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

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 & PRIME;,N & PRIME;-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 & mu;A 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 (& tau;(1/2) = 9.0 days). Additionally, the performance of the developed biosensor in blood serum was investigated.

Automated summary

Reagentless electrochemical glucose biosensors were developed using graphite rod electrodes modified with dendritic gold nanostructures and redox mediators in combination with glucose oxidase. Among various combinations, the biosensor based on threefold-layer-by-layer-deposited phenathroline-5,6-dione (PD) and glucose oxidase was found to be the most suitable for glucose determination. The performance of the biosensor was further improved by modifying the electrode surface with polypyrrole, resulting in a wide linear dynamic range, high sensitivity, low limit of detection, and good repeatability.