Constructing fluorine-doped Zr-MOF films on titanium for antibacteria, anti-inflammation, and osteogenesis

Implant infection, undesirable inflammation, and poor osseointegration are the primary reasons for implant failure, so it is pivotal to endow bone implants with antibacterial, anti-inflammatory, and osteogenic properties. Here, a multifunctional fluorine-doped zirconium-metal organic framework (Zr-MOF) film was constructed on the titanium to modify its biological performances. The fumaric acid, a common antioxidant, was selected as the ligand of Zr-MOF, and the hydrofluoric acid was used as the modulator to control the growth of Zr-MOF film. The obtained fluorine-doped Zr-MOF film possessed good biocompatibility and osteogenic ability, and it showed good antibacterial effects against both gram-positive S. aureus and gram-negative E. coli due to the release of fluoride ions. In addition, the doping of fluorine could reduce the stability of Zr-MOF by substituting fumaric acid, and stimulating the releases of fumaric acid. Furthermore, the fumaric acid released from Zr-MOF could down-regulate the expression of pro-inflammatory genes (NF-κB and IL-6), but up-regulate the expression of anti-inflammatory gene of IL-4 of macrophage, showing good anti-inflammatory ability. This study provided a reference for the modulation synthesis of MOF film, and proposed a promising strategy of designing Zr-MOF film to endow bone implants with antibacterial, anti-inflammatory, and osteogenic abilities.