Iron Ion-Doped Tricalcium Phosphate Coatings Improve the Properties of Biodegradable Magnesium Alloys for Biomedical Implant Application

Iron-substituted tricalcium phosphate (Fe-TCP) (about 1 wt%) coatings are deposited on biodegradable Mg-Ca alloys to improve their corrosion resistance. Pulsed laser deposition technique is used for coating preparation. The 2 µm thick coatings are uniformly deposited. (Ca+Fe)/P ratio for the Fe-TCP coatings is close to the stoichiometric value. Coated and uncoated Mg-Ca alloys are subjected to electrochemical tests to investigate the influence of the coatings on their corrosion resistance in simulated body fluid (SBF). Tafel curves corresponding to coated and uncoated Mg-Ca alloy samples in SBF show that the most electropositive corrosion potential is reached for the Fe-TCP-coated Mg-Ca deposited at 300 °C. From the obtained and calculated values of the electrochemical parameters it follows that this sample possesses the best characteristics: it has the smallest porosity and the highest protective efficiency in SBF. Equine adipose tissue-derived mesenchymal stem cells are used for 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test and osteogenic differentiation study. Microbiology tests are performed with Escherichia coli (E. coli) (Gram−) and Staphylococcus aureus (Gram+) bacteria strains. The Fe-TCP-coated Mg-Ca deposited at 300 °C is characterized by the best cytocompatibility and good ability to inhibit the growth of E. coli and is recommended for biomedical implant applications.