Nonenzymatic Sweat-Based\nGlucose Sensing by Flower-like\nAu Nanostructures/Graphene Oxide

Abstract

The development of a nonenzymatic glucose sensor working\nin real\nhuman body conditions through a noninvasive sampling approach has\nattracted considerable attention. Hence, this work focuses on the\ndevelopment of a new nonenzymatic glucose sensor based on flower-like\nAu nanostructures (F-AuNTs) and graphene oxide (GO) as a supporting\nmatrix. The F-AuNTs–GO hybrid was synthesized by simple drop\ncasting of the GO suspension onto the graphite sheet (GS) followed\nby electrodeposition of F-AuNTs on GO nanosheets at 3 V in a two-electrode\nsystem. The electrocatalytic activity of the F-AuNTs–GO/GS\nsensor toward glucose electrooxidation was initially evaluated in\na 0.1 M buffer phosphate solution (pH 7.4). The fabricated electrode\nshows a linear range (5 nM to 5 μM), a fast response time (6\ns), a low detection limit (385 nM), and high sensitivity (162,210\nμA mM^–1 cm^–2). Furthermore,\nthis sensor exhibits very good selectivity in the presence of interferences\nsuch as lactic acid, uric acid, NaCl, dopamine, ascorbic acid, and\ninorganic salts. After obtaining the desired results, a screen-printed\nelectrode (SPE) modified by the F-AuNTs–GO hybrid was prepared\nfor the determination of glucose concentration from artificial sweat\nto evaluate the noninvasive capability of the proposed sensor. The\nF-AuNTs–GO/SPE exhibits good behavior for glucose detection\nwith a long linear range of 160 nM to 82 μM and 160 μM\nto 5 mM, a high sensitivity of 474,617 μA mM^–1 cm^–1, and a low detection limit of 123 μM.\nTherefore, the electrochemical experiments demonstrated that F-AuNTs–GO\npossessed the excellent ability for electrochemically catalysis of\nglucose oxidation in both buffer solution and artificial sweat. Finally,\nthe capability of the fabricated electrode was successfully investigated\nfor glucose measurement in sweat samples. The outstanding performance\nof the F-AuNTs–GO-based sensor can be attributed to the superior\ncatalytic activity of the F-AuNTs well dispersing onto GO nanosheets,\nwhich provides an excellent sensing platform owing to the enhanced\nelectrical conductivity and large surface area. This study demonstrates\nthat the F-AuNTs–GO hybrid is a promising candidate for the\ndetection of glucose in sensor applications.