Study on the interaction between aflatoxin M1 and DNA and its application in the removal of aflatoxin M1

Abstract

To reveal the interaction between aflatoxin M1 (AFM1) and DNA, and then explore a new method to remove AFM1, spectroscopy, electrophoresis, and fluorescence microscopy were used. Fluorescence spectra assay showed that AFM1 and ethidium bromide (EB) competed for the intercalation sites in DNA, and the binding constant between AFM1 and DNA was 3.81 ± 0.1 × 107 L mol−1. The comparison of single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA) in the fluorescence enhancement of AFM1 further proved that the binding sites were between the base pairs of DNA. In the presence of AFM1, the melting temperature of DNA increased by 6.2 ° C, and the circular dichroism of DNA changed. These events were closely related to the intercalation between AFM1 and DNA. The binding between AFM1 and DNA was firm. AFM1 and DNA did not separate in agarose gel electrophoresis. Based on the intercalation between AFM1 and DNA, with DNA as an intermediate medium, AFM1 can be indirectly adsorbed onto magnetic beads. Then, AFM1 could be removed by magnetic separation. At an initial concentration of 10 μg/L, the removal efficiencies were 95.5%±3.7 and 85.5%±3.3 for aqueous solution and milk, respectively. This research result provided a direction in the detoxification of AFM1, which deserves to be developed further.