端氨基聚乙二醇-聚已内酯二嵌段共聚物的合成及其微球表面氨基和形态的调控

SYNTHESIS OF POLY(ε-CAPROLACTONE)/POLY(ETHYLENE GLYCOL) BLOCK COPOLYMERS AND SURFACE PROPERTY CONTROL OF THEIR MICROSPHERES

生物降解高分子作为一种重要的生物材料已经发展到第3代，实际应用的复杂性不仅要求高分子材料本身具有合适的降解性能、热性能、力学性能和加工性能等，而且还要求高分子材料具有能够刺激细胞生长、识别特定细胞等生物活性特征．高分子材料的这些生物活性主要是通过高分子材料的表面与组织和细胞之间的相互作用来表现出来的．因此，如何模拟细胞外基质（ECM）的结构与性质，利用各种物理和化学的方法，对原本生物惰性的有机高分子材料表面进行改性，使其具有类似于ECM的细胞活性，是当前生物高分子材料研究的重要课题之一，对于开展生物降解高分子材料作为细胞培养和靶向药物释放的载体研究具有重要的意义心。

A method was developed to synthesize amphiphilic poly（ ε-caprolactone）-b-poly（ethylene glycol） （PCL- b-PEO） block copolymers with well-defined structure and with functional amino end-group connected to the PEO block. The molecular weight, composition and chain structure of the resultant copolymers were characterized by GPC and ^1 H-NMR.The microspheres of the copolymers were prepared by W/O/W double emulsion solvent evaporation method. The analysis results by confocal laser scanning microscopy indicate that the amino groups are distributed dominantly on the surface of microspheres due to the hydrophilic property of amino groups and the formation process of microspheres in aqueous phase. The surface morphology of microspheres could be regulated by changing the composition of block copolymers. The results of this work indicate that the surface properties of the microspheres can be controlled by polymer chain structure, and that the microspheres with amino group located on the surface can be further conjugated with peptide such as RGD. Therefore, these microspheres are promising materials as microcarriers for promoting cell growth.