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Bio-Sensor Virus Detector (BSVD) Program

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PC Market Research Data.pdf 11/21/2006 1

Article 1

http://www.indolink.com/SciTech/fr020904-074024.php by: Francis C. Assisi

Single Virus Detector Invented

cantilever and virus particle

Download photo - caption below

West Lafayette, 08 Feb 2004 -- Researchers at reported Feb 4th that they have developed a miniature device sensitive enough to detect a single virus particle. The advancement could have many applications, including better disease detection, environment monitoring and bioterrorism defense.

The research was conducted by Indian American doctoral candidate Amit Gupta, under the supervision of Pakistani American Associate Professor Dr. Rashid Bashir at the Laboratory of Integrated Biomedical Micro/ and Applications at the Birck Nanotechnology Center.

Although the idea still must clear some major hurdles, Bashir says the scientists involved hope it might be commercialized in the next five to eight years. The ability to detect airborne viruses with a small, easy to use device in real time would be a major advantage in the confinement and management of viral epidemics, he says

The device is a tiny "cantilever," a diving board-like beam of silicon that naturally vibrates at a specific frequency. When a virus particle weighing about one-trillionth as much as a grain of rice lands on the cantilever, it vibrates at a different frequency, which was measured by the Purdue researchers.

"Because this cantilever is very small, it is extremely sensitive to added mass, such as the addition of even a single virus particle," said Rashid Bashir, an associate professor of electrical and and .

Findings are detailed in a paper to appear March 8th in Applied Physics Letters, a journal published by the American Institute of Physics.

PC Market Research Data.pdf 11/21/2006 3 The work, funded by the National Institutes of Health, is aimed at developing advanced sensors capable of detecting airborne viruses, bacteria and other contaminants. Such sensors will have applications in areas including environmental-health monitoring in hospitals and homeland security.

Disease Detector

"This work is particularly important because it demonstrates the sensitivity to detect a single virus particle," Gupta said. "Also, the device can allow us to detect whole, intact virus particles in real time. Currently available biosensing systems for deadly agents require that the DNA first be extracted from the agents, and then it is the DNA that is detected."

As part of the grant, the researchers intended to demonstrate three things: that the sensors have the sensitivity needed to detect a single virus particle; that the sensors can detect the viruses selectively without becoming clogged with other particles; and that it’s possible to concentrate enough particles near the sensors to detect airborne viruses.

So far, Bashir says, they have demonstrated the first of these: that the sensors have the sensitivity to detect a single virus particle. “The challenges will be active concentration of the particles, and removal of the non-specifically bound particles -- different viruses we’re not looking for that could give a false positive.”

The scientists now hope to be awarded funding for three more years, Bashir says, adding that the grant then would total $2.1 million. If they are awarded the three-year extension, they will attempt to construct devices that can look for different virus particles simultaneously, and they also may begin seeking additional funding for their project, he says.

At the end of the five years, Bashir says, the researchers might be in a position to start a company in an effort to commercialize the technology, which has other possible applications as well. For example, viruses are between 50 and 200 nm in size, Bashir says. Meanwhile, bacteria and spores range between 1 and 2 micrometers. “If we can detect the smaller particles, then the same technology is extendable to spores and bacteria,” he says.

The researchers have filed a patent application on their technology, Bashir says.

The next step for the scientists will be to coat a cantilever with the antibodies for a specific virus, meaning only those virus particles would stick to the device. Coating the cantilevers with antibodies that attract certain viruses could make it possible to create detectors sensitive to specific pathogens.

"The long-term goal is to make a device that measures the capture of particles in real time as air flows over a detector," Bashir said.

Earlier, Bashir and colleagues, including Arun Bhunia an Associate Professor of Food Science, created the first protein "biochips," mating silicon computer chips with biological proteins that could quickly and cheaply detect specific microbes, disease cells and harmful or therapeutic chemicals. It would save lives detecting toxins in food immediately. The chip could speed diagnosis, test in real-time for poisoning (as opposed to the days currently

PC Market Research Data.pdf 11/21/2006 4 required for food samples to be cultured) and even prevent tainted foods from ever being shipped.

