Atomically Resolved Interfacial Analysis of Bone-Like Hydroxyapatite Nanoparticles on Titanium

Titanium is commonly used for medical devices, including osseointegrating implants, owing to its biocompatibility and mechanical properties. Nanostructuring titanium implants is known to enhance the healing process by promoting bone growth on the implant surface. Hydroxyapatite nanoparticles, resembling natural bone mineral, have been used to further improve osseointegration. While previous studies have investigated the osseointegration of titanium implants using atom probe tomography, limited research has focused on the attachment of synthetic hydroxyapatite to titanium. Herein, electron microscopy and atom probe tomography are used to reveal the assembly of synthetic hydroxyapatite nanoparticles in the titanium oxide surface. By sputter coating with chromium, a suitable matrix is formed for detailed interfacial analysis. The results demonstrate the diffusion of calcium, phosphorus, and carbon from hydroxyapatite nanoparticles into the titanium oxide surface.