Tag Archives: Purdue University

US Air Force wants to merge classical and quantum physics

The US Air Force wants to merge classical and quantum physics for practical purposes according to a May 5, 2014 news item on Azonano,

The Air Force Office of Scientific Research has selected the Harvard School of Engineering and Applied Sciences (SEAS) to lead a multidisciplinary effort that will merge research in classical and quantum physics and accelerate the development of advanced optical technologies.

Federico Capasso, Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering, will lead this Multidisciplinary University Research Initiative [MURI] with a world-class team of collaborators from Harvard, Columbia University, Purdue University, Stanford University, the University of Pennsylvania, Lund University, and the University of Southampton.

The grant is expected to advance physics and materials science in directions that could lead to very sophisticated lenses, communication technologies, quantum information devices, and imaging technologies.

“This is one of the world’s strongest possible teams,” said Capasso. “I am proud to lead this group of people, who are internationally renowned experts in their fields, and I believe we can really break new ground.”

A May 1, 2014 Harvard University School of Engineering and Applied Sciences news release, which originated the news item, provides a description of project focus: nanophotonics and metamaterials along with some details of Capasso’s work in these areas (Note: Links have been removed),

The premise of nanophotonics is that light can interact with matter in unusual ways when the material incorporates tiny metallic or dielectric features that are separated by a distance shorter than the wavelength of the light. Metamaterials are engineered materials that exploit these phenomena, producing strange effects, enabling light to bend unnaturally, twist into a vortex, or disappear entirely. Yet the fabrication of thick, or bulk, metamaterials—that manipulate light as it passes through the material—has proven very challenging.

Recent research by Capasso and others in the field has demonstrated that with the right device structure, the critical manipulations can actually be confined to the very surface of the material—what they have dubbed a “metasurface.” These metasurfaces can impart an instantaneous shift in the phase, amplitude, and polarization of light, effectively controlling optical properties on demand. Importantly, they can be created in the lab using fairly common fabrication techniques.

At Harvard, the research has produced devices like an extremely thin, flat lens, and a material that absorbs 99.75% of infrared light. But, so far, such devices have been built to order—brilliantly suited to a single task, but not tunable.

This project, however,is focused on the future (Note: Links have been removed),

“Can we make a rapidly configurable metasurface so that we can change it in real time and quickly? That’s really a visionary frontier,” said Capasso. “We want to go all the way from the fundamental physics to the material building blocks and then the actual devices, to arrive at some sort of system demonstration.”

The proposed research also goes further. A key thrust of the project involves combining nanophotonics with research in quantum photonics. By exploiting the quantum effects of luminescent atomic impurities in diamond, for example, physicists and engineers have shown that light can be captured, stored, manipulated, and emitted as a controlled stream of single photons. These types of devices are essential building blocks for the realization of secure quantum communication systems and quantum computers. By coupling these quantum systems with metasurfaces—creating so-called quantum metasurfaces—the team believes it is possible to achieve an unprecedented level of control over the emission of photons.

“Just 20 years ago, the notion that photons could be manipulated at the subwavelength scale was thought to be some exotic thing, far fetched and of very limited use,” said Capasso. “But basic research opens up new avenues. In hindsight we know that new discoveries tend to lead to other technology developments in unexpected ways.”

The research team includes experts in theoretical physics, metamaterials, nanophotonic circuitry, quantum devices, plasmonics, nanofabrication, and computational modeling. Co-principal investigator Marko Lončar is the Tiantsai Lin Professor of Electrical Engineering at Harvard SEAS. Co-PI Nanfang Yu, Ph.D. ’09, developed expertise in metasurfaces as a student in Capasso’s Harvard laboratory; he is now an assistant professor of applied physics at Columbia. Additional co-PIs include Alexandra Boltasseva and Vladimir Shalaev at Purdue, Mark Brongersma at Stanford, and Nader Engheta at the University of Pennsylvania. Lars Samuelson (Lund University) and Nikolay Zheludev (University of Southampton) will also participate.

The bulk of the funding will support talented graduate students at the lead institutions.

The project, titled “Active Metasurfaces for Advanced Wavefront Engineering and Waveguiding,” is among 24 planned MURI awards selected from 361 white papers and 88 detailed proposals evaluated by a panel of experts; each award is subject to successful negotiation. The anticipated amount of the Harvard-led grant is up to $6.5 million for three to five years.

For anyone who’s not familiar (that includes me, anyway) with MURI awards, there’s this from Wikipedia (Note: links have been removed),

Multidisciplinary University Research Initiative (MURI) is a basic research program sponsored by the US Department of Defense (DoD). Currently each MURI award is about $1.5 million a year for five years.

I gather that in addition to the Air Force, the Army and the Navy also award MURI funds.

Nanomaterials and safety: Europe’s non-governmental agencies make recommendations; (US) Arizona State University initiative; and Japan’s voluntary carbon nanotube management

I have three news items which have one thing in common, they concern nanomaterials and safety. Two of these of items are fairly recent; the one about Japan has been sitting in my drafts folder for months and I’m including it here because if I don’t do it now, I never will.

First, there’s an April 7, 2014 news item on Nanowerk (h/t) about European non-governmental agencies (CIEL; the Center for International Environmental Law and its partners) and their recommendations regarding nanomaterials and safety. From the CIEL April 2014 news release,

CIEL and European partners* publish position paper on the regulation of nanomaterials at a meeting of EU competent authorities

*ClientEarth, The European Environmental Bureau, European citizen’s Organization for Standardisation, The European consumer voice in Standardisation –ANEC, and Health Care Without Harm, Bureau of European Consumers

… Current EU legislation does not guarantee that all nanomaterials on the market are safe by being assessed separately from the bulk form of the substance. Therefore, we ask the European Commission to come forward with concrete proposals for a comprehensive revision of the existing legal framework addressing the potential risks of nanomaterials.

1. Nanomaterials are different from other substances.

We are concerned that EU law does not take account of the fact that nano forms of a substance are different and have different intrinsic properties from their bulk counterpart. Therefore, we call for this principle to be explicitly established in the REACH, and Classification Labeling and Packaging (CLP) regulations, as well as in all other relevant legislation. To ensure adequate consideration, the submission of comprehensive substance identity and characterization data for all nanomaterials on the market, as defined by the Commission’s proposal for a nanomaterial definition, should be required.

Similarly, we call on the European Commission and EU Member States to ensure that nanomaterials do not benefit from the delays granted under REACH to phase-in substances, on the basis of information collected on their bulk form.

