Application of 2-(4-Formylphenyl) [60]Fulleropyrrolidine as an electrode matrix for cross linker-free immobilization of HCG-antibody and the sensing analysis

A novel fullerene derivative, 2-(4-Formylphenyl) [60]fulleropyrrolidine (FPD) has been synthesized through 1, 3-dipole cycloaddition reaction of C60 with terephthalaldehyde and glycine. The structure of the product was characterized by 1H NMR, mass spectrometry, FT-IR and UV-vis. Based on the unique zero-dimensional structure and highly active aldehyde group, the FPD was used as an electrode material for the construction of an impedimetric immunosensor for human chorionic gonadotrophin (HCG). First, the FPD was cast onto the surface of a glassy carbon electrode by the direct coating method, then the HCG antibody (anti-HCG) was covalently grafted onto electrode surface through a condensation reaction between aldehyde group of FPD and amine group of anti-HCG, without assistance of any cross-linker. Combined the high specificity of immunoreaction and high sensitivity of electrochemical impedance spectroscopy, the immunosensor shows a wide range from 0.1 to 10 ng mL−1 for HCG detection. Based on 3σ, the detection limit was estimated to be 0.03 ng mL−1. Satisfactory results were obtained for determination of HCG in human serum samples of the diagnostic patients, showing potential application of the proposed method in clinical diagnosis.