Professors Develop Hand-Held Device to Detect Pathogens

29/12/06 Testing for deadly food, air and water pathogens may get a lot easier and cheaper thanks to the work of a Michigan State University researcher and his team.

Syed Hashsham, an associate professor in the Department of Civil and Environmental Engineering and the Center for Microbial Ecology, is developing a portable, hand-held device capable of detecting up to 50 microbial threat agents in air, water and food.

"This device will give us the ability to measure pathogens in a manner and at a price that really matters for human health," Hashsham said. "If we can screen for all pathogens together, we can minimize the threat significantly."

Hashsham intends for the portable, hand-held device to be an all-in-one pathogen testing center where DNA amplification and pathogen identification will happen on the same DNA biochip. A DNA biochip has signature pieces of DNA attached to a silica surface, similar to a computer chip, and is about the size of a thumbnail.

Today, testing air, water or food for pathogens like cholera and dysentery must be done one pathogen at a time. Testing for each pathogen on an individual basis is dangerous, more expensive and time consuming. Simultaneous testing simplifies the process, making it safer and more cost effective.

Earlier this year, Hashsham was awarded $966,608 from the 21st Century Jobs Fund to develop and commercialize the device.

Hashsham, James Tiedje, University Distinguished Professor of crop and soil sciences and director of the Center for Microbial Ecology, and Erdogan Gulari, professor at the University of Michigan's Department of Chemical Engineering, formed a cross-disciplinary team to develop this technology.

The procedure begins with sample processing that extracts DNA from all microorganisms present in the sample. The DNA can then be introduced into the device where it will undergo polymerase chain reaction for the selected harmful pathogens. Polymerase chain reaction is a process that takes a small amount of DNA and makes billions of copies so the pathogens can be easily detected, Hashsham explained.

Most of the genetic material in any bacteria isn't harmful. For instance, the bacterium Vibrio cholerae, responsible for the waterborne illness cholera, has many housekeeping genes that maintain the organism, but are not dangerous to humans by themselves. But the gene producing the cholera toxin is harmful. These genes serve as good markers for detection. Hashsham's device will be designed to look for such marker genes.

"This technology is rugged and highly parallel; it can analyze lots of marker genes in a lot of samples, together with significantly lower false positives," Hashsham said.

He said the hand-held testing device could be used anywhere that cost-effective testing of food, water or air is needed for a number of pathogens.

"Because of the lower cost, there also will be applications in countries where fewer resources are available for drinking water safety," Hashsham said.

Looking toward the future, Hashsham has been in touch with several organizations that might be interested in the device. AquaBioChip LLC, a Lansing-based company formed by the same team through a previous grant from the Michigan Economic Development Corp., will test the device under field conditions.

He has a team of six graduate students and technicians working on this device. "They are the heart of the project as well as the scientists being trained for the future," Hashsham said. That number of employees is likely to increase when the device gets to the commercialization stage.