Bashir and his group are striving to create "lab-on-a-chip" technologies in which miniature sensors perform essentially the same functions now requiring bulky laboratory equipment, saving time, energy and materials. Thousands of the cantilevers can be fabricated on a 1- square-centimeter chip.

The Purdue researchers used the device to detect a particle of the vaccinia virus, which is a member of the Poxviridae family and forms the basis for the smallpox vaccine.

The cantilever is about one micron wide - or about one-hundredth the width of a human hair - 4 microns long and 30 nanometers thick. A nanometer is a billionth of a meter, or roughly the length of 10 hydrogen atoms strung together.

"This cantilever mechanically resonates at a natural frequency, just like anything that vibrates has a natural frequency," Bashir said. "What we do is measure the natural frequency of the cantilever, which is a function of its mass. As you increase the mass, the frequency decreases. And the way to increase the sensitivity is to make that starting mass very, very small."

A single vaccinia virus particle weighs about 9 femtograms, or quadrillionths of a gram. "So, if a grain of rice weighs a couple of milligrams, one of these virus particles weighs about one-trillionth as much," Bashir said.

MEM devices

Because the cantilevers are mechanical parts measured primarily on the scale of microns, or millionths of a meter, they are called "micromechanical devices."

The cantilever measures just about one micron wide, four microns long and 30 nanometers thick. A human hair, for comparison, measures about 100 microns wide. There are major challenges to the development of MEM devices. At the scale they work, the physical forces of importance are not those of our world. Gravity, for example, becomes less important than atomic forces.

But the benefits of MEM have attracted much attention. For starters, thousands of MEM machines can be cheaply manufactured from a small piece of silicon.

Much research is focused on using MEM for sensors and the construction of a "lab-on-a- chip." Miniaturization allows for extremely sensitive sensors that can detect single molecules, and a lab-on-a-chip would take advantage of such sensitivity to perform rapid, cheap and portable diagnostic tests.

There is much overlap between MEM and nanotechnology, which is concerned with nanometer-scale objects. A MEM device shrunk to the nanoscale could enable molecular nanotechnology, the theorized ability to manipulate molecules using nanoscale "machines."

PC Market Research Data.pdf 11/21/2006 5 Article 2 http://www.news.harvard.edu/gazette/2004/10.07/01-nanovirus.html

HARVARD GAZETTE ARCHIVES

Charles Lieber holds a silicon chip (also inset) containing sensors capable of detecting single viruses that could cause disease epidemics or be used in bioterrorism attacks. (Staff photos Jon Chase/Harvard News Office)

Sensor detects, identifies single viruses

Early warning for disease and bioterrorism By William J. Cromie Harvard News Office

Two of the world's biggest threats may someday be reduced by wires thousands of times thinner than a hair but capable of detecting a single virus. The specter of worldwide viral epidemics is always with us, so detecting them quickly offers the possibility of saving thousands of lives. The pathogens also can be stealthy biological weapons, making their positive detection a vital national defense requirement.

"We want to find a single virus before it finds you," says Charles Lieber, Hyman Professor of Chemistry at Harvard University. Tests recently completed in his laboratory show that these unimaginably thin nanowires can sense and distinguish between viruses that cause PC Market Research Data.pdf 11/21/2006 6 flu, measles, and eye infections. Lieber believes future versions will be able to spot HIV, Ebola, SARS, West Nile, hepatitis, bird flu, and other dangerous viruses.

"Viruses are among the most important causes of human disease and are of increasing concern as agents for bioterrorism," Lieber says. "Our work shows that nanoscale silicon wires can be configured as detectors that turn on or off in the presence of a single virus particle. Such detectors could be fashioned into arrays capable of sensing thousands of different viruses, ushering in a new era for diagnoses, biosafety, and quick response to viral outbreaks."

"Nano" refers to a "nanometer," one billionth of a meter, four hundred

billionths of an inch, or about 10 atoms in size. One hundred thousand wires, each 20 nanometers long, would fit on the head of a pin.

