterial activity against two
representative bacteria, Staphylococcus
aureus and Klebsiella pneumoniae and
promising protection against UV radiation
by nano-ZnO impregnated cotton textiles.
Apart from nano-ZnO, nano-silver coating
onto cotton fabrics was also found to
increase the UPF factor due to their
absorption in the near-UV-region.
Nanocrystalline titanium dioxide coatings
have received much attention as
photocatalysts in practical applications such
as environmental purification, deodorization,
UV-absorbancy, sterilization, anti-fouling and
self-cleaning glass due to their high
oxidizing ability, nontoxicity, long term
stability and low cost. Among the different
crystalline phases of titania, anatase is
reported to have the best performance.
These titania-coated cotton textiles possess
significant photocatalytic self-cleaning
properties, such as bactericidal activity,
colorant stain decomposition and
degradation of red wine and coffee stains.
Dr. N. Vigneshwaran is a scientist at the
Nanotechnology Research Group of the
Central Institute for Research on Cotton
Technology in Mumbai, India.
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Fine tuning
Optical techniques for
selective fluorescence
LASER SCANNING MICROSCOPES ARE AT THE FOREFRONT OF SCIENTIFIC RESEARCH.
ADVANCES IN MICROSCOPY ARE ALREADY ENABLING RESEARCHERS TO IMAGE LIVE
CELLS AND TISSUES IN THREE DIMENSIONS, BUT THERE ARE IMPROVEMENTS TO BE MADE.
GAIL MCCONNELL EXPLAINS SOME OF THE SHORT-COMINGS OF LASER SCANNING
MICROSCOPES AND DESCRIBES HER VISION TO IMPROVE OPTICAL IMAGING.
ew techniques in optical
microscopy have brought a vast
change in the approach to life
science imaging over the past twenty years.
The ability to add fluorescent labels to live
tissues and cells, combined with confocal
laser scanning microscopy, has enabled the
creation of high resolution, three
dimensional, cross-sectional images that
facilitate new understanding and
investigation of cells and systems.
N
Fluorescence is a natural phenomenon first
described in 1852 that has come to great
use in modern imaging. By definition,
fluorescence can be described as the
emission of a photon from a mineral or
molecule when light of a specific
wavelength, such as ultraviolet, shines
on it. Different fluorophores – the name for
molecules that emit fluorescence – absorb
and emit different wavelengths of light
specific to that molecule.
In imaging, fluorophores such as quantum
dots can be attached to cells or tissues to
act as labels or markers or, indeed, some
biological media is inherently autofluorescent and no fluorophores need to be
applied. Additionally, biological systems can
be developed that incorporate naturally
occurring fluorescent proteins throughout
part of or an entire animal.
In confocal laser scanning microscopy
(CLSM), a laser beam (referred to as the
laser source) is passed through a series of
specifically chosen optical elements to
create a tightly focussed laser spot within
034
the fluorescent specimen. As each
fluorophore absorbs the laser light, it
radiates its own light, which is detected and
used to construct a high-resolution image of
the specimen pixel by pixel. Varying
intensities of the pixels indicate the
presence and intensity of the fluorophore at
that specific point, enabling threedimensional reconstructions of complex
objects. However, current CLSM systems
and subsequent applications are limited by
the lack of suitable photonics technology.
The argon-ion laser, with a primary
wavelength of 480nm conveniently matches
the excitation wavelength of many synthetic
fluorophores and is one of the most
commonly used laser sources for CLSM.
However, the laser source is not wavelength tunable and hence excitation of
fluorophores is restricted to the blue-green
part of the spectrum. Fluorophores with
excitation parameters at different spectral
regions will therefore not be excited by this
laser. A lot of interest in the use of laser
diode sources have helped to overcome this
shortfall in shorter wavelengths, however,
there remain significant gaps in spectral
coverage at longer visible wavelengths.
Another problem with conventional CLSM is
that it has not kept pace with improving
labelling techniques. Many applications
involve using more than one type of
fluorophore: the ability to rapidly switch the
wavelength of the incoming light to match a
selected fluorophore is therefore sought
after, but not possible with conventional
CLSM. This lack of wavelength tunability
severely restricts the fluorescent dyes
that can be used and the samples that
can be imaged.
Other problems of CLSM are the high noise
picked up by the system as fluctuations in
laser intensity at the sample can greatly
affect the ability to perform quantitative
and qualitative analysis of CLSM images.
