Hemin functionalized graphene nanosheets-based dual biosensor platforms for hydrogen peroxide and glucose

In this paper, we present dual biosensor platforms based on hemin functionalized graphene nanosheets (H-GNs). The nanomaterial combines the features of both graphene (high conductivity and surface area) and hemin (excellent catalysis and intrinsic peroxidase-like activity). It not only shows excellent electrocatalysis of the reduction of H2O2 but also exhibits intrinsic peroxidase-like activity that can catalyze H2O2 to oxidize 3,3,5,5-tetramethylbenzidine (TMB) to produce a blue color reaction. Based on these properties, the simple, economical, and highly sensitive amperometric and colorimetric biosensors for H2O2 and glucose have been developed. The linear relationships for H2O2 and glucose were obtained from 0.5 mu M to 0.4 mM and 0.05 mu M to 0.5 mM by amperometric and colorimetric methods, respectively. The detection limits for H2O2 and glucose reached to 0.2 mu M and 0.3 mu M by amperometric method. By colorimetric methods, the detection limits for H2O2 and glucose were as low as 20 nM and 30 nM, respectively. The rapid, simple and sensitive sensing platform showed great promising applications in the pharmaceutical, clinical and industrial detection of v and glucose. (C) 2011 Elsevier B.V. All rights reserved.