Aptamer as capture agent in enzyme-linked apta-sorbent assay (ELASA) for ultrasensitive detection of Aflatoxin B₁

Aflatoxin B₁ (AFB₁), is one of the most toxic mycotoxins found to contaminate various food commodities like cereals, dried fruits, tree nuts, spices and crude vegetable oils. In spite of considerable progress in analytical techniques, there is still a need to develop rapid and highly sensitive detection platforms for AFB₁. In this study, AFB₁ specific aptamer was used as a capture molecule to develop an enzyme-linked apta-sorbent assay (ELASA) for ultrasensitive detection of AFB₁. Under optimized conditions, the assay had a linear detection range from 1 μg to 1 pg with a limit of detection (LOD) of 1 pg/mL in buffer. Conventional ELISA with AFB₁ hapten as the capture agent (LOD = 10 pg/mL) was also carried out to compare the results with the present method. Recovery studies in food samples like dried red chillies, groundnut and pepper using both the methods was found to be in the range of 88.49-106.4% at 10 ng/mL and 87.4% to 95.8% at 5 ng/mL for ELASA and 76.56-127.68% at 10 ng/mL and 82-101.2% at 5 ng/mL for ELISA. Higher detection (10 fold) and better recovery using ELASA suggest that the method could offer an early, ultrasensitive, high-throughput, qualitative and semi-quantitative detection of AFB₁ in contaminated food samples.