Calcium Phosphate Deposition on Planar and Stepped (101) Surfaces of Anatase TiO2: Introducing an Interatomic Potential for the TiO2/Ca-PO4/Water Interface.

Titanium is commonly employed in orthopaedic and dental surgery, owing to its good mechanical properties. The titanium metal is usually passivated by a thin layer of its oxide, and in order to promote its integration with the biological tissue, it is covered by a bioactive material such as calcium phosphate (CaP). Here, we have investigated the deposition of calcium and phosphate species on the anatase phase of titanium dioxide (TiO2) using interatomic potential-based molecular dynamics simulations. We have combined different force fields developed for CaP, TiO2, and water, benchmarking the results against density functional theory calculations. On the basis of our study, we consider that the new parameters can be used successfully to study the nucleation of CaP on realistic anatase and rutile TiO2 nanoparticles, including surface defects.