Detection of AFP by Electrochemical Immunosensor Based on Ag/Fe3O4/g-C3N4

Herein, a novel electrochemical immunosensor was prepared to detect cancer alpha-fetoprotein (AFP). An iron oxide/graphite-phase carbon nitride/silver (Fe3O4-g-C3N4-Ag) composite was used as the carrier. Metal-free graphitic carbon nitrides (g-C3N4) have been recently recognized as high-performance photocatalysts; however, their large-scale applications are limited because of their poor electronic properties and low dispersion. Fe3O4 particles were incorporated in the composite to improve the conductivity and dispersibility of g-C3N4. Silver nanoparticles were prepared through UV irradiation and did not involve the use of reducing agents. A signal probe was prepared from Fe3O4-g-C3N4-Ag and acetylene black. Cyclic voltammetry was conducted to detect AFP. Under optimized conditions, the proposed immunosensor exhibited excellent analytical abilities. The dynamic response range of the AFP concentration was 0.0001-80 ng . mL(-1). The detection limit was relatively low at 0.078 pg . mL(-1) (S/N=3). The immunosensor also exhibited high specificity and good reproducibility. The results showed that the proposed immunosensor can be successfully used to detect AFP in human serum samples.