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 (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. Electronic Supplementary Material Supplementary material (the operation procedure and cost of the materials needed of NIR-II lateral flow assays, the dynamic light scattering spectrum of the NIR-II nanoparticles, the components and testing principle, optimization of main parameters pertaining to the LFA performance, the colloidal gold LFA strip, the fluorescence intensity distribution curves and the T/C values of the strips for clinical samples by NIR-II LFA, and results of clinical swab samples detected by colloidal gold LFA) is available in the online version of this article at 10.1007/s12274-022-4351-1.

Recent Advances of Representative Optical Biosensors for Rapid and Sensitive Diagnostics of SARS-CoV-2

“…Hu and his colleagues fabricated NIR-II nanoparticles by encapsulating organic dyes in polyethylene and used them as a sensing platform for the rapid detection of the SARS-CoV-2 antigen. The biosensor possesses a wide analytical range of 0.02–120 ng/mL, and the LOD is 0.01 ng/mL, which cannot be compared with traditional colloidal gold technology [ 50 ]. These results suggest that the NIR-II biosensor with enhanced performances is suitable for mass screening.…”

Introduction of graphene oxide-supported multilayer-quantum dots nanofilm into multiplex lateral flow immunoassay: A rapid and ultrasensitive point-of-care testing technique for multiple respiratory viruses

“…The NP antigen of SARS-CoV-2 has been proven more conserved than other structural proteins including Spike antigen [30,31]. Previous studies have demonstrated that highly sensitive and specific detection of SARS-CoV-2 can be achieved by using NP as target antigen [32][33][34]. Thus, we chose NP as target for SARS-CoV-2 detection.…”

Paper Device Combining CRISPR/Cas12a and Reverse-Transcription Loop-Mediated Isothermal Amplification for SARS-CoV-2 Detection in Wastewater

“…Currently, the most commonly used analytical methods for SARS-CoV-2 detection are RT-qPCR, serological assays, and paper-based sensors, such as lateral flow kits. 13 − 15 RT-qPCR requires expensive instruments, sophisticated operations, and professionals to conduct the experiment for more than 6 h, limiting its field use. 16 Although serological methods can be completed in a short time and require no complicated equipment, their low sensitivity to mild and asymptomatic infections and long time to produce an antibody response restrict their utilization in WBS.…”

“…However, the use of the WBS approach for developing a warning system and a consequent effective intervention system requires a rapid analytical method for the on-site detection of SARS-CoV-2 in wastewater collection points. Currently, the most commonly used analytical methods for SARS-CoV-2 detection are RT-qPCR, serological assays, and paper-based sensors, such as lateral flow kits. − RT-qPCR requires expensive instruments, sophisticated operations, and professionals to conduct the experiment for more than 6 h, limiting its field use . Although serological methods can be completed in a short time and require no complicated equipment, their low sensitivity to mild and asymptomatic infections and long time to produce an antibody response restrict their utilization in WBS. , Herein, lateral flow kits developed via serological methods are also not suitable for WBS.…”