聚己二酸丁二酯纳米纤维构建的微球的制备

建立了采用异相成核和可控水解相结合的方法制备由纳米纤维构建的聚合物微球的新方法.根据多取代卞叉山梨醇(TM6)对聚己二酸丁二酯(PBA)的异相成核作用以及结晶形态的影响,采用两种乳液溶剂挥发法、并在聚合物溶液中加入成核剂TM6制备了PBA微球,研究了成核剂含量对PBA微球在酶促降解之后形态变化的影响.研究结果表明,二次乳液溶剂挥发法可以制备具有多孔结构的PBA微球,这种多孔结构有利于酶溶液进入到微球内部,促进PBA微球的均匀水解,最终获得由PBA纳米纤维构建的微球.当TM6的含量为3 wt%时,采用二次乳液溶剂挥发法制备的PBA微球,经过5 h酶促降解处理,可以得到表面和内部由PBA纳米纤维均匀组成的微球.进一步的细胞实验表明,微球的纳米纤维结构,有利于MG-63细胞在聚合物微球上的黏附、铺展和向内生长.

FABRICATION OF POLY (BUTYLENE ADIPATE) NANOFIBEROUS MICROSPHERES

A new method was developed to fabricate polymeric microspheres which were composed of homogeneous nanofibers by means of the combination of heterogeneous nucleation and controlled hydrolysis.According to the role of heterogeneous nucleation of multimethyl-benzilidene sorbitol(TM6) and its influences on the crystalline morphology of poly(butylene adipate)(PBA),the PBA microspheres were first fabricated by means of single emulsion solvent evaporation(O/W) or double emulsion solvent evaporation(W/O/W),and then the influences of the nucleating agent TM6 on the morphological change of microspheres in the course of enzymatic degradation were studied.The results indicated that the PBA microspheres with porous structure were fabricated via the W/O/W method.The porous structure of microspheres is favorable for the diffusion of lipase buffer solution into the porous inner of microspheres,leading to the homogenous hydrolysis of PBA chains in microspheres,and finally resulting in the microspheres with nanofibrous structures.By means of W/O/W method,the PBA microspheres with homogeneous nanofibers in whole microspheres were fabricated when 3 wt% TM6 was added in PBA solution and the microspheres were degraded in lipase buffer solution for 5 h.The cell experiments revealed that the nanofibrous structure can greatly improve the adhesion,spread and in-growth of MG-63 cells on microspheres.These microspheres composed of nanofibers show great potentials for large-scaled cell proliferation in bioreactors.