A new and label-free capacitive immunosensor based on antibody-functionalized epoxysilane on a glassy carbon electrode has been developed for quantitative detection of human chorionic gonadotropin (hCG). Monitoring the changes in the capacitance signals of antibodies before and after the binding of the antigen provides the basis for an immunoassay. The performance and factors influencing the immunosensor were also studied. Under the optimized conditions, the developed immunosensor quantitatively detected serum hCG in the range of 18–450 mIU/ml with a detection limit of 5.0 mIU/ml (at 3δ). Thirty-five patients’ sera were assayed by the proposed immunosensor, and the results agreed with those given by the commercial radioimmunoassay test kit, with correlation coefficient of 0.998. Further research about the intrinsic electroactivity of antibodies and their target molecules would surely provide new and sensitive screening assays as well as extensive data regarding their interaction mechanisms.
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The author gratefully acknowledges financial support of the Natural Science Foundation of Chongqing City and the Education Committee of Chongqing City, China.
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Liao, J. Detection of human chorionic gonadotrophin hormone using a label-free epoxysilane-modified capacitive immunosensor. Appl Microbiol Biotechnol 74, 1385–1391 (2007). https://doi.org/10.1007/s00253-006-0778-7
- Capacitive immunoassay
- Human chorionic gonadotropin hormone