Serological assays to detect antibody responses to SARS-CoV-2 are critical to study immune responses to the virus, determine precise rates of infection, track progression of infections, and identify immune individuals in order to limit exposure of susceptible groups or as potential sources of convalescent serum therapeutics. The development of such assays currently lags considerably behind molecular tests that detect viral genetic material, however. This project will develop Raman-based immunoassays to detect SARS-CoV-2 and anti-virus serological responses, and adapt our current handheld instrument for rapid, highly sensitive point-of-care detection.
Recombinant antibodies (scFvs) will be isolated against receptor-binding domain (RBD) from SARS-CoV-2 spike protein at NUI Galway. Binding of scFvs will be confirmed using recombinant RBD and validated using patient samples. In parallel, RBD and full-length spike protein will be expressed in mammalian cells. ScFvs and recombinant antigens will be utilised to develop a no-wash, surface-enhanced Raman scattering (SERS) assay using expertise at the University of Wyoming, USA. The assay will be carried out with nanoparticles in solution with magnetic separation, which we have previously used to detect viruses to 10 pg/ml in complex biological matrices, and anti-virus antibodies at 400x ELISA sensitivity. Three different Raman reporters will be used to detect viral particles from nasal swabs, and anti-virus IgMs and anti-virus IgGs in serum. The assays will be validated with clinical samples in Wyoming Public Health Lab and adapted to our current commercial handheld, battery-operated Raman device in Metrohm Raman, USA.
The cross-sectoral Project Team combines extensive, synergistic track records in antibody isolation and characterisation; assay development and virus detection using SERS spectroscopy; clinical virology and diagnostic methods; and device development and industrial production. This creates a unique opportunity to successfully produce the proposed device to advance current SARS-CoV-2 detection capability and, critically, identify seroconverters as well as acute infection events.