Further, nanomaterials, due to their properties, are generally much more reactive than their bulk counterpart, thereby increasing the risk of harmful impact of nanomaterials compared to an equivalent mass of bulk material. Therefore, the present REACH thresholds for the registration of nanomaterials should be lowered.

Before 2018, all nanomaterials on the market produced in amounts of over 10kg/year must be registered with ECHA on the basis of a full registration dossier specific to the nanoform.

2. Risk from nanomaterials must be assessed

Six years after the entry into force of the REACH registration requirements, only nine substances have been registered as nanomaterials despite the much wider number of substances already on the EU market, as demonstrated by existing inventories. Furthermore, the poor quality of those few nano registration dossiers does not enable their risks to be properly assessed. To confirm the conclusions of the Commission’s nano regulatory review assuming that not all nanomaterials are toxic, relevant EU legislation should be amended to ensure that all nanomaterials are adequately assessed for their hazardous properties.

Given the concerns about novel properties of nanomaterials, under REACH, all registration dossiers of nanomaterials must include a chemical safety assessment and must comply with the same information submission requirements currently required for substances classified as Carcinogenic, Mutagenic or Reprotoxic (CMRs).

3. Nanomaterials should be thoroughly evaluated

Pending the thorough risk assessment of nanomaterials demonstrated by comprehensive and up-to-date registration dossiers for all nanoforms on the market, we call on ECHA to systematically check compliance for all nanoforms, as well as check the compliance of all dossiers which, due to uncertainties in the description of their identity and characterization, are suspected of including substances in the nanoform. Further, the Community Roling Action Plan (CoRAP) list should include all identified substances in the nanoform and evaluation should be carried out without delay.

4. Information on nanomaterials must be collected and disseminated

All EU citizens have the right to know which products contain nanomaterials as well as the right to know about their risks to health and environment and overall level of exposure. Given the uncertainties surrounding nanomaterials, the Commission must guarantee that members of the public are in a position to exercise their right to know and to make informed choices pending thorough risk assessments of nanomaterials on the market.

Therefore, a publicly accessible inventory of nanomaterials and consumer products containing nanomaterials must be established at European level. Moreover, specific nano-labelling or declaration requirements must be established for all nano-containing products (detergents, aerosols, sprays, paints, medical devices, etc.) in addition to those applicable to food, cosmetics and biocides which are required under existing obligations.

5. REACH enforcement activities should tackle nanomaterials

REACH’s fundamental principle of “no data, no market” should be thoroughly implemented. Therefore, nanomaterials that are on the market without a meaningful minimum set of data to allow the assessment of their hazards and risks should be denied market access through enforcement activities. In the meantime, we ask the EU Member States and manufacturers to use a precautionary approach in the assessment, production, use and disposal of nanomaterials

This comes on the heels of CIEL’s March 2014 news release announcing a new three-year joint project concerning nanomaterials and safety and responsible development,

Supported by the VELUX foundations, CIEL and ECOS (the European Citizen’s Organization for Standardization) are launching a three-year project aiming to ensure that risk assessment methodologies and risk management tools help guide regulators towards the adoption of a precaution-based regulatory framework for the responsible development of nanomaterials in the EU and beyond.

Together with our project partner the German Öko-Institut, CIEL and ECOS will participate in the work of the standardization organizations Comité Européen de Normalisation and International Standards Organization, and this work of the OECD [Organization for Economic Cooperation and Development], especially related to health, environmental and safety aspects of nanomaterials and exposure and risk assessment. We will translate progress into understandable information and issue policy recommendations to guide regulators and support environmental NGOs in their campaigns for the safe and sustainable production and use of nanomaterials.

The VILLUM FOUNDATION and the VELUX FOUNDATION are non-profit foundations created by Villum Kann Rasmussen, the founder of the VELUX Group and other entities in the VKR Group, whose mission it is to bring daylight, fresh air and a better environment into people’s everyday lives.

Meanwhile in the US, an April 6, 2014 news item on Nanowerk announces a new research network, based at Arizona State University (ASU), devoted to studying health and environmental risks of nanomaterials,

Arizona State University researchers will lead a multi-university project to aid industry in understanding and predicting the potential health and environmental risks from nanomaterials.

Nanoparticles, which are approximately 1 to 100 nanometers in size, are used in an increasing number of consumer products to provide texture, resiliency and, in some cases, antibacterial protection.

The U.S. Environmental Protection Agency (EPA) has awarded a grant of $5 million over the next four years to support the LCnano Network as part of the Life Cycle of Nanomaterials project, which will focus on helping to ensure the safety of nanomaterials throughout their life cycles – from the manufacture to the use and disposal of the products that contain these engineered materials.

An April 1, 2014 ASU news release, which originated the news item, provides more details and includes information about project partners which I’m happy to note include nanoHUB and the Nanoscale Informal Science Education Network (NISENet) in addition to the other universities,

Paul Westerhoff is the LCnano Network director, as well as the associate dean of research for ASU’s Ira A. Fulton Schools of Engineering and a professor in the School of Sustainable Engineering and the Built Environment.

The project will team engineers, chemists, toxicologists and social scientists from ASU, Johns Hopkins, Duke, Carnegie Mellon, Purdue, Yale, Oregon’s state universities, the Colorado School of Mines and the University of Illinois-Chicago.

Engineered nanomaterials of silver, titanium, silica and carbon are among the most commonly used. They are dispersed in common liquids and food products, embedded in the polymers from which many products are made and attached to textiles, including clothing.

Nanomaterials provide clear benefits for many products, Westerhoff says, but there remains “a big knowledge gap” about how, or if, nanomaterials are released from consumer products into the environment as they move through their life cycles, eventually ending up in soils and water systems.

“We hope to help industry make sure that the kinds of products that engineered nanomaterials enable them to create are safe for the environment,” Westerhoff says.

“We will develop molecular-level fundamental theories to ensure the manufacturing processes for these products is safer,” he explains, “and provide databases of measurements of the properties and behavior of nanomaterials before, during and after their use in consumer products.”

Among the bigger questions the LCnano Network will investigate are whether nanomaterials can become toxic through exposure to other materials or the biological environs they come in contact with over the course of their life cycles, Westerhoff says.

The researchers will collaborate with industry – both large and small companies – and government laboratories to find ways of reducing such uncertainties.

Among the objectives is to provide a framework for product design and manufacturing that preserves the commercial value of the products using nanomaterials, but minimizes potentially adverse environmental and health hazards.

In pursuing that goal, the network team will also be developing technologies to better detect and predict potential nanomaterial impacts.

Beyond that, the LCnano Network also plans to increase awareness about efforts to protect public safety as engineered nanomaterials in products become more prevalent.

