Specific detection of Escherichia coli by using metallic mesh sensor in THz region

We demonstrated specific and rapid detection of Escherichia coli (E. coli) without culturing and labeling, using a metallic mesh sensor. Streptavidin and biotinylated antibody, specific for E. coli, were immobilized on the metallic mesh surface via amination and maleimidation. E. coli in PBS were captured, and attached to the surface of the metallic mesh, by immunoreaction with the antibody for E. coli. Transmission spectra of these samples were then measured around 10 THz, where the size of the generated, localized, electric field is the same as that of E. coli. After demonstrating a significant relationship between the frequency shift on the metallic mesh sensor and antibody for E. coli concentration, we then went on to specifically and quantitatively measure E. coli concentration. As E. coli concentration increased so did the spectral frequency shift, with detection limit being observed at 10⁶ mL^-1.