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Biodesign appoints Tao to lead Center for Bioelectronics and Biosensors

December 15, 2008

The Biodesign Institute at Arizona State University is pleased to announce the appointment of Nongjian (N.J.) Tao as director of the Center for Bioelectronics and Biosensors. The center will focus on research to develop advanced sensors that can quickly and reliably detect trace chemicals and biomolecules to improve healthcare, environmental safety, pollution and sustainability, and national security.

The ability to develop fast and accurate technology platforms that detect the presence of specific chemicals in the environment or in the body can often be a matter of life or death. Exposure to toxic gases, monitoring of biomarkers in body fluids, testing for harmful compounds in foods and water, and early alert of chemical and biological warfare agents all require reliable and sensitive sensing integrated devices.

While adopting the computer industry’s mantra of faster, cheaper and more reliable, Tao’s research moves beyond silicon-based microelectronics to advance molecular electronics that are needed to develop sensing tools capable of detecting trace chemicals, as few as a single or just a few molecules. The surge of interest in nanotechnology --the science of the very small-- lets scientists develop devices by manipulating extremely small materials, on the scale of atoms and molecules.

“Dr. Tao’s elegant and innovative research crosses seamlessly into multiple disciplines of science, enabling him to make groundbreaking discoveries,” said George Poste, director of the Biodesign Institute and chief scientist for ASU’s Complex Adaptive Systems Initiative (CASI).  “This boundary-breaking approach is what the Biodesign Institute believes is needed to improve human health and the health of our planet, and we are excited to have Dr. Tao join us.”

“I am excited and attracted by the ambitious and forward-looking vision, by the first class research facilities and by the large crowd of multidisciplinary talents already gathered at Biodesign,” said Tao. “This is a dream place for anyone who believes in the need of collaborative and multidisciplinary efforts to solve many complex and challenging problems in today’s world.”

Tao’s research team discovers fundamental laws of nature and properties of materials at the molecular scale and develops practical electronics and sensing integrated devices. To reach the goal, the team takes a multi-length scale approach that integrates the synthesis of molecules, fabrication of nano- and micro-structures, characterization of device properties, and validation of device functions.

His research team involves a diverse group of researchers and students from electrical engineering, device physics, chemistry and biochemistry, and materials. Among Tao’s collaborators are work with organic chemists and theoreticians around the world, and industry researchers from Motorola, Intel, Dial, Biosensing Instruments and other companies.

Tao is a professor of electrical engineering in ASU’s Ira A. Fulton School of Engineering and also a researcher in the Center for Solid State Electronics Research. Tao joined the ASU faculty as a professor of electrical engineering and an affiliated professor of chemistry and biochemistry in August 2001. While serving as director of the institute’s Center for Bioelectronics and Biosensors, he will also maintain his academic appointment as an electrical engineering professor in the Ira A Fulton School of Engineering.

Big Impact from Small Technology: Benefits for environmental safety and monitoring and for health care

While the basic science of molecular electronics and sensor technology is still unfolding, many of the discoveries are already being transformed into useful technologies. To date, his ASU research team has developed a variety of different kinds of nanosensors. One of the principles used in these devices is based on a sensor’s ability to recognize and bind a target molecule. Scientists call this a “binding event.” The sensor then converts this binding event into a signal that can be ultimately measured electronically. The difference is in the type of signal that each sensor produces.

In one area of his research that has received international recognition and multimillion dollar grant support, Tao has fashioned tiny tuning forks out of quartz and turned them into sensors capable of detecting individual molecules in everything from disease agents to environmental contaminants.

The tuning forks produce different vibrations depending on the type of molecules that attach to them. The tuning fork technology transforms chemical signals to electrical ones, creating data readouts that can be analyzed instantaneously across wireless networks.

Tao and his colleagues tweak the basic design of these sensors so that they work well for different applications. The simple, cheap and powerful tuning fork array contained in a prototype can detect many different molecules at once. These cell-phone size devices may one day analyze breath samples for the first telltale signs of disease, identify pollutants in air or drinking water, or keep society safe by detecting trace vapors and signatures of explosives.

Tao’s research team, along with industrial collaborators from Motorola, also have made a key advancement in the use of single-walled carbon nanotubes as transistors to sense biological and chemical agents. This developing sensor technology could be used to monitor a host of environmental and health issues including air and water quality, industrial chemicals and biological agents.

Their method functionalizes Single-Walled Carbon Nanotubes (SWNTs) with peptides to produce low-power SWNT-Field Effect Transistors (FETs) that are highly sensitive and can selectively detect heavy metal ions down to the parts-per-trillion level.

Tao says the nanotubes are extremely versatile, "We tested heavy metal ions in water as well as RNA strands from Hepatitis C virus, but the platform can be applied to many other areas to sense toxic chemicals in the air, or other biomarkers for biomedical purposes"

In another area of biomedical research, Tao, along with a team of ASU researchers including the institute’s Peiming Zhang, has developed a breakthrough technique for the detection of DNA mutations. The team’s breakthrough relies on an intrinsic physical property of DNA ¾conductivity¾ or how well the molecule can carry an electrical current.

"We have developed a technology that allows us to wire single molecules into an electrical circuit," said Tao, “and we can now directly read the biological information in a single DNA molecule." The measurement is extremely sensitive, as the alteration of a single base (known by the single letters A, T, C, or G) in the DNA stack can either increase or decrease the conductivity of a DNA helix, depending on the type of mismatched base.

Their results demonstrated for the first time, the possibility of directly identifying these mutations, or single nucleotide polymorphisms (SNPs), by means of measuring the electrical conductance of a single DNA molecule. SNPs are buried in the 3 billion DNA bases of the human genome. On average, SNPs occur about once in every 1,000 DNA bases, though not every SNP found will necessarily cause a disease mutation. Cataloging these subtle DNA differences among the populace will aid the ongoing quest to understand and prevent disease.

The next goal of the research is to make the measurement steps easier and faster through automation, which will allow many different DNA sequences to be analyzed at once.

All of the technologies have integrated wireless capabilities to optimize rapid and remote sensing of environmental exposure, or may be wearable for monitoring the body’s response to stress. Also, many devices will employ multiple technologies because sensors require different conditions to detect trace amounts of materials. The ultimate goal of Tao’s research is to develop a host of new devices for human health, security and environmental applications.

“Detecting trace amount of chemicals in the presence of a large amount of interference species in the real-world environment is a challenge,” Tao said. “We’re trying to take an integrated approach. If you’re trying to optimize a device on the device level, it may not be good enough. You need to think about the system level. You have to think about sample collection and delivery, data processing and transmission. Everything needs to be considered, from molecular and nanometer to meter or even kilometer scales, not just a single sensing element.”

Tao’s has received funding from a variety of government agencies and industry partners, such as the NIH, NSF, DOE, DARPA, Motorola, Dial and others. Before joining ASU, Tao worked as an assistant and associate professor at Florida International University. He holds five U.S. patents, has published 160 refereed journal articles and book chapters and has given over 150 invited talks and seminars worldwide.