Antibacterial and biocompatible Zn and Cu containing CaP magnetron coatings for MgCa alloy functionalization

The application of bioresorbable magnesium-based alloys in medical implants has been limited by their rapid dissolution rate. In order to enhance their suitability for medical use, this study proposes the deposition of calcium phosphate (CaP) onto Mg (0.8) Ca alloy using an RF magnetron sputtering with stoichiometric hydroxyapatite and Zn- or Cu-substituted hydroxyapatites. The comparison study assessed structure, composition, and mechanical properties of Mg (0.8) Ca alloy, Zn, and Cu containing CaP coatings. CaP coatings showed an increased Ca/P ratio due to re-sputtering. Sputtering of Zn- and Cu-substituted hydroxyapatites resulted in CaP dopant concentrations of 0.6 +/- 0.2 wt% and 0.4 +/- 0.1 wt%, respectively. All deposited coatings were found to be amorphous. Addition of Cu or Zn dopant slightly changed the CaP coatings' scratch resistance, with critical loads of 2.19 +/- 0.60 N, 2.55 +/- 0.95 N, and 2.76 +/- 1.29 N for CaP, ZneCaP, and CueCaP coatings, respectively. CaP coatings reduced corrosion current and increased electrical resistance compared to MgCa samples, but Cu addition accelerated corrosion. Biological tests revealed that the hAMSCs survival was improved and the bacteriostatic effect on the pathogenic SA strain was enhanced for ZneCaP coatings when compared to CaP and CueCaP coatings. These findings suggest that the deposition of CaP coatings onto Mg (0.8) Ca alloy, and particularly the use of Zn-substituted hydroxyapatites, could be a promising approach to enhance the suitability of magnesium-based alloys for medical implant applications. (c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).