Abstract

In this work, we have studied the interaction between graphene oxide (GO) and the biomolecules immobilized on an electrode surface, which has been further employed to develop new kind of biosensors by fabricating gammaglutamyltransferase (γ-GGT) sensor as an example. Specifically, glutathione (GSH) is firstly immobilized on the surface of a gold electrode, and GO nanosheet is introduced to recognize the charge change of GSH caused by the catalysis of γ-GGT. Then, the introduction of reductant and Ag⁺ induces silver deposition and partial reduction of GO, forming GOAgNPs complex for electrochemical readout. Since this complex may have excellent electric conductivity and the solidstate voltammetry of Ag/AgCl can provide a well-defined symmetrically sharp silver stripping peak, a sensitive electrochemical biosensor for the detection of γ-GGT is thus developed. Moreover, the experimental results obtained in this work indicate that GO itself can serve as a general recognition element for biosensor fabrication and GO-AgNPs can be a promising material in a general sensing platform, so such kind of more biosensors can be developed in the future.

Keywords: Electrochemical assay, gamma-glutamyltransferase, graphene oxide, in situ reduction, silver nanoparticles, solidstate voltammetry.