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

摘要

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(COVID-19).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 ng·mL^(−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 ng·mL^(−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.