Department of Life Sciences, University of Trieste, Via Licio Giorgieri 5, Trieste, I-34127, Italy.
Department of Medicine, Surgery and Health Sciences, University of Trieste, Piazza dell'Ospitale 1, Trieste, I-34129, Italy.
Macromol Biosci. 2020 Dec;20(12):e2000236. doi: 10.1002/mabi.202000236. Epub 2020 Sep 25.
Mounting evidences have recognized that dual cross-link and double-network gels can promisingly recapitulate the complex living tissue architecture and overcome mechanical limitations of conventional scaffolds used hitherto in regenerative medicine. Here, dual cross-link gels formed of a bioactive lactose-modified chitosan reticulated via both temporary (boric acid-based) and permanent (genipin-based) cross-linkers are reported. While boric acid rapidly binds to lactitol flanking diols increasing the overall viscosity, a slow temperature-driven genipin binding process takes place allowing for network strengthening. Combination of frequency and stress sweep experiments in the linear stress-strain region shows that ultimate gel strength, toughness, and viscoelasticity depend on polymer-to-genipin molar ratio. Notably, herewith it is demonstrated that linear stretching correlates with strain energy dissipation through boric acid binding/unbinding dynamics. Strain-hardening effect in the nonlinear regime, along with good biocompatibility in vitro, points at an interesting role of present system as biological extracellular matrix substitute.
越来越多的证据表明，双交联和双网络凝胶可以很好地再现复杂的活体组织结构，并克服再生医学中迄今为止使用的传统支架的机械限制。本文报道了一种由生物活性乳糖修饰壳聚糖通过临时（硼酸基）和永久（京尼平基）交联剂形成的双交联凝胶。虽然硼酸迅速与乳糖醇配位，增加了二醇的整体粘度，但缓慢的温度驱动的京尼平结合过程允许网络加强。在线性应力-应变区进行频率和应力扫描实验的组合表明，最终凝胶强度、韧性和粘弹性取决于聚合物与京尼平的摩尔比。值得注意的是，本文证明了线性拉伸与通过硼酸结合/解吸动力学的应变能耗散有关。非线性区的应变硬化效应以及体外良好的生物相容性表明，该体系在作为生物细胞外基质替代物方面具有重要作用。
