The oral delivery of macromolecular therapeutics to the intestinal tract requires novel, robust, and controlled formulations. Here, we report on fabrication by molding of composite hydrogel cylinders made of cellulose nanocrystals (CNCs) and chitosan (Cht) and their performance as delivery vehicles. CNCs provide excellent mechanical and chemical stress resistance, whereas Cht allows scaffold degradation by enzyme digestion. The release of a representative medium size protein (bovine serum albumin) dispersed in the hydrogel is slow and shows a sigmoidal profile; meanwhile, the hydrogel scaffold degrades according to a preferred route, that is the cylinder is eroded along the vertical axis. The cup‐like, scarcely interconnected porous network, with a gradient of hardness along the cylinder axis, and the compact skin‐like layer covering the lateral wall which stayed in contact with the mold during gelification, explain the preferred erosion direction and the long‐term protein release. The possible effect of the molding process on hydrogel structure suggests that molding could be a simple and cheap way to favor surface compaction and directional scaffold degradation.

中文翻译：

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具有空间定向降解和大分子延迟释放的复合纳米纤维素基水凝胶。

将大分子治疗剂口服递送至肠道需要新颖、稳健且可控的制剂。在这里，我们报告了由纤维素纳米晶体 (CNCs) 和壳聚糖 (Cht) 制成的复合水凝胶圆柱体的成型及其作为运载工具的性能。CNCs 提供出色的机械和化学应力耐受性，而 Cht 允许通过酶消化降解支架。分散在水凝胶中的代表性中等大小蛋白质（牛血清白蛋白）的释放缓慢且呈 S 形曲线；同时，水凝胶支架按照优选的路线降解，即圆柱体沿垂直轴被侵蚀。杯状，几乎不互连的多孔网络，沿圆柱轴具有硬度梯度，和覆盖在侧壁上的致密类皮层在凝胶化过程中与霉菌保持接触，解释了优选的侵蚀方向和长期的蛋白质释放。成型工艺对水凝胶结构的可能影响表明，成型可能是一种有利于表面压实和定向支架降解的简单且廉价的方法。