The grant will enable the project team to develop educational programs, including a museum exhibit about nanomaterials based on the LCnano Network project. The exhibit will be deployed through a partnership with the Arizona Science Center and researchers who have worked with the Nanoscale Informal Science Education Network.

The team also plans to make information about its research progress available on the nanotechnology industry website Nanohub.org.

“We hope to use Nanohub both as an internal virtual networking tool for the research team, and as a portal to post the outcomes and products of our research for public access,” Westerhoff says.

The grant will also support the participation of graduate students in the Science Outside the Lab program, which educates students on how science and engineering research can help shape public policy.

Other ASU faculty members involved in the LCnano Network project are:

• Pierre Herckes, associate professor, Department of Chemistry and Biochemistry, College of Liberal Arts and Sciences
• Kiril Hristovski, assistant professor, Department of Engineering, College of Technology and Innovation
• Thomas Seager, associate professor, School of Sustainable Engineering and the Built Environment
• David Guston, professor and director, Consortium for Science, Policy and Outcomes
• Ira Bennett, assistant research professor, Consortium for Science, Policy and Outcomes
• Jameson Wetmore, associate professor, Consortium for Science, Policy and Outcomes, and School of Human Evolution and Social Change

I hope to hear more about the LCnano Network as it progresses.

Finally, there was this Nov. 12, 2013 news item on Nanowerk about instituting  voluntary safety protocols for carbon nanotubes in Japan,

Technology Research Association for Single Wall Carbon Nanotubes (TASC)—a consortium of nine companies and the National Institute of Advanced Industrial Science and Technology (AIST) — is developing voluntary safety management techniques for carbon nanotubes (CNTs) under the project (no. P10024) “Innovative carbon nanotubes composite materials project toward achieving a low-carbon society,” which is sponsored by the New Energy and Industrial Technology Development Organization (NEDO).

Lynn Bergeson’s Nov. 15, 2013 posting on nanotech.lawbc.com provides a few more details abut the TASC/AIST carbon nanotube project (Note: A link has been removed),

Japan’s National Institute of Advanced Industrial Science and Technology (AIST) announced in October 2013 a voluntary guidance document on measuring airborne carbon nanotubes (CNT) in workplaces. … The guidance summarizes the available practical methods for measuring airborne CNTs:  (1) on-line aerosol measurement; (2) off-line quantitative analysis (e.g., thermal carbon analysis); and (3) sample collection for electron microscope observation. …

You can  download two protocol documents (Guide to measuring airborne carbon nanotubes in workplaces and/or The protocols of preparation, characterization and in vitro cell based assays for safety testing of carbon nanotubes), another has been published since Nov. 2013, from the AIST’s Developing voluntary safety management techniques for carbon nanotubes (CNTs): Protocol and Guide webpage., Both documents are also available in Japanese and you can link to the Japanese language version of the site from the webpage.

Researchers at Purdue University (Indiana, US) and at the Indian Institute of Technology Madras (Chennai, India) develop Star Trek-type ‘tricorders’

To be clear, the Star Trek-type ‘tricorder’ referred to in the heading is, in fact, a hand-held spectrometer and the research from Purdue University and the Indian Institute of Technology Madras represents a developmental leap forward, not a new product. From a March 26, 2014 news item on Azonano,

Nanotechnology is advancing tools likened to Star Trek’s “tricorder” that perform on-the-spot chemical analysis for a range of applications including medical testing, explosives detection and food safety.

Researchers found that when paper used to collect a sample was coated with carbon nanotubes, the voltage required was 1,000 times reduced, the signal was sharpened and the equipment was able to capture far more delicate molecules.

Dexter Johnson in his March 26, 2014 posting (Nanoclast blog on the IEEE [Institute of Electrical and Electronics Engineers] website) provides some background information about the race to miniaturize spectrometers (Note: A link has been removed),

Recent research has been relying on nanomaterials to build smaller spectrometers. Late last year, a group at the Technische Universität Dresden and the Fraunhofer Institute in Germany developed a novel, miniature spectrometer, based on metallic nanowires, that was small enough to fit into a mobile phone.

Dexter goes on to provide a summary about this latest research, which I strongly recommend reading, especially if you don’t have the patience to read the rest of the news release. The March 25, 2014 Purdue University news release by Elizabeth K. Gardner, which originated the news item, provides insight from the researchers,

“This is a big step in our efforts to create miniature, handheld mass spectrometers for the field,” said R. Graham Cooks, Purdue’s Henry B. Hass Distinguished Professor of Chemistry. “The dramatic decrease in power required means a reduction in battery size and cost to perform the experiments. The entire system is becoming lighter and cheaper, which brings it that much closer to being viable for easy, widespread use.”

Cooks and Thalappil Pradeep, a professor of chemistry at the Indian Institute of Technology Madras, Chennai, led the research.

“Taking science to the people is what is most important,” Pradeep said. “Mass spectrometry is a fantastic tool, but it is not yet on every physician’s table or in the pocket of agricultural inspectors and security guards. Great techniques have been developed, but we need to hone them into tools that are affordable, can be efficiently manufactured and easily used.”

The news release goes on to describe the research,

The National Science Foundation-funded study used an analysis technique developed by Cooks and his colleagues called PaperSpray™ ionization. The technique relies on a sample obtained by wiping an object or placing a drop of liquid on paper wet with a solvent to capture residues from the object’s surface. A small triangle is then cut from the paper and placed on a special attachment of the mass spectrometer where voltage is applied. The voltage creates an electric field that turns the mixture of solvent and residues into fine droplets containing ionized molecules that pop off and are vacuumed into the mass spectrometer for analysis. The mass spectrometer then identifies the sample’s ionized molecules by their mass.

The technique depends on a strong electric field and the nanotubes act like tiny antennas that create a strong electric field from a very small voltage. One volt over a few nanometers creates an electric field equivalent to 10 million volts over a centimeter, Pradeep said.

“The trick was to isolate these tiny, nanoscale antennae and keep them from bundling together because individual nanotubes must project out of the paper,” he said. “The carbon nanotubes work well and can be dispersed in water and applied on suitable substrates.”

The Nano Mission of the Government of India supported the research at the Indian Institute of Technology Madras and graduate students Rahul Narayanan and Depanjan Sarkar performed the experiments.

In addition to reducing the size of the battery required and energy cost to run the tests, the new technique also simplified the analysis by nearly eliminating background noise, Cooks said.

