Pluronic修饰脂质体的结构特性、稳定性和细胞摄取的变化及其相互关系

Surface modification have been remarkable developed to improve liposomal stability and cellular uptake in pharmaceutical biology in recent years. In our previous studies, pluronic modified nanoliposomes were prepared, the results indicated that the liposomal structures characteristics were closely related to the functional properties. However, the interaction mechanism between pluronic and liposomes, and how the pluronic influence on the structural characteristics, stability and cellular uptake of liposomes need to be further studied. Thus, in the present study, pluronic modified nanoliposomes will be designed through film dispersion method and dynamic high pressure microfluidization, the structural characteristics of pluronic nanoliposomes, including microstructure, membrane fluidity, phase transformation behavior and surface tension, are measured by modern analytical instruments, the interactions between pluronic and liposomes are simulated by dissipative particle dynamics, the stability such as chemical stability, in vitro digestion stability and membrane stability are measured, the relationship between structure and stability is studied. A new folic acid coated pluronic nanoliposomes will be prepared, the cell uptake characteristics, including cellular compatibility, distribution and location in the cell, cell uptake rate are measured, the mechanism of cellular uptake and the relationship between cellular uptake and structural characteristics are studied. This project will provide the theoretical basis for the effective regulation of liposomal structure, stability and cellular uptake.

采用表面修饰技术改善传统脂质体的稳定性、细胞摄取是生物医药领域的研究热点。课题组前期构建了Pluronic修饰的纳米脂质体，结果显示脂质体的结构特性与其功能性质密切相关，但Pluronic与脂质体的作用机制，及Pluronic如何影响脂质体的结构特性、稳定性和细胞摄取等问题有待深入研究。因此，本项目拟采用薄膜分散法结合动态高压微射流技术构建Pluronic修饰的纳米脂质体，采用现代仪器分析表征其结构特性的变化，以耗散动力学模拟Pluronic与脂质体的作用方式；通过测定其稳定性，探讨Pluronic纳米脂质体结构特性与稳定性的关系；构建新型含叶酸的Pluronic纳米脂质体，通过测定其细胞摄取性质，探讨细胞摄取机理及其与结构特性的关系，本项目为深入研究Pluronic对脂质体结构特性、稳定性和细胞摄取的有效调控提供新方向和理论参考。

采用表面修饰技术改善传统脂质体的稳定性、细胞摄取是生物医药领域的研究热点。课题组前期构建了Pluronic修饰的纳米脂质体，结果显示脂质体的结构特性与其功能性质密切相关但Pluronic与脂质体的作用机制，及Pluronic如何影响脂质体的结构特性、稳定性和细胞摄取等问题有待深入研究。.本项目采用薄膜分散法结合动态高压微射流技术成功构建了三种Pluronic修饰的纳米脂质体，结果表明Pluronic F127、F87和P85修饰的脂质体均呈单层球形结构，脂质体经Pluronic修饰后粒径均变小，但脂质体粒径大小与Pluronic的PEO嵌段的长度有关；Pluronic修饰使脂质体膜稳定性增强，此外，脂质体的结构与Pluronic的添加量有关，当Pluronic F127在低浓度条件下可与脂质体结合形成球形单层结构，而高浓度条件下Pluronic F127可胶束和囊泡共存的状态。采用Pluronic修饰的脂质体包埋姜黄素，结果表明Pluronic修饰可以增强姜黄素的pH稳定性和热稳定，体外模拟胃肠道研究表明Pluronic修饰能显著提高姜黄素的吸收。姜黄素脂质体的生物可接受度依次增加: 未修饰脂质体<Pluronic F87< Pluronic P85<Pluronic F127。通过脱水缩合的方式成功合成了含叶酸靶向的F127，细胞实验显示含有叶酸的修饰脂质体比不含叶酸的修饰脂质体更能够有效地将姜黄素运输到叶酸受体过度表达的KB细胞中，且作用时间越长，细胞毒性越明显。上述工作为脂质体修饰过程中结构特性、稳定性和细胞摄取的有效调控提供理论借鉴。.本项目还进一步探讨了动态高压微射流技术在脂质体修饰过程中对结构特性和理化性质的影响，结果表明动态高压微射流技术具有明显降低脂质体粒径大小的功能，且Pluronic修饰脂质体的微观形态由不规则的多层结构转变为单层球状结构，且稳定性能明显提高。这些工作为脂质体的品质调控提供技术指导。