Mitani Chizu, Okajima Maiko, Ohashira Tomomi, Ali Mohammad Asif, Taniike Toshiaki, Kaneko Tatsuo
Graduate School of Advanced Science and Technology, JAIST, Nomi 923-1292, Japan.
Key Laboratory of Synthetic and Biological Colloids, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China.
Gels. 2024 May 7;10(5):321. doi: 10.3390/gels10050321.
Sacran is a supergiant cyanobacterial polysaccharide that forms mesogenic supercoil rods that exhibit liquid crystalline (LC) gels at deficient concentrations of around 0.5 wt%, and has several bioactive stimuli-responsive functions. Here, we attempted to form oriented microfibers of sacran by electrospinning, following structural analyses of the sacran rods. A heterogeneous acid-hydrolysis method using a protonated cation-exchange resin was adopted to examine the short-time exposition of concentrated acid to sacran rods. From the supernatant, the oligomeric fraction that was soluble in water and methanol was isolated. The oligomeric fraction had a main sugar ratio of -Glc:-Glc:-Xyl:-Xyl:-Rha of 2:5:1.5:1.5:4 (Glc:Xyl:Rha = 7 (=4 + 3):3:4), and it was speculated that the sacran structure includes rhamnoglucan and xyloglucan (4:3), which are generally rigid enough to exhibit LC. To make oriented microfibers of LC sacran, solubility testing was performed on sacran to find good new solvents of polyhydroxy alcohols such as ethylene glycol, 1,2-propanediol, and glycerol. The oriented film was prepared from a sacran aqueous solution where calcium compound particles deposited on the film are different from polyhydroxy alcohol solutions. Although sacran could not form microfibers by itself, polymer composite microfibers of sacran with poly(vinyl alcohol) were prepared by electrospinning. Cross-polarizing microscopy revealed the molecular orientation of the microfibers.
Sacran是一种超巨型蓝细菌多糖，它形成介晶超螺旋棒，在约0.5 wt%的低浓度下呈现液晶（LC）凝胶，并且具有多种生物活性刺激响应功能。在此，我们在对Sacran棒进行结构分析之后，尝试通过静电纺丝形成Sacran的取向微纤维。采用使用质子化阳离子交换树脂的非均相酸水解方法来研究浓酸对Sacran棒的短时间暴露。从上清液中分离出可溶于水和甲醇的低聚级分。该低聚级分的主要糖比例为-Glc:-Glc:-Xyl:-Xyl:-Rha为2:5:1.5:1.5:4（Glc:Xyl:Rha = 7(=4 + 3):3:4），据推测Sacran结构包括鼠李糖葡聚糖和木葡聚糖（4:3），它们通常足够刚性以呈现液晶态。为了制备LC Sacran的取向微纤维，对Sacran进行了溶解度测试，以寻找诸如乙二醇、1,2 - 丙二醇和甘油等多元醇的良好新溶剂。取向膜由Sacran水溶液制备，其中沉积在膜上的钙化合物颗粒与多元醇溶液不同。尽管Sacran自身不能形成微纤维，但通过静电纺丝制备了Sacran与聚乙烯醇的聚合物复合微纤维。交叉偏振显微镜揭示了微纤维的分子取向。