“Under these conditions, the analysis is nearly noise free and a sharp, clear signal of the sample is delivered,” he said. “We don’t know why this is – why background molecules that surround us in the air or from within the equipment aren’t being ionized and entering into the analysis. It’s a puzzling, but pleasant surprise.”

The reduced voltage required also makes the method gentler than the standard PaperSpray™ ionization techniques.

“It is a very soft method,” Cooks said. “Fragile molecules and complexes are able to hold together here when they otherwise wouldn’t. This could lead to other potential applications.”

The team plans to investigate the mechanisms behind the reduction in background noise and potential applications of the gentle method, but the most promising aspect of the new technique is its potential to miniaturize the mass spectrometry system, Cooks said.

Here’s a link to and a citation for the paper,

Molecular Ionization from Carbon Nanotube Paper by Rahul Narayanan, Depanjan Sarkar, Prof. R. Graham Cooks, and Prof. Thalappil Pradeep. Angewandte Chemie International Edition Article first published online: 18 MAR 2014 DOI: 10.1002/anie.201311053

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

Fundamental mechanical behaviour of cellulose nanocrystals (aka nanocrystalline cellulose)

Emil Venere at Purdue University offers an excellent explanation of why there’s so much international interest in cellulose nanocrystals (CNC aka, nanocrystalline cellulose [NCC]) in his Dec. 16, 2013 Purdue University (Indiana, US) news release (also on EurekAlert), Note: A link has been removed,

The same tiny cellulose crystals that give trees and plants their high strength, light weight and resilience, have now been shown to have the stiffness of steel.

The nanocrystals might be used to create a new class of biomaterials with wide-ranging applications, such as strengthening construction materials and automotive components.

Calculations using precise models based on the atomic structure of cellulose show the crystals have a stiffness of 206 gigapascals, which is comparable to steel, said Pablo D. Zavattieri, a Purdue University assistant professor of civil engineering.

Here’s an image of the cellulose crystals being examined,

This transmission electron microscope image shows cellulose nanocrystals, tiny structures that give trees and plants their high strength, light weight and resilience. The nanocrystals might be used to create a new class of biomaterials that would have a wide range of applications. (Purdue Life Sciences Microscopy Center)

This transmission electron microscope image shows cellulose nanocrystals, tiny structures that give trees and plants their high strength, light weight and resilience. The nanocrystals might be used to create a new class of biomaterials that would have a wide range of applications. (Purdue Life Sciences Microscopy Center)

You’ll notice this image is not enhanced and made pretty as compared to the images in my Dec. 16, 2013 posting about Bristol University’s Art of Science competition. It takes a lot of work to turn the types of images scientists use into ‘art’.

Getting back to the CNC, this news release was probably written by someone who’s not familiar with the other work being done in the field (university press officers typically write about a wide range of topics and cannot hope to have in depth knowledge on each topic) and so it’s being presented as if it is brand new information. In fact, there has been several years work done in five other national jurisdictions that I know of (Sweden, Finland, Canada, Brazil, and Israel) and there are likely more. That’s not including other US states pursuing research in this area, notably Wisconsin.

What I (taking into account  my limitations) find particularly exciting in this work is the detail they’ve been able to determine and the reference to quantum mechanics. Here’s more from the news release (Note: Links have been removed),

“It is very difficult to measure the properties of these crystals experimentally because they are really tiny,” Zavattieri said. “For the first time, we predicted their properties using quantum mechanics.”

The nanocrystals are about 3 nanometers wide by 500 nanometers long – or about 1/1,000th the width of a grain of sand – making them too small to study with light microscopes and difficult to measure with laboratory instruments.

The findings represent a milestone in understanding the fundamental mechanical behavior of the cellulose nanocrystals.

“It is also the first step towards a multiscale modeling approach to understand and predict the behavior of individual crystals, the interaction between them, and their interaction with other materials,” Zavattieri said. “This is important for the design of novel cellulose-based materials as other research groups are considering them for a huge variety of applications, ranging from electronics and medical devices to structural components for the automotive, civil and aerospace industries.”

From an applications perspective (which is what excites so much international interest),

The cellulose nanocrystals represent a potential green alternative to carbon nanotubes for reinforcing materials such as polymers and concrete. Applications for biomaterials made from the cellulose nanocrystals might include biodegradable plastic bags, textiles and wound dressings; flexible batteries made from electrically conductive paper; new drug-delivery technologies; transparent flexible displays for electronic devices; special filters for water purification; new types of sensors; and computer memory.

Cellulose could come from a variety of biological sources including trees, plants, algae, ocean-dwelling organisms called tunicates, and bacteria that create a protective web of cellulose.

“With this in mind, cellulose nanomaterials are inherently renewable, sustainable, biodegradable and carbon-neutral like the sources from which they were extracted,” Moon said. “They have the potential to be processed at industrial-scale quantities and at low cost compared to other materials.”

Biomaterials manufacturing could be a natural extension of the paper and biofuels industries, using technology that is already well-established for cellulose-based materials.

“Some of the byproducts of the paper industry now go to making biofuels, so we could just add another process to use the leftover cellulose to make a composite material,” Moon said. “The cellulose crystals are more difficult to break down into sugars to make liquid fuel. So let’s make a product out of it, building on the existing infrastructure of the pulp and paper industry.”

Their surface can be chemically modified to achieve different surface properties.

“For example, you might want to modify the surface so that it binds strongly with a reinforcing polymer to make a new type of tough composite material, or you might want to change the chemical characteristics so that it behaves differently with its environment,” Moon said.

Zavattieri plans to extend his research to study the properties of alpha-chitin, a material from the shells of organisms including lobsters, crabs, mollusks and insects. Alpha-chitin appears to have similar mechanical properties as cellulose.

“This material is also abundant, renewable and waste of the food industry,” he said.

Here’s a link to and a citation for the paper,

Anisotropy of the Elastic Properties of Crystalline Cellulose Iβ from First Principles Density Functional Theory with Van der Waals Interactions by Fernando L. Dri, Louis G. Hector Jr., Robert J. Moon, Pablo D. Zavattieri.  Cellulose December 2013, Volume 20, Issue 6, pp 2703-2718. 10.1007/s10570-013-0071-8

This paper is behind a paywall although you can preview the first few pages.

Erasing time to create a temporal invisibility cloak

The idea of taking an eraser and just rubbing out embarrassing (or worse) incidents in one’s life is tempting but not yet possible despite efforts by researchers at Purdue University (Indiana, US). From a June 5, 2013 news item on ScienceDaily,

Researchers have demonstrated a method for “temporal cloaking” of optical communications, representing a potential tool to thwart would-be eavesdroppers and improve security for telecommunications.

