Chemically regulated bioactive ion delivery platform on a titanium surface for sustained controlled release

The efficacy of biomedical titanium implants mainly depends on their surface characteristics such as surface morphology, microstructure, and components, and the resulting performances. In this work, hierarchical hybrid micro/nanotip films incorporated with bioactive Sr2+/Mg2+ ions were prepared on a titanium surface by combining acid etching, hydrothermal treatment and a subsequent ion exchange process with Sr2+ and Mg2+ ions respectively. A Sr/Mg delivery platform is thus successfully obtained on a titanium surface and can allow for sustained release of Sr2+/Mg2+ ions at a slow rate for a period of time. In vitro SBF tests confirm that the Sr/Mg loaded titanate films possess good bioactivity accompanying the controlled release. Meanwhile, cell experiments further demonstrate that the Sr/Mg loaded micro/nanostructured titanium surfaces possess good biocompatibility and osteogenic activity. This is a successful attempt to apply an ion exchange technique to the surface modification of biomedical titanium materials and the strategy described here offers a general, facile, and straightforward chemical approach to functionalize various titanium-based material surfaces by constructing micro/nanostructures and using ion exchange with bioactive ions under mild synthetic conditions, and provides insight into the design of better biomedical implant surfaces for the future.