Layer-by-layer self-assembly of films of nano-Au and Co(bpy)33+ for the determination of Japanese B encephalitis vaccine

Nano-Au and Co(bpy)33+ in a variety of charge states were assembled layer-by-layer into films on the gold electrode modified by l-cysteine to immobilize anti-Japanese B encephalitis for the assay of Japanese B encephalitis vaccine. The electrode modification process was characterized by electrochemical impedance spectroscopy (EIS). The factors influencing the performance of the potentiometric immunosensor were studied in detail. The immunosensor exhibited fast potentiometric response and the linear range was from 8.1 × 10−8 to 3.0 × 10−6 lgpfu/ml (plaque forming unit) with a detection limit of 3.5 × 10−8 lgpfu/ml. Moreover, the studied immunosensor exhibited high sensitivity and long-term stability. The present work supplied a promising test method for biological products.