The Department of Defense, Office of Naval Research, and National Cancer Institute all supported Lieber's research, and at least two commercial companies have shown interest in manufacturing nanosensors.

In his office, Lieber shows visitors a two- inch-square silicon and metal chip containg an array of nanowires and two pinhead-size entry ports through which blood, saliva, or other bodily fluids can enter. Air samples put into a fluid solution would also be tested this way.

Surfaces of the nanowires, through which a minute current flows, hold A spiky virus binds to Y-shaped receptors built specks of protein (antibodies) to which into ultrathin wires carrying a small electric specific viruses bind. These antibodies, charge. The binding causes a change in produced naturally by the immune electric conductance (middle right) which system, can be attached to the surface immediately identifies the germ. When it of the nanowires, and they will, in turn, becomes unbound (bottom), the conductance bind viruses. Such binding causes a returns to a set value. change in current, which signals the presence of a virus or viruses, like a burglar alarm detecting intruders.

Immediate alarm

The alarm goes off immediately, a major advantage. Other methods of virus detection involve time-consuming steps such as taking blood samples, which must be sent to a laboratory for analysis. It's easy to imagine adding such sensors to security gates at

PC Market Research Data.pdf 11/21/2006 7 airports. Dangerous viruses could be spotted before they spread to other passengers and other places in the world.

Besides detection, such laboratories-on-a-chip might someday be employed for monitoring diseases, like following the progress of patients undergoing treatment to stem the activity of HIV, the AIDS virus. Like other viruses, it begins to duplicate itself after it enters a cell. Eventually, the cells burst and spread newborn pathogens to other cells. If such reinforcements can be spotted and treated by drugs before they overwhelm the body's immune system, there is less likelihood that the infection will turn into full-blown AIDS.

Combining selective virus and protein recognition in one nanowire chip could expand its diagnostic potential. Many cancer-related proteins are secreted into the blood. Prostate specific antigen (PSA), for example, is watched as a marker for the seriousness of prostate cancer. Low PSA levels provide one signal that close monitoring of the disease may be a better choice than surgery or radiation, with their distressing side effects of impotence and incontinence. Rather than taking a blood test and waiting for the result, it may be possible to consult a sensor the way diabetics watch their blood sugar daily, or women check for a pregnancy.

Taking the possibilities one step further, how a virus particle bonds to a cell's surface might be examined closely for ways to prevent such unions. If researchers know exactly what molecules are involved in breaking into and entering cells, they will be better be able to develop drugs and vaccines to prevent losses of cell valuables.

Pushing forward

Such a list of intriguing applications provides what Lieber calls "strong near-term motivation for pushing this work forward."

He and his collaborators have done extensive tests to validate the selectivity of the sensor. First, they fed the device two viruses from different families, one that causes influenza A and one responsible for respiratory and eye infections. The detector sensed the difference.

Then they paired the influenza bug with a closer viral relative that causes mumps and measles. These two boast similar surfaces, but the device was not fooled.

PC Market Research Data.pdf 11/21/2006 8

Besides verifying these captures by measuring changes in electrical conductance, researchers marked the viruses with fluorescent dyes so the binding could be seen with very powerful microscopes. The wires involved are only about a hundred atoms across.

The team that did such nanomagic includes students and faculty from Harvard departments of chemistry and chemical biology, physics, and the Division of Engineering and Applied Sciences. They published a detailed description of the research in the Sept. 28 issue of Proceedings of the National Academy of Sciences. The lead author is postdoctoral fellow Fernando Patolsky.

Lieber's team now plans to work on a larger detector, one that could sense up to 100 different viruses simultaneously. Such an array will make it more likely that the federal government and/or private companies will act to move this exciting new technology from a Harvard basement laboratory to a factory floor.

PC Market Research Data.pdf 11/21/2006 9 Article 3 http://www.trnmag.com/Stories/2004/102004/Biochip_spots_single_viruses_102004.html

Biochip spots single viruses

By Eric Smalley, Technology Research News

Environmental sensors and handheld devices that quickly and easily detect and identify individual viruses would provide early warning of infections in individuals, the spread of disease in populations, and biological weapons attacks.

