Nanostructurally Designed Ultra-hydrophilic Hard Ceramic Oxide Coatings for Orthopaedic Application

Abstract

This paper addresses the application of engineered nanocrystalline ultrahydrophilic titanium oxide films to artificial orthopaedic implants. Titanium (Ti) is the material of choice for orthopaedic applications and has been used for over fifty years because of its known bio-compatibility. Recently it was shown that biocompatibility of Ti metal is due to the presence of a thin native sub-stoichiometric titanium oxide layer [1] which enhances the adsorption of mediating proteins on the surface thus enhancing cell adhesion and growth [2,3,4]. Improving the quality of surface oxide, i.e. fabricating stoichiometric oxides as well as nanoengineering the surface topology that matches the dimensions of adhesive proteins, is crucial for the increase of protein adsorption [2] and, as a result, the biocompatibility of Ti implant materials. We have fabricated ultrahydrophilic nano-crystalline transparent films of anatase phase of titania (TiO2) by ion beam assisted deposition (IBAD) processes in an ultrahigh vacuum system. Source material was 99.9% pure rutile TiO2. Various ion beam conditions were used to produce these coatings with different grain sizes (4 to 70 nm) that affect the wettability, roughness, and the mechanical and optical properties of the coating [5]. Our biological experiments have shown that biocompatibility of these ultrahydrophilic nanoengineered TiO2 coatings are superior to commonly used orthopaedic titanium and even hydroxyapatite.

Surface nano-modification by ion beam–assisted deposition alters the expression of osteogenic genes in osteoblasts

“…7 Surface morphology and crystal structures of these IBAD-produced surfaces (ZrO 2 and TiO 2 films on different substrates) have been reported previously by transmission microscopy (TEM), atomic force microscopy (AFM), and contact angle measurements. 7–18…”

Effects of nano-engineered surfaces on osteoblast adhesion, growth, differentiation, and apoptosis

“…23 Surface structure and morphology have been studied by Namavar et al using transmission microscopy (TEM), atomic force microscopy (AFM), and contact angle measurements. [23][24][25][26][27][28][29][30] Using the IBAD technique to modify surface properties was previously shown to result in stressfree films with more durable adhesion to a titanium substrate. 31 Although this study tested nano-coatings on glass substrates, our previous study using titanium substrates showed similar results.…”