Nonenzymatic determination of glucose at near neutral pH valuesbased on the use ofnafion and platinum black coated microneedle electrode array.

Abstract

The authors report on a microneedle-based amperometric nonenzymatic glucose sensor for painless and continuous monitoring of glucose. It consists of 3 × 5 sharp stainless steel microneedles micromachined from a stainless steel substrate. The microneedles are 600 and 100μm in height and width, respectively. Nafion and platinum black were sequentially coated onto the tip of gold-coated microneedles and used for nonenzymatic (direct) sensing of glucose. Attractive features of the modified microneedle electrode include (a) a low working potential (+0.12V vs. Ag/AgCl), (b) a linear response in the physiologically relevant range (1-40mM), (c) a sensitivity as high as 175μAmM-1cm-2, (d) a 23μM detection limit, and (e) a response time of 2s. The sensor also exhibits good reproducibility and stability. The sensor is selective for glucose even in the presence of 10-fold higher concentrations of ascorbic acid, lactic acid, dopamine, uric acid, and acetaminophen. Graphical abstract Schematic representation of the fabrication sequence for a nonenzymatic electrochemical glucose sensor using Nafion and platinumblack coated microneedle electrode array. The sensor is based on measuring the faradaic current at +0.12V vs. Ag/AgCl by the direct electrochemical oxidation of glucose to gluconic acid on the surface of aPt black sensing layer.