Potentiometric immunosensor based on immobilization of hepatitis B surface antibody on platinum electrode modified silver colloids and polyvinyl butyral as matrixes

A highly sensitive immunosensor based on immobilization of hepatitis B surface antibody (HBsAb) on platinum electrode (Pt) modified silver colloids and polyvinyl butyral (PVB) as matrixes has been developed for potentiometric immunoanalysis to detect hepatitis B surface antigen (HBsAg) in this study. HBsAb molecules were immobilized successfully on nanometer-sized silver colloid particles associated with polyvinyl butyral on a platinum electrode surface. The modification procedure was etectrochemically monitored by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The 'HBsAb-silver-PVB-modified electrode exhibited direct electrochemical behavior toward H13sAg. The factors influencing the performance of the resulting immunosensor were studied in detail. More than 94.7% of the results of human serum samples obtained by this method were in agreement with those obtained by enzyme-linked immunosorbent assays (ELISAs). The resulting immunosensor exhibited a sigmoid curve with log HBsAg concentration, high sensitivity (39.8 mV/decade), wide linear range from 16.0 to 800 ng mL-1 with a detection limit of 3.6 ng mL(-1), fast potentiometric response (< 3 min) and long-term stability (> 4 months). The response mechanism of the immunosensors was also studied with AC impedance techniques.