Sandwich Immunoassay for Hepatitis C Virus Non-Structural 5A Protein Using a Glassy Carbon Electrode Modified with an Au-MoO₃/Chitosan Nanocomposite

Abstract

A novel electrochemical immunosensor was prepared for the detection of the hepatitis C virus non-structural 5A protein. A glassy carbon electrode was modified with an Au-MoO₃/Chitosan nanocomposite that warranted good conductivity and biocompatibility. Mesoporous silica with a large specific surface served as a nanocarrier for horseradish peroxidase and the polyclonal antibody as the reporter probe. The immunosensor was characterized by scanning electron microscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. Following the sandwich-type immunoreaction, horseradish peroxidase was efficiently captured on the surface of the electrode to catalyze the decomposition of hydrogen peroxide. The analytical signal was obtained as an amperometric i-t curve (chronoamperometry). The assay reported here had a wide detection range (1 ng mL⁻¹ −50 µg mL⁻¹) and detection limit as low as 1 ng mL⁻¹ of hepatitis C virus non-structural 5A protein. The electrochemical biosensor experiments showed excellent reproducibility, high selectivity, and outstanding stability for the determination of hepatitis C virus non-structural 5A protein, and it was successfully applied to the detection of the analyte in real serum samples.

Keywords:

• Amperometric i-t curve
• Electrochemical immunosensor
• Hepatitis C virus non-structural 5A protein
• Hexagonal mesoporous silicas
• Molybdenum trioxide nanoparticles

Acknowledgments

This work was supported by the Natural Science Foundation of China (NO. 81171415), the Foundation of National Key Discipline in Laboratory Medicine (NO. 2010303), and the Science and Technology Project of Jiulongpo District Committee in Chongqing.

Notes

Note: CNTs, carbon nanotubes; Ab, antibody; Ag, antigen; PVA, polyvinyl alcohol; HSA, human serum albumin.