Department of Pharmaceutics, School of Pharmaceutical Sciences, Peking University, Beijing 100191, People's Republic of China.
Acta Biomater. 2011 Dec;7(12):4149-59. doi: 10.1016/j.actbio.2011.07.011. Epub 2011 Jul 14.
A novel thermoreversible hydrogel based on poly(2-ethyl-2-oxazoline)-derived amphiphilic triblock copolymer, poly(2-ethyl-2-oxazoline)-poly(D,L-lactide)-poly(2-ethyl-2-oxazoline) (PEOz-PLA-PEOz), was developed. The synthesis of PEOz-PLA-PEOz was carried out by coupling monohydroxylated PEOz-PLA diblocks with adipoyl chloride as coupling agent and dimethylamino pyridine as catalyst. The tube inverting and rheological tests showed that triblock copolymers had sol-gel-sol transition behavior with increasing temperature, and the gelation was found to be thermoreversible. The critical gelation concentration, the sol-gel transition temperature at a given concentration depended on the EOz/LA ratio and the molecular weight of PEOz. Scanning electron microscopy observation revealed that the resultant bulky gel exhibited an interconnected porous three-dimensional (3D) microstructure after freeze-drying. In addition, the hydrogels showed good cytocompatibility in vitro. MTT assays revealed that the human skin fibroblast cells encapsulated within the hydrogels were viable and proliferated inside the 3D scaffold. This newly described thermoreversible hydrogel demonstrated attractive properties to serve as cell matrix for a variety of tissue engineering applications or pharmaceutical delivery vehicles.
一种基于聚（2-乙基-2-恶唑啉）衍生的两亲性三嵌段共聚物聚（2-乙基-2-恶唑啉）-聚（D,L-丙交酯）-聚（2-乙基-2-恶唑啉）（PEOz-PLA-PEOz）的新型温敏水凝胶被开发出来。PEOz-PLA-PEOz 的合成是通过将单羟基化的 PEOz-PLA 二嵌段与己二酰氯作为偶联剂和二甲氨基吡啶作为催化剂进行偶联来进行的。管反转和流变测试表明，三嵌段共聚物具有随温度升高的溶胶-凝胶-溶胶转变行为，凝胶化是热可逆的。临界胶凝浓度和给定浓度下的溶胶-凝胶转变温度取决于 EOz/LA 比和 PEOz 的分子量。扫描电子显微镜观察表明，冻干后的所得大块凝胶呈现出相互连接的多孔三维（3D）微观结构。此外，水凝胶在体外表现出良好的细胞相容性。MTT 测定表明，包封在水凝胶中的人皮肤成纤维细胞在 3D 支架内是存活和增殖的。这种新描述的温敏水凝胶具有作为各种组织工程应用或药物传递载体的细胞基质的有吸引力的特性。