The rapid development of nanotechnology in recent years has given researchers tools for building highly sensitive virus detectors. A team from Harvard University has built a detector from nanowires transistors that can identify individual virus particles in real time in unpurified samples.

The researchers' prototype uses antibody proteins attached to the nanowires to briefly capture individual virus particles. "The binding causes a change in the current of the nanowire-based electronic device, which signals the virus presence," said Charles Lieber, a professor of chemistry at Harvard University.

Labs-on-a-chip that are based on the device could be used to monitor diseases, said Lieber. For example, the AIDS virus, like other viruses, begins to duplicate itself after it enters a cell, he said. "If [these additional pathogens] can be spotted and treated by drugs before they overwhelm the body's immune system, there is less likelihood that the infection will turn into full-blown AIDS."

The device could also be used to study how viruses bind to receptors by determining which viruses bind to which receptors, how long virus particles bind to receptors, and what substances block or disrupt binding, Lieber said. The device could also eventually be used to detect individual biomolecules, including DNA and proteins, he said.

The researchers made their prototype by growing 20-nanometer-diameter silicon nanowires, mixing the nanowires with fluid, and flowing them into position across nickel contacts spaced two microns apart to form nanowire transistors. They coated the nanowires with aldehyde, then added antibody proteins, which adhered to the aldehyde. They configured a microfluidic channel to flow fluid containing the viruses across the nanowire sensors.

When an individual virus binds to a nanowire transistor antibody receptor, the transistor's electrical conductance changes, increasing or decreasing depending on whether the transistor carries positive or negative charge and the virus is positively or negatively charged. "Our detection method is based on a pure electrical detection of selective binding- unbinding of a single viral particle," said Lieber.

The researchers found that the duration of the bind-and-release cycle depends on the density of the antibody proteins on the nanowires. The cycle averaged just over one second at a low concentration of antibody proteins, about 20 seconds at a moderate density, and 5

PC Market Research Data.pdf 11/21/2006 10 to 10 minutes at a high density.

The researchers attached antibody proteins that bind to influenza A to one portion of the nanowire array and antibody proteins that bind to adenovirus to another portion and demonstrated that they can detect simultaneous binding of the two different types of viruses. "These nanowire detectors... could be scaled easily to enable sensing thousands of different viruses simultaneously," said Lieber.

Researchers have been able to detect individual virus particles in the laboratory for years using optical microscopes, but these approaches require purifying the samples and labeling the viruses with fluorescent markers, which makes them inappropriate for clinical and field diagnostics, said Lieber. They are also not able to detect viruses in samples with very low virus concentrations or detect multiple types of viruses, he said.

In recent years, researchers have also developed methods of detecting viruses using nanowire-and nanotube-based transistors, but these approaches involve processing purified samples to break down virus particles so that the virus DNA can bind to receptors on the devices.

Another technique that has emerged recently is detecting individual virus particles using microscopic cantilevers coated with antibody receptors. The additional mass of an attached virus particle changes the vibration rate of the cantilever, which can be detected electrically. These techniques require high-resolution imaging to confirm that only one virus particle has attached to the cantilever, however, said Lieber.

The researchers' next step is scaling up the nanowire transistor device, said Lieber. "We are working on a larger detector array, one that could sense up to 100 different viruses simultaneously," he said.

The researchers' sensor arrays could be used practically in two to five years, said Lieber.

Lieber's research colleagues were Fernando Patolsky, Gengfeng Zheng, Oliver Hayden, Melike Lakadamyali, and Xiaowei Zhuang. The work appeared in the September 13, 2004 issue of the Proceedings of the National Association of Science. The research was funded by the Defense Advanced Research Projects Agency (DARPA), the National Cancer Institute, the Ellison Medical Foundation, the Office of Naval Research, and the Searle Scholar Program.

