| Affiliation: | 1. Departamento de Química Inorgânica, Universidade Federal Fluminense (UFF), Campus Do Valonguinho, Outeiro de São João Batista, S/n, 24020-141, Niterói, RJ, Brazil;2. Departamento de Química, Pontifícia Universidade Católica Do Rio de Janeiro (PUC-Rio), Rio de Janeiro, RJ, 22451-900, Brazil;3. Gerência de Desenvolvimento Tecnológico, Instituto Vital Brazil, Niterói, RJ, 24230-410, Brazil;4. Fazenda Instituto Vital Brazil, Niterói, RJ, 24230-410, Brazil;5. Departamento de Genética e Morfologia, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, 70910-900, Brazil;6. Programa de Pós-graduação Em Ciência e Tecnologia de Alimentos, Universidade Federal Do Tocantins, 77001-090, Brazil;7. Divisão de Metrologia de Materiais, Instituto Nacional de Metrologia, Qualidade e Tecnologia (Inmetro), Duque de Caxias, RJ, 25250-020, Brazil;8. Centro de Tecnologias Estratégicas Do Nordeste, Av. Prof. Luiz Freire 01, Recife, Pernambuco, 50740-540, Brazil |
| Abstract: | Due to the unprecedented and ongoing nature of the coronavirus outbreak, the development of rapid immunoassays to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its highly contagious variants is an important and challenging task. Here, we report the development of polyclonal antibody-functionalized spherical gold nanoparticle biosensors as well as the influence of the nanoparticle sizes on the immunoassay response to detect the SARS-CoV-2 spike protein by dynamic light scattering. By monitoring the increment in the hydrodynamic diameter (ΔDH) by dynamic light scattering measurements in the antigen–antibody interaction, SARS-CoV-2 S-protein can be detected in only 5 min. The larger the nanoparticles, the larger ΔDH in the presence of spike protein. From adsorption isotherm, the calculated binding constant (KD) was 83 nM and the estimated limit of detection was 13 ng/mL (30 pM). The biosensor was stable up to 90 days at 4 °C. Therefore, the biosensor developed in this work could be potentially applied as a fast and sensible immunoassay to detect SARS-CoV-2 infection in patient samples. |
