Controlled-release of cinnamaldehyde from MXene/ZIF8/gelatin composite coatings: An integrated strategy to combat implant-associated infection.

Infections and chronic inflammation surrounding titanium implants frequently impair angiogenesis and osseointegration, substantially heightening the risk of implant failure. In this study, titanium dioxide nanotube arrays (TN) were fabricated on titanium metal substrates to serve as reservoirs for cinnamaldehyde (CA). Subsequently, MXene and ZIF-8 were deposited onto the TN surface to seal the nanotube pores. Finally, the gelatin methacrylate (GelMA) hydrogel system was utilized as a nanoparticle-controlled release platform to construct the Gel@MX-ZIF8/CA functional integrated coating. The results demonstrated that the Gel@MX-ZIF8/CA coating exhibited optimized roughness, improved hydrophilicity, and superior bioactivity. Furthermore, the Gel@MX-ZIF8/CA coating exhibited robust antibacterial efficacy against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). At the cellular and molecular levels, Gel@MX-ZIF8/CA modulated mouse macrophage cells (RAW264.7) polarization toward the M2 phenotype, enhanced human umbilical vein endothelial cell (HUVEC) angiogenesis, and facilitated the osteogenic differentiation of mouse embryo osteoblast precursor cell (MC3T3-E1). In vivo studies using a rat bone defect model highlighted the coating's strong anti-inflammatory, antibacterial, angiogenic, and osteogenic capabilities of Gel@MX-ZIF8/CA. Additionally, Gel@MX-ZIF8/CA exhibited excellent blood compatibility and biosafety. In conclusion, the Gel@MX-ZIF8/CA coating integrated multiple advantages, offering significant potential in addressing orthopedic implant-associated infections and bone defects.