Development of a rapid test for detection of foot-and-mouth disease virus specific antibodies using gold nanoparticles.

Foot and mouth disease is an economically important transboundary disease of wildlife and cloven hoofed animals including ruminants. In the absence of vaccination, detection of antibodies against structural proteins (SPs) of foot-and-mouth disease virus is an indicator of infection. In the present study, a rapid dot blot assay using gold nanoparticlees was developed for the detection of antibodies against SPs of FMDV. Commercially available FMD vaccine was used as a source of FMD antigen. After the synthesis of gold nanoparticles (GNPs), the GNP-dot blot assay was tested and was found very sensitive, as the detection of antibody was up to 10-4 of serum dilution. The GNP-dot assay was found specific as it didn't give dot with normal horse sera, fetal bovine sera and neonatal bovine calf serum samples when tested at 10-3 working dilution. When 30 serum samples from post-vaccinated buffaloes were tested at dilution of 10-3, all the samples were found positive with the variable intensity of dot. The synthesized GNPs and conjugated GNPS with antibody were characterized for their absorption limit, for their stability and for their approximate size. These characterized conjugated and non-conjugated GNPs were also analyzed by Transmission electron microscopy and Scanning electron microscopy. The GNP dot blot assay developed in this work gave promising results using vaccine antigen and can form an important tool for rapid diagnosis of FMD in FMD free countries, zones free of FMD and during last stage of FMD eradication when FMD vaccination will be withdrawn.