Scientists from two Indian Institutes of Technology – BHU, Varanasi and Guwahati – have designed an electrochemical biosensor that can selectively detect the diarrhoea-causing bacteria Escherichia coli in biological samples super fast1. The sensor works by zeroing in on a highly specific gene (STG) in the bacteria to detect E.coli within 20 minutes.

Conventional microbiological analyses take almost two days to detect enterotoxigenic E. coli in samples. The researchers worked around this by using a nanocomposite biosensor made of STG specific probes. STG imparts heat stability to the bacteria. They analysed the ‘STG hybridization’ through the electrochemical impedance spectroscopy (EIS) technique. The sensor’s efficacy was validated using polymerase chain reaction.

While trying to ensure that it has practical application, the researchers successfully detected STG in bacteria present on surface water.

The scientists are now hoping to develop a prototype miniature hand-held device for biomedical diagnosis. “The strategy described is easy, quick, inexpensive, and universal, and hence can facilitate point-of-care detection,” the researchers say.