▎ 摘　　要

The detection of hepatitis B surface antigen (HBsAg), a coat protein secreted by hepatitis B virus, is a common method for confirming infection in early diagnosis. A new composite of graphene oxide-ferrocene-chitosan (GO-Fc-CS) was synthesized and used to develop an electrochemical immunosensor with a GO-Fc-CS/Au-nanoparticle layer film for HBsAg detection. The modified layer film exhibited not only enhanced electron conductivity, but also strong reversible redox signal for current changes, excellent biocompatibility, and good film-forming ability for binding a large number of antibodies. The immunosensor exhibits a wide linear range from 0.05 to 150 ng/mL and detection limit of 0.01 ng/mL for HBsAg. The excellent performance in HBsAg detection suggests that the proposed immunosensor has potential application in clinical diagnosis.