An Electrochemical Glucose Biosensor with a Silicon Nanowire Array Electrode

Abstract

In this study, a novel electrochemical glucose biosensor, which integrates the silicon metal-assisted etching (MAE) technique and the glucose biosensor principle, is proposed. Metal-assisted etching (MAE) method using an AgNO3 and HF mixing solution as the etchant was employed to grow the silicon nanowire array (SNA) electrode. A thin gold shell is then sputtered over each silicon nanowire. Potassium ferricyanide, glucose oxidase (GOx), and a Nafion thin film were then sequentially coated onto the fabricated SNA for glucose detection. The processing time of the MAE and sputtering as well as the GOx concentration were optimized in terms of the redox peak currents of the SNA electrode. Compared with the corresponding plane gold electrode, the effective sensing area of the synthesized SNA electrode was measured to be 6.12 folds. Actual glucose detections illustrated that the SNA based devices could function at a sensitivity of 390.5 μA mM−1 cm−2 with a linear detection range from 55.1 μM–16.53 mM and detection limit of 11 μM. The proposed SNA electrode based glucose biosensor possesses advantages of simple fabrication process, low cost, and high sensitivity. It is feasible for future clinical applications.