Performance of whole-cell electrochemical biosensor using integrated microbes/Si nano-forest structure

A new structure, integrating microbial cells on Si nano-forest, combines whole cell biosensors with a functional nanostructured electrode is described in the current work. E.Coli microbes that expressed and displayed recombinant ZZ proteins were immobilized to a functionalized electrode using IgG antibodies. The presence of E.Coli cells was verified visually and electrochemically using scanning electron microscopy and impedance spectroscopy, respectively. Such structure produces unique electrochemical impedance spectrum that was affected by the analyte concentration. That signal, which is analyzed by both Nyquist diagram and the Bode plot, provide a proof of concept for the feasibility of such integrated whole cell biosensor. Moreover, the selectivity of the system was also confirmed using control cells displaying proteins different form ZZ.