Increased Osteoblast Functions on Nanophase Hydroxyapatite Coatings on Titanium

Abstract

In order to improve orthopedic implant performance, the objective of this in vitro study was to synthesize nanocrystalline hydroxyapatite (HA) powders and use such powders to coat titanium. HA was synthesized through a wet chemical process. The precipitated powders were either sintered in order to produce UltraCap (or traditionally-used microcrystalline size) or were treated hydrothermally to produce nanocrystalline size HA powders. Some of the UltraCap and nanocrystalline HA powders were doped with yttrium (Y) since previous studies demonstrated that Y-doped HA in bulk improved osteoblast (or bone-forming cell) functions over undoped HA. The original HA particles were characterized using XRD, ICP-AES, BET, a laser particle size analyzer, and SEM. These powders were then deposited onto titanium by a novel roomtemperature process, called IonTite™. The properties of the resulting HA-coatings on titanium were compared to respective properties of the original HA powders. The results showed that the chemical and physical properties of the original HA powders were retained when coated on titanium by IonTite™, as determined by XRD, SEM, and AFM analysis. More importantly, results showed increased osteoblast adhesion on the nanocrystalline HA IonTite™ coatings compared to traditionally used plasma-sprayed HA coatings. These results encourage further studies on nanocrystalline IonTite™ HA coatings on titanium for orthopedic applications.