Enhancing bioactivity and stability of polymer-based materialtissue interface through coupling multiscale interfacial interactions with atomic-thin TiO2 nanosheets

Stable and bioactive material-tissue interface(MTF)basically determines the clinical applications of biomaterials in wound healing,sustained drug release,and tissue engineering.Although many inorganic nanomaterials have been widely explored to enhance the stability and bioactivity of polymer-based biomaterials,most are still restricted by their stability and biocompatibility.Here we demonstrate the enhanced bioactivity and stability of polymer-matrix bio-composite through coupling multiscale material-tissue interfacial interactions with atomically thin TiO_(2)nanosheets.Resin modified with TiO_(2)nanosheets displays improved mechanical properties,hydrophilicity,and stability.Also,we confirm that this resin can effectively stimulate the adhesion,proliferation,and differentiation into osteogenic and odontogenic lineages of human dental pulp stem cells using in vitro cell-resin interface model.TiO_(2)nanosheets can also enhance the interaction between demineralized dentinal collagen and resin.Our results suggest an approach to effectively up-regulate the stability and bioactivity of MTFs by designing biocompatible materials at the sub-nanoscale.

A novel dentin bonding scheme based on extrafibrillar demineralization combined with covalent adhesion using a dry-bonding technique

Dentin bonding is a dynamic process that involves the penetration of adhesive resin monomers into the extrafibrillar and intrafibrillar demineralized collagen matrix using a wet-bonding technique.However,adhesive resin monomers lack the capacity to infiltrate the intrafibrillar space,and the excess water that is introduced by the wet-bonding technique remains at the bonding interface.This imperfectly bonded interface is inclined to hydrolytic degradation,severely jeopardizing the longevity of bonded clinical restorations.The present study introduces a dentin bonding scheme based on a dry-bonding technique,combined with the use of extrafibrillar demineralization and a collagen-reactive monomer(CRM)-based adhesive(CBA).Selective extrafibrillar demineralization was achieved using 1-wt%high-molecular weight(MW)carboxymethyl chitosan(CMCS)within a clinically acceptable timeframe to create a less aggressive bonding substance for dentin bonding due to its selectively extrafibrillar demineralization capacity.CMCS demineralization decreased the activation of in situ collagenase,improved the shrinking resistance of demineralized collagen,and thus provided stronger and more durable bonding than traditional phosphoric acid etching.The new dentin bonding scheme that contained CMCS and CBA and used a dry-bonding technique achieved an encouraging dentin bonding strength and durability with low technical sensitivity.This bonding scheme can be used to improve the stability of the resin-dentin interface and foster the longevity of bonded clinical restorations.