Timeline: 2-5 years Funding: Government, Private TRN Categories: Sensors; Biotechnology; Nanotechnology Story Type: News Related Elements: Technical paper, "Electrical Detection of Single Viruses," Proceedings of the National Association of Sciences, September 13, 2004

PC Market Research Data.pdf 11/21/2006 11 Article 4

http://www- bsac.eecs.berkeley.edu/scripts/show_pdf_publication.php?pdfID=1080259221

PC Market Research Data.pdf 11/21/2006 12 Articles 5, 6, 7 and 8 have been removed. Article 9 http://www.temperatures.com/sarssensors.html

Introduction

There are numerous reports of increased SARS-related temperature sensor uses in the news and available on the Web. This page is aimed at providing a summary of the related types of temperature sensors involved from the manufacturer's web site, our pages and various news releases.

Additionally, since this is primarily an educational web site about temperature sensors, there are links to more details on the different types of sensors where indicated. One of them, ThermoSense website is valuable resource to workers and researchers using Thermal Imagers. It reports current and recent programmming from the Conference, now in its 26th year. ThermoSense Conference Proceeding, published by SPIE: The International Optical Engineering Society, can be found in most engineering and scientific libraries worldwide. They represent one of the most complete documentation sources available on Thermal Imaging application know-how and technology. In 2003, SPIE published a complete set of the papers from ThermoSense's 25 year history in a 2-CD set. Check SPIE's Online Store for availabliity.

Primarily, Infrared Thermal Imagers are used in screening people for elevated body temperature. While not the most precise method to measure human body temperature, infrared thermal imagers or scanners are good at determining if someone appears hotter or colder than another person, or the average for a group of people under the same viewing conditions.

By having a very stable and drift free measurement and system software that enables averaging, selecting the hotest spot in a viewed scene and then recording and alarming capability, a Thermal Imaging System is an excellent tool for screening large numbers of people such as passengers exiting an airplane.

See the table below for recent information about equipment and software from various vendors aimed specifically at uses in detecting people that may have SARS. One must be very careful in using infrared measurement devices because large errors are possible sometimes even under the best circumstances.

Typical sources of measurement errror include: Errors within the instrument itself related to calibration and calibration stability (goes to the quality of the instrument design); Possible errors due to the interaction of the instrument and the temperature of its surroundings; Errors due to excess thermal radiation from sources other than the object of measurement entering the instrument and more. Then there are the serious questions raised by the use trying to quantify the measured temperature of a person's skin to the core body temperature. Not tasks for a newcomer to the business.

PC Market Research Data.pdf 11/21/2006 25 Oral or ear fever thermometers are used also for screening when thermal imaging is not available. They also can be excellent tools to accurately verify a person's body temperature when a person have been selected for further checking by a Thermal Imaging System. A very recent, published article shows that not all ear thermometers are equally accurate, however. Some units tested at The National Physical Laboratory in the UK showed worst case errors of up to 0.5 °C in some models when all were compared against the same high- quality reference source at a fixed temperature (see reference citation below*).

Forehead, or temporal artery, infrared thermometers are a less-well known instrument, but available commercially. These devices have been pioneered by The Exergen Corporation in the USA as an adjunct or possible alternative to the ear thermometer. There is a description and link below not only to their device information, but also to the listing of some extensive technical work including medically-supervised comparisons between the forehead thermometer and other means of measuring human body temperature.

Spot infrared thermometers, or radiation thermometers, have been suggested as a lower cost, and more readily available option to thermal imagers for screening people for temperature elevated above the average norm, . They both work the same basic way, depend upon the same physics for their operation and are suceptible to the same sources of error. Among many popular models are handheld portable units that incorporate aiming lasers. Anyone tring to use such laser-equiped devices should be careful not to allow the laser spot to enter someone's eye. That could cause temporary "flash" blindness or even, in limited cases, possible permanent injury.

PC Market Research Data.pdf 11/21/2006 26 Article 10 http://www.rsc.org/chemistryworld/Issues/2003/August/detectives.asp

Disease detectives

A disposable polymer microchip promises to make medical diagnostics easier and more convenient, say Joël Rossier and Frédéric Reymond.

