| (1) A novel sandwich electrochemical immunoassay was developed for ultrasensitive detection of avian leukosis virus subgroup J(ALVs-J) using graphene quantum dots(GQDs)and apoferritin-encapsulated Cu(Cu-apoferritin) nanoparticles for signal ampli?cation. GQDs were used both for the conjugation of primary ALVs-J antibodies(Ab1), and immobilization of secondary ALVs-J antibodies(Ab2) after compounded with Fe3O4. Cu-apoferritin nanoparticles were ?rst selected to immobilize onto Fe3O4@GQDs hybrid as electroactive probes. After the well-known sandwich-type assembly, Cu was released from the apoferritin cavity, and then detected by differential pulse voltammetry(DPV). Owing to the huge surface area GQDs provided, a considerable number of antibodies were loaded onto the immunosensor, which effectively increased the electrical signal. And the introduction of Cuapoferritin nanoparticles increased the loading amount of electroactive probes signi?cantly;hence the signal was once again ampli?ed. To embody the signal ampli?cation property of the protocol, the performance of various labels was compared in detail. The immunosensor displayed excellent analytical performance for the detection of ALVs-J range from 102.08to104.50 TCID50/mL with a detection limit of 115 TCID50/mL(S/N=3), and the resulting immunosensor also showed high sensitivity, good reproducibility and stability.(2) A novel pH-controlled immunosensor using hollow mesoporous silica and apoferritin combined system has been reported for the ?rst time. The goal of this study was to introduce more electroactive probes into the electrochemical immunosensor. Under such background,we focused our attention on hollow mesoporous silica and apoferritin, both of which have admirable accommodating performances and can be applied for encapsulating electroactive probes. Based on the pH-controlled disassociation-reconstitution process of apoferritin and the mesoporous channels of silica, after the appropriate chemical modi?cation, apoferritin could be fabricated with silica. The results showed that the hollow mesoporous silica and apoferritin combined system was successfully assembled. The excellent performance of the combined system can be applied for ultrasensitive detection of a target virus.(3) A sandwich-type electrochemical immunosensor for the detection of avian leucosis 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 andreductive 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 ampli?ed method in ALV-J detection.Furthermore, β-cyclodextrin functional grapheme 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: ?rstly, 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 TCID 50 /mL(S/N=3).Thus, the newly designed immunosensor showed a promising potential in clinical applications. |
PDF Full Text Request