Materials based on renewable biopolymers, selective permeability and stimuli-responsive release/loading properties play an important role in biomedical applications. Here, in order to mimic the plant primary cell-wall, microcapsules have been fabricated using cell wall polysaccharides, namely pectin, xyloglucan and cellulose nanofibers. For the first time, a large amount of xyloglucan was successfully included in such capsules. These capsules demonstrated stimuli-responsive (ON/OFF) permeability and biocompatibility. The live cell staining revealed that the microcapsules’ surface enhanced cell growth and also the non-toxic nature of the microcapsules. In water, the microcapsules were completely and partially permeable to fluorescent dextrans with an average molecular weight of 70 kDa (hydrodynamic diameter of ca. 12 nm) and 2000 kDa (ca. 54 nm), respectively. On the other hand, the permeability dropped quickly when the capsules were exposed to 250 mM NaCl solution, trapping a fraction of the 70 kDa dextrans in the capsule interior. The decrease in permeability was a direct consequence of the capsule-wall composition, i.e. the presence of xyloglucan and a low amount of charged molecules such as pectin. The low permeability of capsules in saline conditions (and in a model biological medium), combined with a capsule wall that is made from dietary fibers only, potentially enables their use in biological applications, such as colon targeted delivery in the gastro-intestinal tract.

Statement of Significance:

For the first time, microcapsules have been prepared that possess capsule walls that mimic the primary cell wall found in natural plant cells. The capsules were assembled using pectin, xyloglucan and cellulose in the form of cellulose nanofibers. The capsules demonstrated stimuli-responsive (ON/OFF) permeability and biocompatibility. The low permeability of capsules in saline conditions (and in a model biological medium), combined with a capsule wall that is made from dietary fibers only, potentially enables their use in biological applications, such as colon targeted delivery in the gastro-intestinal tract. Such model plant cell capsules might also further improve the understanding for the digestion and release of nutrients from natural plant cells found in vegetables and fruits.

中文翻译：

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基于纳米纤维素，木葡聚糖和果胶的生物启发胶囊-胶囊壁成分对通透性的影响

基于可再生生物聚合物，选择性渗透性和刺激性释放/负载特性的材料在生物医学应用中起着重要作用。在这里，为了模拟植物的原代细胞壁，已经使用细胞壁多糖即果胶，木葡聚糖和纤维素纳米纤维制备了微胶囊。首次成功地将大量木葡聚糖包含在这种胶囊中。这些胶囊表现出刺激反应性（ON / OFF）通透性和生物相容性。活细胞染色表明，微囊的表面增强了细胞的生长，并增强了微囊的无毒性质。在水中，微胶囊对荧光葡聚糖具有完全和部分渗透性，其平均分子量为70 kDa（流体动力学直径约为12 nm）和2000 kDa（约54 nm），分别。另一方面，当将胶囊暴露于250 mM NaCl溶液中时，通透性迅速下降，从而将一部分70 kDa葡聚糖捕获在胶囊内部。渗透性的降低是胶囊-壁组合物的直接结果，即木葡聚糖的存在和少量带电分子如果胶。胶囊在盐水条件下（以及在典型的生物介质中）的低渗透性，再加上仅由膳食纤维制成的胶囊壁，有可能使其在生物学应用中使用，例如在胃肠道中靶向结肠递送。渗透性的降低是胶囊-壁组合物的直接结果，即存在木葡聚糖和少量带电分子如果胶。胶囊在盐水条件下（以及在典型的生物介质中）的低渗透性，再加上仅由膳食纤维制成的胶囊壁，有可能使其在生物学应用中使用，例如在胃肠道中靶向结肠递送。渗透性的降低是胶囊-壁组合物的直接结果，即木葡聚糖的存在和少量带电分子如果胶。胶囊在盐水条件下（以及在典型的生物介质中）的低渗透性，再加上仅由膳食纤维制成的胶囊壁，有可能使其在生物学应用中使用，例如在胃肠道中靶向结肠递送。

重要声明：

首次制备了具有模拟天然植物细胞中原代细胞壁的囊壁的微胶囊。使用果胶，木葡聚糖和纤维素纳米纤维形式的纤维素组装胶囊。胶囊表现出刺激反应性（ON / OFF）通透性和生物相容性。胶囊在盐水条件下（以及在典型的生物介质中）的低渗透性，再加上仅由膳食纤维制成的胶囊壁，有可能使其在生物学应用中使用，例如在胃肠道中靶向结肠递送。这种模型植物细胞胶囊还可以进一步增进人们对从蔬菜和水果中发现的天然植物细胞中营养物质的消化和释放的理解。