The dynamic properties of the polymeric components of cartilage are important for understanding the many biological functions of this biological tissue. Knowledge of the rheology of these materials is also crucial for the development of therapeutic treatments for diseases, such as arthritis, in which cartilage loses its functional physiological properties. In the present work complementary noninvasive techniques, rheology and dynamic light scattering (DLS) are used to probe the structural and dynamic properties of solutions of the principal proteoglycan components of cartilage extracellular matrix at different levels of structural hierarchy (chondroitin sulfate, aggrecan, aggrecan-hyaluronic acid complex). It is shown that the bottlebrush shaped aggrecan molecules form large, loosely organized polyelectrolyte domains comprised of molecules organized into diffuse branched polymer network structures permeated by a diffuse cloud of counter-ions. The rheological behaviors of these polymer solutions vary from viscoelastic solutions, consistent with the formation of dynamic polymer clusters in solution, to “weak gel” materials exhibiting approximate power law shear stress relaxation or creep over a wide range of timescales.

中文翻译：

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软骨聚合物：从粘弹性溶液到弱凝胶*

软骨聚合物成分的动态特性对于了解这种生物组织的许多生物学功能很重要。了解这些材料的流变学对于开发治疗疾病（例如关节炎）也至关重要，因为在这些疾病中，软骨会失去其功能性生理特性。在目前的工作中，互补的无创技术、流变学和动态光散射 (DLS) 用于探测软骨细胞外基质的主要蛋白多糖成分溶液在不同结构层次（硫酸软骨素、聚集蛋白聚糖、聚集蛋白聚糖-透明质酸复合物）。结果表明，瓶刷状聚集蛋白聚糖分子形成较大，组织松散的聚电解质结构域，由组织成扩散的支化聚合物网络结构的分子组成，该结构被扩散的反离子云渗透。这些聚合物溶液的流变行为从粘弹性溶液（与溶液中动态聚合物簇的形成一致）到“弱凝胶”材料在很宽的时间范围内表现出近似幂律剪切应力松弛或蠕变。