Immunoassay is the workhorse tool of biomedical diagnostics. Annual sales for immunoassay reagents and supplies are currently ca $7000m (>£4000m) worldwide and ca $2000m in the US. In medicine, immunoassay is used in two general classes of applications: for identifying the organism responsible for a disease (diagnosis), and for monitoring disease treatment. Despite its success, however, immunoassay does have drawbacks. In particular long assay times, complex and expensive equipment, and the need for trained technicians have restricted its use mainly to centralised laboratories. But things look set to change. In this competitive market-place, medical diagnostic companies are already looking at new technologies that allow fast, quantitative and portable assays with simplified instrumentation.

Lab-on-a-chip systems capable of analysing minute volumes of sample currently offer the best hope. Microchips should not only greatly simplify the process of immunoassay, but could also allow diagnosis to be carried out in local analytical laboratories, A&E departments, doctors' surgeries or even pharmacies. In this way, they may one day be used by all health professionals at 'point of care' regardless of location, and ultimately even by patients in the home.

At the Laboratoire of Electrochimie of the Ecole Polytechnique Fédérale de Lausanne in Switzerland, we first became interested in the area of microanalysis in the mid-1990s. Other researchers had at that time begun to report the first experiments performed on miniaturised platforms such as silicon chips. A few of these research groups had also demonstrated machining processes for fabricating polymer microstructures, though well-defined and reproducible manufacturing processes were still lacking.

Coming from the glucose sensing area, our laboratory head, Hubert Girault, had in mind the idea of developing new types of electrochemical . Electrochemical sensors have to date mainly been devoted to glucose sensing, which is one of the biggest markets for in vitro diagnostics. Our own interest, however, lay in developing a portable affinity system using disposable microchips for detecting proteins. We reasoned that we should be able to detect the interactions of proteins of interest with the corresponding enzymes or receptors by following small changes in electrical currents.

With this idea in mind, polymers (rather than silicon typically used for chip manufacture) seemed to be a good material of choice for our chips. Not only do proteins adhere easily to polymers, but for the purposes of electrochemical sensing our chip also needed to be non- conducting. As well as offering considerable flexibility, both in terms of performance and ease of processing, polymers have the advantage of being cheap and readily disposable - thereby avoiding any possibility of cross-contaminating samples.

PC Market Research Data.pdf 11/21/2006 27 As a first step, we wanted to demonstrate the feasibility of polymer-based microsystems for generating electroosmotic flow and performing electrophoretic separations. By electrically controlling the flow of solutions along microchannels etched into the surface of a polymer chip, we believed that it should be possible to separate the various solutes electrochemically. Since our laboratory was already equipped with an excimer laser capable of drilling micro-holes in polymer sheets, we used photoablation to produce the microchannels by vaporising polymer, and then sealed these by lamination. The success of our electrophoretic separation depended on generating sufficient charges on the microchannel surface - and hence a big enough 'zeta potential' - to control fluid flow.

With this achieved, the next step was to develop these microchips as electrochemical sensors, notably for protein assays. By 1997, we could integrate carbon ink microelectrodes within our microchips and use them as transducers - capable of detecting electrical currents resulting from, for example, an oxidation reaction. Then in 1998 we were able to use our chips to immobilise on the microchannel walls a radioactively labelled bacterial toxin, namely Staphylococcal enterotoxin B (SEB). Measuring the resulting levels of radioactivity confirmed the efficiency of our immobilisation procedure - an essential prerequisite for performing enzyme-linked immunoassays (Elisa). We went on to demonstrate the ability of the chips to perform such Elisa tests in 1999, in this case the test involved detecting a particular compound, D-Dimer, by following electrochemical changes.

