A preliminary study of surface enhanced Raman scattering immunoassay based on graphene oxide substrate

Graphene Oxide (GO), the oxidized form of graphene, has received considerable attention in the field of biology and medicine. Based on its advantages of surface enhanced Raman scattering (SERS) activities and high enrichment of biomolecules, here we report a sandwich-type SERS immunoassay format, which uses GO as solid substrates to attach antibodies, and Ag nanoparticles (AgNPs) covalently immobilizing 4-mercaptobenzoic acid (4-MBA) as Raman tag nanoparticles. The research results show that the new immunoassay has excellent specificity in the capture of target molecules, and the detectable limit of model antigen concentration is 2 ng/mL, which is close to the detectable level of many biomolecules or harmful substance. The preliminary study suggests that GO-based SERS immunoassay has a great potential in the field of biomedicine, food inspection, environmental monitoring, and so on.