Mechanical properties and chemical stability of alginate-based anisotropic capillary hydrogels.
Mechanical properties and chemical stability of alginate-based anisotropic capillary hydrogels.
复制标题
DOI：
10.1016/j.jmbbm.2022.105397
复制
发表时间：
2022-07
影响因子：
3.9
通讯作者：
Maximilian Nützl;Manuel Schrottenbaum;T. Müller;R. Müller
中科院分区：
文献类型：
--
作者：
Maximilian Nützl;Manuel Schrottenbaum;T. Müller;R. Müller
各向异性毛细管水凝胶是通过海藻酸钠水溶液在单向扩散和与二价阳离子络合过程中形成离子型凝胶而形成的。用于凝胶形成的阳离子类型决定了所得毛细管结构的大小，这可能有助于在组织工程和再生医学中作为生物材料支架的应用。到目前为止，这种毛细管水凝胶结构的机械性能尚未得到表征，我们假设宏观毛细管结构和化学交联剂的浓度都会影响水凝胶的机械性能和在生理环境中抵抗降解和溶解的稳定性。我们使用含有 Ba2+、Sr2+、Zn2+ 或 Ni2+ 阳离子的电解质溶液制备了毛细管尺寸在 12 至 100 μm 之间的各向异性凝胶。它们与浓度在 1 至 100 mmol L−1 之间的六亚甲基二异氰酸酯进行化学交联。水凝胶的特性通过溶胀实验、振荡流变测定法和微压痕分析来确定，并在 37°C 磷酸盐缓冲溶液中孵育长达三个月的过程中进行监测。我们发现，机械强度通常随着毛细管直径的增加而降低。交联剂的浓度越高，机械强度越高。海藻酸盐水凝胶的抗降解能力与交联剂的浓度呈正相关。此外，显微压痕实验揭示了由于聚合物纤维相对于毛细管轴的垂直取向而导致的机械性能的微观各向异性。
Anisotropic capillary hydrogels are formed by ionotropic gel formation of an aqueous sodium alginate solution during unidirectional diffusion and complexation with divalent cations. The type of cation used for gel formation dictates the size of the resulting capillary structure which might facilitate applications as biomaterial scaffolds in tissue engineering and regenerative medicine. Until now, such capillary hydrogel structures have not been characterized regarding their mechanical properties, and we hypothesise that both, the macroscopic capillary structure and the concentration of a chemical crosslinking agent, influence the mechanical properties and the stability of the hydrogels against degradation and dissolution in physiological environment. We prepared anisotropic gels with capillary sizes ranging between 12 and 100 μm using electrolyte solutions containing Ba2+, Sr2+, Zn2+or Ni2+cations. They were chemically crosslinked with hexamethylene diisocyanate in concentrations varying between 1 and 100 mmol L−1. Hydrogel properties were determined by swelling experiments, oscillatory rheometry and microindentation analysis and monitored during incubation in phosphate-buffered solution at 37 °C for up to three months. We found, that the mechanical strength generally decreases with increasing capillary diameter. The higher the concentration of the crosslinking agent, the higher is the mechanical strength. The resistance of the alginate hydrogels against degradation is positively correlated with the concentration of the crosslinking agent. Furthermore, microindentation experiments revealed a microscopic anisotropy of the mechanical properties resulting from a perpendicular orientation of the polymer fibres relative to the capillary axis.