Ionic‐Liquid‐Doped Polyaniline Inverse Opals: Preparation, Characterization, and Application for the Electrochemical Impedance Immunoassay of Hepatitis B Surface Antigen

Abstract

Abstract A 3D ordered macroporous (3DOM) ionic‐liquid‐doped polyaniline (IL‐PANI) inverse opaline film is fabricated with an electropolymerization method and gold nanoparticles (AuNPs) are assembled on the film by electrostatic adsorption, which offers a promising basis for biomolecular immobilization due to its satisfactory chemical stability, good electronic conductivity, and excellent biocompatibility. The AuNP/IL‐PANI inverse opaline film could be used to fabricate an electrochemical impedance spectroscopy (EIS) immunosensor for the determination of Hepatitis B surface antigen (HBsAg). The concentration of HBsAg is measured using the EIS technique by monitoring the corresponding specific binding between HBsAg and HBsAb (surface antibody). The increased electron transfer resistance ( R et ) values are proportional to the logarithmic value of the concentration of HBsAg. This novel immunoassay displays a linear response range between 0.032 pg mL −1 and 31.6 pg mL −1 with a detection limit of 0.001 pg mL −1 . The detection of HBsAg levels in several sera showed satisfactory agreement with those using a commercial turbidimetric method.