Gold nanotriangle-enhanced high-sensitive determination of alpha-fetoprotein via lateral flow immunoassay in serum.

The first visual lateral flow immunoassay (LFIA) is reported using gold nanotriangles (AuNTs) as labeling materials for high-sensitivity alpha-fetoprotein (AFP) detection in serum. Compared with traditional gold nanoparticles, the use of anisotropic AuNTs significantly reduces the detection limit of AFP due to larger surface area and strong localized surface plasmon resonance, which can reach 5 ng/mL in serum samples with naked eyes. Under optimized conditions, this method demonstrates excellent accuracy and reproducibility in both buffer and serum systems. More importantly, the direct use of gold nanotriangles as labeling materials has the advantages of simple synthesis and strong controllability compared with complex composite labeling materials. This work pioneers the application of AuNTs in LFIA, bridging the gap between simplicity (visual readout) and high sensitivity, and provides a scalable platform for point-of-care diagnostics and is expected to have commercial application prospects.