Label-free optical antibody testing kit based on a self-assembled whispering-gallery-mode microsphere

J Biophotonics. 2021 Mar;14(3):e202000338. doi: 10.1002/jbio.202000338. Epub 2020 Nov 23.

Abstract

The appearance of antibodies in blood is a critical signal to suggest the infection. A rapid and accurate detection method for the antibody is significant to the disease diagnosis, especially for the epidemic. To this end, a highly sensitive whispering-gallery-mode (WGM) optical testing kit is designed and fabricated for detecting the specific immunoglobulin antibodies. The key component of the kit is a silica self-assembled microsphere decorated with the nucleocapsid proteins (N-proteins) of the SARS-CoV-2 virus. After the N-protein antibody immunoglobulin G (N-IgG) and immunoglobulin M (N-IgM) solutions being injected into the kit, the WGM red-shifts due to the antigen-antibody reaction. The wavelength displacement rates are proportional to the concentrations of these two antibodies from 1 to 100 μg/mL. A good specificity of the kit is demonstrated by the nonspecific human immunoglobulin G (H-IgG) and immunoglobulin M (H-IgM).

Keywords: WGM sensor; antibody detection; biosensor; self assembly.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Viral / immunology*
  • Antigens / immunology
  • Biosensing Techniques
  • COVID-19 / diagnosis*
  • COVID-19 / immunology
  • COVID-19 Serological Testing*
  • Coronavirus Nucleocapsid Proteins / immunology
  • Epidemics
  • Humans
  • Immunoglobulin G / immunology
  • Immunoglobulin M / immunology
  • Microspheres*
  • Optics and Photonics
  • Phosphoproteins / immunology
  • Polymethyl Methacrylate / chemistry
  • SARS-CoV-2
  • Silanes
  • Silicon Dioxide / chemistry*

Substances

  • Antibodies, Viral
  • Antigens
  • Coronavirus Nucleocapsid Proteins
  • Immunoglobulin G
  • Immunoglobulin M
  • Phosphoproteins
  • Silanes
  • nucleocapsid phosphoprotein, SARS-CoV-2
  • Silicon Dioxide
  • Polymethyl Methacrylate