Molecular Investigation of the Initial Nucleation of Calcium Phosphate on TiO₂ Substrate: The Effects of Surface Nanotopographies

Journal Article · Mon May 07 00:00:00 EDT 2018 · Crystal Growth and Design

DOI:https://doi.org/10.1021/acs.cgd.7b01546· OSTI ID:1566342

Zheng, Ting  ^[1]; Wu, Chunya ^[2]; Zhang, Yu ^[3]; Chen, Mingjun ^[2]; Cummings, Peter T. ^[3]

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1. Dalian Maritime Univ. (China); Harbin Inst. of Technology (China)
2. Harbin Inst. of Technology (China)
3. Vanderbilt Univ., Nashville, TN (United States)

Nucleation and biomineralization of apatite on titanium-based material surfaces is crucial to improve surface biocompatibility, osseointegration, and rapid bone ingrowth in biomedical applications such as joint replacements. Here, this work is designed to provide new insights on the molecular processes in the initial nucleation of calcium phosphate on TiO₂ surface by means of classical molecular dynamics (MD) simulations. Aggregation of calcium and phosphate ions in pure aqueous solution was studied, and the free energies during ion adsorption was investigated by the calculation of PMFs. The MD results suggest surface hydroxylation rate and nanotopographies of TiO₂ substrate contribute significantly to the initial nucleation of calcium phosphate. Our simulations suggest that surface hydroxyls on TiO₂ provide active sites for the aggregation of calcium phosphate. Both calcium ions and phosphate ions could bind to the hydroxylated TiO₂ surface directly or indirectly via the first water layer. Surface nanotopographies (e.g., grooves or ridges) seem to be able to restrict the diffusion of calcium ions and phosphate ions, hence offering more opportunities for adsorption by trapping ions inside channels. In conclusion, it can be inferred that apatite may be formed more favorably on porous or concave surfaces.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Fluid Interface Reactions, Structures and Transport Center (FIRST); UT-Battelle LLC/ORNL, Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1566342
• Journal Information: Crystal Growth and Design, Vol. 18, Issue 6; ISSN 1528-7483
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

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