Immunoassay for Human Chorionic Gonadotropin Based on Glassy Carbon Electrode Modified with an Epitaxial Nanocomposite

Document Type : Research Paper


1 Department of Chemistry, Ilam University, Ilam, Iran

2 Department of Chemistry, University of Ilam, Ilam, Iran


      A highly sensitive electrochemical
immunosensor was developed to detect hCG based on immobilization of
hCG-antibody (anti-hCG) onto robust nanocomposite containing Gr, Chit,
1-methyl-3-octyl imidazolium tetra fluoro borate ionic liquid (IL)
(Gr-IL-Chit). AuNPs were used to immobilize hCG antibody on the modified
electrode. The amine groups of the antibody are covalently attached to
AuNPs/Gr-IL-Chit nanocomposite. CV, EIS and SEM were employed to characterize
the assembly process and the performance of the immunosensor. DPV and EIS
studies demonstrated that the formation of antibody-antigen complexes decreased
peak current and increased Rct of [Fe(CN)6]3−/4−
redox pair at the AuNPs/Gr-IL-Chit/GCE. The optimization of the pH of
supporting electrolyte and the incubation time were studied in details. Because
of the synergistic effect of IL, Chit and Gr and the unique properties of
AuNPs, the obtained immunosensor exhibited a wide linear response to hCG in two
ranges from 0.005-1.484 and 1.484-411.28 (mIU ml-1). A relatively
low detection limit of 0.0016 mIU ml-1 (S/N = 3) was calculated from
DPV. Satisfactory results were obtained for determination of hCG in human serum


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