Enhancing Titanium-Osteointegration: Antimicrobial, anti-inflammatory and osteogenic properties of multifunctional coatings through Layer-by-Layer Self-Assembly

Titanium metal-based bone defect healing demands a balance between antimicrobial and osseointegration processes. The development of functionally integrated titanium surfaces possessing antimicrobial, antiinflammatory, and pro-angiogenic/osteogenic qualities is of great significance. In this study, a novel approach was adopted where graphene oxide (GO), copper (Cu), and antimicrobial peptide (KR12) were loaded onto titanium surfaces with titanium dioxide nanorods (TN) structures to fabricate multifunctional coatings with multilayer "sandwich" structures, termed PGK-CuTN. The PGK-CuTN coating exhibited excellent mechanical properties, hydrophilicity, corrosion resistance, and bioactivity. In vitro, it effectively inhibited E. coli and S. aureus, with inhibition rates of approximately 63.22 % and 77.79 %, respectively. Cellular experiments on the PGK-CuTN surface demonstrated that RAW264.7 (in terms of polarization), HUVEC (regarding vasculogenesis), and MC3T3-E1 (for osteogenesis) displayed favorable adhesion and proliferation activities. At the molecular level, PGK-CuTN could direct RAW264.7 polarization towards the M2-type, enhance HUVEC migration and vascularization, and promote MC3T3-E1 differentiation into osteogenesis. In the in vivo bone defect model, the PGK-CuTN coating manifested potent anti-inflammatory, antibacterial, and bone-repair capabilities. Additionally, it exhibited remarkable biosafety and hemocompatibility. Overall, the PGK-CuTN coating integrates antibacterial, anti-inflammatory, angiogenic, and osteogenic functions, holding great promise for the treatment of infected bone defects.