Rapid and Sensitive Detection of anti-SARS-CoV-2 IgG, Using Lanthanide-Doped Nanoparticles-Based Lateral Flow Immunoassay

Anal Chem. 2020 May 19;92(10):7226-7231. doi: 10.1021/acs.analchem.0c00784. Epub 2020 May 5.


The outbreak of 2019 coronavirus disease (COVID-19) has been a challenge for hospital laboratories because of the huge number of samples that must be tested for the presence of the causative pathogen, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Simple and rapid immunodiagnostic methods are urgently needed to identify positive cases. Here we report the development of a rapid and sensitive lateral flow immunoassay (LFIA) that uses lanthanide-doped polysterene nanoparticles (LNPs) to detect anti-SARV-CoV-2 IgG in human serum. A recombinant nucleocapsid phosphoprotein of SARS-CoV-2 was dispensed onto a nitrocellulose membrane to capture specific IgG. Mouse anti-human IgG antibody was labeled with self-assembled LNPs that served as a fluorescent reporter. A 100-μL aliquot of serum samples (1:1000 dilution) was used for this assay and the whole detection process took 10 min. The results of the validation experiment met the requirements for clinical diagnostic reagents. A value of 0.0666 was defined as the cutoff value by assaying 51 normal samples. We tested 7 samples that were positive by reverse-transcription (RT-)PCR and 12 that were negative but clinically suspicious for the presence of anti-SARS-CoV-2 IgG. One of the negative samples was determined to be SARS-CoV-2 IgG positive, while the results for the other samples were consistent with those obtained by RT-PCR. Thus, this assay can achieve rapid and sensitive detection of anti-SARS-CoV-2 IgG in human serum and allow positive identification in suspicious cases; it can also be useful for monitoring the progression COVID-19 and evaluating patients' response to treatment.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Antibodies, Viral / blood*
  • Betacoronavirus / immunology
  • Coronavirus Infections / blood
  • Coronavirus Infections / diagnosis*
  • Humans
  • Immunoassay / methods*
  • Immunoglobulin G / blood*
  • Lanthanoid Series Elements / chemistry*
  • Metal Nanoparticles / chemistry*
  • Nanoparticles
  • Pandemics
  • Pneumonia, Viral / blood
  • Pneumonia, Viral / diagnosis*
  • Sensitivity and Specificity


  • Antibodies, Viral
  • Immunoglobulin G
  • Lanthanoid Series Elements

Supplementary concepts

  • COVID-19
  • severe acute respiratory syndrome coronavirus 2