At the Centre for Biophotonics at the
University of Strathclyde in Glasgow,
we have been devising new photonics
technologies to overcome these
shortcomings in CLSM and to develop
enhanced imaging techniques for life
science and biomedical imaging.
Fine tuning
One technique involves replacing
laser source with a white-light
supercontinuum, or WLS, that spans the
visible light spectrum. Photonic crystal
fibres, or PCFs, are a type of optical fibre
capable of confining light in solid silica
cores a few microns in diameter that is
surrounded by an air-silica microstructure
that propagates the length of the fibre. This
unique system provides control over the
dispersion of the PCF and by judicious
choice of the input laser source, it is
possible to generate a WLS. This
revolutionary source has found application
in a range of systems such as frequency
metrology, spectroscopy and imaging techniques in which it is often necessary
to alter the wavelength of the excitation
light source.
◊nano
Wavelength switching, however, poses
another problem. Although the WLS
provides output across the entire visible
spectrum and beyond, for CLSM it is
necessary to extract only the necessary
wavelength band to efficiently excite the
fluorophores and reduce background signal
on the image. Interference filters, prisms
and apertures, as well as electronically
controlled systems, have been used to
select specific wavelengths of interest from
the white light spectrum. But they are very
slow and not always convenient when
studying rapid cellular processes.
We have devised a technique using a digital
mirror device (DMD) system to overcome
these problems to create a “hands free”
mechanism for selecting specific
wavelengths from a white light
supercontinuum. The DMD consists of an
array of 1024 x 768 moving microscopicmirrors that can be arranged to reflect and
direct only the desired wavelength towards
a target and can be switched to reflect
different wavelengths as required.
This simple method of isolating specific
wavelengths presents several advantages
over alternative approaches such as
bandpass filters and prisms. Firstly, it is
computer-controlled and therefore handsfree, which is always of benefit when
working with lasers and sophisticated
equipment. Secondly, the DMD enables
precise control over the selected
wavelength range. We predict that
subnanometre wavelength accuracy is
theoretically possible with the device.
This switching technique, first published in
the Review of Scientific Instruments in 2006,
provided a first step towards fast switching
for example, real-time three-dimensional
monitoring of activity in live cells.
More recently, in the same journal, we
reported on an alterative to argon ion lasers
for use in CLSM.
Solid state
Solid-state lasers (which contain a solid
active medium in contrast to a gas active
medium in gas-based lasers, such as argon
ion) provide a practical alternative to argon
ion lasers in terms of lower noise levels and
improved beam quality. The downside is a
large and expensive system.
We have explored the use of VECSELs
(vertical external cavity surface emitting
lasers) as a replacement for argon ion
lasers in CLSM.
VECSELs operate at a range of
wavelengths, chosen at the design stage,
offering opportunities for wavelength tuning.
The beam quality and power output are also
excellent and so the technology is ideally
suited for compact and inexpensive laser
systems, such as CLSM.
VECSEL systems commercially available
today, however, are not designed for
CLSM and typically do not support
wavelength tuning. To overcome this
problem, we have designed a customspec adapted VECSEL dedicated for
use in a CLSM.
A VECSEL designed for emission
around 980nm formed the basis for our
experiments. A crystal diamond placed
in the laser beam causes the phenomenon
of frequency-doubling, whereby the
wavelength output from the laser is
halved – in this case to 490nm, which
directly compares with the output from
an argon ion laser.
This enabled us to compare images
created using VECSEL-based and argon
ion-based CLSM and we found a number of
improvements with the VECSEL system.
Firstly, VECSEL offered wavelength
tunability, which, as described previously, is
becoming an increasingly essential part of
CLSM imaging. Also, the VECSEL system
was less susceptible to noise interference
and it required less energy to operate. The
VECSEL therefore provides an attractive,
low noise, low cost alternative to an argon
ion laser while offering improved imaging.
Such progress represents an example of
the type of research and advances that are
being made in the field of microscopy.
Optical imaging continues to surprise and
enhance and there is great scope for further
development, new ideas and inventive
solutions to shortfalls in current systems to
create new devices that can move with the
ever-changing field of science. µ
Gail McConnell is a RCUK Academic
Fellow at the Centre for Biophotonics at
the University of Strathclyde
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Functionalising
textiles at the nanoscale using plasma
The need for high performance textiles
Increased textile performance is desirable
in many modern applications ranging from
personal protection from hazards and
severe environments to extreme sports. But
nowhere are textiles subjected to more
severe testing than in the healthcare sector
where they may be required to survive
within the human body or provide barriers
to highly infectious and pathogenic agents.
