Wu Daqing, Zhang Xianzheng, Chu Chih-Chang
Fiber and Polymer Science Program, Department of Textiles and Apparel, Cornell University, Ithaca, NY 14853-4401, USA.
J Biomater Sci Polym Ed. 2003;14(8):777-802. doi: 10.1163/156856203768366521.
A biodegradable polymer network hydrogel with both hydrophobic and hydrophilic components was synthesized and characterized. The hydrophobic and hydrophilic components were a three-arm poly(epsilon-caprolactone) maleic acid (PGCL-Ma, as the hydrophobic constituent) and poly(ethylene glycol) diacrylate macromer (PEGDA, as a hydrophilic constituent), respectively. These two polymers were chemically photo-crosslinked to generate a three-dimensional network structure, which were characterized by FT-IR, DSC and SEM. The swelling property of the networks was studied in phosphate-buffered saline (PBS, pH 7.4). The results of this study showed that a wide-range swelling property was obtained by changing the composition ratio of PGCL-Ma to PEGDA. The in vitro release of bovine serum albumin (BSA) from these hydrogels as a function of the PEGDA to PGCL-Ma composition ratio and incubation time was examined and we found that the incorporation of PEGDA into PGCL-Ma increased the initial burst release of BSA. As the PEGDA component increased, the rate of formation of a loose three-dimensional (3D) network structure increased; consequently, the sustained rate and extent of BSA release increased. We suggest that the release of BSA was controlled by both diffusion of BSA through swelling of the hydrophilic phase during an early stage and degradation of the hydrophobic phase during a late stage; and that the relative magnitude of diffusion versus degradation controlled release depended on composition ratio and immersion time.
合成并表征了一种具有疏水和亲水成分的可生物降解聚合物网络水凝胶。疏水成分和亲水成分分别是三臂聚（ε-己内酯）马来酸（PGCL-Ma，作为疏水成分）和聚乙二醇二丙烯酸酯大分子单体（PEGDA，作为亲水成分）。这两种聚合物通过化学光交联生成三维网络结构，并用傅里叶变换红外光谱（FT-IR）、差示扫描量热法（DSC）和扫描电子显微镜（SEM）对其进行了表征。在磷酸盐缓冲盐水（PBS，pH 7.4）中研究了该网络的溶胀性能。本研究结果表明，通过改变PGCL-Ma与PEGDA的组成比可获得宽范围的溶胀性能。研究了牛血清白蛋白（BSA）从这些水凝胶中的体外释放随PEGDA与PGCL-Ma组成比和孵育时间的变化，发现将PEGDA掺入PGCL-Ma中可增加BSA的初始突释。随着PEGDA成分的增加，松散三维（3D）网络结构的形成速率增加；因此，BSA释放的持续速率和程度增加。我们认为，BSA的释放早期受BSA通过亲水相溶胀的扩散控制，后期受疏水相降解控制；扩散与降解控制释放的相对大小取决于组成比和浸泡时间。