“More work has to be done before this approach finds practical application, but it does use technology that could integrate smoothly into the existing telecommunications infrastructure,” said Purdue University graduate student Joseph Lukens, working with Andrew Weiner, the Scifres Family Distinguished Professor of Electrical and Computer Engineering.

Other researchers in 2012 invented temporal cloaking, but it cloaked only a tiny fraction — about a 10,000th of a percent — of the time available for sending data in optical communications. Now the Purdue researchers have increased that to about 46 percent, potentially making the concept practical for commercial applications.

The Purdue University June 5, 2013 news release, which originated the news item, describes the new technique,

The technique works by manipulating the phase, or timing, of light pulses. The propagation of light can be likened to waves in the ocean. If one wave is going up and interacts with another wave that’s going down, they cancel each other and the light has zero intensity. The phase determines the level of interference between these waves.

“By letting them interfere with each other you are able to make them add up to a one or a zero,” Lukens said. “The zero is a hole where there is nothing.”

Any data in regions where the signal is zero would be cloaked.

Controlling phase allows the transmission of signals in ones and zeros to send data over optical fibers. A critical piece of hardware is a component called a phase modulator, which is commonly found in optical communications to modify signals.

In temporal cloaking, two phase modulators are used to first create the holes and two more to  cover them up, making it look as though nothing was done to the signal.

“It’s a potentially higher level of security because it doesn’t even look like you are communicating,” Lukens said. “Eavesdroppers won’t realize the signal is cloaked because it looks like no signal is being sent.”

Such a technology also could find uses in the military, homeland security or law enforcement.

“It might be used to prevent communication between people, to corrupt their communication links without them knowing,” he said. “And you can turn it on and off, so if they suspected something strange was going on you could return it to normal communication.”

The technique could be improved to increase its operational bandwidth and the percentage of cloaking beyond 46 percent, he said.

In a July 14, 2011 posting I wrote about some of the research that laid the groundwork for this breakthrough at Purdue University,

Ian Sample in his July 13, 2011 posting on The Guardian Science blogs describes an entirely different approach, one that focusses on cloaking events rather than objects. From Samples’s posting,

The theoretical prospect of a “space-time” cloak – or “history editor” – was raised by Martin McCall and Paul Kinsler at Imperial College in a paper published earlier this year. The physicists explained that when light passes through a material, such as a lens, the light waves slow down. But it is possible to make a lens that splits the light in two, so that half – say the shorter wavelengths – speed up, while the other half, the longer wavelengths, slow down. This opens a gap in the light in which an event can be hidden, because half the light arrives before it has happened, and the other half arrives after the event.

In their paper, McCall and Kinsler outline a scenario whereby a video camera would be unable to record a crime being committed because there was a means of splitting the light such that 1/2 of it reached the camera before the crime occurred and the other 1/2  reached the camera afterwards. Fascinating, non?

It seems researchers at Cornell University have developed a device that can in a rudimentary fashion cloak events (from Samples’s posting),

The latest device, which has been shown to work for the first time by Moti Fridman and Alexander Gaeta at Cornell University, goes beyond the more familiar invisibility cloak, which aims to hide objects from view, by making entire events invisible.

Zeeya Merali in her extensive June 5, 2013 article (Temporal cloak erases data from history) for Nature provides an in depth explanation of the Purdue research,

To speed up the cloaking rate, Lukens and his colleagues exploited a wave phenomenon that was first discovered by British inventor Henry Fox Talbot in 1836. When a light wave passes through a series of parallel slits called a diffraction grating, it splits apart. The rays emanating from the slits combine on the other side to create an intricate interference pattern of peaks and troughs. Talbot discovered that this pattern repeats at regular intervals, creating what is now known as a Talbot carpet. There is also a temporal version of this effect in which you manipulate light over time to generate regular periods with zero light intensity, says Lukens. Data can be then be hidden in these holes in time.

Lukens’ team created its Talbot carpet in time by passing laser light through a ‘phase modulator’, a waveguide that also had an oscillating electrical voltage applied to it. As the voltage varied, the speed at which the light travelled through the waveguide was altered, splitting the light into its constituent frequencies and knocking these out of step. As predicted, at regular time intervals, the separate frequencies recombined destructively to generate time holes. Lukens’ team then used a second round of phase modulation to compress the energy further, expanding the duration of the time windows to 36 picoseconds (or 36 trillionths of a second).

The researchers tested the cloak to see if it was operating correctly by inserting a separate encoded data stream into the fibre during the time windows. They then applied two more rounds of phase modulation — to “undo the damage of the first two rounds”, says Lukens — decompressing the energy again and then combining the separated frequencies back into one. They confirmed that a user downstream would pick up the original laser signal alone, as though it had never been disturbed. The cloak successfully hid data added at a rate of 12.7 gigabits per second.

Unfortunately, the researchers were a little too successful and managed to erase the event entirely, which seems to answer a question I posed facetiously in my July 14, 2011 posting,

If you can’t see the object (light bending cloak), and you never saw the event (temporal cloak), did it exist and did it happen?

In addition to the military applications that Lukens imagines for temporal invisibility cloaks, Merali notes a another possibility in her Nature article,

Ironically, the first application of temporal cloaks may not be to hide data, but to help them to be read more accurately. The team has shown that splitting and recombining light waves in time creates increased periods in which the main data stream can be made immune to corruption by inserted data. “This could be useful to cut down crosstalk when multiple data streams share the same fibre,” says Lukens.

Gaeta agrees that the primary use for cloaking will probably be for innocent, mundane purposes. “People always imagine doing something illicit when they hear ‘cloaking’,” he says. “But these ways for manipulating light will probably be used to make current non-secret communication techniques more sophisticated.”

The research paper can be found here,

A temporal cloak at telecommunication data rate by Joseph M. Lukens, Daniel E. Leaird & Andrew M. Weiner. Nature (2013) doi:10.1038/nature12224 Published online 05 June 2013

This paper is behind a paywall. Fortunately, anyone can access my June 5, 2013 posting (Memories, science, archiving, and authenticity) which seems relevant here for two reasons. First, there’s a mention of a new open access initiative in the US which would make this research more freely available in the future with a proposal (there may be others as this initiative develops) called the Clearinghouse for the Open Research of the United States (CHORUS).  I imagine there would be some caveats and I notice that Nature magazine has signed up for this proposal. I think the second reason for mentioning yesterday’s post is pretty obvious, memory/erasing, etc.