To carry out such an immunoassay, we first immobilise on the walls of the microchannel an antibody that can specifically bind to an antigen of interest ( see below). Next, we allow a sample of plasma, blood or urine containing this antigen ( eg D-Dimer) to flow through the system. This antigen binds to the immobilised antibodies to form an antigen-antibody complex and excess sample is washed away. At this stage we introduce a second antibody labelled with an enzyme ( eg alkaline phosphatase, peroxidase or glucose oxidase) into the microchannel. This secondary antibody further binds to the antigen-antibody complex, and after washing away any excess, we add an enzyme substrate ( p-aminophenyl phosphate in the case of alkaline phosphatase) to the microchannel.

PC Market Research Data.pdf 11/21/2006 28 Immunoassay on a polymer microchip: chip preparation and assay procedure

The enzyme transforms this substrate into an electroactive product that can be oxidised at the electrodes, releasing electrons that are detected as an electrical current in the process. The magnitude of the current is therefore directly proportional to the concentration of the antigen or other analyte. This is a big advantage of electrochemistry, because the measured current is not limited by the number of analyte molecules present in the system but by its concentration; the response obtained with microchips is therefore identical to that obtained for much larger scale assays.

Our initial experiment worked well, but would our microchips be sensitive enough to compete with more conventional immunoassay techniques? To find out, we performed Elisa- type assays, with eg a biotin-alkaline phosphatase (ALP) complex in a buffer solution, to evaluate the detection limit and the dynamic range of the assay. After complex formation of biotin with avidin coated on the microchannel walls, we added an enzyme substrate, p- aminophenyl phosphate, to the avidin-biotin-ALP complex and this was transformed by ALP into p-aminophenol (Scheme 1).

PC Market Research Data.pdf 11/21/2006 29 Scheme 1. Electrochemical detection for Elisa assays

This p-aminophenol in turn can then be oxidised to quinonimide by applying a small voltage, releasing two electrons for detection. Our results showed that we could detect biotin down to subpicomolar (<10-12 mol l-1) levels - which compares very favourably with other immunoassay detection levels (which are typically in the range of 10-13 mol l-1 to 10-6 mol l- 1).

On the basis of these early promising results, in 1999, we (with lab head H. Girault) officially launched DiagnoSwiss to develop and commercialise our microchips. DiagnoSwiss headquarters are in Monthey, close to both Lausanne and Geneva. The company started with just one R&D contract and has now grown to six employees.

One of the first steps towards commercialising our chips was to identify a technology for producing them in mass, and at low cost. Laser photoablation is a good prototyping tool, because you can use the laser as a pen to 'draw' the structure you want to test. However, as a serial process, this is probably too expensive for large-scale production.

It was through our collaborations with a printed circuit board manufacturer that we hit upon the idea of adapting plasma etching technology to produce our chips. Plasma etching has the advantage of operating in parallel, which significantly reduces production costs. Most usefully, this technique allows us to integrate the electrode components of our chip directly, without the need for subsequent processing steps.

DiagnoSwiss chips are thin polymer foils made of polyimide and comprising microchannels with integrated gold microelectrodes. These chips are generic platforms that can be used for any micro-analytical application, but we are currently focusing on medical diagnostics and protein screening. Typically, our microchips consist of 50nl microchannels with a series of gold electrodes of 50µm in diameter, produced in 75µm thick polyimide films and sealed by a 35µm lamination layer of polyethylene (PE) covered by polyethylene terephthalate (PET). Our chips are not yet commercialised, but various laboratories already use them for research purposes.

One of the main advantages of our microchips is speed of analysis. Incubation times are generally less than five minutes, while detection takes under a minute. Conventional Elisa tests, by comparison, are typically done in well plates and take 1-2 hours for a quantitative result. The rate of detection in all these assays generally depends on how quickly the two binding partners diffuse together in the sample to form, say, an antigen-antibody complex. By reducing the volume of the sample, and hence the distance between molecules, complex formation occurs much faster. The large (microchip) surface to (sample) volume ratio - about

PC Market Research Data.pdf 11/21/2006 30 100 times larger than with standard well plates - also favours the immobilisation of one of the binding partners (eg the antibody) on the chip surface, accelerating antigen-antibody complex formation still further, and increasing the dynamic range of the assay.

