Innovative micro-textured hydroxyapatite and poly(L-lactic)-acid polymer composite film as a flexible, corrosion resistant, biocompatible, and bioactive coating for Mg implants

The utility of a novel ceramic/polymer-composite coating with a micro-textured microstructure that would significantly enhance the functions of biodegradable Mg implants is demonstrated here. To accomplish this, bioactive hydroxyapatite (HA) micro-dots can be created by immersing a Mg implant with a micro-patterned photoresist surface in an aqueous solution containing calcium and phosphate ions. The HA micro-dots can then be surrounded by a flexible poly(t-lactic)-acid (PLLA) polymer using spin coating to form a HA/PLLA micro-textured coating layer. The HA/PLEA micro-textured coating layer showed an excellent corrosion resistance when it was immersed in a simulated body fluid (SBF) solution and good biocompatibility, which was assessed by in vitro cell tests. In addition, the HA/PLEA micro-textured coating layer had high deformation ability, where no apparent changes in the coating layer were observed even after a 5% elongation, which would be unobtainable using HA and PLEA coating layers; furthermore, this allowed the mechanically-strained Mg implant with the HA/PLIA micro-textured coating layer to preserve its excellent corrosion resistance and biocompatibility in vitro. (C) 2017 Elsevier B.V. All rights reserved.