The range of properties required of modern
textiles are numerous… they may be
required to be resistant to water, to oil, to
acidic or alkaline environments, be able to
resist soiling or biological film formation, or
to form an effective barrier against
microorganisms. At the same time textiles
are bulk produced materials and any
processes used to impart such important
properties must be efficient, cost-effective
and at the same time ecologically
acceptable. One increasingly important
process in textile treatment is surface
functionalisation using plasmas.
Plasma basics
Plasma is commonly referred to as the
fourth state of matter after solid, liquid and
gaseous. Plasmas are the most common
form of matter accounting for over 90% of
the matter in the apparent universe
including interstellar space.
A plasma
• can be characterised as a gas
containing charged and neutral
species including electrons, positive
ions (cations), negative ions (anions),
molecules and atoms (radicals)
036
• is generated by application of an
electric field
• is neutral on average
• requires an input of energy in order to
be sustained (due to loss of charged
particles by recombination, diffusion
and convection)
• Plasmas may be formed at both low
and atmospheric pressures. Examples
of natural plasmas include flames, the
aurora borealis, lightning, the solar
wind, the solar corona and the solar
core. Examples of man-made plasmas
include those in neon signs,
fluorescent lighting tubes, welding
arcs and magnetic fusion reactors.
Differences between a gas and a plasma
Plasmas for laboratory or industrial
application may be created using the
following elements: a power (frequency:
from DC to microwave, continuous or
pulsed); a mass flow controller to inject a
gas and precursors; a coupling element
(electrodes, antenna, waveguides,
dielectric); a substrate holder ; a vacuum
chamber (for low pressure plasmas)
For man-made or industrial plasmas, some
key characteristics include
• density
• ion density
• electron temperature
• the interactions between its species
(collisions between charged particles)
• the plasma potential
The potential of a plasma may be exploited
industrially by taking advantage of its
thermal energy (e.g. in a welding arc or
plasma torch); photonic energy to produce
light; kinetic energy (e.g. to etch a surface
or to activate it by increasing its surface
energy); chemical reactivity (e.g. to create
radicals and ions and chemically
functionalise a surface).
By manipulating these properties, a plasma
may be made to interact with a substrate
either to remove materials (e.g. in cleaning,
sterilising or etching) or to add materials or
functionality (e.g. by temporarily activating a
surface by adding energy, permanently
functionalising a surface by adding
chemical groups, or by depositing or
coating a material). Various types of
materials may be added by including a
precursor in the plasma gas stream.
Treating textiles with plasmas
Plasmas may be used to impart a variety of
properties to a wide range of textiles without
changing their bulk properties. These include:
• chemical inertia and affinity
• wetting capacity
• resistance to oils
◊nano
• biocompatibility
• capillarity, e.g. for subsequent dyeing
• bond strength
• lubricity
• cleanliness and sterility
• washability
• durability and anti-wear properties
• mechanical properties, e.g. anti-creasing
• electrical properties, e.g. anti-static
Different gases or precursors in the plasma
system may be used to impart these desired
properties and the following represent
some typical uses of different gases:
• argon may be used to increase
surface roughness
• fluorocarbons may be used to
promote polymerization and improve
water repellency
• oxygen may be used to modify surface
chemical groups and improve wettability
• ammonia and carbon dioxide may be
used to modify surface chemical groups
Some typical advantages of plasma
processes for textile treatment include
• the fact that plasma processes are a
“dry” technology and are intrinsically
ecologically and environment friendly.
• their suitability for being be applied as
low temperature treatments adaptable
to plastics and polymers as well as
other types of substrates
• the possibility to fabricate metastable
materials
• the possibility to act and impart
changes or functional properties only
to the surface of the material without
acting on the bulk of the textile
A nanoscale features
produced by plasma treatment
Surface functionalisation
• the ability to apply anisotropy
or preferential orientation of
desired features
• the ability to create a variety of different
nanoscale features such as
nanodomes, nanopillars, nanocraters
and nanopores, or features at the
microscale, e.g. channels that can be
used to guide cell growth on implants
or tissue engineering substrates
• the ability to create cost-effective and
efficient processes, e.g. the use of low
quantities of gases and precursors
(sometimes greater than 800 times less
in low pressure plasma systems)
Some typical plasma applications
for textiles
Antibacterial coatings
The antibacterial properties of silver are
well-known and, in recent years,
manufacturers have begun to incorporate
silver nanoparticles into textiles in wound
dressings and, more recently, in sportswear
and other clothing. This may also be done
by using plasma processing and further
materials may be added to the process to
stabilize the silver nanoparticles in a
surface layer, e.g. polymer ethylene oxide
type films where the C-O group reduces
protein and cell adhesion, on the fabric.
