Electrochemical study of nanoporous gold revealing anti-biofouling properties

Abstract

Nanoporous gold (NPG) has remarkable catalytic activity and biocompatibility and could potentially be used in biomedical devices. Herein, we have assessed the long term effects of biofouling on NPG interface. Nanoporoes (25 nm) in gold electrode are fabricated using a de-alloying treatment resulting in an 18 fold increase in surface area as compared to the planar gold. The effects of biofouling on the planar gold interface were evidenced by the rapid decrease in faradaic current to 55% in just eight minutes of incubation in 2 mg ml⁻¹ of bovine serum albumin (BSA). On the other hand NPG showed barely any decline in the peak current when incubated in a similar biofouling solution. NPG upon incubation in a solution of higher concentration of BSA showed immediate peak current degradation which was subsequently recovered when the electrode was left idle in the biofouling solution. For instance, the peak current regenerated from (60% to 80%) when left idle for 60 minutes in 16 mg ml⁻¹ of BSA solution. The regeneration mechanism indicated that even after long term incubation in the biofouling solution, the accumulated organic layer on its interface is not impervious and allows the diffusion of small analytes molecules. Thereby, NPG could be used in biomedical devices such as biosensor or drug reservoir.