Lateral flow assay with automatic signal amplification based on delayed substrate release

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• Lateral flow assays (LFAs) offer rapid detection but suffer from low sensitivity for trace targets.
• Nanozyme-based LFAs (nanozyme-LFAs) enhance performance for point-of-care testing (POCT), yet require complex multi-step operations for substrate catalysis.
• Simplifying nanozyme-LFA protocols is crucial for broader POCT applications.

Purpose of the Study:

• To develop a simplified, one-step LFA for sensitive nucleic acid detection of influenza A virus H1N1.
• To integrate delayed substrate release into LFA technology, eliminating complex operational steps.
• To enhance signal amplification and improve the limit of detection (LOD) compared to conventional nanozyme-LFAs.

Main Methods:

• Designed a substrate-integrated glass fiber (SGF) membrane for delayed substrate release, embedded within the LFA sample pad.
• Utilized Au@PtNP nanozyme catalysis for signal amplification via 3,3'- diaminobenzidine (DAB) oxidation and deposition.
• Evaluated the SGF-LFA for H1N1 nucleic acid detection in buffer and serum samples.

Main Results:

• The SGF-LFA achieved a one-step operation for H1N1 nucleic acid detection.
• Demonstrated a linear detection range of 0.02-50 nM with a low LOD of 0.02 nM, representing a 25-fold improvement over pre-catalysis nanozyme-LFAs.
• Achieved high recovery rates (96%-102.7%) when applied to serum samples, comparable to manual amplification methods.

Conclusions:

• The developed SGF-LFA offers a simplified, highly sensitive, and rapid method for H1N1 nucleic acid detection.
• This one-step nanozyme-LFA approach holds significant potential for improving point-of-care diagnostics.
• The delayed substrate release strategy effectively overcomes operational complexities in nanozyme-based LFAs.