Department of Life Sciences, University of Trieste , Via Licio Giorgieri 5, I-34127 Trieste, Italy.
Department of Medical, Surgical, and Health Sciences, University of Trieste , Piazza dell'Ospitale 1, I-34127 Trieste, Italy.
Biomacromolecules. 2017 Dec 11;18(12):4206-4213. doi: 10.1021/acs.biomac.7b01237. Epub 2017 Nov 8.
The present paper explores the effect of boric acid on Chitlac, a lactose-modified chitosan which had previously shown interesting biological and physical-chemical features. The herewith-reported experimental evidences demonstrated that boric acid binds to Chitlac, producing conformational and association effects on the chitosan derivative. The thermodynamics of boric acid binding to Chitlac was explored by means of B NMR, circular dichroism (CD), and UV-vis spectroscopy, while macromolecular effects were investigated by means of viscometry and dynamic light scattering (DLS). The experimental results revealed a chain-chain association when limited amounts of boric acid were added to Chitlac. However, upon exceeding a critical boric acid limit dependent on the polysaccharide concentration, the soluble aggregates disentangle. The rheological behavior of Chitlac upon treatment with boric acid was explored showing a dilatant behavior in conditions of steady flow. An uncommonly high dependence in the scaling law between the zero-shear viscosity and the concentration of Chitlac was found, i.e., η ∝ C, pointing to interesting potential implications of the present system in biomaterials development.
本文探讨了硼酸对 Chitlac 的影响，Chitlac 是一种经过乳糖修饰的壳聚糖，先前已显示出有趣的生物和物理化学特性。本报告的实验证据表明，硼酸与 Chitlac 结合，对壳聚糖衍生物产生构象和聚集效应。通过 B NMR、圆二色性 (CD) 和紫外可见光谱研究了硼酸与 Chitlac 的结合热力学，通过粘度和动态光散射 (DLS) 研究了大分子效应。实验结果表明，当向 Chitlac 中加入少量硼酸时，会发生链链聚集。然而，当超过取决于多糖浓度的硼酸临界限制时，可溶性聚集体会解缠。研究了硼酸处理后 Chitlac 的流变行为，在稳态流动条件下显示出扩张行为。发现零剪切粘度与 Chitlac 浓度之间的标度定律之间存在异常高的依赖性，即 η∝C，这表明本系统在生物材料开发方面具有有趣的潜在意义。
