New sensor being designed to detect, identify invisible agents faster

February 22, 2002

BLACKSBURG, Va., Feb. 22, 2002 -- Research on a new sensing device able to simultaneously identify more than 3,000 biological materials shows great promise, says one of its developers, Ravi Saraf of Virginia Tech's chemical engineering department. Saraf, who holds 27 U.S. patents, hopes such a device will have multiple military and industrial applications, especially as concerns continue over the threat of terrorist attacks.

A key advantage of this new sensor is its ability to detect a specific biological agent even if its trace amount is only one part per billion in a sample volume of air or water.

The new detector or biochip under development has an optical based system. Its designers have increased the sensitivity of what the chip can "see" or sense, consequently improving its response time. Each pixel on the detector reads the mass and conformation of a different chemical. The new detector will more closely measure the actual level of each chemical in an affected area, which will aide in the design of the corresponding treatment for exposure.

An immediate application is in "remote medicine" such as a battlefield where medical personnel might not be readily available. As a portable unit, the detector and readout device allow sophisticated diagnosis in the field. Knowing quickly which chemical(s) a soldier was exposed to or what pathogens are present in body fluids lends to immediate treatment, possibly averting the full effects of the chemical damage. Saraf believes his device could be the basis for smaller lab instruments that would allow for the practice of medicine even while at sea or in space when a quick diagnosis could save a life, as well as conserve critical work time.

The new detection device will also be able to monitor the environment - soil, water, and air - to identify the presence of pathogens.

Other applications include the new field of proteomics, the study of the formation of proteins in a biological system under a certain stimulation, as well as how proteins will act only in certain conformations. Saraf's new sensor, unlike prior versions, will be able to detect the shape of the protein and the DNA sequence without any chemical tag.

This device could also fit into the idea of having an entire laboratory on a single microchip. As the major microelectronics manufacturers have sought other applications for their "silicon-chip" technology besides computers, the industry has focused on biotechnology, where the applications for silicon-chip technology to integrate multitudes of (biological) operations on a monolith are numerous. Lab instruments could be significantly reduced in size, making it easier for hospitals to do lab work on site. Sample sizes of bodily fluids needed could be greatly reduced. In some instances, such as crime investigation, a hand-held Polymerase Chain Reaction (PCR) device could duplicate the DNA present in a very small sample, such as one drop of blood, so that multiple tests can be performed on the sample, instead of only one or none. This capability could make a critical difference in solving and preventing crimes.

Saraf's sponsor for this research is Carilion Biomedical Institute of Roanoke, Va. The institute is a partnership between Carilion Health System, the University of Virginia, and Virginia Tech.

Another benefit of Saraf's work will be in genotyping, which will enhance personalized medicine, said Sam English, manager of research projects at the institute. For example, a patient can be tested to see if the breast cancer susceptibility gene is present in her DNA sequence. If detected, a physician can then factor in the patient's genetic make-up for customized preventative care.

This personalized approach to medicine has the potential to revolutionize healthcare. However, there are many obstacles in the development and implementation of these new technologies. One that concerns Saraf is how to eliminate the need for the PCR in advanced diagnostic testing. The PCR process amplifies a small piece DNA so there is enough to test. The use of the PCR is time consuming and expensive and is currently done only in a lab setting.

Carilion Biomedical Institute has been sponsoring about $1 million worth of projects in the Optical Sciences and Engineering Research Center (OSER) at Virginia Tech for the past three years, including Saraf's research. The center employs optics to provide new biological research tools for visualization, measurement, analysis, and manipulation.

Saraf began working with the institute on the recommendation of Bill Spillman, OSER director. OSER provided the seed money for Saraf's work on the DNA chip. "We are currently in the process of discussing how to commercialize what Saraf has developed with industrial partners," Spillman said.
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PR CONTACT: Karen Gilbert (540)231-4787 karenise@vt.edu

Virginia Tech

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