Multiplexed detection and quantification of human antibody response to COVID-19 infection using a plasmon enhanced biosensor platform

Biosens Bioelectron. 2021 Jan 1:171:112679. doi: 10.1016/j.bios.2020.112679. Epub 2020 Oct 9.


The 2019 SARS CoV-2 (COVID-19) pandemic has illustrated the need for rapid and accurate diagnostic tests. In this work, a multiplexed grating-coupled fluorescent plasmonics (GC-FP) biosensor platform was used to rapidly and accurately measure antibodies against COVID-19 in human blood serum and dried blood spot samples. The GC-FP platform measures antibody-antigen binding interactions for multiple targets in a single sample, and has 100% selectivity and sensitivity (n = 23) when measuring serum IgG levels against three COVID-19 antigens (spike S1, spike S1S2, and the nucleocapsid protein). The GC-FP platform yielded a quantitative, linear response for serum samples diluted to as low as 1:1600 dilution. Test results were highly correlated with two commercial COVID-19 antibody tests, including an enzyme linked immunosorbent assay (ELISA) and a Luminex-based microsphere immunoassay. To demonstrate test efficacy with other sample matrices, dried blood spot samples (n = 63) were obtained and evaluated with GC-FP, yielding 100% selectivity and 86.7% sensitivity for diagnosing prior COVID-19 infection. The test was also evaluated for detection of multiple immunoglobulin isotypes, with successful detection of IgM, IgG and IgA antibody-antigen interactions. Last, a machine learning approach was developed to accurately score patient samples for prior COVID-19 infection, using antibody binding data for all three COVID-19 antigens used in the test.

Keywords: Antibody; Biosensor; COVID-19; Multiplex; Plasmonic; Quantitative.

Publication types

  • Evaluation Study

MeSH terms

  • Antibodies, Viral / blood*
  • Antibodies, Viral / immunology
  • Betacoronavirus / immunology*
  • Betacoronavirus / isolation & purification
  • Biosensing Techniques / instrumentation*
  • COVID-19
  • COVID-19 Testing
  • Clinical Laboratory Techniques*
  • Coronavirus Infections / blood*
  • Coronavirus Infections / diagnosis
  • Coronavirus Infections / immunology
  • Dried Blood Spot Testing
  • Equipment Design
  • Fluorescence
  • Humans
  • Immunoglobulin G / blood
  • Immunoglobulin G / immunology
  • Lab-On-A-Chip Devices
  • Pandemics
  • Pneumonia, Viral / blood*
  • Pneumonia, Viral / diagnosis
  • Pneumonia, Viral / immunology
  • SARS-CoV-2
  • Sensitivity and Specificity


  • Antibodies, Viral
  • Immunoglobulin G