Solar cells made even more leaflike with inclusion of nanocellulose fibers

Researchers at the US Georgia  Institute of Technology (Georgia Tech)  and Purdue University (Indiana) have used cellulose nanocrystals (CNC), which is also known as nanocrystalline cellulose (NCC), to create solar cells that have greater efficiency and can be recycled. From the Mar. 26, 2013 news item on Nanowerk,

Georgia Institute of Technology and Purdue University researchers have developed efficient solar cells using natural substrates derived from plants such as trees. Just as importantly, by fabricating them on cellulose nanocrystal (CNC) substrates, the solar cells can be quickly recycled in water at the end of their lifecycle.

The Georgia Tech Mar. 25, 2013 news release, which originated the news item,

The researchers report that the organic solar cells reach a power conversion efficiency of 2.7 percent, an unprecedented figure for cells on substrates derived from renewable raw materials. The CNC substrates on which the solar cells are fabricated are optically transparent, enabling light to pass through them before being absorbed by a very thin layer of an organic semiconductor. During the recycling process, the solar cells are simply immersed in water at room temperature. Within only minutes, the CNC substrate dissolves and the solar cell can be separated easily into its major components.

Georgia Tech College of Engineering Professor Bernard Kippelen led the study and says his team’s project opens the door for a truly recyclable, sustainable and renewable solar cell technology.

“The development and performance of organic substrates in solar technology continues to improve, providing engineers with a good indication of future applications,” said Kippelen, who is also the director of Georgia Tech’s Center for Organic Photonics and Electronics (COPE). “But organic solar cells must be recyclable. Otherwise we are simply solving one problem, less dependence on fossil fuels, while creating another, a technology that produces energy from renewable sources but is not disposable at the end of its lifecycle.”

To date, organic solar cells have been typically fabricated on glass or plastic. Neither is easily recyclable, and petroleum-based substrates are not very eco-friendly. For instance, if cells fabricated on glass were to break during manufacturing or installation, the useless materials would be difficult to dispose of. Paper substrates are better for the environment, but have shown limited performance because of high surface roughness or porosity. However, cellulose nanomaterials made from wood are green, renewable and sustainable. The substrates have a low surface roughness of only about two nanometers.

“Our next steps will be to work toward improving the power conversion efficiency over 10 percent, levels similar to solar cells fabricated on glass or petroleum-based substrates,” said Kippelen. The group plans to achieve this by optimizing the optical properties of the solar cell’s electrode.

The news release also notes the impact that using cellulose nanomaterials could have economically,

There’s also another positive impact of using natural products to create cellulose nanomaterials. The nation’s forest product industry projects that tens of millions of tons of them could be produced once large-scale production begins, potentially in the next five years.

One might almost  suspect that the forest products industry is experiencing financial difficulty.

The researchers’ paper was published by Scientific Reports, an open access journal from the Nature Publishing Group,

Recyclable organic solar cells on cellulose nanocrystal substrates by Yinhua Zhou, Canek Fuentes-Hernandez, Talha M. Khan, Jen-Chieh Liu, James Hsu, Jae Won Shim, Amir Dindar, Jeffrey P. Youngblood, Robert J. Moon, & Bernard Kippelen. Scientific Reports  3, Article number: 1536  doi:10.1038/srep01536 Published 25 March 2013

In closing, the news release notes that a provisional patent has been filed at the US Patent Office.And one final note, I have previously commented on how confusing the reported power conversion rates are. You’ll find a recent comment in my Mar. 8, 2013 posting about Ted Sargent’s work with colloidal quantum dots and solar cells.

$14.5M to take nanoHUB to the ‘next level’

According to the Feb. 5, 2013 news item on Nanotechnology Now, nanoHUB , online science and engineering gateway based at Purdue University, Indiana, is going to be receiving a $14.5M five year grant from the US National Science Foundation (NSF),

“Thousands of times a day the leading researchers ‘come’ to Purdue through the globally unique tool of nanoHUB,” Purdue President Mitch Daniels said Tuesday (Feb. 5) in announcing the grant. “The new NSF investment is an affirmation of the brilliance of nanoHUB’s Purdue creators and of its worldwide scientific significance.”

Annually, nearly 250,000 users in 172 countries participate in nanoHUB, an online meeting place for simulation, research, collaboration, teaching, learning and publishing. The nanoHUB provides a library of 267 simulation tools, free from the limitations of running software locally, used in the scientific computing cloud by more than 12,000 people every year.

The Internet-based initiative provides 3,000 resources from more than 1,000 authors for research and education in the areas of nanoelectronics and nanoelectromechanical systems and their application to nano-biosystems. The nanoHUB menu also includes courses, tutorials, seminars, discussions and facilities to foster nano-research collaboration, including the Birck Nanotechnology Center in Purdue’s Discovery Park.

The Purdue University Feb. 5, 2013 news release, which originated the news item, provides more details although some are a bit confusing (Note: Links have been removed),

The Purdue-led Cyber Platform, a part of the Network for Computational Nanotechnology (NCN), will assist researchers across the globe by developing a virtual society that shares simulation software, data and other innovative content to provide engineers and scientists with the fundamental knowledge required to advance nanoscience into nanotechnology.

Through Cyber Platform developments and community engagement efforts, the nanoHUB in its next phase is designed to:

* Accelerate research by transforming nanoscience to nanotechnology through the integration of simulation with experimental data.

* Inspire and educate the next-generation nanoscience and nanotechnology workforce.

* Expand the nanoHUB society that uses and shares content on the Web-based portal.

“Our long-term vision for the Cyber Platform is to use the nanoHUB as an online nano society that researchers, practitioners, educators and students depend on daily,” said Purdue electrical and computer engineering professor Gerhard Klimeck, principal investigator of the Purdue-led Cyber Platform. “At the same time, we are excited about how this tool has extended into professional practice as a computational resource for a multidisciplinary culture of innovation grounded in cloud services-enabled workflows.”

The NSF award abstract helps to clear up matters,

Network for Computational Nanotechnology (NCN) was founded in 2002 to advance nanoscience toward nanotechnology via online simulations on nanoHUB.org. Not only has nanoHUB become the first broadly successful, scientific end-to-end cloud computing environment, but it also has evolved well beyond online simulation. Annually, nanoHUB provides a library of 3,000 learning resources to 195,000 users worldwide. Its 232 simulation tools, free from the limitations of running software locally, are used in the cloud by over 10,800 annually. Its impact is demonstrated by 720+ citations to nanoHUB in the scientific literature with over 4,807 secondary citations, yielding an h-index of 31, and by a median time from publication of a research simulation program to classroom use of less than 6 months. Cumulatively, over 14,000 students in over 760 formal classes in over 100 institutions have used nanoHUB simulations.

