The Fabrication of Electrochemical Impedance Immunosensor Based on Aldehyde-containing Self-assembled Monolayers for Hepatitis B Surface Antigen Detection

Abstract

In this work, thiol aromatic aldehyde was used as a substrate material to be assembled on the electrode surface through Au-S chemical bond, resulting in an aldehyde-containing self-assembled monolayer. The aldehyde groups of this self-assembled monolayer can immobilize antibodies directly through the covalent bonding with amino groups of antibody, in which no additional chemical cross-linker is required. We fabricated an electrochemical impedance immunosensor based on aldehyde-containing self-assembled monolayers for the detection of hepatitis B surface antigen within the range from 0.1 to 70 ng mL⁻¹ with a detection limit of 0.06 ng mL⁻¹ obtained by 3σ. The proposed immunosensor is simple and has a good specificity and reproducibility.