Non-covalent modification of glassy carbon electrode with isoorientin and application to alpha-fetoprotein detection by fabricating an immunosensor

Abstract

In this study, the glassy carbon electrode (GCE) surface substructure and geometry were originally modeled by first principles density functional theory (DFT) methods with a simple basis set AFPD/3−21 G. Isoorientin was then used as a model to explore the adsorbates bonding effect on GCE surface with experimental and computational methods. It was confirmed that the modification of the electroactive molecule, isoorientin onto GCE was no-covalent. Further, it was found that the Isoorientin/Anti-alpha-fetoprotein (AFP) antibody modified GCE, prepared by in turn depositing isoorientin and anti-AFP antibody (Ab) onto the GCE surface, could be used as an immunosensor for detecting the cancer biomarker AFP at GCE with differential pulse voltammetry (DPV). The peak current of isoorientin fixed at the modified GCE was negatively proportional to the concentration of AFP in solution with a linear range from 0.001–10 ng mL−1 and a detection limit of 0.0002 ng mL−1 by DPV. The practical determination of AFP in human serum is also investigated, indicating a potential application of the presented immunosensor in clinical tests and disease diagnosis.