3D printed TC4 titanium alloy bone scaffolds with TNTs-VA-PLGA composite coating on the surface: Improved infection resistance and biocompatibility

Titanium-based bone scaffolds are prone to aseptic infection and loosening after implantation,which seriously limits their clinical applications. Preparation of titanium dioxide nanotubes (TNTs) on the surface of the scaffolds and loading of anti-infective drugs is an effective method to solve this problem, but the current TNTs prepared on the surface of titanium-based scaffolds have a high internal and external variability in morphology and low drug loading capacity. In this study, we prepared TNTs on the surface of three kinds of TC4 titanium alloy scaffolds with TPMS structure with controllable morphology, tube diameter of 90–125 nm and tube length of 14–35 μm,and the difference between inner and outer diameters of the tubes was less than 2 μm,and the drug released from the composite scaffolds was maintained at a concentration of more than 1.5 μg/ml within 11 days after loading anti-infective drug Vancomycin-polylactic acid-hydroxyacetic acid copolymer(VA-PLGA) on the surface of the TNTs. Based on the simulation of drug release, the TNTs-VA-PLGA drug delivery system conforms to the Korsmeyer-Peppas model. Cell experiments confirmed that the composite scaffolds significantly increased cell proliferation by 65.33 % compared with the unmodified scaffolds. The results indicated that the TNTs coating containing vancomycin and polylactic acid-hydroxyacetic acid copolymer had a promising application in orthopedic implants.