Highly sensitive and selective electrochemical immunosensors by substrate-enhanced electroless deposition of metal nanoparticles onto three-dimensional Graphene@Ni foams

Abstract In this study, we have for the first time preformed the facile substrate-enhanced electroless deposition (SEED) of metal nanoparticles onto monolithic graphene@Ni foams for construction of disposable three-dimensional (3D) electrochemical immunosensors. Specifically, we first used the SEED method to deposit gold nanoparticles (AuNPS) for immobilization of antibody (Ab1) onto the graphene@Ni foam. Then, a second step SEED deposition was followed to produce silver nanoparticles (AgNPs) for electrochemical stripping detection. Using α-fetoprotein antigen (AFP) as a module analyte, the newly-developed sensor showed a wide linear response, ranging from (5.0 pg–5.0 ng)/mL and a low detection limit down to 2.3 pg/mL. This 3D-immunosensor is sensitive, reliable, and easy to make, showing great potential for clinic applications.