Determination Of Aflatoxin B1 In Vinegar By Surface Plasmon Response Biosensor With Aptamer

Aflatoxins are produced by Aspergillus flavus which may contaminate food and agricultural products. The aflatoxins can be divided into six categories:aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), aflatoxin G2 (AFG2), aflatoxin M1 (AFM1) and aflatoxin M2 (AFM2). Aflatoxin B1 (AFB1) is acutely toxic and the most carcinogenic amongst all mycotoxins. Because mycotoxins pose health risks for humans and animals, their levels are monitored throughout many countries and organizations. For example, the Chinese Standard has set maximum levels of 5.0?g·kg-1 for aflatoxin B1 in the seasoning. Therefore, it is very important to establish sensitive, selective and simple methods for the determination of AFB1 in food and agricultural products. Surface plasmon resonance (SPR) is an optical phenomenon which occurs at the interface between thin conducting films and media of different refractive indexes. Aptamers are single-stranded oligonucleotides, and they can specifically bind to a target molecule. In this research, we reported a sensitivity and rapid method for detection of aflatoxin B1 by SPR biosensor with aptamer technology.1. Based on the research of literature, the sequence of AFB 1-aptamer in our study:bio-5'-GTTGGGCACGTGTTGTCTCTCTGTGTCTCGTG CCCTTCGCTAGGCCCACA-3'. To confirm the binding status and intensity of AFB 1 to aptamer, we perform ITC experiments firstly. The concentration of AFB 1 and aptamer was 5?M and 64?M respectively. The data from ITC were fitted by one-site model within the ITC analysis software. The results obtained from this study showed a strong binding event between the AFB 1 and aptamer. In detail, the apparent equilibrium constant KA was 1.51×106±1.68×105 M-1 with the Aptamer/AFB1 and the stoichiometry was 0.9993±0.0205.2. In our study, the streptavidin protein was immobilized on the surface of a sensor chip as a crosslinker and the biotin-aptamer was captured through affinity capture. After optimization, the assay had a dynamic range between 0.19 and 200 ng·mL-1 (linear range from 0.19 to 50 ng·mL-1) of AFB 1 in buffer.3. Determination of AFB1 in vinegar was further performed in the SPR biosensor. Recoveries of AFB1 at 2,10,20 ng·mL-1 from spiked vinegar samples ranged from 94.1 to 125.9%.4. The LC-MS/MS method was performed as a comparison to the SPR method. The line range of this method was from 1 to 200 ng·mL-1 with a detection limit of 0.5 ng·mL-1.5. The HPLC method was employed as a comparison to the SPR method. The line range of this method was from 1.56 to 200 ng·mL-1 with a detection limit of 0.78 ng·mL-1.