Diffusion-limited biosensing of dissolved oxygen by direct electron transfer-type bioelectrocatalysis of multi-copper oxidases immobilized on porous gold microelectrodes

Diffusion-controlled amperometric biosensors for dissolved oxygen (O2) were constructed by immobilization of multi-copper oxidases (copper efflux oxidase and bilirubin oxidase) on porous gold microdisk electrodes fabricated by anodization in a glucose solution. The immobilized enzymes rapidly consumed O2 near the electrode at potentials more negative than 0.2 V vs. Ag|AgCl|sat. KCl via direct electron transfer-type bioelectrocatalysis and the...