Mof-Coated Clear Aligners: Preparation And Comprehensive Performance Evaluation

Aim or purpose: To develop three metal-organic framework (MOF) coatings (Ag-, Cu-, Ce-TCPP) for clear aligners using Ag(I), Cu(II), Ce(III), and TCPP, and compare their antibacterial/anti-inflammatory efficacy, biocompatibility, and physical properties. Materials and methods: MOFs were synthesized via metal coordination with TCPP. Morphology, elemental distribution, crystallinity, and coordination bonds were analyzed via SEM, EDS, PXRD, and FTIR. MOF-coated aligners were prepared via spin-coating. Metal ion release kinetics were assessed using ICP-OES/MS. Antibacterial activity was evaluated via agar diffusion (ZOI), broth dilution (MIC/MBC), and crystal violet biofilm assays. Bacterial membrane damage and biofilm viability were studied using SEM and CLSM. Biocompatibility was tested via HGF/HOK cell proliferation, hemolysis, live/dead staining, and cytoskeleton imaging. Macrophage polarization (RAW264.7) was analyzed via immunofluorescence and flow cytometry. Mechanical (tear strength, modulus) and aesthetic properties (transparency, haze, hydrophilicity, roughness) were assessed. Results: Ag/Cu/Ce-TCPP MOFs exhibited sustained metal ion release. Ag-TCPP demonstrated superior antibacterial/antibiofilm activity and enhanced M1-to-M2 macrophage polarization, while all coatings maintained biocompatibility (no cytotoxicity/hemolysis). Coated aligners retained mechanical integrity and aesthetic/physical properties comparable to uncoated controls. Conclusions: Ag-TCPP MOF-coated aligners outperformed Cu/Ce-TCPP in antibacterial efficacy and immunomodulation, with excellent biocompatibility and minimal impact on aligner performance, providing a promising strategy for clinical applications.