UC San Diego

The biological response to implant materials has been a topic of extensive research and discussion throughout the years. More recently, the field has become particularly exciting due to advances in nanotechnology, and the indications and belief that living cells sense and respond to cues on the nanoscale. A nanostructured material of special interest for orthopedic implant applications is the vertically aligned, laterally spaced titanium oxide (TiO₂) nanotube arrays formed via electrochemical anodization techniques. Foundational work in the Jin Lab has demonstrated the advantages of the TiO₂ nanotube surface due to indications that the nanotube architecture significantly accelerates osteoblast cell growth, improves bone-forming functionality, and even directs mesenchymal stem cell fate. However, these findings raise questions such as whether the same nano-architecture can be equally effective when exhibiting different surface chemistries. In addition, the feasibility of fabricating the nanotube structure from a thin film of titanium on the surface of an orthopedic implant composed of another material as a bioactive coating has been uncertain. The work reviewed in this dissertation attempts to answer these questions by providing in-depth experimental analysis of (a) comparative osteogenic behavior on nanotube surfaces of varying surface chemistries including ZrO₂, TiO₂, Ta, and Ta₂O₅, and (b) optimized anodization parameters for thin film TiO₂ nanotube layers applied to industry-supplied orthopedic implant materials (i.e. zirconia and CoCr alloy), and initial osteoblast cell response to such coatings. The research of this dissertation conveys substantial contributions towards the field of orthopedic surface technology, and for furthered understanding of cellular interactions with complex nano-interfaces