Electrochemical Detection of Bacteria Using Bacteriophage

Immobilization of bacteriophage T4 onto the SPEs was achieved by formation of amide bonds between the protein coating of the phage and the electrochemically generated carboxylic groups at the carbon surface. The immobilized T4 were then used to specifically detect target bacteria (E.coli). Impedance measurements (Nyquist plots) show significant shifts in both the real (Zr) and imaginary (Zi) impedances due to binding of the bacteria to the T4. No significant change in impedance was observed due to binding of non-specific bacteria such as Salmonella, and the results have also been confirmed with fluorescence microscopy. Fluorescence microscope images of the functionalized electrodes show lysis of the bacteria as a function of time, while no disappearance of bacteria was observed on non-functionalized SPEs.