Strategies for enhancing sensitivity in lateral flow assays
TL;DR
A critical analysis of recent strategies that have been developed to improve the sensitivity of aptamer‐based LFAs and the emerging transition from passive biological selection to active molecular engineering is discussed, outlining the future trajectory of ultra‐sensitive next‐generation LFAs.
Abstract
Lateral flow assays (LFAs) have become the foundation of point‐of‐care (POC) diagnostics, valued for their user‐friendly format, cost‐effectiveness, and rapid turnaround time. However, despite their widespread success, most notably in pregnancy testing and infectious disease monitoring, conventional colourimetric LFAs often suffer from insufficient sensitivity, typically failing to reach sub‐picomolar detection limits, limiting their utility for the early‐stage detection of low‐abundance biomarkers. In recent years, aptamer‐based LFAs have emerged as a promising alternative to conventional antibody‐based formats owing to their superior stability, reproducibility and programmability. This review provides a critical analysis of recent strategies that have been developed to improve the sensitivity of aptamer‐based LFAs. Enhancement strategies are systematically classified into six distinct domains: (i) flow modulation techniques that optimise reaction kinetics; (ii) sample preconcentration methods; (iii) advanced signal transduction reporters beyond traditional gold nanoparticles; (iv) chemical signal amplification, including nanozyme and enzymatic catalysis; (v) structural strategies for maximising label accumulation; and (vi) the engineering of aptamers as programmable recognition elements. Particular emphasis is placed on amplification strategies that are compatible with or uniquely enabled by aptamer‐based detection systems. Finally, the emerging transition from passive biological selection to active molecular engineering is discussed, outlining the future trajectory of ultra‐sensitive next‐generation LFAs.