Hierarchical architecture of bacterial cellulose and composite plant cell wall polysaccharide hydrogels using small angle neutron scattering
Hierarchical architecture of bacterial cellulose and composite plant cell wall polysaccharide hydrogels using small angle neutron scattering
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DOI：
10.1039/c5sm02085a
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发表时间：
2016-01-01
期刊：
影响因子：
3.4
通讯作者：
Gilbert, Elliot P.
中科院分区：
文献类型：
--
作者：
Martinez-Sanz, Marta;Gidley, Michael J.;Gilbert, Elliot P.
小角中子散射（SANS）已被应用于表征纯细菌纤维素水凝胶的结构，及其复合材料，与两种植物细胞壁多糖（阿拉伯木聚糖和木葡聚糖）。传统的已发表模型假设细菌纤维素带是固体单相系统，无法充分描述纯细菌纤维素的SANS数据。拟合的中子散射曲线，而不是表明，子结构的纤维素微纤维内的丝带的结果在创建的区域具有不同的值的中子散射长度密度，当水凝胶进行H2O/D2 O交换。这可以在核-壳形式主义内表示，该核-壳形式主义认为纤维素带包括含有被次晶纤维素和紧密结合的水的网络包围的不可渗透的微晶的核，以及仅含有次晶纤维素和水的壳。因此，一个拟合函数，包括一个幂律项的总和，以占大规模结构的交织带，加上一个核-壳圆柱体与多分散半径，已被应用;它被证明同时描述所有SANS对比度变化数据的纯和复合细菌纤维素水凝胶。此外，得到的拟合参数表明不同的相互作用机制的阿拉伯木聚糖和木葡聚糖与纤维素，揭示了这种方法的潜力，以调查不同的植物细胞壁多糖的纤维素的生物合成过程中的作用。
Small angle neutron scattering (SANS) has been applied to characterise the structure of pure bacterial cellulose hydrogels, and composites thereof, with two plant cell wall polysaccharides (arabinoxylan and xyloglucan). Conventional published models, which assume that bacterial cellulose ribbons are solid one-phase systems, fail to adequately describe the SANS data of pure bacterial cellulose. Fitting of the neutron scattering profiles instead suggests that the sub-structure of cellulose microfibrils contained within the ribbons results in the creation of regions with distinct values of neutron scattering length density, when the hydrogels are subjected to H2O/D2O exchange. This may be represented within a core-shell formalism that considers the cellulose ribbons to comprise a core containing impermeable crystallites surrounded by a network of paracrystalline cellulose and tightly bound water, and a shell containing only paracrystalline cellulose and water. Accordingly, a fitting function comprising the sum of a power-law term to account for the large scale structure of intertwined ribbons, plus a core-shell cylinder with polydisperse radius, has been applied; it is demonstrated to simultaneously describe all SANS contrast variation data of pure and composite bacterial cellulose hydrogels. In addition, the resultant fitting parameters indicate distinct interaction mechanisms of arabinoxylan and xyloglucan with cellulose, revealing the potential of this approach to investigate the role of different plant cell wall polysaccharides on the biosynthesis process of cellulose.