Anisotropic swelling behavior of the cornea.
Anisotropic swelling behavior of the cornea.
复制标题
角膜的各向异性肿胀行为。
DOI：
10.1021/jp907232h
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
M. Annaka
中科院分区：
文献类型：
--
作者：
T. Matsuura;H. Ikeda;N. Idota;R. Motokawa;Y. Hara;M. Annaka
通过对猪角膜在不同条件下的溶胀行为、动态光散射（DLS）和小角X射线散射（SAXS）的宏观观察，研究了猪角膜的相平衡性质、结构和动力学性质。结果发现，角膜凝胶根据外部条件各向同性或各向异性地塌陷成致密状态。由于胶原蛋白的变性，角膜凝胶在高于55 ℃的温度下均匀地塌陷成致密状态，而随着NaCl浓度的增加，其沿着平行于光轴的轴塌陷。在干燥过程中也观察到各向异性的去溶胀。SAXS测量结果表明，即使在较高的NaCl浓度下，角膜胶原纤维的周期性也不改变，这表明盐浓度变化引起的水合和脱水仅引起糖胺聚糖（GAG）的溶胀和去溶胀，糖胺聚糖位于胶原纤维的规则二维晶格之间，这迫使厚度发生变化。从角膜凝胶散射光的动态观察，强度自相关函数，揭示了两个独立的扩散系数。发散行为的测量总散射光强度和扩散系数随温度的变化进行了观察。也就是说，观察到伴随着增加的“静态”散射强度的动态模式的减慢。这表明发生了作为温度函数的相变。
The phase equilibrium property and structural and dynamical properties of pig cornea were studied by macroscopic observation of swelling behavior, dynamic light scattering (DLS), and small-angle X-ray scattering (SAXS) under various conditions. It was found that the corneal gel collapses into a compact state isotropically or anisotropically depending on the external conditions. The corneal gel collapses uniformly into a compact state at a temperature above 55 degrees C because of the denaturation of collagen, whereas it collapses along an axis parallel to the optic axis with increasing NaCl concentration. Anisotropic deswelling was also observed during desiccation. SAXS measurements revealed that the periodicity of the collagen fiber of the cornea does not change even at higher NaCl concentration, which indicates that hydration and dehydration resulting from changes in salt concentration simply cause swelling and deswelling of the glycosaminoglycan (GAG), which is located between the regular two-dimensional lattices of collagen fibers, which obliges the change in thickness. From observations of the dynamics of light scattered by the corneal gel, intensity autocorrelation functions that revealed two independent diffusion coefficients were obtained. Divergent behavior in the measured total scattered light intensities and diffusion coefficients with varying temperature was observed. That is, a slowing of the dynamic modes accompanied by increased "static" scattered intensities was observed. This is indicative of the occurrence of a phase transition as a function of temperature.