Nanostructured Porous Electrodes by the Anodization of Gold for an Application as Scaffolds in Direct-electron-transfer-type Bioelectrocatalysis

Abstract

In this study, nanostructured porous gold electrodes were prepared by the anodization of gold in the presence of oxalic acid or glucose as a reductant, and applied as scaffolds for direct electron transfer (DET)-type bioelectrocatalysis. Gold cations generated in the anodization seem to be reduced by the reductant to construct a porous gold structure. The DET-type performance of the electrode was examined using two DET-type model enzymes, bilirubin oxidase (BOD) and peroxidase (POD), for the four-electron reduction of dioxygen and the two-electron reduction of peroxide, respectively. BOD and POD on the anodized porous gold electrodes exhibited well-defined sigmoidal steady-state waves corresponding to DET-type bioelectrocatalysis. Scanning electron microscopy images revealed sponge-like pores on the electrodes. The anodized porous gold electrodes demonstrate promise as scaffolds for DET-type bioelectrocatalysis.

Recent Progress in Applications of Enzymatic Bioelectrocatalysis

“…These reactions proceed in the following schemes in the simple case of the substrate's oxidation. On the other hand, we note here that some redox enzymes that have a catalytic site alone, without any other redox site(s), are also able to show DET-type bioelectrocatalysis, e.g., cytochrome c peroxidase [24], horseradish peroxidase (HRP) [25][26][27], ferredoxin-NADP + reductase [28], flavin adenine dinucleotide (FAD)-dependent glucose oxidase (FAD-GOD) [29,30], and FAD-dependent glucose dehydrogenase (FAD-GDH) [31]. Figure 1.…”

Development Perspective of Bioelectrocatalysis-Based Biosensors

“…Recently, it was found that HRP showed a DET-type bioelectrocatalytic activity at mesoporous carbon and nanostructured gold electrodes [ 103 , 104 ] and third generation OP-type biosensors using the DET-type reaction of HRP were reported. Xia et al reported glucose and putrescine biosensors using GOD and putrescine oxidase, respectively [ 41 , 103 ].…”

Development Perspective of Bioelectrocatalysis-based Biosensors

“…Recently, it was found that HRP showed a DET-type bioelectrocatalytic activity at mesoporous carbon and nanostructured gold electrodes [103,104], and 3rd generation OP-type biosensors using the DET-type reaction of HRP were reported. Xia et al reported glucose and putrescine biosensors using GOD and putrescine oxidase, respectively [41,103].…”