Despite a decade of transformational success for a broad nanotechnology research and education community, significant gaps remain as work is still performed by isolated individuals and small groups. This fragmentation by specialty hinders tool and data sharing across knowledge domains. Nano areas such as bio, photonics, and materials are only beginning to use nanoHUB while manufacturing, informatics, environmental-health-and-safety are to date not even represented on nanoHUB. The NCN Cyber Platform proposes to address these gaps through efforts in three strategic goals to: 1) accelerate research by transforming nanoscience to nanotechnology through the integration of simulation with experimentation; 2) inspire and educate the next-generation nanoscience and nanotechnology workforce; and 3) grow the nanoHUB society that uses and shares nanoHUB content. Five cross-cutting thrust areas focus on the cyberinfrastructure (CI) and social dynamics of the nanoHUB virtual society: CI innovation; content stewardship and node engagement; education research and precollege/college and lifelong learning; outreach, diversity, and marketing; and CI operations. The 10-year NCN nanoHUB Cyber Platform vision is that nanoHUB will be the online nano society that researchers, practitioners, educators and students depend on day-to-day while simultaneously immersed in professional practice and computational resources for a multidisciplinary culture of innovation grounded in cloud services-enabled workflows.

Intellectual Merit: The NCN nanoHUB strategic plan will answer two fundamental challenges to the next-generation nanoHUB experience: 1) development of technologies that enable simple management and publication of scientific data (experimental and simulation) without additional complex steps: and 2) the establishment of a value system that fosters publication of data, tools, and lectures similar to today’s rewards for journal publications. CI innovation, developed through the leading HUBzero platform as well as in cooperation with other CI efforts, will enable new connection points for research, education, and commercialization, expanded platform tool features to help users exchange and publish data; combined data and tools for verification, validation, and engineering activities; and increase immersive and pervasive features. Through partnerships with professional societies and commercial publishers, nanoHUB will change how researchers publish their simulation results through novel interactive journals that reflect a user’s workflow, link directly back to their data, and make the work reproducible. This value system will drive new content toward nanoHUB, obviating the need for content generation to be monetarily supported by NCN. Through partnerships with the three new NCN content nodes and other NSF-funded nano efforts, NCN will continue to foster content creation to demonstrate value to the authors and will prototype, test, and host the proposed new technologies for broad usage.

Broader Impacts: NCN has developed processes that enabled researchers to rapidly deploy their research codes and innovative tutorials and classes on nanoHUB. To date, these processes harvested research and educational results from 890 contributors world-wide. Expansion into new areas of nano research and education, including pre-college education, represent a huge growth potential for nanoHUB that goes beyond simulation to embracing data management, search, and exploration. Focus on diversity will continue to be an integral part of NCN’s outreach program, in particular through focused workshops and new initiatives such as EPICS High. The NCN-pioneered HUBzero already powers 40 HUBs at 12 institutions, serving a broad range of science and engineering disciplines and commercialization. Through impact assessment and continual contributions to HUBzero software stack releases, nanoHUB will continue to drive impact beyond its nano society into other disciplines and institutions.

While this duplicates some of the text in the NSF award abstract, it does offer some new nuggests, from the Purdue University news release,

The nanoHUB has become the first broadly successful, cloud-computing environment for research across multiple disciplines, with more than 960 citations in scientific literature and 8,000 secondary citations, with nearly one-third of those papers involving experimental data. It also has evolved well beyond online simulation for research.

From New York to London and Moscow to Madrid, more than 14,000 students in 760 formal classes at 185 institutions have used nanoHUB simulations for classroom teaching, homework and projects. The nanoHUB also provides a library of 3,000 learning materials.

“Most of these tools are adopted for formal education in six months, compared with the 3.8 years it takes for the release of new college textbook editions,” Klimeck said.

NCN founding director Mark Lundstrom, the Don and Carol Scifres Distinguished Professor of Electrical and Computer Engineering at Purdue, said a key part of the Cyber Platform project is to engage an ever-larger and more diverse cyber community that shares novel, high-quality nanoscale computation and simulation research and educational resources.

“The reason we created the nanoHUB cyberinfrastructure 10 years ago was to connect those who are doing simulation with experimental collaborators,” Lundstrom said. “Today, it’s called cloud computing.”

Here’s a for those who want to check out the Network for Computational Nanotechnology (NCN.  For another history of nanoHUB, check my Nov. 6, 2010 posting and for the little bit I have on HUBzero, there’s my Feb. 20, 2012 posting about the session concerning that platform at the American Association for the Advancement of Science (AAAS) 2012 annual meeting.

Christmas-tree shaped ‘4-D’ nanowires

This Dec. 5, 2012 news item on Nanowerk features a seasonal approach to a study about ‘4-D’ nanowires,

A new type of transistor shaped like a Christmas tree has arrived just in time for the holidays, but the prototype won’t be nestled under the tree along with the other gifts.

“It’s a preview of things to come in the semiconductor industry,” said Peide “Peter” Ye, a professor of electrical and computer engineering at Purdue University.

Researchers from Purdue and Harvard universities created the transistor, which is made from a material that could replace silicon within a decade. Each transistor contains three tiny nanowires made not of silicon, like conventional transistors, but from a material called indium-gallium-arsenide. The three nanowires are progressively smaller, yielding a tapered cross section resembling a Christmas tree.

Sadly, Purdue University (Indiana, US) will not be releasing any images to accompany their Dec. 4, 2012 news release (which originated the news item) about the ‘4-D’ transistor  until Saturday, Dec. 8, 2012.  So here’s an image of a real Christmas tree from the National Christmas Tree Organization’s Common Tree Characteristics webpage,

Douglas Fir Christmas tree from http://www.realchristmastrees.org/dnn/AllAboutTrees/TreeCharacteristics.aspx

 

The Purdue University news release written by Emil Venere provides more detail about the work,

“A one-story house can hold so many people, but more floors, more people, and it’s the same thing with transistors,” Ye said. “Stacking them results in more current and much faster operation for high-speed computing. This adds a whole new dimension, so I call them 4-D.”

The work is led by Purdue doctoral student Jiangjiang Gu and Harvard postdoctoral researcher Xinwei Wang.

The newest generation of silicon computer chips, introduced this year, contain transistors having a vertical 3-D structure instead of a conventional flat design. However, because silicon has a limited “electron mobility” – how fast electrons flow – other materials will likely be needed soon to continue advancing transistors with this 3-D approach, Ye said.

