Preparation of functional nanocapsules with polylactide marosurfactant

首先，以2-乙基己酸亚锡为催化剂，合成了聚（环氧乙烷单油酸酯-嵌段-D，L-丙交酯）（MOPEO-PLA）。两亲性MOPEO-PLA可利用其表面活性剂的性质和活性双键，对聚合物纳米胶囊的各种特性、表面和内部结构、表面形态、释放性能等进行调控。MOPEO-PLA-甲苯/水体系的界面张力测定表明，MOPEO-PLA具有与MOPEO相当的表面活性。采用溶剂流延法制备了MOPEO-PLA/PLA共混膜。接触角测定证实了亲水性PEO链段选择性地聚集到油水界面。其次，利用合成的MOPEO-PLA在油相中的自组装，尝试了蛋白质的包埋和蛋白质的有效提取。氯仿相中的水含量随着MOPEO-PLA浓度的增加而急剧增加，表明MOPEO-PLA微乳液形成了大量的水分子。MOPEO-PLA微乳液相中的细胞色素c在水相的pH接近于细胞色素c的p/时被萃取量最大，且萃取性能随温度的升高而提高。从这些结果中，提取细胞色素c的主要因素被发现是MOPEO-PLA和细胞色素c之间的疏水相互作用。这种MOPEO-PLA微乳液为蛋白质提供了一个良性的提取过程。MOPEO-PLA微乳液系统将能够在可生物降解的聚合物基质中实现新的包封系统，用于递送蛋白质和肽。

This research was conducted to clarify the effect of process parameters which affected the release and dispersion properties of functional polylactide nanocapsulesAt first, poly(ethyleneoxide monooleate-block-D, L-lactide) (MOPEO-PLA) was synthesized in the presence of stannous 2-ethylhexanoate catalyst. Amphiphilic MOPEO-PLA would have potential to control of various characteristics of polymer nanocapsules, surface and internal structure, surface morphology, release property and so on, by utilizing the surfactant property and the reactive double bond. Furthermore, the interfacial tension measurement of MOPEO-PLA-toluene/water system revealed that MOPEO-PLA had a good surface activity which was almost equal to that of MOPEO. The MOPEO-PLA/PLA blend films were prepared by solvent-cast on water layer. It was confirmed from contact angle measurement that the hydrophilic PEO segments were selectivity accumulated to the oil-water interface.Secondly, protein encapsulation was tried and proteins were effectively extracted by using self-assembly of synthesized MOPEO-PLA in the oil phase. The water content in the chloroform phase dramatically increased with the MOPEO-PLA concentration, indicating that a MOPEO-PLA microemulsion was formed with a large amount of water molecules. The largest amount of cytochrome c in the MOPEO-PLA microemulsion phase was extracted when the pH of the aqueous phase was close to p/ of cytochrome c, and the extraction performance increased at higher temperatures. From these results, the main factor for the extraction of cytochrome c was found to be the hydrophobic interaction between MOPEO-PLA and cytochrome c. This MOPEO-PLA microemulsion provides a benign extraction process for proteins. A MOPEO-PLA microemulsion system would enable a new encapsulation system in a biodegradable polymer matrix for delivery of proteins and peptides.