High-molar-mass, cationic polymers such
polydiallyldimethylammonium chloride
(poly-DADMAC) may also be applied by
plasma processes and have proved
effective in producing antibacterial coatings.
Some nanoscale features
produced by plasma treatment
Antifouling coatings
Plasma enhanced chemical vapor
deposition functionalisation of the textile
surface with a combination of certain
perfluorochemicals, as precursors can
produce useful coatings with good antifouling properties.
Water and oil repellence
A surface treatment imparting resistance
to wetting (hydrophobicity) and oil
(oleophobicity) may be achieved by the
addition of various fluorinated hydrocarbons
to the plasma system. Other plasma
treatments that can increase the contact
angle at the surface can prevent water
and oil seeping through a fabric.
Wear resistance
By integrating SiO2 nanoparticles into the
fabric, the abrasion resistance of textiles in
the washing process may be increased.
Woven-in nanowires can also be used to
increase the textile strength.
UV protection
TiO2 nanoparticles may be incorporated
into textiles to protect against ultraviolet
light degradation.
The ACTECO FP6 Project
ACTECO is an Integrated Project within
Framework Programme 6 (FP6) of the
European Union. The practical application
of plasma requires the development of
reliable and versatile plasma and precursor
systems, such as those very briefly
described in this article, outside the
laboratory the project’s objectives have
been to develop breakthrough efficient
plasma technologies and processes to
produce hyperfunctional surfaces with
applications in the textile, food packaging
and biomedical industry. Another important
project objective is to replace “wet textile
treatment” technologies, characterised by
the consumption of large amounts of water
and solvents, with so-called “dry” and
environmentally-friendly technology.
The project is due to run until the end of
April 2009 when a project report will be
published and made publicly available with
the aim of disseminating the results of the
collaborative research to industry with a
particular emphasis on SMEs.
www.acteco.org
Richard Moore is Manager of
Nanomedicine and Life Sciences at the
Institute of Nanotechnology
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Nanosensors
Big Benefit or Big Brother
BY SHIRLEY COYLE AND DERMOT DIAMOND
TEXTILES AS A UNIVERSAL INTERFACE ARE CONSTANTLY INTERACTING WITH
OUR BODIES AND THEIR ENVIRONMENT, THEREBY PRESENTING AN IDEAL
PLATFORM FOR PLACING OR INTEGRATING SENSING DEVICES. WHILE THE
EARLIEST SENSING GARMENTS HAVE APPEARED AS CUMBERSOME DEVICES,
WITH TRIED AND TRUSTED MACRO-ELECTRONICS ATTACHED ON TOP, NEW
TECHNOLOGY IS ENABLING A MORE SEAMLESS INTEGRATION.
Nanotechnology is solving the problems of
connecting hard, brittle electronics with soft,
pliable textiles. “Smart” garments with
integrated nanosensors are now becoming
wearable rather than portable.
an increased awareness of their own health
status which may serve to reinforce a
healthy lifestyle, monitor fitness levels,
provide early detection of illness and
prevent disease.
A ‘smart’ garment must be just like any other
garment in our wardrobe, i.e. comfortable,
durable, washable and be able to withstand
the general hardship that we put our clothes
through every day. This is critical for
wearable technology to move outside of the
laboratories and into realistic settings.
By gathering data in the home and
community setting, nanosensors can help
overcome the problems associated with
clinical visits, which only provide a snapshot
of personal health status. Vital signs such as
heart rate, respiration and temperature can
be measured on a continuous basis.
Wearable sensors allow remote monitoring
of a patient, in familiar surroundings,
thus facilitating a more normal lifestyle,
uninterrupted by time-consuming hospital
visits that often contribute to patient anxiety
and stress.
Through the use of functionalised fibres and
yarns the fabric itself becomes the sensor
thus creating garments with inherent
sensing capabilities. Conductive metallic
yarns are knitted or woven to create
electrodes for ECG signals, while piezoresistive conducting polymer fabrics may
be used to measure breathing patterns, gait
and joint movements.
