Detecting Biorecognition Events at Blocked Interface Polymeric Membrane Ion-Selective Electrodes Using Electrochemical Impedance Spectroscopy and Atomic Force Microscopy

Immobilization of a biorecognition element onto a polymeric membrane ion‐selective electrode (ISE) using a self‐assembly approach may provide scope for a novel biosensor technology platform based on the altered potentiometric response at the blocked ISE interface. In this paper, the authors have investigated the influence of solution adsorption of the model biorecognition element, avidin‐biotin, on the electrode kinetics of a conventional polymeric membrane Ca2+ ISE using atomic force microscopy (AFM) coupled with electrochemical impedance spectroscopy (EIS). It is demonstrated that solution adsorption of avidin followed by biotin incorporation leads to a demonstrable biorecognition event characterized by an impediment in the Ca2+ ion transfer kinetics of the modified ISE surface. This kinetic principle is amenable to biosensing using pulsed chronopotentiometric polymeric ISEs, which is an established dynamic electrode technique for use with polymeric membrane ISEs.