  Although the immobilization of oligonucleotides (nucleic acid) on mineral
surfaces is at the basis of different biotechnological applications, an
atomistic understanding of the interaction of the nucleic acid components with
the titanium dioxide surfaces has not yet been achieved. Here, the adsorption
of the phosphate anion, of the four DNA bases (adenine, guanine, thymine, and
cytosine) and of some entire nucleotides and dinucleotides on the TiO 2 anatase
(101) surface is studied through dispersion-corrected hybrid density functional
theory (DFT) calculations. Several adsorption configurations are identified for
the separated entities (phosphate anion or base) and then considered when
studying the adsorption of the entire nucleotides. The analysis shows that both
the phosphate anion and each base may anchor the nucleotides to the surface in
a collaborative and synergistic adsorption mode. The tendency is that the
nucleotides containing the guanine base present the strongest adsorption while
those made up with the thymine base have the lowest adsorption energies.
Nucleotides based on adenine and cytosine have a similar intermediate behavior.
Finally, we investigated the adsorption of competing water molecules to
understand whether in the presence of the aqueous solvent, the nucleotides
would remain bonded to the surface or desorb.
