In situ real-time detection of E. coli in water using antibody-coated magnetostrictive microcantilever

Magnetostrictive microcantilever (MSMC), as a high-performance biosensor platform, was introduced recently. By using physical absorption, an antibody against Escherichia coli is immobilized onto the surface of the MSMC to form a biosensor. The real-time and in situ detection of E. coli in water using the biosensor is reported. The responses of the biosensor in E. coli suspension with different concentrations were studied, which were used to determine the detection limit of the biosensor. It is confirmed by using SEM observation and a control sensor approach, respectively, that the experimentally observed response of the biosensor is due to the binding of E. coli on the surface of the biosensor. It is found that the detection limit is improved by reducing the size of the MSMC, which is consistent with the theoretical calculation. For an MSMC with the size of 1.5 mm × 0.8 mm × 35 μm, the detection limit is 105 cfu/ml.