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 B₁ (AFB₁) 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 AFB₁. In corn spiked experiments, the recovery rates ranged from 98 % to 102 %, with coefficients of variation (CV) between 1.4 % and 6.86 %, confirming the reliability of this method. Furthermore, the IC₁₀ value in soy sauce samples was 0.069 ng/mL, indicating its suitability for detecting AFB₁ in dark-colored matrices. This approach provides a novel strategy for the rapid and accurate detection of trace toxins in complex matrix samples.