Yamamoto Naoki, Totani Masayasu, Kadokawa Jun-Ichi
Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima 890-0065, Japan.
Molecules. 2024 Dec 24;30(1):16. doi: 10.3390/molecules30010016.
In recent years, increased attention has been given to the effective use of chitin nanofibers (ChNFs). We have developed a method to fabricate thinner chitin nanomaterials, called scale-down chitin nanofibers (SD-ChNFs), by a bottom-up procedure at the nanoscale level, with subsequent disintegration by electrostatic repulsion. The surface modification of SD-ChNFs is anticipated to provide new properties and functions for their practical applications. Inspired by our previous reports, which found hydrophobicity in partially 2-deoxygenated (P2D-) amylose obtained by the glucan phosphorylase (GP)-catalyzed enzymatic copolymerization of α-d-glucose 1-phosphate/d-glucal as comonomers, this work investigated the hydrophobization of SD-ChNFs via an enzymatic approach. After the modification of maltooligosaccharide primers on SD-ChNFs was performed by a reductive alkylation toward ChNFs, the grafting of the P2D-amyloses was performed by GP-catalyzed enzymatic copolymerization. H NMR analysis supported the production of P2D-amylose-grafted SD-ChNFs with different d-glucose/2-deoxy-d-glucose unit ratios on SD-ChNFs. The X-ray diffraction analysis of the products confirmed that the chain lengths and unit ratios of the grafted polysaccharides strongly affected the entire crystalline structures. Water contact angle measurements of the cast films of the products indicated that successful hydrophobization was achieved by the grafting of P2D-amylose chains with a sufficient chain length, a relatively high 2-deoxy-d-glucose unit ratio, and low crystallinity.
近年来，人们越来越关注几丁质纳米纤维（ChNFs）的有效利用。我们开发了一种方法，通过纳米级的自下而上的过程制造更细的几丁质纳米材料，称为缩微几丁质纳米纤维（SD-ChNFs），随后通过静电排斥使其分解。预计SD-ChNFs的表面改性将为其实际应用提供新的性能和功能。受我们之前报告的启发，该报告发现在通过葡聚糖磷酸化酶（GP）催化的α-d-葡萄糖1-磷酸/d-葡糖醛作为共聚单体的酶促共聚获得的部分2-脱氧（P2D-）直链淀粉中存在疏水性，这项工作研究了通过酶法对SD-ChNFs进行疏水化。在通过对ChNFs的还原烷基化对SD-ChNFs上的麦芽寡糖引物进行修饰后，通过GP催化的酶促共聚进行P2D-直链淀粉的接枝。1H NMR分析支持在SD-ChNFs上生产具有不同d-葡萄糖/2-脱氧-d-葡萄糖单元比的P2D-直链淀粉接枝的SD-ChNFs。产物的X射线衍射分析证实，接枝多糖的链长和单元比强烈影响整个晶体结构。产物流延膜的水接触角测量表明，通过接枝具有足够链长、相对较高的2-脱氧-d-葡萄糖单元比和低结晶度的P2D-直链淀粉链实现了成功的疏水化。
