A multiple-promoted silver enhancement strategy in electrochemical detection of target virus

A sandwich-type electrochemical immunosensor for the detection of avian leukosis virus subgroup J (ALV-J) based on a novel multiple-promoted silver enhancement strategy is described. Owing to the admirable features of carbon nanotubes-iron oxides magnetic composites (CIMC), catalytic performance of gold nanoparticles (Au NPs) and adsorptive and reductive properties of humic acids (HAs), the Au NPs and HAs labeled, antibody functionalized, and bovine serum albumin (BSA) blocked CIMC (CIMC-Au-HAs/Ab2-BSA) were assembled and applied as a triple signal amplified method in ALV-J detection. Furthermore, β-cyclodextrin functional graphene sheets (CD-GS) were used as matrixes for immobilization of antibodies due to the huge surface area and superior electrical conductivity. The primary procedures are as follows: firstly, CD-GS were used as the immunosensor platform for immobilizing antibodies. Subsequently, after the sandwich-type assembly, CIMC-Au-HAs/Ab2-BSA was fabricated onto the immunosensor surface to adsorb and catalytic reduction of Ag+ to Ag. Then the deposited Ag was detected by differential pulse voltammetry (DPV) in KCl solution. To embody the function of CIMC, adsorptive and reductive properties of HAs, and catalytic performance of Au NPs, response signals of various labels were compared in detail. The immunosensor displayed good analytical performance for the detection of ALV-J ranging from 102.05 to 104.50 TCID50/mL with a detection limit of 110 TCID50/mL (S/N = 3). Thus, the newly designed immunosensor showed a promising potential in clinical applications.