Wireless, remote-query, and high sensitivity Escherichia coli O157:H7 biosensor based on the recognition action of concanavalin A.

Escherichia coli O157:H7 is detected using a remote-query (wireless, passive) magnetoelastic sensor platform to which a 1 microm thick layer of Bayhydrol 110 and then a layer of functionalized mannose is applied. The multivalent binding of lectin concanavalin A (Con A) to the E. coli surface O-antigen and mannose favors the strong adhesion of E. coli to the mannose-modified magnetoelastic sensor; E. coli is rigidly and strongly attached on the mannose-modified sensor through Con A, which works as a bridge to bind E. coli to the mannose-modified sensor surface. As E. coli is bound to the sensor, its resonance frequency shifts, enabling quantification of E. coli concentration with a limit of detection of 60 cells/mL and a linear logarithmic response range of 6.0 x 10(1) to 6.1 x 10(9) cells/mL. The analysis can be directly conducted without incubation and completed in 3 h or less.