Flow-injection amperometric glucose biosensors based on graphene/Nafion hybrid electrodes

In this research, we demonstrated the fabrication of flow-injection amperometric glucose biosensors based on RGO/Nafion hybrids. The nanohybridization of the reduced graphene oxide (RGO) by Nafion provided the fast electron transfer (Er) for the sensitive amperometric biosensor platforms. The ET rate (k(s)) and the charge transfer resistance (R-CT) of GOx-RGO/Nafion hybrids were evaluated to verify the accelerated ET. Moreover, hybrid biosensors revealed a quasi-reversible and surface controlled process, as confirmed by the low peak-to-peak (Delta E-p) and linear relations between I-p and scan rate (nu). Hybrid biosensors showed the fast response time of similar to 3 s, the sensitivity of 3.8 mu A mM(-1) cm(-2), the limit of detection of 170 mu M, and the linear detection range of 2-20 mM for the flow-injection amperometric detection of glucose. Furthermore, interference effect of oxidizable species such as ascorbic acid (M) and uric acid (UA) on the performance of hybrid biosensors was prevented at the operating potential of -0.20 V even under the flow injection mode. Therefore, the fast, sensitive, and stable amperometric responses of hybrid biosensors in the flow injection system make it highly suitable for automatically monitoring glucose. (C) 2011 Elsevier Ltd. All rights reserved.