Textile-based nanosensors form part of a
personalised healthcare system providing
valuable information regarding the wearer’s
physiology. This empowers the wearer with
038
By 2050 approximately 20% of the world
population will be at least 60 years old, and
the healthcare system must adapt to cope
with this demographic change.
Nanosensors embedded into clothing or
home textiles may be used to monitor health
and activity while nanosensors furnishing a
“smart” home provide a network of
intelligent devices that learn the user’s
routine and respond accordingly.
A central monitoring unit can aggregate
information from the physiological and
environmental sensors and contact a
relative or ambulance in the event of an
emergency. This type of monitoring
technique has many applications related to
home care of patients with cognitive
impairments such as Alzheimer’s, geriatric
dementia or psychological problems.
Remote health monitoring is a key strategy
that can increase autonomy and assist in the
activities of daily living enabling people,
who currently may require high-cost
constant caring, to continue to live largely
independent lives.
While nanosensors can have huge potential
in the healthcare sector, there are many
other applications of this technology. Just
recently at the Beijing Olympics we saw
how highly engineered textiles have
assisted in breaking records in swimming
through the use of swimsuits that minimise
◊nano
drag, while also reducing muscle fatigue.
The sports industry is continually using
technology to increase capabilities and
push athletes to higher limits.
Nanocoatings are producing better
moisture wicking fabrics to keep the
wearer cool and comfortable. Nanosensors
embedded into sportswear allow athletes to
track their performance and develop a
personalised training program.
The importance of using new functionalised
clothes is that athletes can be monitored
during normal training sessions, i.e. they
can train as usual out on the track or on the
football pitch, as opposed to being hooked
up to machines in a lab.
Body position and limb movements can be
recorded in addition to physiological data
such as heart rate and breathing patterns.
Novel research into on-body chemical
sensors may assist in developing
personalised nutritional and hydration
strategies. These applications are not
restricted to the elite athlete, but
increasingly apply to all levels of ability
in order to maximise the benefits of a
work-out.
In the gym, aerobic training machines
display the number of calories burned,
distance travelled and have an inbuilt heart
rate monitor to keep the user within training
zone specifications. Nanosensors can take
this a step further in providing individual
monitoring and assist in personal
achievement of training goals, outside of the
specialised gym environment.
In extreme environmental conditions and
hazardous situations there is a need for realtime information technology to increase the
protection and survivability of the people
working in those conditions. Improvements
in performance and additional capabilities
would be of immense assistance within
professions such as the defence forces and
emergency response services.
Nanosensors may be used to monitor vital
signs and ease injuries while also
monitoring environment hazards such as
toxic gases. Wireless communication to a
central unit allows medics to conduct
remote triage of casualties to help them
respond more rapidly and safely.
Monitoring in such scenarios is of huge
benefit by increasing the efficiency of the
team as a whole and also the safety of each
individual. This technology may open up a
wide range of other markets where people
are faced with hazardous activities, from
extreme sports through to transportation
maintenance and building workers.
There are other applications extending past
healthcare and human performance where
nanosensors have a part to play. Fashion
and art have always had a strong overlap,
and what better way to portray interactive
art than through the clothes we wear?
XSlabs have used wearable technologies
and sensors to focus on aesthetics,
personal expression, and the idea of play.
Designers such as Hussein Chalayan are
bringing haute tech couture to the catwalks
of Paris, with luminated fabrics and
mechanical dresses.
Clothes may be programmed to respond to
our mood, physiology or environment. This
could be a heated glove which switches on
when we are cold, a hat that tells us we are
too tired to drive, or a shirt that lights up
when we are excited. Aesthetics are an
important factor of what we wear and
responsive garments may be used as a
visual expression of inner emotions,
if that is what the wearer chooses.
Therefore nanosensors have an important
contribution to make, pushing the
boundaries of creativity, and it is up to
us individually to choose how we use
them in innovative ways.
So if we have a shirt to monitor our
daily activities along with our fitness
level and general health, is it an intrusion
of our existence?
