Direct Detection of Viral Infections from Swab Samples by Probe-Gated Silica Nanoparticle-Based Lateral Flow Assay

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Infectious Disease Diagnostics

Background:

• Point-of-care diagnosis is critical for controlling viral infection spread.
• Existing methods may lack the speed and adaptability for diverse viral targets.
• Developing rapid, sensitive, and versatile diagnostic tools is essential.

Purpose of the Study:

• To develop a universal, modifiable probe-gated silica nanoparticle (SNP) based lateral flow assay (LFA).
• To enable rapid and early detection of various viral infections directly from human swab samples.
• To demonstrate the assay's efficacy using severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) as a model.

Main Methods:

• Synthesized silica nanoparticles (SNPs) loaded with fluorescein and rhodamine B as reporters.
• Developed a probe-gated SNP system targeting specific viral genes (NSP9, NSP12, E gene of SARS-CoV-2).
• Evaluated the SNP-LFA performance using synthetic viral solutions and unprocessed human samples, comparing results to RT-qPCR.

Main Results:

• The NSP12-gated SNPs-based LFA detected viral infections within 15 minutes.
• Achieved a limit of detection of 0.73 pg/mL for synthetic viral solutions.
• Demonstrated high sensitivity (100%), specificity (83%), and accuracy (92%) compared to RT-qPCR, with improved test line intensity in unprocessed samples.

Conclusions:

• The developed modifiable nanoparticle system offers a high-performance sensing technique for viral detection.
• This SNP-LFA is adaptable for detecting various viruses and shows promise for point-of-care applications.
• The assay provides a rapid, sensitive, and specific alternative for early viral infection diagnosis.