Enhanced antimicrobial properties and bioactivity of 3D-printed titanium scaffolds by multilayer bioceramic coating for large bone defects

The restoration of large bone defects caused by trauma, tumor resection, or infection is a major clinical problem in orthopedics and dentistry because postoperative infections, corrosion, and limited osteointegration of metal implants can lead to loosening of the implant. The aim of this study was to improve the surface properties of a 3D-printed (electron beam melting) Ti6Al4V-based macroporous scaffold by multilayer coating with bioactive silicate glasses (BAGs) and hydroxyapatite doped with a silver (AgHAP) or AgHAP additionally sonochemically modified with ZnO (ZnO-AgHAP). The coated scaffolds AgHAP_BAGs_Ti and ZnO-AgHAP_BAGs_Ti enhanced cytocompatibility in L929 and MRC5 cell lines and expressed bioactivity in simulated body fluid. A lower release of vanadium ions in coated samples compared to bare Ti scaffold indicates decreased dissolution of Ti alloy in coated samples. The coated samples reduced growth of Escherichia coli and Staphylococcus aureus for 4-6 orders of magnitude. Therefore, the 3D-printed Ti-based scaffolds coated with BAGs and (ZnO-)AgHAP have great potential for application as a multifunctional implant with antibacterial properties for the restoration of defects in load-bearing bones.