A Novel and Simple Electrochemical Glucose Biosensor Based on a Silicon Nanowire Array Electrode

In this study, a novel and simple electrochemical glucose biosensor based on a silicon nanowire array (SNA) electrode was 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 demonstrated that the proposed SNA array electrode could operate in a linear range of 0.55 mM-11.02 mM and a very high sensitivity of 346 μA mM−1 cm−2. 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.