Pathogen testing in hand

MichiganStateUniversity researchers are developing a hand-held device that could make testing for deadly food, air and water pathogens easier and cheaper.

Syed Hashsham, an associate professor in the Department of Civil and Environmental Engineering and the Centre for Microbial Ecology, is developing a portable 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 minimise the threat significantly.’

Hashsham intends for the portable, hand-held device to be an all-in-one pathogen testing centre 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.

Currently, 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.

Hashsham, James Tiedje, University Distinguished Professor of crop and soil sciences and director of the Centre 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.

‘This technology is rugged and highly parallel; it can analyse 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.

AquaBioChip, a company formed through a grant from the Michigan Economic Development Corporation, will test the device under field conditions before taking it to market.