Analytical Sciences


Abstract − Analytical Sciences, 20(3), 537 (2004).

Silica Sol-gel Amperometric Immunosensor for Schistosoma Japonicum Antibody Assay
Tong-Sheng ZHONG* and Guodong LIU**
*Department of Chemistry and Environmental Engineering, Hunan City College, Yiyang 413049, P. R. China
**Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico State 88003, USA
An amperometric immunosensor was constructed by dispersing graphite, schistosoma-japonicum antigen (SjAg) and silica sol-gel at low temperature. The performance characteristics of the prepared immunosensor were examined in the buffered solution of o-aminophenol (o-AP) used as a substrate. It exhibited excellent physical and electrochemical stability with a renewable external surface. A competitive binding assay was employed to determine schistosomajaponicum antibody (SjAb) with the aid of horseradish peroxidase labeled SjAb (HRP-SjAb). The experimental parameters for SjAb assay were optimized, including the amount of labeled SjAb in incubation solution, incubation time, temperature and the pH of solution. The use of o-AP substrate and amperometric detection at -250 mV (vs. SCE) results in a determination limit of 0.32 µg/ml and a linear range extending up to 0.18 µg/ml. The results of SjAb assay in serum samples demonstrate the feasibility of using the proposed immunosensor for clinical analysis.