Sensitively detecting antigen of SARS-CoV-2 by NIR-II fluorescent nanoparticles

Abstract

Early detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is an efficient way to prevent the spread of coronavirus disease 2019 . Detecting SARS-CoV-2 antigen can be rapid and convenient, but it is still challenging to develop highly sensitive methods for effective diagnosis. Herein, a lateral flow assay (LFA) based on fluorescent nanoparticles emitting in the second near-infrared (NIR-II) window is developed for sensitive detection of SARS-CoV-2 antigen. Benefiting from the NIR-II fluorescence with high penetration and low autofluorescence, such NIR-II based LFA allows enhanced signal-to-background ratio, and the limit of detection is down to 0.01 ngmL -1 of SARS-CoV-2 antigen. In the clinical swab sample tests, the NIR-II LFA outperforms the colloidal gold LFA with higher overall percent agreement with the polymerase chain reaction test. The clinical samples with low antigen concentrations (~ 0.015-~ 0.068 ngmL -1 ) can be successfully detected by the NIR-II LFA, but fail for the colloidal gold LFA. The NIR-II LFA can provide a promising platform for highly sensitive, rapid, and cost-effective method for early diagnosis and mass screening of SARS-CoV-2 infection. coronavirus disease 2019 (COVID-19), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), antigen detection, the second near-infrared (NIR-II) fluorophores, lateral flow assay