Switchable Bioelectrocatalysis of Glucose Oxidase Immobilized into Multilayers with Lamellar Nanoparticles of Amino-Functionalized Magnesium Phyllosilicate Clay

Abstract

Lamellar organic clay consisting of amino-functionalized magnesium phyllosilicate (AMPC) with controllable positive charges was successfully prepared by simple one-pot synthesis. Then, the positively charged AMPC was assembled layer by layer with negatively charged glucose oxidase (GOx) enzyme into {AMPC/GOx} n multilayer films on pyrolytic graphite (PG) electrode surface, where n is the number of the bilayers. The {AMPC/GOx} n film electrodes demonstrated sensitive and reversible pH-responsive switchable behavior toward the cyclic voltammetric (CV) responses of the ferrocenedicarboxylic acid (Fc(COOH)2) probe in solution. The CV peak currents were strongly enhanced at pH 5.0 and were significantly reduced at pH 9.0. The pH-sensitive behavior of the system originated from the electrostatic interactions between the nanolayered films and Fc(COOH)2 in solution. This property was applied to realize pH-triggered electrocatalytically oxidation of glucose by GOx enzyme in the {AMPC/GOx} n films. This model system demonstrates the great potential perspective of the fabrication of novel multiple factor-switchable biosensors with immobilized enzymes.