Silver nanoparticles coated graphene electrochemical sensor for the ultrasensitive analysis of avian influenza virus H7

A new, highly sensitive electrochemical immunosensor with a sandwich-type immunoassay format was designed to quantify avian influenza virus H7 (AIV H7) by using silver nanoparticle-graphene (AgNPs-G) as trace labels in clinical immunoassays. The device consists of a gold electrode coated with gold nanoparticle-graphene nanocomposites (AuNPs-G), the gold nanoparticle surface of which can be further modified with H7-monoclonal antibodies (MAbs). The immunoassay was performed with H7-polyclonal antibodies (PAbs) that were attached to the AgNPs-G surface (PAb-AgNPs-G). This method of using PAb-AgNPs-G as detection antibodies shows high signal amplification and exhibits a dynamic working range of 1.6 × 10−3∼16 ng/mL, with a low detection limit of 1.6 pg/mL at a signal-to-noise ratio of 3σ. In summary, we showed that this novel immunosensor is highly specific and sensitive to AIV H7, and the established assay could potentially be applied to rapidly detect other pathogenic microorganisms. [Display omitted] •A novel highly sensitive electrochemical immunosensor based on the dual amplification strategy was developed.•For the first time, Au nanoparticle-graphene-chitosan nanocomposite was used as platform.•Silver nanoparticle-graphene-chitosan nanocomposite was used as electrochemical signal material.•A highly competitive low detection limit of 1.6 pg/mL is achieved.