Diffusivity of ions in agarose gels and intervertebral disc: Effect of porosity
Diffusivity of ions in agarose gels and intervertebral disc: Effect of porosity
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DOI：
10.1007/s10439-004-7823-4
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发表时间：
2004-12-01
影响因子：
3.8
通讯作者：
Flagler, D
中科院分区：
文献类型：
--
作者：
Gu, WY;Yao, H;Flagler, D
使用电导率方法研究了组织孔隙度对琼脂糖凝胶和猪椎间盘组织中离子（钠、钾和氯）扩散性的影响。提出了多孔纤维介质中溶质扩散率 (D) 的经验本构模型： D/D-0 = exp[-alpha(r(s)/kappa(1/2))(beta)] 其中 r(s) 是溶质的斯托克斯半径，kappa 是多孔介质的达西渗透性，D-0 是自由溶液中的扩散率，a 和 是两个正数 其值取决于材料结构的参数。结果发现，琼脂糖凝胶的 α = 1.25 +/- 0.138，β = 0.681 +/- 0.059（95% 置信区间，R-2 = 0.92，n = 72），α = 1.29 +/- 0.171，β = 0.372 +/- 0.088（95% 置信区间，R-2 = 0.88， n = 86) 对于猪环 纤维化。推导了溶质扩散率与组织变形之间的函数关系。我们的模型预测与文献中关于大分子（蛋白质、葡聚糖、聚合物珠）在琼脂糖凝胶中扩散系数的实验数据进行了比较。我们的结果还与文献中报道的带电凝胶和软骨组织中的离子扩散率数据进行了比较。我们的模型预测与文献中的数据非常吻合。本研究提供了有关不带电凝胶和带电组织中溶质扩散性的附加信息，对于了解不同机械负荷条件下无血管软骨组织的营养输送非常重要。
The effect of tissue porosity on ion (sodium, potassium, and chloride) diffusivity in agarose gels and porcine intervertebral disc tissues was investigated using an electrical conductivity method. An empirical, constitutive model for diffusivity (D) of solutes in porous fibrous media was proposed: D/D-0 = exp[-alpha(r(s)/kappa(1/2))(beta)] where r(s) is the Stokes radius of a solute, kappa is the Darcy penneability of the porous medium, D-0 is the diffusivity in free solution, a and are two positive parameters whose values depend on material structure. It is found that alpha = 1.25 +/- 0.138, beta = 0.681 +/- 0.059 (95% confidence interval, R-2 = 0.92, n = 72) for agarose gels and alpha = 1.29 +/- 0.171 and beta = 0.372 +/- 0.088 (95% confidence interval, R-2 = 0.88, n = 86) for porcine annulus fibrosus. The functional relationship between solute diffusivity and tissue deformation was derived. Comparisons of our model prediction with experimental data on diffusion coefficients of macromolecules (proteins, dextrans, polymer beads) in agarose gels in the literature were made. Our results were also compared to the data on ion diffusivity in charged gels and in cartilaginous tissues reported in the literature. There was a good agreement between our model prediction and the data in the literature. The present study provides additional information on solute diffusivity in uncharged gels and charged tissues, and is important for understanding nutritional transport in avascular cartilaginous tissues under different mechanical loading conditions.