Pulsed laser deposition of copper and zinc doped hydroxyapatite coatings for biomedical applications

Abstract

Research on biomaterials which promote osseointegration and reduce bacterial colonization is of great interest because of their potential to enhance metal prostheses for the repair or regeneration of critically damaged or fractured bone. Hydroxyapatite (HA) coatings doped with copper (Cu) and zinc (Zn) emerge as good candidates for this purpose since both elements are parts of the biological metabolism and exhibit antibacterial properties. Two series of Cu-HA and Zn-HA coatings with different concentrations were fabricated by pulsed laser deposition (PLD). Their physicochemical characterization, performed by fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS), revealed typical apatite growth in globular aggregates and demonstrated the efficient incorporation of Cu and Zn into the HA coatings. Using the MC3T3-E1 pre-osteoblast cell line, the evaluation of the biological response showed proper cell proliferation and osteogenic activity, confirmed respectively by the MTT test and the alkaline phosphatase quantification. Cu and Zn doping adds antibacterial properties to the coating, resulting in significant reductions of Escherichia colt and Staphylococcus aureus biofilms. In conclusion, this study advances that either Cu-HA or Zn-HA materials offer promising alternatives to be used in metallic prostheses for the repair or regeneration of critically damaged or fractured bone tissue.