Abstract
Ti-24Nb-4Zr-8Sn (Ti2448), a new β-type Ti alloy, consists of nontoxic elements and exhibits a low uniaxial tensile elastic modulus of approximately 45 GPa for biomedical implant applications. Nevertheless, the bio-corrosion resistance and biocompatibility of Ti2448 alloys must be improved for long-term clinical use. In this study, a rapid electrochemical anodization treatment was used on Ti2448 alloys to enhance the bio-corrosion resistance and bone cell responses by altering the surface characteristics. The proposed anodization process produces a unique hybrid oxide layer (thickness 50–120 nm) comprising a mesoporous outer section and a dense inner section. Experiment results show that the dense inner section enhances the bio-corrosion resistance. Moreover, the mesoporous surface topography, which is on a similar scale as various biological species, improves the wettability, protein adsorption, focal adhesion complex formation and bone cell differentiation. Outside-in signals can be triggered through the interaction of integrins with the mesoporous topography to form the focal adhesion complex and to further induce osteogenic differentiation pathway. These results demonstrate that the proposed electrochemical anodization process for Ti2448 alloys with a low uniaxial tensile elastic modulus has the potential for biomedical implant applications.
Highlights
Millions bone graft procedures are expected to be performed annually to fill bone defects or to improve fracture healing and repair
After the electrochemical anodization treatment, a mesoscale porous topography was formed on the anodized Ti2448 (Ti2448-A1 and Ti2448-A2) surface (Fig. 1(c) and (d))
The results showed that on day 7 of the incubation, the cells cultured on the anodized Ti2448-A1 and Ti2448-A2 exhibited greater OPN expression compared with the cells on the untreated Ti-M and Ti2448-M
Summary
Millions bone graft procedures are expected to be performed annually to fill bone defects or to improve fracture healing and repair. The elastic moduli of the commonly used commercial Ti and Ti-based alloys (100–110 GPa)[6], such as commercially pure Ti (CP-Ti), Ti-6Al-4V and Ti-6Al-7Nb, are still an order of magnitude greater than that of human cortical bone (10–30 GPa)[7,8] This mismatch between the elastic modulus of bone and that of the implant will cause an insufficient load transfer from the implant to the adjacent bone and, induce a stress-shielding effect at the sites of load-bearing bones during long-term implantation. This novel alloy consists of biocompatible elements and possesses a low uniaxial tensile elastic modulus of approximately 45 GPa13,14, which is close to that of human cortical bone Such a low elastic modulus may prevent the stress-shielding effect caused by the inhomogeneous stress transfer between a metal implant and the adjacent bone. The electrochemical anodization treatment is used to produce a nano-networked oxide layer on the surfaces of CP-Ti and Ti-based alloys to improve the bio-corrosion resistance, hemocompatibility and cell responses[27,28,29]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
