Rapid and sensitive immunochromatographic assay based on gold nanoparticles for detection of aflatoxin B1 in lotus seeds

Aflatoxin B1 (AFB1) is a highly toxic mycotoxin that is frequently found in traditional Chinese medicines (TCM), representing a serious threat to the health of both humans and animals. The application of lateral flow immunochromatography (LFIC) test strips in complex matrices such as TCM is constrained by their detection sensitivity. In our study, a competitive LFIC test strip was created for the ultrasensitive determination of AFB1 in lotus seeds. AFB1 antigens were fixed as test-lines, allowing for quick detection within 8 min using a single strip, without requiring expensive instrumentation. The developed assay demonstrated a dynamic detection range of 0.01 ng·mL -1 ~10 ng·mL -1 with an ultra-low limit of detection (vLOD) of 0.05 ng·mL -1 in standard samples, which outperformed previously reported single-toxin LFIC strips based on gold nanoparticles by 2- and 17- fold, respectively. The proposed LFIC test strips were successfully validated in spiked and naturally contaminated lotus seed samples with an LOD of 1.0 μg·kg -1 , exhibiting excellent accuracy, reproducibility, and sensitivity, which aligned well with the HPLC-FLD and HPLC-MS/MS results. Collectively, this approach provides a sensitive, rapid, and user-friendly platform for on-site AFB1 monitoring in traditional Chinese medicines. • We developed a sensitive competitive lateral-flow immunochromatography test strip based on gold nanoparticles. • The sensitivity of the LFIC test strip is 0.05 ng·mL -1 , which is lower than previously reported. • The LFIC test strip was applied to detect AFB1 in a traditional Chinese medicine complex matrix.