Binding Group of Oligonucleotides on TiO 2 Surfaces: Phosphate Anions or Nucleobases?

TL;DR

This study uses advanced computational methods to analyze how oligonucleotides and their components interact with TiO2 surfaces, revealing the roles of phosphate groups and nucleobases in surface binding.

Contribution

It provides an atomistic understanding of oligonucleotide adsorption mechanisms on TiO2, highlighting the synergistic effects of phosphate and nucleobases and their relative binding strengths.

Findings

Phosphate and nucleobases can collaboratively anchor nucleotides to TiO2.

Guanine-containing nucleotides exhibit the strongest adsorption.

Water molecules influence nucleotide desorption and surface stability.

Abstract

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.