Electrochemical biosensor based on modified graphene oxide for tuberculosis diagnosis

In this paper, graphene oxide (GO) was modified in-situ on an electrochemical electrode array for attachment of protein. GO suspension made from natural graphite flakes was directly dip-coated onto the Au working electrodes. Detected by cyclic voltammetry, the peak current of GO on Au electrode increased by 1μA as compared with bare gold electrode. Modified graphgene oxide (MGO) with stable active esters was formed by in-situ modifying GO with N-ethyl-N´-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDAC)/ N-hydroxysuccinimide (NHS). MGO was ready for protein attachment. An immunesensor chip (GO-antigen) was prepared by tuberculosis (TB) antigens bound with MGO. The peak of CV curve of GO-antigen increased by about 3μA as compared with that of MGO, however, after the GO-antigen reaction with the antibody, the peak of the current decreased 4μA. Such results showed potential applications of the immunosensor.