Detection of human chorionic gonadotrophin hormone using a label-free epoxysilane-modified capacitive immunosensor.
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 3delta). 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.
Liao
Jia-Yao
JY
College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, People's Republic of China. liaoswu@msn.com
D015374:Biosensing Techniques / Q000379:methods*; D006063:Chorionic Gonadotropin / Q000032:analysis* / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007118:Immunoassay / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D015394:Molecular Structure; D015203:Reproducibility of Results
D006063:Chorionic Gonadotropin