A novel liquid-phase piezoelectric immunosensor for detecting Schistosoma japonicum circulating antigen

AimsA new liquid-phase piezoelectric immunosensor (LP-PEIS), which can detect Schistosoma japonicum (Sj) circulating antigens (SjCAg) quantificationally, was developed.MethodsThe IgG antibodies were purified from the sera of rabbits which had been infected or immunized by Sj and were immobilized on the surface of piezoelectric quartz crystal in LP-PEIS by staphylococcal protein A (SPA). It was used to detect SjCAg in sera of rabbits which had been infected by Sj in order to acquire some optimum conditions for detecting SjCAg. Finally, the LP-PEIS with optimum conditions was used to detect SjCAg in sera of patients who had been infected by Sj, and was compared with sandwich ELISA.ResultsA lot of optimum conditions of LP-PEIS for detecting SjCAg had been acquired. In the detection of patients' sera with acute Schistosomiasis, LP-PEIS has higher positive rate (100%) and lower false positive rate (3.0%) than sandwich ELISA (92.8%, 6.0%). However, there were no significant difference between LP-PEIS and sandwich ELISA.ConclusionsLP-PEIS can quantificationally detect SjCAg in patients' sera as well as sandwich ELISA.

Research Highlights
► Piezoelectric immunosensor (PEIS) is a new technique for quantitative analysis. It has some advantages over common serological tests, such as simpler operation, quicker detection and real-time monitoring for antigen-antibody reaction in liquid.
► In this study, piezoelectric immunosensor was used to detect SjCAg. A lot of important data about optimum condition for detection was acquired.
► In the detection of patients’ sera with acute Schistosomiasis, LP-PEIS has higher positive rate (100%) and lower false positive rate (3.0%) than sandwich ELISA (92.8%, 6.0%, respectively).
► This novel PEIS was believed to be a good method for quantificationally detecting SjCAg in sera, and can be used to diagnose Schistosomiasis japonica early and present infection of Sj.