Multifunctional signal probe-based immunochromatographic test strip for rapid detection of aflatoxin B1 in complex matrix samples

Immunochromatographic test strips (ICTS) are widely used for the immediate and rapid detection of toxins; however, they are prone to false-positive results and insufficient sensitivity when applied to complex sample matrices. To overcome these limitations, herein, a multifunctional signal probe-based ICTS was developed for the rapid detection of aflatoxin B 1 (AFB 1 ) in complex matrix samples by conjugating biotinylated nanobodies (G8-Bio) with streptavidin-modified magnetic beads (MB-SA) as the probes. The constructed ICTS achieved a limit of detection (LOD) of 0.063 ng/mL for AFB 1 . In corn spiked experiments, the results ranged from 98 % to 102 %, with coefficients of variation (CV) between 1.4 % and 6.86 %, confirming the reliability of this method. Furthermore, the IC 10 value in soy sauce samples was 0.069 ng/mL, indicating its suitability for detecting AFB 1 in dark-colored matrices. This approach provides a novel strategy for the rapid and accurate detection of trace toxins in complex matrix samples. • A nanobody-based test strip with anti-interference properties was developed for aflatoxin B 1 (AFB 1 ) detection. • The designed multifunctional signal probe simultaneously facilitates AFB 1 enrichment, specific recognition, and signal amplification. • The signal probes effectively mitigate background interference caused by sample impurities on the detection strip. • This test strip demonstrates a satisfactory detection limit and high specificity.