Mechanical and diffusive properties of homogeneous alginate gels in form of particles and cylinders
Mechanical and diffusive properties of homogeneous alginate gels in form of particles and cylinders
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DOI：
10.1002/jbm.a.31680
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发表时间：
2008-12-01
影响因子：
4.9
通讯作者：
Grassi, M.
中科院分区：
文献类型：
--
作者：
Pasut, E.;Toffanin, R.;Grassi, M.
在这项研究中，藻酸盐聚合物用于获得均匀的圆柱形或球形凝胶。 MRI 技术用于研究这些凝胶的均匀性。使用四种不同的藻酸盐，并且对于每种藻酸盐，研究了用于机械测试的五种不同浓度和用于释放测试的三种不同浓度。进行机械测试以获得凝胶的线性粘弹性区域，然后评估其交联密度与聚合物浓度的关系。随后，将三种模型分子（茶碱、维生素 B-12 和肌红蛋白）加载到凝胶中，以研究圆柱形和球形凝胶在水中的释放动力学。然后使用从这些实验计算出的扩散系数来估计聚合物网络网格宽度。这项工作表明，无论考虑的藻酸盐类型如何，交联密度如何随着聚合物浓度的增加而增加。此外，虽然维生素 B-12 扩散系数与交联密度成反比，但肌红蛋白太大而无法通过聚合物网络扩散，无论藻酸盐类型和聚合物浓度如何。同时，茶碱太小而不会受到增加聚合物网络交联密度的明显影响。最后，MRI 分析和维生素 B-12 扩散系数值证明，从结构上讲，圆柱体和球体是相似且均质的。 (C) 2008 Wiley periodicals, Inc. J Biomed Mater Res 87A: 808-818, 2008
In this study, alginate polymers are used to get homogeneous cylindrical or spherical gels. MRI techniques are employed to study homogeneity of these gels. Four different alginates are used and, for each one, five different concentrations for mechanical tests and three different concentrations for release tests are studied. Mechanical tests are performed to get gels' linear viscoelasticity region and then to evaluate their crosslink density in relation to polymer concentration. Afterwards, three model molecules (theophylline, vitamin B-12, and myoglobin) are loaded within gels to study the release kinetics in water from both cylindrical and spherical gels. Diffusion coefficients calculated from these experiments are then used to estimate the polymeric network mesh wideness. This work shows how crosslink density increases with polymer concentration regardless of the alginate type considered. In addition, while vitamin B-12 diffusion coefficient is inversely proportional to crosslink density, myoglobin is too large to diffuse through the polymeric network, whatever the alginate type and polymer concentration. At the same time, theophylline is too small to be sensibly affected by increasing the polymeric network crosslink density. Finally, MRI analysis and vitamin B-12 diffusion coefficient values prove that, structurally speaking, cylinders and spheres are similar and homogeneous. (C) 2008 Wiley Periodicals, Inc. J Biomed Mater Res 87A: 808-818, 2008