Nanoporous Structure of Gold Electrode Fabricated by Anodization and Its Efficacy for Direct Electrochemistry of Human Cytochrome P450

Preparation, Modification, Characterization, and Biosensing Application of Nanoporous Gold Using Electrochemical Techniques

“…Proper orientation of the enzyme and minimal distance from the active centers to the surface of the electrode can highly enhance the DET. Np-Au is found to be a suitable support for DET of enzyme-based electrochemical sensors [ 106 , 107 , 108 , 109 ]. This is due to (1) biocompatible nature of np-Au to maintain the enzymatic activity of an enzyme [ 1 ], (2) constraint of porous environment to increase stability of enzyme by decreasing the tendency to unfold [ 29 , 30 ], (3) tunability of pore and ligament sizes to reduce leaching of trapped enzymes [ 29 ], (4) SAMs forming ability to strongly bind enzymes with an increase in loading and decrease in leaching [ 110 , 111 ], and (5) high surface area to amplify the response of the analyte [ 112 ].…”

“…This is due to (1) biocompatible nature of np-Au to maintain the enzymatic activity of an enzyme [ 1 ], (2) constraint of porous environment to increase stability of enzyme by decreasing the tendency to unfold [ 29 , 30 ], (3) tunability of pore and ligament sizes to reduce leaching of trapped enzymes [ 29 ], (4) SAMs forming ability to strongly bind enzymes with an increase in loading and decrease in leaching [ 110 , 111 ], and (5) high surface area to amplify the response of the analyte [ 112 ]. Enzymes, such as horseradish peroxidase (HRP) [ 106 ], human cytochrome P450 [ 107 ], laccase [ 108 ], and bilirubin oxidase [ 109 ] have already been immobilized on np-Au with an enhancement in the DET process. The np-Au immobilized enzymes are also useful in biofuel cells, where np-Au anode and cathode are modified with two different enzymes to generate high power density [ 104 , 113 ].…”

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

“…Some characteristics of the anodization of gold have been reported previously. [41][42][43][44] However, the precise mechanism for the formation of porous structures by the anodization of gold in an oxalic acid or glucose solution remains unclear, although carbonaceous passivation film formation has been suggested to play a significant role in the development of porous structures. 41 Meanwhile, the formation mechanism of the porous structures during anodization in an HCl solution has been reported to be the combination of electrodissolution, disproportion, and deposition.…”

“…40 Thus far, the anodization of gold electrodes has been carried out in hydrochloric acid (HCl)-and organic acid-containing solutions. [41][42][43][44] For instance, the DET-type reaction of cytochrome P450 on an anodized gold electrode has been reported. 44 In this study, porous gold electrodes for DET-type bioelectrocatalysis were prepared by anodization in solutions containing oxalic acid or glucose as a reductant.…”

“…[41][42][43][44] For instance, the DET-type reaction of cytochrome P450 on an anodized gold electrode has been reported. 44 In this study, porous gold electrodes for DET-type bioelectrocatalysis were prepared by anodization in solutions containing oxalic acid or glucose as a reductant. Bilirubin oxidase (BOD) from Myrothecium verrucaria and peroxidase (POD) from horseradish were used as two model enzymes.…”