The dentin collagen scaffold is fundamentally involved in the adhesion of resin-based restorative materials to the tooth. Intrinsic degradation of the collagen scaffold, originating from beneath the resin-dentin interface, remains a core problem in adhesive dentistry, limiting the service life of dental restorations. Objectives. This research intends to exploit the use of emergent multi-functional materials termed metal-organic frameworks (MOFs) - which are formed by the self-assembly of metal ions and organic building blocks - in the preservation of the collagen integrity in demineralized dentin matrices. Inspired by recent applications of MOFs at the biointerface, we posit that collagen fibrils (from demineralized human dentin) can induce the biomimetic mineralization of MOF crystals as protective coatings to stabilize and strengthen the bare fibrils. The purpose of the biomimetically mineralized MOF coating is to afford enhanced mechanical behavior and biostability to the dentin collagen scaffold, positively affecting the longevity of the resin-dentin bonds. Methods. Zeolitic imidazolate framework-8 (ZIF-8), a zinc-based microporous MOF, is selected as a candidate material for this study due to its remarkable chemical stability under physiological conditions and good biocompatibility. Besides, ZIF-8 has been used as protective coating for different biomacromolecules before. Collagen scaffolds (obtained by acid etching of precut dentin samples) will be incubated individually in aqueous solutions containing the typical building blocks for growing ZIF-8 crystals. The formation of protective MOF coatings relies on the affinity of the fibrillar protein toward the MOF precursors. The collagen fibrils modified with ZIF-8 coating will be characterized with respect to their morphology, mechanical/nano-mechanical behavior and biostability against enzymatic challenges with collagenases. Expected outcomes. We hope to identify a potential biomedical application of biomimetically mineralized protective MOFs in the stabilization/repair of tissues that are key for the service life of modern dental restorations.
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