Ren Ying, Xie Hongguo, Liu Xiaocen, Yang Fan, Yu Weiting, Ma Xiaojun
Laboratory of Biomedical Material Engineering, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Laboratory of Biomedical Material Engineering, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
Int J Biol Macromol. 2016 Oct;91:1090-100. doi: 10.1016/j.ijbiomac.2016.06.034. Epub 2016 Jun 23.
The goal of this work is to tune the formation and stability of the alginate-chitosan (AC) polyelectrolyte complexes (PECs) and microcapsules. Particularly, we explore the role of the conformation of chitosan on its interaction with alginate to understand the mechanism underpinning their interactions at the molecular level. Reducing the charge density by increasing pH will increase the compactness of chitosan, the values of the enthalpy (H) and stoichiometry (N) of binding between chitosan and alginate. Consequently, chitosan has advantage in being adsorbed on alginate beads to form microcapsules, including the binding rate and binding amount. Though the total heat release remain similar in the range of ionic strength, chitosan diffuses much easier into alginate hydrogels when in higher ionic strength. Increasing pH and ionic strength both help AC microcapsules to have higher stability. The results indicate that the formation and stability of AC microcapsules are related to the rigidity and conformations of chitosan molecules. After increasing acetylation degree (DA) of chitosan, the binding rate of chitosan and mechanical strength of AC microcapsules are both reduced. This work demonstrates the versatility and feasibility of tuning the formation and stability of polysaccharide microcapsules by physical factors and chitosan chemical structures.
这项工作的目标是调节海藻酸钠-壳聚糖（AC）聚电解质复合物（PEC）和微胶囊的形成及稳定性。具体而言，我们探究壳聚糖构象在其与海藻酸钠相互作用中的作用，以了解在分子水平上支撑它们相互作用的机制。通过提高pH值来降低电荷密度会增加壳聚糖的紧密程度、壳聚糖与海藻酸钠结合的焓（H）值和化学计量比（N）。因此，壳聚糖在吸附于海藻酸钠珠粒上以形成微胶囊方面具有优势，包括结合速率和结合量。尽管在离子强度范围内总热释放保持相似，但在较高离子强度下壳聚糖更容易扩散到海藻酸钠水凝胶中。提高pH值和离子强度均有助于AC微胶囊具有更高的稳定性。结果表明，AC微胶囊的形成和稳定性与壳聚糖分子的刚性和构象有关。提高壳聚糖的乙酰化度（DA）后，壳聚糖的结合速率和AC微胶囊的机械强度均降低。这项工作证明了通过物理因素和壳聚糖化学结构调节多糖微胶囊形成和稳定性的多功能性和可行性。
