A Biosensor Electrode with Self-Assembled Monolayer of Gold Nanoparticle on a Micro Hemisphere Array

In this study, we first proposed a low-cost and highly reproducible method for the mass production of a novel biosensor electrode with self-assembled monolayer of gold nanoparticle on a micro hemisphere array. An ordered array of micro hemispherical features was formed on a 6-inch reclaimed silicon wafer using photolithography. Then, a thin gold layer was sputtered onto the hemispheres. The wafer was then immersed into a 5 mM ethanol solution of 1,6-hexanedithiol (1,6-HDT) to enable the attachment of one thio-end of 1,6-HDT to the thin gold layer. Finally, a colloidal gold (similar to 13.5 nm) solution was dripped onto the wafer and baked on a hot plate in such a way that the monolayer of gold nanoparticles could self-assemble on the 1,6-HDT surface. The features of the fabricated biosensor electrodes were then applied for non-enzymatic glucose detections. Chronoamperometry (CA) detection of glucose demonstrated that the proposed non-enzymatic glucose biosensor can operate in a linear range from 1.39 to 13.89 mM with a sensitivity of 336.1 mu A.mM(-1).cm(-2) and a detection limit of 5.2 mu M. The accuracy of the developed glucose biosensor reaches +/- 1.29%, which is significantly better than the FDA and ISO 15197 standard of +/- 15%. The relatively high repeatability of the proposed glucose biosensor can be attributed to the uniform semiconductor fabrication process and the extremely ordered self-assembled monolayer of gold nanoparticles. The proposed biosensor can be easily produced on a large scale, the cost of fabrication is low, repeatability is high, and is easy to preserve on a long-term basis. (C) 2019 The Electrochemical Society.