Efficiency of the interfacial charge transfer complex between TiO2 nanoparticles and caffeic acid against DNA damage in vitro: A combinatorial analysis

The genotoxic and antigenotoxic behavior of the interfacial charge transfer (ICT) complex between nano-sized TiO2 particles and caffeic acid (CA) was studied in in vitro experiments. The formation of the ICT complex is indicated by the appearance of absorption in visible-spectral range. The continual variations method indicated bridging coordination between the ligand, caffeic acid, and the surface Ti atoms, while the stability constant of the ICT complex was found to be 1.5x10(3) mol(-1) L. An agreement between the experimental data and the theoretical results, based on the density functional theory, was found. The ICT complex and its components did not display genotoxicity in the broad concentration range 0.4. 8.0 mg mL(-1) TiO2 at a mole ratio c(TiO2)/c(CA) = 8. On the other hand, post-treatment of damaged DNA by the ICT complex induced antigenotoxic effect at lower concentrations, but at higher concentrations, 5.125-10.250 mg mL(-1) ICT, the ICT complex did not show any beneficial effect on H2O2-induced DNA damaged cells. The experimental data were analyzed using the combinatorial method to determine the effect of component interaction on the genotoxic and antigenotoxic behavior of the ICT complex