Lou Xia, Vijayasekaran Sarojini, Sugiharti Runi, Robertson Terry
Centre for Ophthalmology and Visual Science and Lions Eye Institute, University of Western Australia, 2 Verdun Street, Nedlands, Western Australia 6009, Australia.
Biomaterials. 2005 Oct;26(29):5808-17. doi: 10.1016/j.biomaterials.2005.02.034. Epub 2005 Apr 25.
Poly(2-hydroxyethyl methacrylate) hydrogels were prepared in the presence of varying concentrations of water, or a co-monomer ethoxyethyl methacrylate at different strengths of crosslinking agent ethylene glycol dimethacrylate. Calcification tendency and its correlation with monomer mixture composition, topography and porosity of these materials were investigated. Scanning (SEM) and transmission electron microscopy (TEM) was used to study topography and porosity respectively. Calcification and calcium diffusion ability in to the hydrogels were investigated by light microscopy, SEM and energy dispersive analysis of X-rays (EDAX) after incubation of the materials in a metastable calcifying solution for 48 days. Polymer and solvent volume fractions were also studied to determine if a correlation existed between porosity and calcification. Most of the series of hydrogels showed surface irregularities. Internal structure showed evidence of a porous structure in one of the series. Calcification studies indicated diffusion of calcium ions in some of the series. The diffusion of calcium is limited to 30-40 microm in most calcified specimens. For hydrogels that exhibited substantial surface irregularities and micro channels, the infiltration of calcium up to 200 microm was observed. Attempts to detect porosity by electron microscopy failed in some of the hydrogels due to difficulty in sample processing and sectioning. However, collaboration of the results with different techniques used, indicated that surface defects are the major contributors to calcium deposition. Decrease in porosity reduces the amount of calcium deposits and infiltration with decreasing solvent volume fraction which is associated with crosslinking concentration and initial water content of the polymer.
在不同浓度的水或共聚单体甲基丙烯酸乙氧基乙酯存在的情况下，使用不同强度的交联剂乙二醇二甲基丙烯酸酯制备聚甲基丙烯酸2-羟乙酯水凝胶。研究了这些材料的钙化趋势及其与单体混合物组成、形貌和孔隙率的相关性。分别使用扫描电子显微镜（SEM）和透射电子显微镜（TEM）研究形貌和孔隙率。将材料在亚稳态钙化溶液中孵育48天后，通过光学显微镜、SEM和X射线能量色散分析（EDAX）研究水凝胶中的钙化和钙扩散能力。还研究了聚合物和溶剂的体积分数，以确定孔隙率和钙化之间是否存在相关性。大多数系列的水凝胶表面都有不规则之处。其中一个系列的内部结构显示出多孔结构的迹象。钙化研究表明，部分系列中存在钙离子扩散。在大多数钙化标本中，钙的扩散限制在30-40微米。对于表面存在大量不规则和微通道的水凝胶，观察到钙的渗透深度可达200微米。由于样品处理和切片困难，在一些水凝胶中通过电子显微镜检测孔隙率的尝试失败了。然而，不同技术结果的综合表明，表面缺陷是钙沉积的主要原因。孔隙率的降低会减少钙沉积物的数量和渗透，随着溶剂体积分数的降低，这与聚合物的交联浓度和初始含水量有关。
