The fabrication of a label-free electrochemical immunosensor using an aldehyde-functionalized pyridinium salt for antibody immobilization

Abstract

This paper reported a strategy based on the use of an aldehyde-functionalized pyridinium salt for the fabrication of a label-free electrochemical immunosensor. The aldehyde-functionalized pyridinium salt was incorporated into Nafion to form a composite film modified on the surface of an Au electrode. The aldehyde-functionalized pyridinium salt was used to capture an antibody directly and improve the conductivity of the sensing interface, which ensured the convenient fabrication of a sensitive label-free electrochemical immunosensor for α-fetoprotein detection. Under optimal conditions, α-fetoprotein was detected in the range from 0.005 to 25 ng mL⁻¹ with a detection limit of 0.003 ng mL⁻¹ based on a signal-to-noise ratio of 3. This strategy would offer potential promise for the convenient fabrication of immunosensors and for clinical applications.