Characteristics and In Vitro Biologic Assay of Apatite/Titania Composite Coatings on Ti–6Al–4V for Medical Applications

Abstract

To improve the bioactivity, corrosion resistance, and long‐term biocompatibility of Ti–6Al–4V, apatite/titania composite coatings were synthesized on its surface using a H2O2‐oxidation and subsequent accelerated biomimetic deposition method. Scanning electron microscopic (SEM) examination of coating surfaces and cross‐sections showed that the composite coatings were dense and uniform. The phase composition of titania inner layer and apatite outer layer was investigated using transmission electron microscopy (TEM) and X‐ray diffraction (XRD). In addition, chemical composition of titania inner layer and apatite outer layer was determined using Fourier transform infrared spectroscopy (FTIR). Considering the results from TEM, XRD, and FTIR analyses, it could be concluded that titania inner layer consisted of poorly crystalline anatase phase, and apatite outer layer was composed of low crystalline, calcium‐deficient, and carbonated hydroxyapatite (HA). Based on variations of pH values of five‐time‐strength simulated body fluid (5SBF) during the accelerated biomimetic deposition, possible processes for the formation of the apatite outer layer were discussed. The chemical stability of the apatite/titania composite coatings was also investigated using potentiodynamic polarization tests. After 3 days in culture, viability of MCF‐7 cells seeded on uncoated and coated samples showed that the composite coatings were noncytotxic and could improve the biocompatibility of Ti–6Al–4V.

Novel Layered Hydroxyapatite/Tri‐Calcium Phosphate–Zirconia Scaffold Composite with High Bending Strength for Load‐Bearing Bone Implant Application

“…2, the scaffold composite has a superior bending strength of 321 MPa and may offer an alternative to metal-only load-bearing implants (such as titanium) used currently to replace critical bone defects. [26][27][28]…”