A highly sensitive dual-mode lateral flow immunoassay based on plasmonic hollow Ag/Au nanostars enhancing light absorption

The conventional lateral flow immunoassay (LFIA) based on gold nanoparticles (Au NPs) is limited by low sensitivity due to the insufficient brightness of Au NPs. To address this problem, noble metal nanomaterials with localized surface plasmon resonance (LSPR) and synthetic tunability are potential signal outputs for LFIA, which can achieve better optical properties by adjusting the preparation conditions. Herein, this study prepared the hollow silver/gold nano-stars (HAg/Au NSts) as LFIA signal output via the galvanic replacement method. HAg/Au NSts with anisotropic hollow alloy nanostructures exhibit a wide visible light absorption band and great NIR thermal conversion efficiency (η = 37.32 %), which endows them with enhanced colorimetric and photothermal signals. Further, we constructed a colorimetric-photothermal (CM-PT) dual-signal HAg/Au NSts-LFIA and chose staphylococcal enterotoxin B as the target analyte. The linear range of HAg/Au NSts-LFIA is 0.19-100 ng mL