It depends how the information is being
used. If personal data is being circulated ‘
039
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CLARITY, a Science Foundation Ireland
funded Centre for Science, Engineering
and Technology, has a mission to “Bring
Information to Life”. This refers to the
harvesting and harnessing of large
volumes of sensed information, from
both the physical world in which we live,
and the digital world of modern
communications & computing. While this
may suggest a “Big Brother” type world
the motivation of the research is to
benefit the citizen by improving their
quality of life through a new generation of
smarter, more proactive, information
services. One area of research is
focussing on functionalised fabrics used
to create “smart” clothing that can
monitor and respond to the wearer.
Further reading
1. Coyle, S., Y. Wu, K. Lau, D. De Rossi,
G. Wallace, and D. Diamond, Smart
Nanotextiles: A Review of Materials and
Applications. MRS Bulletin, 2007. 32(5).
2. Troester, G., The Agenda of Wearable
Healthcare, in IMIA Yearbook of Medical
Informatics, R. Haux and C. Kulikowski,
Editors. 2005, Schattauer: Stuttgart. p.
125-138.
3. www.un.org/esa/socdev/ageing/
popageing.html” (accessed Sept. '08).
within a communications network, it is vital
to ensure that encryption and security
methods are in place. Patient confidentiality
must be preserved and the users’ informed
consent must be given.
As wearable sensors are integrated into the
field of e-health it is important to uphold the
e-Health Code of Ethics. This policy “is to
ensure that people worldwide can
confidently and with full understanding of
known risks realise the potential of the
Internet in managing their own health and
the health of those in their care”. This must
therefore apply to all nanosensor
applications that relate to an individual’s
personal health.
Another concern related to remote health
monitoring is that virtual visits threaten to
turn physicians and nurses into distant
medical technicians and technology may
cut off the trust and close contact between
doctor and patient. In recent years patients’
perception of doctors has changed, and
they are no longer regarded as the
paternalistic figures they once were, but
rather as a technician to health services.
This must be weighed up against the very
considerable benefits of remote monitoring
with the added well-being of a patient being
040
treated in their own home, rather than in a
hospital or some other impersonal institution.
Provided moral and ethical standards are in
place and that users are kept aware of the
operation of monitoring systems there is no
doubt that these tiny devices offer huge
potential in many areas of our lives, giving
us access to the right information at the
right time.
One thing is certain, the current model
of healthcare delivery is unsustainable,
and it is clear that delivery of health
services must become increasingly
distributed, with more status
monitoring happening locally, on an
individualised basis. Associated with
this is the realisation that we need to
take more responsibility for our own
health, and systems need to assist
people to remain independent to a
much greater degree than happens
at present. The implementation of
this vision depends critically on
technologies like wearable sensing. µ
Shirley Coyle and Dermot Diamond are
researchers at CLARITY: The centre for
web technologies bringing information to
life (see side panel)
4. Ramachandran, T., K. Rajendrakumar,
and R. Rajendran, Antimicrobial Textiles an Overview. Textile Engineering, 2004.
84(2): p. 42-47.
5. www.biotex-eu.com (accessed
Sept. 2008).
6. www.proetex.org (accessed Sept '08).
7. http://web.mit.edu/isn/aboutisn/
index.html (accessed Sept. '08).
8. www.xslabs.net/ (accessed Sept. '08).
9. Rippen, H. and A. Risk, e-Health ethics
code. Journal of Medical Internet
Research, 2000. 2(1): p. e9.
10. Kmietovicz, Z., R.E.S.P.E.C.T.—why
doctors are still getting enough of it. British
Medical Journal, 2002. 5(324): p. 7328.
EACH MONTH WE BRING YOU OUR CHOICE
OF NANOART. PLEASE EMAIL THE EDITOR
[email protected]
TO SUBMIT YOUR PICTURES
NanoArt
Roy Kaltschmidt has been an award-winning professional
photographer in the San Francisco Bay Area for more than 35 years.
For the last 12 years he has served as the photographer for the US
Department of Energy’s Lawrence Berkeley National Laboratory,
where he has been dedicated to chronicling the Lab’s leadingedge science. Whether he is dangling from a harness a mile
underground to photographing the Sudbury Neutrino Observatory,
or sailing the Southern Ocean for clues to carbon sequestration,
Kaltschmidt has illuminated the mystery and beauty of the scientific
world to audiences worldwide. His work has been published in
Physics Today, Science, National Geographic, the New York
Times and numerous other publications.
This image demonstrates how DOE researchers discovered 85
strains of living colonies of microbes being harbored in basalt in
the Columbia River in Idaho. Using the infrared beamline at LBL's
Advaced Light Source, researchers studied the living colonies of
microbes in thin slices from unaltered cores.
