Molecular dynamics simulations of the adsorption and dynamical behavior of single DNA components on TiO2

The adsorption of the four DNA bases (adenine, guanine, thymine, and cytosine) on a mineral surface (titanium dioxide) is studied through classical molecular dynamics simulations and potential of mean constrained force calculations to give a reliable description of their binding behavior, identify the best binding arrangement, and quantify the strength of their interactions with the inorganic surface. Several configurations are identified, and the analysis of the data has revealed that the general tendency is to adsorb on structured solvent layers, which are in direct contact with the substrate. In this region, the molecules are perpendicular to the slab most of the time, do not adopt a preferential orientation, and explore different areas of the interposing water layers. Frequent escape into the bulk solvent is observed, suggesting that the interactions between the bases and the solvent layers are not strong enough to keep the molecule close to the surface