The Development and Evaluation of Reagentless Glucose Biosensors Using Dendritic Gold Nanostructures as a Promising Sensing Platform

Abstract

Reagentless electrochemical glucose biosensors were developed and investigated. A graphite rod (GR) electrode modified with electrochemically synthesized dendritic gold nanostructures (DGNs) and redox mediators (Med) such as ferrocenecarboxylic acid (FCA), 1,10-phenathroline-5,6-dione (PD), N,N,N′,N′-tetramethylbenzidine (TMB) or tetrathiafulvalene (TTF) in combination with glucose oxidase (GOx) (GR/DGNs/FCA/GOx, GR/DGNs/PD/GOx, GR/DGNs/TMB/GOx, or GR/DGNs/TTF/GOx) were developed and electrochemically investigated. A biosensor based on threefold-layer-by-layer-deposited PD and GOx (GR/DGNs/(PD/GOx)3) was found to be the most suitable for the determination of glucose. To improve the performance of the developed biosensor, the surface of the GR/DGNs/(PD/GOx)3 electrode was modified with polypyrrole (Ppy) for 5 h. A glucose biosensor based on a GR/DGNs/(PD/GOx)3/Ppy(5 h) electrode was characterized using a wide linear dynamic range of up to 39.0 mmol L−1 of glucose, sensitivity of 3.03 µA mM−1 cm−2, limit of detection of 0.683 mmol L−1, and repeatability of 9.03% for a 29.4 mmol L−1 glucose concentration. The Ppy-based glucose biosensor was characterized by a good storage stability (τ1/2 = 9.0 days). Additionally, the performance of the developed biosensor in blood serum was investigated.