Myricetin-loaded ZIF-8 improves dentin bonding durability via antibacterial activity, collagen stabilization and MMP inhibition.

OBJECTIVES: This study aimed to develop a myricetin-loaded ZIF-8 (Myr@ZIF-8)-modified universal adhesive with antibacterial, collagen-stabilizing, and matrix metalloproteinase (MMP)-inhibitory properties to improve bonding durability. METHODS: Myr@ZIF-8 nanoparticles were synthesized and characterized. Myr loading efficiency, drug loading, and pH-responsive release were evaluated. Myr@ZIF-8 was incorporated into a universal adhesive at 2.5-10 wt%, and the optimal concentration was selected according to degree of conversion, dentin wettability, and antibiofilm activity. Dentin collagen stability, MMP-mediated gelatinolytic activity, microtensile bond strength (μTBS), interfacial nanoleakage, interfacial mechanical properties, and in vitro cytocompatibility were evaluated. Short-term systemic toxicity was preliminarily assessed by oral gavage of cured adhesive extracts. Molecular docking was performed to investigate potential interactions between myricetin and collagen, MMP-2, and MMP-9. RESULTS: Myr@ZIF-8 exhibited a Myr loading efficiency of 50.72%, drug loading of 50.36%, and pH-responsive release. The adhesive containing 5 wt% Myr@ZIF-8 showed the best overall performance, including enhanced antibiofilm activity, improved collagen stability, and reduced MMP-mediated gelatinolytic activity. Incorporation of 5 wt% Myr@ZIF-8 increased immediate μTBS from 22.79 MPa to 32.07 MPa and aged μTBS after 10,000 thermocycles from 13.91 MPa to 27.99 MPa. Molecular docking predicted potential interactions between myricetin and collagen, MMP-2, and MMP-9. The modified adhesive showed acceptable in vitro cytocompatibility, with no obvious short-term systemic toxicity after oral gavage of cured adhesive extracts. SIGNIFICANCE: These findings demonstrate that Myr@ZIF-8 functions as a multifunctional bioactive nanoplatform and represents a promising strategy for improving bonding durability.