Development of Latex Microsphere-Based Immunochromatographic Strips for Detecting Key Aflatoxins

Due to the severe hazard of aflatoxins (AFs) to humans, it is of great significance to detect the key aflatoxins, aflatoxin B₁ (AFB₁) and aflatoxin G₁ (AFG₁), in food and feed in simple, rapid, and semi-quantitative ways. The hybridoma clone 3A1 was prepared in this study, and anti-AFB₁ monoclonal antibody (mAb) with high specificity and affinity (9.38 × 10⁸ L/mol) from 3A1 was purified. The indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) demonstrated that the linear detection range for AFB₁ was 0.029-1.526 ng/mL with a limits of determination (LOD) of 0.023 ng/mL. A latex microsphere-based immunochromatographic test strip (LM-ICTS) was constructed based on 3A1, which showed that the strip could detect AFB₁ (LOD: lower than 1.79 ng/mL) and AFG₁ (LOD: lower than 8.08 ng/mL), and the linear detection ranges for AFB₁ and AFG₁ are 1.79-48.46 ng/mL and 8.08-107.40 ng/mL, respectively. The average recoveries of intra-assay and inter-assay for peanuts were (98.4 ± 4.7)% and (92.6 ± 7.6)%, and the average coefficient of variation (CVs) were 4.38% and 8.15%, respectively. For sunflower seeds, the intra-assay and inter-assay recoveries were (94.4 ± 7.2)% and (89.2 ± 4.3)%, and the average CVs were 6.6% and 4.9%, respectively. In summary, the developed LM-ICTS exhibited excellent sensitivity and specificity, which provided a rapidly stable on-site detection choice for AFB₁ and AFG₁ to contaminated agricultural samples, including grain and feed.