Growth of LDH on AZ31 Alloy for Applications in Orthopedics

Among biodegradable metallic materials, AZ31 Mg alloy is one of the most studied for biomedical applications. In orthopedics it is of particular interest for temporary implants in order to avoid a subsequent surgical removal. In addition to the biodegradability, the advantages of AZ31 include excellent biocompatibility, excellent osseointegration and an elastic modulus value similar to the human bone one. Furthermore, Mg is essential for the metabolism in many biological mechanisms and the Mg2+ ions, which are produced as a result of its degradation, are useful to promote healing and tissue growth. Finally, the alloy contains a low amount of Al which, in high concentration, could be harmful for the nervous system and osteoblasts. Like other Mg alloys, AZ31 has the disadvantage of quickly degradation in presence of biological fluids, therefore it is necessary controlling the corrosion rate in relation to bone tissue healing process. Corrosion processes can lead to a reduction of the implant's mechanical properties, compromising its functionality. The growth of LDH (Layered Double Hydroxides) on the surface of the AZ31 alloy is not only aimed to delay corrosion processes but also to incorporate medicines that can be released in-situ from the implant with local anti-inflammatory, analgesic, and antimicrobial action. The material would thus play an active role in the healing of bone tissue. This work reports and discusses the first results of an experimental campaign aimed at the identification of the optimal conditions for the LDH growth on the AZ31 alloy for applications in orthopedics.