Efficacy of laser shock processing of biodegradable Mg and Mg-1Zn alloy on their in vitro bacterial response
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Abstract
The development of biomaterials for biodegradable and bioabsorbable implants in bone repair continues to gain popularity. Magnesium and its alloys have emerged as firm candidates because they combine a suitable Young's modulus, close to that of the bone, low density, good biocompatibility andbioactivity. Despite these interesting properties, magnesium alloys also have some draw backs. For example, their relatively fast degradation rates which, depending on the nature and amount of alloying elements, can induce some toxicity. An important factor in the use for these applications is that degradation products could be at bacterial adhesion, and so contribute avoiding infection and the consequent implant failure. The antibacterial capacity of Mg–base alloys has been evaluated in previous studies but there is still a lack of consensus.
Different approaches have been implemented to partly overcome disadvantages associated with the fast corrosion rate. In this work, the application of laser shock processing (LSP) technology to bioabsorbable magnesium is presented for the specificcase of a commercially pure Mg and a Mg-1Zn alloy. Zinc as an alloying element has the capability of enhancing the corrosion resistance and the mechanical properties of magnesium. Our aim is to relate the possible generated subsurface residual stresses, together with the modification of the surface microstructure, the modification of corrosion behaviour, the adhesion and viability of a strain of Staphylococcus epidermidis, which is one of the main bacteria present in nosocomial implant related infections and the specific effects of the inclusion of 1 wt% Zn in solid solution on LSP Mg.
