Direct Electrochemistry and Glucose Biosensing of Glucose Oxidase-Gold Nanoparticles Composite Synthesized by Enzyme Method

Glucose oxidase(GOx)-gold nanoparticles(Au NPs) composite was synthesized by the one-pot enzyme reaction in the mixture solution of Na Au Cl4, GOx and glucose, and a Nafion/GOx-Au NPs/glassy carbon electrode was fabricated by the cast-coating method to examine the direct electrochemistry of GOx and the biosensing performance on this electrode. Such a GOx-Au NPs composite showed good direct-electrochemistry activity and bioactivity of GOx, probably because the enzyme-mediated Au NPs are close to the redox active centers of GOx. This enzyme electrode exhibited a linear amperometric response to glucose concentration(0.5 ~ 4 mmol·L-1) at-0.4 V(vs. SCE), and a detection limit of 0.2 μmol·L-1was obtained.