Indium-gallium-arsenide is among several promising semiconductors being studied to replace silicon. Such semiconductors are called III-V materials because they combine elements from the third and fifth groups of the periodic table.

Transistors contain critical components called gates, which enable the devices to switch on and off and to direct the flow of electrical current. Smaller gates make faster operation possible. In today’s 3-D silicon transistors, the length of these gates is about 22 nanometers, or billionths of a meter.

The 3-D design is critical because gate lengths of 22 nanometers and smaller do not work well in a flat transistor architecture. Engineers are working to develop transistors that use even smaller gate lengths; 14 nanometers are expected by 2015, and 10 nanometers by 2018.

However, size reductions beyond 10 nanometers and additional performance improvements are likely not possible using silicon, meaning new materials will be needed to continue progress, Ye said.

Creating smaller transistors also will require finding a new type of insulating, or “dielectric” layer that allows the gate to switch off. As gate lengths shrink smaller than 14 nanometers, the dielectric used in conventional transistors fails to perform properly and is said to “leak” electrical charge when the transistor is turned off.

Nanowires in the new transistors are coated with a different type of composite insulator, a 4-nanometer-thick layer of lanthanum aluminate with an ultrathin, half-nanometer layer of aluminum oxide. The new ultrathin dielectric allowed researchers to create transistors made of indium-gallium- arsenide with 20-nanometer gates, which is a milestone, Ye said.

This work will be presented at the 2012 International Electron Devices (IEEE [Institute of Electrical and Electronics Engineers]) meeting in San Francisco, California, Dec. 10 – 12, 2012 (as per the information on the registration page) with the two papers written by the team will be published in the proceedings.

I have a full list of the authors, from the news release,

The authors of the research papers are Gu [Jiangjiang Gu]; Wang [Xinwei Wang]; Purdue doctoral student H. Wu; Purdue postdoctoral research associate J. Shao; Purdue doctoral student A. T. Neal; Michael J. Manfra, Purdue’s William F. and Patty J. Miller Associate Professor of Physics; Roy Gordon, Harvard’s Thomas D. Cabot Professor of Chemistry; and Ye [Peide “Peter” Ye].

Eeek! The sticky tape is coming after us!

Fingers emerged from sticky tape to form claws in a research project conducted at Purdue University (Indiana, US), which will be presented at a meeting of the Materials Research Society (MRS) in Boston from Sunday (Nov. 25) to Nov. 30, 2012. The Nov. 20, 2012 news release on EurekAlert describes the new ‘smart’ material,

Researchers used a laser to form slender half-centimeter-long fingers out of the tape. When exposed to water, the four wispy fingers morph into a tiny robotic claw that captures water droplets.

The innovation could be used to collect water samples for environmental testing, said Babak Ziaie, a Purdue University professor of electrical and computer engineering and biomedical engineering.

“It  [the tape] can be micromachined into different shapes and works as an inexpensive smart material that interacts with its environment to perform specific functions,” he said.

Doctoral student Manuel Ochoa came up with the idea. While using tape to collect pollen, he noticed that it curled when exposed to humidity. The cellulose-acetate absorbs water, but the adhesive film repels water.

“So, when one side absorbs water it expands, the other side stays the same, causing it to curl,” Ziaie said.

A laser was used to machine the tape to a tenth of its original thickness, enhancing this curling action. The researchers coated the graspers with magnetic nanoparticles so that they could be collected with a magnet.

“Say you were sampling for certain bacteria in water,” Ziaie said. “You could drop a bunch of these and then come the next day and collect them.”

Sticky tape is one of  my favourite pieces of science equipment along with inkjet printers and ‘Shrinky Dinks’ as I noted in my Nov. 16, 2012 posting about bio-ink. The Nov. 20, 2012 news release by Emil Venere can also be found on the Purdue University website along with photos and other materials such as this animated GIF of the gripper closing available at https://engineering.purdue.edu/ZBML/img/research/plain-gripper-closing.gif.

Blood, tears, and urine for use in diagnostic tools

Frankly, I’d rather just spit into a cup or onto a slide for diagnostic tests than having to supply urine or have my blood drawn. I don’t think that day has arrived yet but scientists at Purdue University (Indiana, US) have made a breakthrough. From the Aug. 23, 2012 news item on ScienceDaily,

Researchers have created a new type of biosensor that can detect minute concentrations of glucose in saliva, tears and urine and might be manufactured at low cost because it does not require many processing steps to produce.

“It’s an inherently non-invasive way to estimate glucose content in the body,” said Jonathan Claussen, a former Purdue University doctoral student and now a research scientist at the U.S. Naval Research Laboratory. “Because it can detect glucose in the saliva and tears, it’s a platform that might eventually help to eliminate or reduce the frequency of using pinpricks for diabetes testing. We are proving its functionality.”

Claussen and Purdue doctoral student Anurag Kumar led the project, working with Timothy Fisher, a Purdue professor of mechanical engineering; D. Marshall Porterfield, a professor of agricultural and biological engineering; and other researchers at the university’s Birck Nanotechnology Center.

The originating Aug. 20, 2012 Purdue University news release by Emil Venere provides details as to how this biosensor works,

The sensor has three main parts: layers of nanosheets resembling tiny rose petals made of a material called graphene, which is a single-atom-thick film of carbon; platinum nanoparticles; and the enzyme glucose oxidase.

Each petal contains a few layers of stacked graphene. The edges of the petals have dangling, incomplete chemical bonds, defects where platinum nanoparticles can attach. Electrodes are formed by combining the nanosheet petals and platinum nanoparticles. Then the glucose oxidase attaches to the platinum nanoparticles. The enzyme converts glucose to peroxide, which generates a signal on the electrode.

“Typically, when you want to make a nanostructured biosensor you have to use a lot of processing steps before you reach the final biosensor product,” Kumar said. “That involves lithography, chemical processing, etching and other steps. The good thing about these petals is that they can be grown on just about any surface, and we don’t need to use any of these steps, so it could be ideal for commercialization.”

In addition to diabetes testing, the technology might be used for sensing a variety of chemical compounds to test for other medical conditions.

Here’s a representation of the ‘rose petal’ nanosheets,

These color-enhanced scanning electron microscope images show nanosheets resembling tiny rose petals. The nanosheets are key components of a new type of biosensor that can detect minute concentrations of glucose in saliva, tears and urine. The technology might eventually help to eliminate or reduce the frequency of using pinpricks for diabetes testing. (Purdue University photo/Jeff Goecker)
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My most recent piece, prior to this, about less invasive diagnostic tests was this May 8, 2012 posting on a handheld diagnostic device that tests your breath for disease.