Immunoassay platform with surface-enhanced resonance Raman scattering for detecting trace levels of SARS-CoV-2 spike protein

Author(s)

Bistaffa, Maria J. ; Camacho, Sabrina A. ; Pazin, Wallance M. ; Constantino, Carlos J. L. ; Oliveira, Osvaldo N., Jr. ; Aoki, Pedro H. B.

• Document type: Journal article
• Source: Talanta; v. 244, p. 9-pg., 2022-03-29.

Abstract

The early diagnosis of Coronavirus disease (COVID-19) requires either an accurate detection of genetic material or a sensitive detection of viral proteins. In this work, we designed an immunoassay platform for detecting trace levels of SARS-CoV-2 spike (S) protein. It is based on surface-enhanced resonance Raman scattering (SERRS) of methylene blue (MB) adsorbed onto spherical gold nanoparticles (AuNPs) and coated with a 6 nm silica shell. The latter shell in the SERRS nanoprobe prevented aggregation and permitted functionalization with SARS-CoV-2 antibodies. Specificity of the immunoassay was achieved by combining this functionalization with antibody immobilization on the cover slides that served as the platform support. Different concentrations of SARS-CoV-2 antigen could be distinguished and the lack of influence of interferents was confirmed by treating SERRS data with the multidimensional projection technique Sammon's mapping. With SERRS using a laser line at 633 nm, the lowest concentration of spike protein detected was 10 pg/mL, achieving a limit of detection (LOD) of 0.046 ng/mL (0.60 pM). This value is comparable to the lowest concentrations in the plasma of COVID-19 patients at the onset of symptoms, thus indicating that the SERRS immunoassay platform may be employed for early diagnosis. (AU)

• FAPESP's process: 17/03879-4 - EMU granted in the process 2013 / 14262-7 thematic project - DLS
• Grantee: Osvaldo Novais de Oliveira Junior
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 18/16713-0 - Photodynamic therapy: from molecular effects in model systems toward photodynamic efficiency in cell culture
• Grantee: Pedro Henrique Benites Aoki
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/22214-6 - Towards a convergence of technologies: from sensing and biosensing to information visualization and machine learning for data analysis in clinical diagnosis
• Grantee: Osvaldo Novais de Oliveira Junior
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 20/12129-1 - Immunoassay for COVID-19 diagnosis based on surface-enhanced Raman scattering technique
• Grantee: Wallance Moreira Pazin
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 18/14692-5 - Photothermal therapy mediated by gold nanoparticles: from model systems of biomembranes toward in vitro culture of tumor cells
• Grantee: Sabrina Aléssio Camacho
• Support Opportunities: Scholarships in Brazil - Post-Doctoral