Scientists at the University of Rochester Medical Center in Rochester, New York, have developed a system in which a treated silicon chip is combined with a digital camera to identify E. coli instantly.
Some types of E. coli produce toxins that can make people sick and can even be fatal. Health inspectors commonly search for the bacteria in meat and other foods. But testing usually meant days of waiting for food or water samples to culture in a laboratory Petri dish.
The new method gets E. coli, and not other bacteria, to adhere to the chip, by adding a capture protein the the surface of the chip. The silicon chip, which is used just once for each sample, is coated with an E. coli protein—called a Translocated Intimin Receptor, or TIR–that harpoons E. coli bacteria and no others.
If E. coli is captured, it causes the chip’s surface to reflect, causing a burst of light that is then caught on the system’s digital camera. A burst on the camera’s screen means E. coli lurk.
The technology, being developed into a commercial product at an independent company, could also be modified to detect other kinds of bacteria. Coating the chip with different proteins would allow it to capture other bacteria. And coating it with a mixture of proteins would in theory let the system detect many types of bacteria in a single sweep.