Reagentless Immunosensing Assay via Electrochemical Impedance for Hepatitis B Surface Antigen Monitoring Based on Polypyrrole and Gold Nanoparticles as Matrices
Project supported by the National Natural Science Foundation of China (No. 29705001), the Chinese Education Ministry Foundation for Excellent Young Teachers (No. 2002-40), the Natural Science Foundation of Chongqing City (Nos. CSTC-2004BB4149 and CSTC-2005BB4100) and the Southwest China Normal University Foundation for Young Teachers (Nos. 2001-Q09 and XSGX02).
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Abstract
A novel simple immunosensing strategy for fabrication of hepatitis B surface antigen detection has been developed via electrochemical impedance spectroscopy (EIS) as a platform. At first, the conductive polymer polypyrrole (PPy) film was electrodeposited on a platinum electrode surface to adsorb the gold nanoparticles (nano-Au) via the opposite-charged adsorption technique, and then hepatitis B surface antibodies were adsorbed onto the surface of nano-Au. The modification procedure was characterized by EIS. Such spectroscopy is attributed to the concomitant conductivity changes of the polymerized pyrrole film and gold nanoparticles. The factors influencing the performance of resulting immunoelectrode were studied in detail. The linear range of the resulting immunoelectrode is from 2.6 to 153.6 ng·mL−1 with a detection limit of 1.3 ng·mL−1 at 3σ. In addition, the experiment results indicate that antibody immobilized on this way exhibits a good sensitivity, selectivity, high stability and a long-term maintenance of bioactivity, implying a great promising alternative approach for reagentless immunosensing analysis in the clinical diagnosis.
