Chemoviscoelasticity of the interfibrillar matrix of the dermis of the black sea cucumber Holuthuria atria
Chemoviscoelasticity of the interfibrillar matrix of the dermis of the black sea cucumber Holuthuria atria
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DOI：
10.1016/j.mechmat.2022.104252
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发表时间：
2022-03-14
影响因子：
3.9
通讯作者：
Gupta, Himadri S.
中科院分区：
文献类型：
--
作者：
Barbieri, Ettore;Mo, Jingyi;Gupta, Himadri S.
海参真皮的可变结缔组织可以根据水中的化学变化呈现出三种不同的力学状态（柔软、标准和坚硬）。广泛的共识是，细胞外基质的可变交联是造成这种变化的原因。本文使用小角x射线散射（SAXS）测量，微力学粘弹性模型和分子扩展重复理论来寻找交联之外的其他原因。我们得出结论，在富含钾离子的海水中，纤维间基质由于交联增加而变硬，但这也必然意味着大分子链的断裂，分子量的变化和链之间的摩擦增加。在软化水溶液（无钙离子的海水）中，纤维间基质因交联减少而软化，同时大分子链重组，链间摩擦减小。这些发现使我们得出结论，零剪切粘度在硬化过程中增加了五倍以上，在软化过程中减少到标准值的3%。此外，我们发现通过SAXS测量的纤维株似乎表明，在参考条件下，纤维间基质（人工海水）的行为类似于共价交联凝胶；相反，在软化和硬化过程中，基质表现出类似于离子交联凝胶的应力松弛。
Mutable connective tissues of the sea cucumbers' dermis can assume three different mechanical states (soft, standard and stiff) according to the chemical changes in the water.There is broad consensus that variable cross-linking of the extracellular matrix is responsible for such changes. This paper uses Small-angle X-ray Scattering (SAXS) measurements, a micromechanical viscoelastic model, and a molecular extended reptation theory to look for other causes beyond cross-linking.We conclude that in potassium-ions enriched seawater, the interfibrillar matrix stiffens due to increased cross-linking, but this must also imply macromolecular chain scission change in molecular weight and increased friction between the chains.In softening water solution (calcium-ions deprived seawater), the interfibrillar matrix softens because of decreased cross-linking, and simultaneously macromolecules chain recombine and friction between the chains decreases.These findings allow us to conclude that the zero-shear viscosity increases more than five times during stiffening and reduces to 3% of its standard value during softening.Also, we find that the fibril strains measured through SAXS seem to suggest that, in reference conditions, the interfibrillar matrix (artificial sea water) behaves similarly to a covalently cross-linked gel; instead, during softening and stiffening, it appears that the matrix shows stress relaxation akin to an ionic cross-linked gel.