A novel label-free electrochemical immunosensor for the detection of hepatitis B surface antigen

A novel label-free electrochemical immunosensor based on trimetallic NiAuPt nanoparticles on reduced graphene oxide nanosheets (NiAuPt-NGs) was developed for the quantitative detection of hepatitis B surface antigen (HBsAg). Due to the synergetic effect present in the trimetallic NiAuPt-NG nanocomposite, the NiAuPt-NG nanocomposite shows better electrocatalytic activity towards the reduction of hydrogen peroxide (H2O2), which is much better than that of monometallic Pt-NG, bimetallic NiPt-NG and AuPt-NG nanocomposites. In this work, the NiAuPt-NG nanocomposite with a large specific surface area, good biocompatibility and excellent electrical conductivity was used to capture antibodies efficiently and amplify the signal of the proposed immunosensor. The amperometric i-t technique was used to record the changes of electrochemical signals when electrodes were modified with different concentrations of HBsAg. Under the optimal conditions, the proposed electrochemical label-free immunosensor exhibits excellent analytical performance for the measurement of HBsAg with the linear range from 0.001 to 80 ng mL(-1) and a detection limit of 0.31 pg mL(-1), which may have promising application in bioassay and enrich the electrochemical immunoassays.