Interaction mechanism between ZnO nanoparticles-whey protein and its effect on toxicity in GES-1 cells

The interaction between zinc oxide nanoparticles (ZnO NPs) and whey protein (WP) was studied. The gastric epithelial cell line (GES-1) was used to evaluate the toxicity intensity of ZnO NPs. The interaction mechanism of ZnO NPs and WP was studied by spectroscopic techniques. The results showed that the inhibitory effect of ZnO NPs on cells activity could be reduced when added to ZnO NPs at a concentration of 50 µg/ml. The fluorescence quenching mechanism of ZnO NPs on WP is a combination of dynamic and static quenching. The interaction force between ZnO NPs and WP can be considered as H-bond and VdW force, and they have two binding sites. The interaction between WP and ZnO NPs leads to the loosening of the structural skeleton of WP and the extension of peptide chain, which exposes the tyrosine (Tyr) and tryptophan (Trp) hydrophobic groups in the hydrophobic region of protein molecules and reduces the hydrophobicity of the microenvironment. The ZnO NPs might form a complex with WP through H-bond, hydrophobic interactions, and so on, leading to peptide chain rearrangement, and finally causing changes in the secondary structure of α-helix. Practical Application This study provides a theoretical basis for future research on the interaction between food ingredients and nanomaterials, the evaluation of toxicity of nanomaterials and the application scope of nanomaterials in food field.