Surface Modification of AZ31 Mg Alloy Based on PLA or PLGA with Caffeic Acid for Bioengineering Applications

The study is focused on the technology for surface modification of AZ31 magnesium alloy for biomedical applications, in particular in implantology. The experimental procedure consists of intentional stages that involve chemical treatment in piranha solution, plasma chemical activation of the alloy surface using Ar and O2 as gaseous precursors, and biopolymer coatings deposition—based on polylactic acid (PLA) and poly(lactic-co-glycolic acid) (PLGA) with the addition of caffeic acid—utilizing the immersion method. In the course of the experiment, the validity of the investigated technology of surface modification of AZ31 magnesium alloy was confirmed. The pre-treatment step guaranteed obtaining a higher surface roughness, resulting in homogeneous and stable biopolymer coatings with proper adhesion to the substrate. Moreover, the corrosion studies conducted confirmed better corrosion behaviour of the modified samples in SBF corrosive medium, and no significant release of the alloy-related ions was observed. Furthermore, the biopolymer coatings ensured non-cytotoxicity towards the MG-63 cell line and promoted cell proliferation with proper morphology. Based on the obtained results, it may be concluded that the proposed technology can be treated as an interesting and promising surface-engineering strategy for implantology and biodegradable materials applications.