Reagentless amperometric immunosensor for alpha-fetoprotein based on gold Nanoparticles/TiO2 colloids/prussian blue modified platinum electrode

A novel reagentless amperometric immunosensor for the determination of alpha-fetoprotein (AFP) was prepared by immobilizing TiO2 colloids on Prussian blue (PB) modified platinum electrode, which yielded a positively charged interface with strong adsorption to deposit gold nanoparticles for immobilization of alpha-fetoprotein antibody (anti-AFP). The factors influencing the performance of the proposed immunosensors were studied in detail. Under the optimized conditions, cyclic voltammograms determination of AFP showed a specific response in two concentration ranges from 3.0 to 30.0 ng/mL and from 30.0 to 300.0 ng/mL with a detection limit of 1.0 ng/mL at a signal-to-noise ratio of 3. The proposed immunosensor exhibited high selectivity, good reproducibility, long-term stability (> 2 months) and good repeatability.