Nano-biosensing meets point-of-care: Critical review of nanoparticle-based signal amplification in lateral flow assays

• The Nitrocellulose membrane (NC) pore size and surface chemistry control capillary flow rate and sensitivity of assay. • the choice of detection labels (colloidal gold nanoparticle, Microsphere latex beads, fluorescent dyes, Quantum dots, Selenium nanoparticles) determine limit of detection and readout modality. • Sample pad treatments (surfactants, buffer additives), Conjugate pad formulation, and protein stabilization strategies optimize bio-receptor release and its binding efficiency. • Control line and Test line geometries influences quantitative accuracy and reproducibility across batches. • Multiplexing strategies managing assay complexity with cross-reactivity risks, forming next-generation LFIA platforms. Nanoparticle-based strategies for signal amplification have significantly enhanced analytical performance of lateral flow immunoassays (LFIAs), extending the prior reported detection limit from the nanomolar range toward picomolar and, in selected cases, femtomolar levels. Lateral flow immunoassays (LFIAs) are quick, minimum-cost, and easy-to-use diagnostic technology that align with the World health organization’s ASSURED criteria (Affordable, Sensitive, Specific, User-friendly, Rapid and robust, Equipment-free, and deliverable to end users) for point-of-care testing (POCT). Over past three decades, LFIAs have become widely used in medical diagnostics, environmental contamination monitoring, veterinary medicine, and food safety with global market projections expected to exceeding USD 13 billion by 2028. This review provides overview of LFIA technology, including strip components such as sample pad, protein-stabilized conjugate pads which detect 1–10 ng/mL, nitrocellulose membranes (8–15 µm), and adsorbent pad are discussed in relation to fluid dynamics, reaction kinetics, and analytical performance. and biological recognition elements such as Antibodies, aptamer and molecularly imprinted polymer (MIP) are highlighted their contribution to assay sensitivity and specificity. Recent advancement in signal amplification labels including colloidal gold nanoparticle (20-40nm size), fluorescent nanoparticles, enzymatic cascades, selenium nanoparticle and SERS tags are critically evaluated with respect to detection limit achieve of approximately 0.1 ng/mL and Multiplexed capability to detect 3–10 analytes simultaneously are increasingly being used in diagnostics and residue testing. This review further highlights LFIA formats, and emerging strategies for quantitative detection. Integration of mathematical modeling of antigen–antibody (Ag-Ab) binding kinetics and capillary flow has improved calibration accuracy and quantitative analysis, enabling strong correlation with conventional methods such as ELISA. Despite significant advances, challenges related to quantitative accuracy, matrix interference, manufacturing variability, and multiplex detection persist. Future integration of nanotechnology, computational modeling, and digital detection is expected to transform LFIAs into highly sensitive, quantitative, and multiplexed platforms for decentralized diagnostics and real-time analytical decision-making.