Abstract: An immunosensor for the analysis of antisperm antibody in human serum was developed. The detection methodology is based on the network-type mixed thin film on gold electrode surface. The network-type mixed thin film was derived by a one-step mixed-assembly-cross-linking route. In this strategy, the mixing of 1,6-hexananedithiol, 3-mercaptopropionic acid and Au nanoparticles in solutions allowed sequential co-assemble, cross-linked and eventual precipitation of the network-type mixed thin film on gold electrode, which yielded an interface containing carboxyl groups for immobilization of sperm antigens. The immunoresponse of the proposed immunosensor was compared with that based on mixed self-assembled monolayer immobilized on plane electrode. It was found that the developed sensing interface could perform more effective antibody-antigen binding and decrease nonspecific adsorption. This immunosensor can quantitatively determine concentrations of antisperm antibody ranging from 10 to 800 mU/mL with a detection limit of 7 mU/mL. Five human serum samples were determined with proposed immunosensor and the results were in good agreement with those obtained by ELISA method, which means the piezoelectric immunosensor could provide a new platform for the clinic detection of antisperm antibody.

Key words: Au nanoparticle, Network-type mixed self-assembled monolayer, Piezoelectric quartz crystal immunosensor, Antisperm antibody