Magnesium, Zinc and Iron Alloys for Medical Applications in Biodegradable Implants

Biodegradable materials are developed for designing temporary medical implants, like fixation devices for fractured bones or stents. At present, polymeric biomaterials such as poly-lactic acid (PLA) are currently used in these applications. The disadvantage of polymers is a low mechanical strength, hardness and wear resistance that is the main limitation for the use in load-bearing implants. For this reason, extensive research activities are focused on metallic biodegradable materials showing higher strength, hardness, wear resistance and toughness. Among various biodegradable metals, only magnesium, zinc and iron also meet the basic requirement of a good biocompatibility. In the present work, magnesium, zinc and iron based alloys are compared in terms of biocompatibility, mechanical properties and corrosion behavior in the human body environment. Advantages, disadvantages and potential application areas of the three groups of materials are demonstrated.