Adsorption of nucleotides on the rutile (110) surface

The present study aims at the computer-aided design of suitably functionalized oxide surfaces for the integration of nanotubes into multi-purpose nano-electronic devices. The adsorption of the nucleotide cytidine monophosphate on the rutile (110) surface is investigated by density-functional-based tight-binding calculations. The nucleotide favors anchoring with two oxygen atoms of its phosphate part. Adsorption occurs preferentially at two neighboring five-fold coordinated Ti atoms along the [001] direction, thus opening a pathway to an ordered adsorption of nanotubes along [001]. The electronic densities of state show that the aromatic part of the cytidine residue remains unchanged upon adsorption on rutile. This implies that no significant changes occur in the nanotube binding capacity by it-stacking of the aromatic part, hence, nucleotide-functionalized oxide surfaces are ideal substrates for the ordered, stable and electronically and chemically inert immobilization of nanotubes.