Dual-Switchable Bioelectrocatalysis Synergistically Controlled by pH and Perchlorate Concentration Based on Poly(4-vinylpyridine) Films

Poly(4-vinylpyridine) (P4VP) films were electropolymerized on a pyrolytic graphite (PG) electrode surface. The cyclic voltammetric (CV) response of ferrocenedicarboxylic acid (Fc(COOH)2) at P4VP film electrodes was very sensitive to the pH and perchlorate (ClO4−) concentration in testing solutions. Fc(COOH)2 was at the “on” state with a relatively large CV oxidation peak current for the films at pH 4.0 but showed the “off” state with significantly suppressed CV response at pH 7.0. The reversible ClO4− concentration-sensitive on−off property of P4VP films toward Fc(COOH)2 at pH 4.0 was also observed. In particular, the influence of pH and ClO4− concentration on the on−off behavior of the system is not independent or separate but synergetic or cooperative, and the electrostatic interaction between the films and the probe plays a predominant role in deciding the pH- and/or ClO4− concentration-dependent behavior for the system. The dual-responsive property of the P4VP films toward Fc(COOH)2 could also be used to control the bioelectrocatalysis of glucose by glucose oxidase. This synergetic-triggered bioelectrocatalysis on the basis of the intelligent interface system may establish a foundation for fabricating novel multiple factor-controllable biosensors based on enzymatic electrocatalysis.