Anthocyanins decrease the internalization of TiO2 nanoparticles into 3D Caco-2 spheroids

Abstract

The influence of food components on nanoparticle (NP) internalization indicates a need to investigate the behaviors of NPs in a complex system. This study measured the changes of TiO₂ NP colloidal stability and quenching of anthocyanin fluorescence to indicate NP-anthocyanin interactions, and cytotoxicity, oxidative stress, expression of ABC transporters and intracellular Ti concentrations in 3D Caco-2 spheroids co-exposed to NPs and anthocyanins to indicate the influence of anthocyanins on NP bio-effects. The anthocyanins were observed to have minimal impacts on colloidal properties of TiO₂ NPs. Meanwhile, NP-anthocyanin co-exposure did not induce cytotoxicity or oxidative stress. The fluorescence quenching study indicated the binding of anthocyanins onto TiO₂ NPs, and the binding affinity was inversely correlated with NP internalization into 3D Caco-2 spheroids. This may be partially related with the up-regulation of ABC transporters. Our results may provide novel insights into understanding the interactions of NPs and anthocyanins with human intestinal cells.

Keywords: 3D Caco-2 spheroids; Anthocyanins; Binding affinity constants; Internalization; TiO(2) nanoparticles (NPs).