Polydopamine-assisted functionalization of heparin and vancomycin onto microarc-oxidized 3D printed porous Ti6Al4V for improved hemocompatibility, osteogenic and anti-infection potencies

Enhanced antiinfection activities, improved hemocompatibility and osteo-compatibility, and reinforced osseointegration are among the most important considerations in designing multifunctional orthopedic biomaterials. Hereby, anti-infective and osteogenic multifunctional 3D printed porous Ti6Al4V implant with excellent hemocompatibility was successfully designed and fabricated. In brief, osteogenic micro-arc oxidation (MAO) coatings with micro/nanoscale porous topography were generated in situ on 3D printed Ti6Al4V scaffolds, on which heparin and vancomycin were easily immobilized. The surface microstructure, morphology, and chemical compositions were characterized employing scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). High loading capacity and sustained vancomycin release profiles were revealed using high performance liquid chromatography (HPLC). Favorable antibacterial and antibiofilm performances against pathogenic Staphylococcus aureus (S. aureus) were validated in vitro through microbial viability assays, Live/Dead bacterial staining, and crystal violet staining. Human mesenchymal stem cells (hMSCs) were seeded on the scaffolds and their proliferation and viability were assessed using Cell Counting Kit and Live/Dead cell viability kit. Further, osteoblastic differentiation abilities were evaluated using alkaline phosphatase (ALP) activity as a hall marker. Additionally, the improved hemocompatibility of the heparinized scaffolds was confirmed by activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT). Overall, our results show that the surface-modified 3D printed porous Ti6Al4V possesses balanced antibacterial and osteogenic functions while exhibiting extra anticlotting effects, boding well for future application in customized functional reconstruction of intricate bone defects.