Using of Tyramine Signal Amplification to Improve the Sensitivity of ELISA for Aflatoxin B-1 in Edible Oil Samples

Tyramine signal amplification (TSA), the excellent signal amplification strategy, has the potential to improve the sensitivities of analytes analysis. In this work, the sensitivity of enzyme-linked immunosorbent assays (ELISA) has significantly improved by coupling TSA system and further biotin-streptavidin (BSA) system. Thus, a sensitive TSA-ELISA based on TSA was developed for detecting aflatoxin B-1 (AFB(1)) in edible oil samples. Under optimal conditions, the limit of detection (LOD, IC10) and the half-maximal inhibition concentration (IC50) of the TSA-ELISA were 0.004 and 0.039 ng/mL for AFB(1), respectively. The developed TSA-ELISA for AFB(1) has an 11-fold improved LOD value and 6-fold improved IC50 value when compared with ELISA. The cross-reactivities of the TSA-ELISA with its analogues were negligible (< 3.48%), which indicated high specificity. The spiked recoveries were 81.4 to 118.8% with relative standard deviations (RSDs) of 3.8 to 9.0% for AFB(1) in edible oil samples. Furthermore, the results of TSA-ELISA correlated well with those obtained by HPLC-fluorescence detector. The proposed TSA-ELISA was a satisfactory tool for sensitive, inexpensive, high-throughput, and alternative detection of AFB(1) in edible oil samples. This study could provide the strategy for improving the sensitivity of ELISA with simple and practical approach, which has significant popularizing value and application prospect.