The development of high sensitive photothermal lateral flow immunoassay for the detection of AFB1 in food based on fluorination boosting photothermal conversion efficiency.

This study developed a photothermal lateral flow immunoassay (LFIA) for sensitive aflatoxin B1 (AFB1) detection. An acceptor-donor-acceptor type photothermal agent BTP-4F (FY6), developed through a fluorination strategy, was fabricated into FY6@DSPE-PEG nanoparticles (NPs) via nanoprecipitation. The NPs demonstrated strong near-infrared (NIR) absorption with an exceptional photothermal conversion efficiency reaching 78.8% at 808 nm. Subsequent covalent conjugation of FY6@DSPE-PEG NPs with AFB1 antibody (Ab) to prepare FY6@DSPE-PEG@Ab photothermal immunoprobes for LFIA. Benefiting from the excellent photothermal performance of FY6@DSPE-PEG NPs, the photothermal LFIA achieved a limit of detection (LOD) of 0.031 μg/L, representing a 10.6-fold improvement on the conventional Au NPs-based LFIA. Spike and recovery experiments with real samples confirmed high consistency between the photothermal LFIA and high-performance liquid chromatography (HPLC) measurements. Overall, the developed photothermal LFIA integrated both qualitative screening and photothermal quantification, which can be extended to the analysis of other hazardous small molecule targets in food.