Biodegradable metals: state of the art
Biodegradable metals have the potential to revolutionize current and future healthcare products, and they have been attracting researchers from both academics and medical industries. Among the three known types of biodegradable metals (iron, magnesium, zinc), magnesium alloys are the most elaborated ones, where advanced clinical tests and product
Monitoring and Evaluation of Biomaterials and their Performance in vivo. http://dx.doi.org/10.1016/B978-0-08-100603-0.00002-X
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Figure 2.1 Examples of biodegradable metal products made of magnesium alloys: (a) Korean K-Met headless screw, (b) German Syntellix compression screw, and (c) German Biotronik absorbable stent.
development have already been done. Iron and its alloys as the first introduced type are still facing the challenge of slow in vivo degradation rate, while new interests are arising for zinc and its alloys . New standards on materials, processes, and testing procedures are under development by the ASTM subcommittee F04.15 . The term “bioabsorbable” is being preferentially used by the ASTM; however, in this chapter we continue to use the term biodegradable. Recently, there are at least three companies that have launched their commercial biodegradable metal products or prototypes, as shown in Fig. 2.1.
When discussing biodegradable metal implants, one will derive at least three key features. They are: (1) the metal from which an implant is made, (2) the implant used for treating a temporary clinical problem, and (3) the degradation, which refers to the corrosion of the metal in in vivo environment. The following sections briefly describe these three features.