Schematic drawing (top left) of a microfluidic biochip for capturing Listeria. A prototype chip, top right, is connected with microfluidic tubings, and at bottom are images of bacteria on a chip. (Image: The American Chemical Society)
Arun Bhunia and colleagues note in the new study that fast, highly effective tests already are available for five of the six known species of Listeria. These tests use antibodies that signal the presence of the bacteria. However, no rapid, sensitive tests are available for detecting Listeria monocytogenes, the deadliest of the species, the researchers say.
The scientists describe development of the biosensor using so-called heat shock proteins — which the body produces in response to stress — instead of the antibodies used in other tests. They showed that their new sensor was faster and more sensitive at detecting the deadly bacterium than antibody-based tests. It had a microbe capture rate up to 83 percent higher than antibody-based tests. The new biosensor will reduce the likelihood of false-positive results for Listeria monocytogenes and may lead to improved tests for detecting other types of dangerous pathogens, the researchers say.