Optimization of aflatoxin B1 removal efficiency of DNA by resonance light scattering spectroscopy

In this paper, firstly, the resonance light scattering spectra of aflatoxin B1 (AFB1) and DNA were measured by resonance light scattering spectroscopy (RLS), and the DNA binding saturation value (DBSV) of AFB1 was calculated from their spectral results. Then the interaction intensity between DNA and AFB1 and the effects of some external factors on the interaction between DNA and AFB1 were evaluated by corresponding DBSVs, so as to establish and optimize a way for removing AFB1 by DNA. DBSV of AFB1 was 2.04 at 30℃ and pH 7.40. However, after adding sodium ion, calcium ion, vitamin E, vitamin C and D-glucose, DBSV of AFB1 was changed to 2.72, 3.17, 2.67, 1.68 and 1.33 respectively. Correspondingly, the removal efficiency of AFB1 by DNA was changed from 90.05% to 93.25%, 95.48%, 93.08%, 82.36% and 78.90% respectively. These results indicated that the external factors had a significant impact on the interaction between DNA and AFB1. Among them, some factors enhanced the interaction between DNA and AFB1, while some factors weakened the interaction between DNA and AFB1. The change of these external factors led to the corresponding changes in DBSV and the removal efficiency of AFB1. DBSV of AFB1 could really be used as an index to evaluate the intensity of the interaction between DNA and AFB1, and to optimize the removal efficiency of AFB1 by DNA. The experimental data also showed that the adsorption of AFB1 to DNA was consistent with the pseudo-second-order kinetic model and the Freundlich isothermal model, was an exothermic and spontaneous process. All these results will give good references for establishing and optimizing a way of AFB1 removal via DNA intercalation.