One-step immobilization antibodies using ferrocene-containing thiol aromatic aldehyde for the fabrication of a label-free electrochemical immunosensor

Abstract

This work focuses on a facile method for antibody immobilization to fabricate a label-free electrochemical immunosensor using ferrocene-containing thiol aromatic aldehyde (FcSA) synthesized by us. The FcSA plays important roles as follows: provides a novel self-assembled monolayer and the aldehyde group was applied to immobilize antibodies directly, in which no additional activation step was required. Ferrocene can improve the electrical conductivity of the sensing interface as compared to the ferrocene-free thiol aromatic aldehyde. Human IgG as a model analyte was detected in the range from 0.01 to 40 ng mL⁻¹ with a detection limit of 0.005 ng mL⁻¹ based on a signal-to-noise ratio (S/N) of 3. The immunosensor showed good specificity, acceptable reproducibility as well as satisfactory stability.