[Development and Biosensor Applications of Novel Functional Electrodes]

Abstract

Phenylboronic acid (PBA) derivatives have been used as alternatives to enzymes in the development of sugar-sensitive systems because the optical and electrochemical properties of these derivatives are significantly modulated upon sugar binding. This article reviews the voltammetric properties of sugar sensors prepared using dithiobis (4-butyrylamino-m-phenylboronic acid) (DTBA-PBA)-modified electrodes and PBA-appended layer-by-layer film-modified electrodes. In addition, the redox properties of reduced graphene oxide (rGO)-modified glassy carbon electrodes (GCEs) are discussed. The surface of a gold electrode was modified with a monolayer of DTBA-PBA to prepare sugar-sensitive electrodes. The modified electrodes exhibited attenuated cyclic voltammograms for Fe(CN)₆^3-/4- in the presence of sugars at neutral pH as a result of their binding to DTBA-PBA on the electrode. Useful calibration curves were obtained for determining 3-300 mM D-glucose and 0.3-30 mM D-fructose. Similarly, gold electrodes coated with multilayer films composed of PBA-modified poly(allylamine hydrochloride) and carboxymethylcellulose exhibited a sugar-dependent response at neutral pH. The dynamic range of these modified electrodes was 0.1-300 mM for D-glucose and D-fructose. The surface of GCE was modified with rGO to evaluate the electrochemical response of the modified GCE to hydrogen peroxide (H₂O₂). The rGO-modified electrodes exhibited significantly higher responses in the redox reactions of H₂O₂ compared with the response of an unmodified GCE.