Looking ahead Our current prototype microchips allow for eight tests to be performed simultaneously. Because the entire analysis takes less than 10 minutes (including incubation, detection and washing), about 50 immunoassays per hour can be conducted on a routine basis. However, our equipment is still at the prototype phase, and at least half of the analysis time is currently for repeated manipulations. With a fully automated set-up, and by increasing the number of simultaneous tests, we anticipate that the output could be easily increased to over 200 tests per hour.

Ultimately, we envisage that the doctor/nurse would take a drop of blood from the patient while in the consulting room, deposit it on the microchip and push a button that begins the fully automated analysis. Conventional immunoassays are performed in about five minutes in our platforms. For tests requiring very high sensitivity, sample accumulation procedures may require extending assay times up to 15 minutes.

Combining the advantages of disposable micro-analytical systems with electrochemical detection has opened up new areas for electrochemical biosensors. Our microchips allow for high-performance and rapid quantitative assays in an easy-to-use and cost effective platform. With its electrochemical microchips, DiagnoSwiss also offers standardised tests that can be used in doctors' offices as well as in centralised biochemical laboratories, or one day perhaps even by patients themselves.

PC Market Research Data.pdf 11/21/2006 31 Article 11 http://news-info.wustl.edu/news/page/normal/726.html Device detects, traps and deactivates airborne viruses and bacteria using 'smart' catalysts

By Tony Fitzpatrick

March 3, 2004 — An environmental engineer at Washington University in St. Louis with his doctoral student has patented a device for trapping and deactivating microbial particles. The work is promising in the war on terrorism for deactivating airborne bioagents and bioweapons such as the smallpox virus, anthrax and ricin, and also in routine indoor air ventilation applications such as in buildings and aircraft cabins.

Pratim Biswas, Ph.D.,Stifel & Quinette Jens Professor of Environmental Engineering Sciences and director of Environmental Engineering Sciences at Washington University, combines an electrical field with soft X-rays and smart catalysts to capture and destroy bioagents such as the smallpox virus.

"When the aerosol particles come into the device they are charged and trapped in an electrical field," Biswas explained. "Any organic material is oxidized, so it completely deactivates the organism."

Biswas noted that conventional corona systems do not charge and effectively trap nanometer-sized particles, such as viruses. But his Pratim Biswas invention combines soft x-rays with a conventional corona that has been proven to be very effective at charging and trapping particles in a range of sizes.

Anthrax is nasty stuff. An environmental engineer at WUSTL uses smart catalysts in his device that can detect the airborne presence of anthrax and other

PC Market Research Data.pdf 11/21/2006 32 On the walls of the device, Biswas has coated bioweapons and disable it. nanoparticles that catalyze the oxidation. These nanoparticles are "smart" objects that are turned "on" and "off" by irradiation.

"This smart catalyst is unique," Biswas said. "If we should encounter some organism that is very difficult to degrade, I can engineer my smart catalysts to function so that they will oxidize those molecules."

Biswas and his collaborators have tested the device using non-potent polio virus and have achieved 99.9999 percent efficiency. He currently is collaborating with the Midwest Regional Center of Excellence for Biodefense and Emerging Infectious Diseases Research (MRCE) and his Washington University colleague, Lars Angenent, to identify the mechanistic pathways of biomolecular degradation.

Washington University in St. Louis has a core group of six faculty who are mainstream aerosol researchers, and work on different aspects related to Aerosol Science and Engineering. This nationally and internationally recognized group of scientists, one of the largest groups in U. S. universities, studies the synthesis and environmental impact of nanoparticles, atmospheric pollution at the regional and global scales, and develops the next generation of instrumentation for detection of these particles, as well as several environmental nanotechnology applications.

Biswas was part of a special colloquium, "Research in Aerosols and Air Quality," held March 2, 2004, at Washington University. The event was organized under the university's Sesquicentennial Environmental Initiative wherein world-renowned researchers reported the latest findings in the aerosol engineering field. The colloquium, was part of a series of environmental dialogues held in honor of Washington University's 150th anniversary.

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