Research data supporting "Effects of Reaction pH on Self-Crosslinked Chitosan-Carrageenan Polyelectrolyte Complex Gels and Sponges"

Macromolecular biomaterials often require covalent crosslinking to achieve adequate stability for their given application. However, the use of auxiliary chemicals may be associated with long-term toxicity in the body. Oppositely-charged polyelectrolytes (PEs) have the advantage that they can self-crosslink electrostatically and those derived from marine organisms such as chitosan (CS) and carrageenan (CRG) are inexpensive non-toxic alternatives to glycosaminoglycans present in the extracellular matrix of human tissues. The aim of this study was to explore the properties of crosslinker-free PEC gels and freeze-dried PEC sponges based on CS and CRG precursors. We offer new insights into the optimisation of conditions and mechanisms involved in the process and offer a systematic study of property changes across a full range of pH values. Zeta potential measurements indicated that the PECs produced at pH 2-6 had a high strength of electrostatic interaction with the highest being at pH 4-5. This resulted in strong intra-crosslinking in the PEC gels which led to the formation of higher yield, viscosity, fibre content and lower moisture content. The weaker interaction between CS and CRG at pH 7-12 resulted in higher levels of CS incorporated into the complex and the formation of more inter-crosslinking through entanglements and secondary interactions between PEC units. This resulted in the production of stable PEC sponge materials compared with the PEC materials produced at pH 6 and below. From the range of samples tested, the PECs produced at pH 7.4 appeared to show the optimum combination of yield, stability and homogeneity.

大分子生物材料通常需要通过共价交联以实现其在特定应用中的充足稳定性。然而，辅助化学物质的使用可能与体内的长期毒性相关。相反电荷的聚电解质（PEs）具有优势，它们能够通过静电自交联，而诸如壳聚糖（CS）和海藻酸钠（CRG）等来源于海洋生物的聚电解质则是不昂贵的无毒替代品，它们存在于人类组织细胞外基质中的糖胺聚糖。本研究旨在探讨基于CS和CRG前体的无交联聚电解质凝胶和冷冻干燥聚电解质海绵的性质。我们对优化过程中涉及的条件和机制提供了新的见解，并对整个pH值范围内的性质变化进行了系统研究。ζ电位测量表明，在pH 2-6条件下生产的聚电解质表现出与电静力的高强度相互作用，其中以pH 4-5为最高。这导致了聚电解质凝胶中的强内部交联，进而形成了更高的产量、粘度、纤维含量和较低的水分含量。在pH 7-12时，CS与CRG之间的较弱相互作用导致了CS在复合物中的更高含量，并通过聚电解质单元之间的缠结和次级相互作用形成了更多的交联。这相比于在pH 6及以下条件下生产的聚电解质材料，产生了稳定的聚电解质海绵材料。在测试的样品范围内，pH 7.4条件下生产的聚电解质似乎显示出产量、稳定性和均一性的最佳组合。