Biomedical applications materials, titanium implants

Titanium and its alloys have many biomedical applications due to their high strength and corrosion resistance, and are commonly incorporated in replacement hip joints and items such as bone pins [1]. Porous Ti foams have been explored for biomedical uses due to their enhanced adhesion to host tissue [15]. Surface-treatment of Ti and Ti alloys to enhance material properties, such as wear resistance, in a biomedical context has been examined [16]. In addition, titanium nitride-based materials could potentially serve as coatings for biomedical implants [17]. NiTi-based shape memory alloys are attractive candidates for biomedical materials due to their shape retention and pseudoelasticity, however, manufacturing and processing these memory alloys for biomedical apphcations is typically not straightforward [18]. 

For instance, equiatomic nickel-titanium alloy (nitinol) is a very attractive material for biomedical applications. However, the high nickel content of the alloy and its potential influence on biocompatibility is an issue for nitinol-composed devices. Corrosion resistance of nitinol components from implantable medical devices should be assessed according to regulatory processes and standard recommendations. It is now well known that nitinol requires controlled processes to achieve optimal good life and ensure a passive surface, predominantly composed of titanium oxide, that protects the base material from general corrosion. Passivity may be enhanced by modifying the thickness, topography, and chemical composition of the surface by selective treatments [46]. 

Titanium is one of the most biocompatible materials and is widely used as dental and orthopaedic implants. An oxide layer is formed at the sruface of the titanium metal onto which cells should be able to grow. Therefore sol-gel derived titania coatings are being developed for biomedical applications. Osteoblast-like and bone marrow stromal cells have been shown to attach well to these sol-gel coating and spread normally at their surface (Haddow, 2000). Such properties could open new opportunities for the encapsulation of living cells within titania gels ... 

Marin, E., S. Fusi, M. Pressacco, L. Paussa, and L. Fedrizzi. 2010. Characterization of cellular sohds in TigAl V for orthopaedic implant applications Trabecular titanium. Journal of the Mechanical Behavior of Biomedical Materials 3(5) 373-381. 

A popular titanium alloy, originally developed for aerospace applications, has the composition Ti-6A1-4V. It contains two phases, the a-phase which has a (he) structure and the P-phase having a (cc) structure. Compared to pure titanium, Ti-6A1-4V exhibits much better mechanical properties, whereas its corrosion resistance in chloride media is almost as good as that of pure titanium. Titanium and its alloys are the materials of choice for biomedical implants that require mechanical strength and good corrosion resistance in chloride media. In addition, titanium and its alloys exhibit good compatibility with biological tissue. 

---