041
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Commercialising
Nanotechnologies
Challenges - Opportunities - Issues
DAVID TOLFREE
THE GLOBAL MARKET FOR NEW PRODUCTS MANUFACTURED USING
NANOTECHNOLOGY WILL PRODUCE UNPARALLELED OPPORTUNITIES AND
HUGE BENEFITS TO CONSUMERS. THE HEALTHCARE AND TEXTILE INDUSTRIES
ARE ALREADY EXPERIENCING THESE BENEFITS. HOWEVER, THE REALISATION
OF THESE OPPORTUNITIES IS INTRINSICALLY LINKED TO PURPOSEFUL AND
SUSTAINABLE INVESTMENT, MANUFACTURING FACILITIES, AND THE RIGHT
INFRASTRUCTURE AND EXPERTISE TO DEVELOP PRODUCTS AND MARKETS.
Recently, over 250 experts from
around the world met in Puerto
Vallarta, Mexico at the annual
Commercialisation of Micro and
Nanosystems conference (COMS) to
address the issues facing this industry.
The key focus of the week long event
was to establish a framework for
transitioning these emerging
technologies from the laboratory to
the marketplace. In this article, David
Tolfree presents some of the key
findings resulting from the work
presented at COMS2008.
It is predicted that the global market for
micro-nano products will exceed $1 trillion
within five years. This alone is incentive to
drive the development of new nanomaterials
for use in a wide range of industrial sectors
from aerospace to healthcare. For example,
the global market for textiles using
nanotechnology is currently estimated to
be US$13.6 billion and, by 2012, expected
to reach US$115 billion.
It is clear that nanotechnology will require
new manufacturing methodologies and
processes together with appropriate
metrology systems before new industries
can emerge. These will need to extend
across multi-disciplinary domains
(mechanical, electrical, optical, chemical,
biological, etc.). Nanomanufacturing has
produced new paradigms that raise
important fundamental issues related to
costs, yields, reproducibility, quality and
acceptability. Standards for quality and
042
safety consistent with existing regulations
are an important element. Governments
around the world, always fearful about
introducing new technology, are reviewing
procedures and practices for manufacturing
nanotechnology-based products. This
emerging field will succeed but may take
longer than anticipated, particularly in the
biomedical and healthcare fields, where
stringent regulations and testing criteria
exist. These are vital issues for the
estimated 600 nanotechnology
companies worldwide.
In addition to new materials and products,
nanotechnology offers possible solutions to
the greatest challenge facing the world, the
supply of sustainable, cheap energy. When
applied to alternative energy sources,
nanotechnology becomes incorporated
under the generic label of ‘clean
technologies’ now being pursued by many
governments. Clean technologies have the
potential to reduce carbon emissions and
improve the performance of existing energy
production. Cheap, renewable and freely
available sources of power will, in the
future, underpin the economy of every
nation. Nanotechnology is likely to have the
greatest impact in the production of new
materials for hydrogen fuel cells and raising
the efficiency of photocells for solar power.
It has been estimated that with a growing
world population reaching about 1010 by
2050, daily energy demand will increase
from the current value of 14 Terawatts to
>60 Terawatts. This demand can only be
met with nano enabled ‘cleantech’.
Acquiring new sustainable energy supplies
and the growth of the global market pose
unprecedented challenges for society.
These are global issues that require people,
nations and regions to come together to
agree on how the emerging technologies
can provide viable solutions to the problems
that face us. A group of like-minded people
from a number of countries established the
Micro and Nanotechnology
Commercialisation and Education
Foundation (MANCEF). Its mission is to
connect and focus the global micro-nano
community on these challenges and
opportunities facing the world.
MANCEF’s mission is achieved by
advancing commercialisation and
educational opportunities in the emergent
technologies through the promotion of
conferences, workshops and seminars. The
Foundation’s origins extend back to 1994
when the first COMS conference was held
in Banff, Canada. Since that time with its
host partners, the foundation has organised
13 international conferences. At COMS2008,
speakers at a session on Nanotechnology
and Alternative Energies addressed the
issues of clean renewable energy sources
such as hydrogen and solar power.
COMS2009 will be in Copenhagen Demark
and will present an opportunity for
European industrialists to meet with their
counterparts from around the world. µ
David Tolfree is a Technology Consultant
and European VP MANCEF