Research Of Electrochemical Immunosensor For Schistosomiasis Japonicum Diagnosis

Schistosomiasis japonicum is a kind of ubiquitous species and has a very wide host range of parasitic disease. At present, the usual methods used to detect Schistosomiasis japonicum are traditional immunoassay techniques. Traditional immunoassay techniques are often complicated by the requirement of an elaborate excitation, detection scheme and skilled analytical workers. Some of the optical detectors are expensive and low-sensitivity, which limits their applications for Schistosoma japonicum. To overcome these problems, the development of immunoassays for highly sensitive detection and accurate analysis of Schistosomiasis japonicum has been of tremendous interest and value to the scientific community. Most of the reported electrochemical immunosensors have simplified the operations, shortened the assay time, and provided a good sensitivity, practical applications of the developed immunosensors have been widely used for molecular diagnosis. The molecular diagnosis comprises the diagnosis of nucleic acid (including DNA and RNA), protein and metabolites and has been potential dectection techniques. In this thesis, electrochemical biosensor was investigated for the application and development in diagnostics Schistosoma japonicum.Firstly, we developed a new electrochemical immunosensor for the detection of Schistosomiasis japonicum antibodies, using horseradish peroxidase (HRP) and a new substrate O-aminophenol (O-AP), which is called "Enzyme O-aminophenol" system. HRP are able to catalyze the oxidation of O-AP to 3-aminohenoxazine, which could be detected with the electrochemistry method.The results indicated that the new protein detection method based on "Enzyme O-aminophenol" is feasible for the detection of Schistosomiasis japonicum antibody in human serum with higher sensitivity.We further designed a multichannel electrochemical immunosensor for the Schistosomiasis japonicum antibodies detection, which is similar with the enzyme linked immunosorbent assay (ELISA) system:The Schistosoma japonicum antigen, antibody and the HRP labeled second antibody were assembled on the screen-printed carbon electrode (SPCE), respectively, based on the specific biochemical interaction between antigen and corresponding antibodies.16 SPCEs each connected with the channel couled be detected simultaneously, which made the serum sample detection faster, more sensitive and more efficient and has led to a new strategy for protein detection.