Analytical Sciences

Abstract − Analytical Sciences, 18(2), 155 (2002).

An Amperometric Immunosensor Based ona Conducting Immunocomposite Electrode for the Determination ofSchistosoma japonicum Antigen
Ya-Min ZHOU, Guo-Dong LIU, Zhao-Yang WU,Guo-Li SHEN,  and Ru-Qin YU
State Key Laboratory for Chemo/BiosensingTechnology and Chemometrics, College of Chemistry and Chemical Engineering,Hunan University, Changsha, 410082, P. R. China
A renewable amperometric immunosensor basedon a graphite-paraffin-Schistosoma japonicum antibody (SjAb)biocomposite electrode has been prepared for the detection ofSchistosoma japonicum antigen (SjAg). Competitive ELISA wasemployed involving HRP-SjAg as a tracer and 3,3',5,5'-tetramethylbenzidine(TMB) as a substrate. The product of an enzyme catalytic reaction wasdetected at +0.1 V (vs. Ag/AgCl reference electrode) for measuringthe amount of HRP-labeled SjAg binding to the electrode surface. The assayconditions were optimized, including the amount of SjAb loading in theelectrode and HRP-SjAg in the incubation solution, the pH of the measuringsolution and the incubation time. The measuring range was 0.5 - 30 ug/mlunder the optimum conditions. Rabbit serum samples of different infectiondegree were measured, which demonstrated that the immunosensor meets thedemands of clinical analysis. It exhibits some advantages, such assimplicity of fabrication, rapidity of measurement, and satisfactorysensitivity and reproducibility.