Ultrasensitive Detection of Severe Fever with Thrombocytopenia Syndrome Virus Based on Immunofluorescent Carbon Dots/SiO₂ Nanosphere-Based Lateral Flow Assay

Abstract

Sensitive detection of severe fever with thrombocytopenia syndrome virus (SFTSV) by a point-of-care assay is of great significance for promoting clinical diagnosis. In this work, ultrasensitive detection of SFTSV was achieved by using fluorescent carbon dots/SiO2 nanospheres (CSNs) as reporters for a lateral flow assay. The prepared CSNs were resistant to extreme environments and had strong stability. The uniform CSNs with the size of about 200 nm were obtained by differential centrifugation. Their absolute quantum yields in the aqueous and solid phases are 56.3 and 36.6%, respectively. The excellent fluorescent properties of CSNs make the test strips more sensitive and have a longer assay lifetime. Thus, the visual detection limit of the lateral flow test strip based on immunofluorescent CSN (iCSN) was as low as 10 pg/mL SFTSV nucleoprotein. The sensitivity of this assay is 2 orders of magnitude higher than that of the colloidal gold-based lateral flow test strip. Besides, the assay owns good reproducibility and high specificity. Then, iCSN-based lateral flow test strips were evaluated in real samples of human serum of patients with satisfactory results. Furthermore, this assay has a general prospect for other fluorescent immunochromatography applications.

Insights and Perspectives Regarding Nanostructured Fluorescent Materials toward Tackling COVID-19 and Future Pandemics

“…In another study, CDs@silica nanoparticles have been used to develop a lateral flow assay for detecting a severe fever with thrombocytopenia syndrome (SFTS), which has very similar symptoms to those of influenza. 215 As shown in Figure 7 B (.eft), the T line and C line on the nitrocellulose were modified by a selective antibody (SmAb) and nonselective antibody (i.e., goat antimouse IgG antibody), respectively. On the one hand, the positive results are shown as two bright lines under UV light (365 nm) ( Figure 7 B, right) when the sample diffuses through a capillary force in the lateral flow kit.…”

“…On the one hand, the positive results are shown as two bright lines under UV light (365 nm) ( Figure 7 B, right) when the sample diffuses through a capillary force in the lateral flow kit. 215 On the other hand, fluorophores with an aggregation-induced emission have also been used for detecting a virus. Kato et al reported the design of tetraphenylethylene-based oligosaccharide fluorescent probes for the detection of an influenza virus.…”

“…(B) Design of a lateral flow assay based on CDs@silica nanoparticles for the detection of a severe fever with a thrombocytopenia syndrome virus (SFTSV) (left) and the florescent images of the assay under 365 nm UV light for positive and negative results. Reproduced from ref ( 215 ). Copyright 2019 American Chemical Society.…”

Point-of-care diagnostics for infectious diseases: From methods to devices

“…Among all those biomedical applications, fluorescence-based biosensing by leveraging their unique fluorescence properties has been extensively investigated for POC diagnostics of infectious diseases. For example, Xu et al [150] developed a fluorescent lateral flow assay using CDs/SiO 2 nanospheres (CSNs) as reporters for ultrasensitive POC detection of severe fever with thrombocytopenia syndrome virus (SFTSV). The fluorescent lateral flow assay owned good reproducibility, high specificity and sensitivity due to the excellent fluorescent properties of CSNs, and was able to achieve a low visual detection limit of as low as 10 pg mL −1 SFTSV nucleoprotein which was 2 orders of magnitude higher than that of the colloidal gold-based lateral flow test strip.…”

Lateral flow assays (LFA) as an alternative medical diagnosis method for detection of virus species: The intertwine of nanotechnology with sensing strategies

“…Anti-SFTSV Abs were also immobilized at the TL to capture detected Ags, and GAM IgG Abs at the CL were used to capture remaining CDSNs. This device was evaluated, and the SFTSV detection results were consistent with PCR showing no cross-reactivity with HCG, AFP, CEA, CA125 [ 170 ]. In another research, Zuo and coworkers developed an LFA using Au NPs conjugated with anti-SFTSV mAbs as reporter probes.…”