Surface morphology-regulated tissue adhesion in solid and mesoporous silica-reinforced gelatin nanocomposite...

Traditional wound closure methods often induce clinical complications such as pain and scarring, driving the urgent need for alternative bioadhesives that can seamlessly integrate robust mechanical integrity with superior wet-tissue adhesion. Herein, we address this by rationally designing a nanocomposite hydrogel platform, where silica nanoparticles with distinct surface architectures (dense dSiO₂vs. mesoporous MSNs) are incorporated into a Zn²⁺-coordinated, tannic acid-modified gelatin network. The influence of the surface morphology of silica nanoparticles on polymer-filler interactions, network mechanics, and adhesive performance was systematically investigated. The results reveal that nanosilica morphology plays a decisive role in regulating hydrogel performance. In particular, MSN-containing hydrogels (GZC) exhibited markedly enhanced tissue adhesion, reaching values of up to 40 kPa, which is significantly higher than those obtained using dSiO₂. This enhancement is attributed to the mesoporous architecture of MSNs, which promotes an increased interfacial contact area and mechanical interlocking between gelatin chains and the silica framework, thereby facilitating efficient stress transfer within the polymer network. In addition, the incorporation of TA and Zn²⁺ endowed the hydrogel with antioxidant and antibacterial functionalities while maintaining favorable cytocompatibility and promoting fibroblast migration. The optimized GZC hydrogel further demonstrated effective hemostatic performance and accelerated wound closure in an in vivo model, supporting the functional relevance of the polymeric system. Overall, this study elucidates the influence of nanosilica morphology on the structure-property relationships governing adhesion in gelatin nanocomposite hydrogels and provides insights for the rational design of functional polymer hydrogels with improved adhesive performance.