Anthrax Detection? Pathogen Identification? It’s in the Bag.

• By Laura Williams
• Aug 03, 2011

When two Cornell University researchers started work on a project to create a pathogen-detection system eight years ago, their first purchase was not some kind of intricate scientific equipment. Instead, it was a reinforced plastic box the size of a small suitcase.

“We were interested in was creating a field-portable instrument, so that no matter what you’re testing, you can get it back immediately,” said Cornell professor Carl Batt, one of the two researchers who developed the device. “You can’t be any more rapid than the time it takes the sample to get to the testing laboratory, so there’s no point in making a rapid test that can only be done in a lab.”

“It really forced the engineers to think inside the box,” he said with a laugh.

Despite its compact size, the device is powerful. It can detect the presence of anthrax in just one hour from a sample containing as few as 40 microscopic spores. Depending on the testing kit used, the device can also detect other pathogens, including salmonella, which makes it ripe for applications in food safety.

Nathaniel Cady, now a professor at University of Albany, was the other researcher on the project.

It identifies the bacteria through a polymerase chain reaction, an established method of simplifying DNA for identification. A user inserts the sample into the machine, which recovers cells from the sample, purifies the DNA and then is able to indicate the nature of the organism from which the cells originated.

"The device looks for particular 'signature' DNA sequences," Cady said. "In our published work we focused on detecting Bacillus anthracis (anthrax). To detect other organisms, we simply change the sequence of DNA that we are looking for."

Because the system is DNA-based, it can also provide genetic information about human samples, including something as simple as a strand of hair. While it can’t conclusively describe the person’s full genetic map based on the sample, it can provide information about a person’s basic traits.

“There are an increasing number of markers that we use as genetic fingerprints, but they’re still not perfect,” Batt said. “It could identify gender, ethnicity – any one of a limited number of genetic markers. It could be helpful to a suspect-elimination process.”

Indeed, Cady said the New York State Police Forensic Lab has evaluated the device for possible use in its forensic examinations. 

It could also be used in the identification process after catastrophic events, such as the Sept. 11 attacks, where victims’ bodies are completely unidentifiable. The device would be able to group pieces of remains of one person, so rescuers would know they have “10 pieces of one person, rather than one piece of 10 people,” Batt said.

Going forward, Batt said the team hopes to focus on making the device smaller. Its electronics and optics have already been downsized, and the pumping element is their next target.

“Pumping liquids is a power-consuming and space-consuming issue,” Batt said. “The smallest pumps are still way too large. We’re working on making fluid-pumping systems that are built along the same principles as we build electronics.”