Detection of SARS-CoV-2 virus via dynamic light scattering using antibody-gold nanoparticle bioconjugates against viral spike protein

Talanta. 2022 Jun 1:243:123355. doi: 10.1016/j.talanta.2022.123355. Epub 2022 Mar 4.

Abstract

Mass testing for the diagnosis of COVID-19 has been hampered in many countries owing to the high cost of genetic material detection. This study reports on a low-cost immunoassay for detecting SARS-CoV-2 within 30 min using dynamic light scattering (DLS). The immunosensor comprises 50-nm gold nanoparticles (AuNPs) functionalized with antibodies against SARS-CoV-2 spike glycoprotein, whose bioconjugation was confirmed using transmission electron microscopy (TEM), UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and surface-enhanced Raman scattering spectroscopy (SERS). The specific binding of the bioconjugates to the spike protein led to an increase in bioconjugate size, with a limit of detection (LOD) 5.29 × 103 TCID50/mL (Tissue Culture Infectious Dose). The immunosensor was also proven to be selective upon interaction with influenza viruses once no increase in size was observed after DLS measurement. The strategy proposed here aimed to use antibodies conjugated to AuNPs as a generic platform that can be extended to other detection principles, enabling technologies for low-cost mass testing for COVID-19.

Keywords: Bioconjugates; Immunosensors; Influenza virus; SARS-CoV-2; Spectroscopic techniques.

MeSH terms

  • Biosensing Techniques* / methods
  • COVID-19 Testing
  • COVID-19* / diagnosis
  • Dynamic Light Scattering
  • Gold / chemistry
  • Humans
  • Immunoassay / methods
  • Metal Nanoparticles* / chemistry
  • SARS-CoV-2
  • Spike Glycoprotein, Coronavirus
  • Viral Proteins

Substances

  • Spike Glycoprotein, Coronavirus
  • Viral Proteins
  • spike protein, SARS-CoV-2
  • Gold