Cost-effective porous metal oxides and mixed metal oxides coatings for Ti- 6Al-4V biomedical implants

Titanium metal and its alloys, such as Ti– 6Al–4V, are widely used for fabricating biomedical implants due to their excellent mechanical and antibacterial properties. However, these implant materials require surface modifications to address limitations in corrosion resistance and biocompatibility. In this regard, porous coatings are essential, as they significantly promote the survival of bone-forming cells (osteoblasts) and support tissue ingrowth into the implant. This leads to improved implant stability and a reduced risk of implant loosening. This study focuses on modifying Ti–6Al–4V surfaces using a cost-effective bottom-up sol–gel method to prepare TiO2, Ta2O5, and TiO2– Ta2O5 nanocomposites in 1:2, 1:1, and 2:1 ratios. A spin-coating technique with optimized rotational speed and deposition time was employed to deposit uniform films onto the Ti–6Al– 4V substrate. Microstructural characterization of the prepared films revealed porous architectures with varying pore sizes, uniform film thickness, and stoichiometric formation of the desired metal oxides and their composites. A detailed corrosion study was conducted in Hank’s solution and simulated body fluid (SBF). Tafel plots and electrochemical impedance spectroscopy (EIS) demonstrated high corrosion resistance, with Icorr values on the order of 10-8 A cm-2 for the coated samples. Pulloff adhesion testing confirmed excellent film-tosubstrate adhesion, effectively overcoming one of the most common limitations of sol–gel-derived coatings. The prepared porous films also exhibited enhanced cell viability and attachment compared to bare Ti–6Al–4V when tested with MG-63 (cancerous osteoblast) and NIH3T3 (fibroblast) cell lines over 1, 3, and 7 days. Overall, this study highlights the efficacy of the cost-effective coating technique and demonstrates the superior surface properties of TiO2, Ta2O5, and TiO2– Ta2O5 composite films relative to bare Ti–6Al– 4V implants.