基于柔性调控构建的多功能纳米脂质体用于颅内肿瘤靶向的研究

The significance of the elasticity of biomedical materials has been widely recognized in the field of biomedical engineering. For example, cell culture substrates of vary elasticity have been showed to direct and control cell fates, optimize cell growth, and even improve the delivery of therapeutics. Similarly, the in vivo fate of nanocarriers were influenced by the elasticity of themselves, which in turn is the premise of active and passive target. It is verified that the elasticity of nanocarrier could have an effect on the MPS clearance, specific receptor-ligand interaction, cellular uptake, lysosome escape and responsive release although the mechanisms are not so clear. The present study aims to construct multi-functional nanoliposomes by (1) the preparation of nanoliposome with tunable structure elasticity; (2) the synthesis of functional phosphate derivatives composed of DSPE and peptides such as c(RGDfK) or tLyp-1; (3) the preparation of nanoliposome with tunable surface elasticity. We will investigate the stability, drug loading and responsive release, brain and tumor targeting, cellular uptake and biodistribution by the combination of multi-discipline technologies and principles, such as biophysics, light scattering, AFM, molecular dynamic model, fluorescence, thermodynamics and kinetic principles. The mechanisms of elasticity of nanoliposomes involved in the opsonization, phagocytosis and macropinocytosis by MPS, BBB and BBTB bypassing efficacy, tumor cellular uptake and lysosome escape will be fully explored. The result would provide the theoretical and experiment basis for the design of the elasticity of nanocarriers.

生物体细胞的柔性在很多生理过程中发挥重要作用；生物医学材料的柔性同样影响其与生物体之间的相互作用，如调节干细胞的分化、优化细胞生长状态、改善药物吸收；纳米载体的体内命运如单核巨嗜系统的调理、特异性受体-配体相互作用、靶细胞的内吞和响应性释放也受其柔性的影响，但规律性和机制尚不明确。脂质体具有类细胞的结构本质，载药性质广泛，分子柔性可通过制备材料、交联和表面修饰来调节，易于构建柔性可调控的纳米载体。本项目拟利用不同链长及饱和程度的磷脂、掺入"边缘活性剂"、内交联结合具高效跨越血脑屏障和肿瘤深部穿透作用的多肽，构建柔性可调控，对胞内还原环境具自响应能力的多功能纳米脂质体。综合利用生物物理技术、光散射技术、原子力显微镜、分子动力学和热力学原理，探讨纳米脂质体柔性影响下的体循环时间、脑靶向和肿瘤深部穿透效率以及响应性释放的一般规律和内在机制，为实现颅内肿瘤靶向的纳米载体结构设计和柔性调控提供依据。

生物体细胞的柔性在很多生理过程中发挥重要作用；生物医学材料的柔性同样影响其与生物体之间的相互作用，如调节干细胞的分化、优化细胞生长状态、改善药物吸收；纳米载体的体内命运如单核巨嗜系统的调理、特异性受体-配体相互作用、靶细胞的内吞和响应性释放也受其柔性的影响，但规律性和机制尚不明确。.脂质体具有类细胞的结构本质，载药性质广泛，分子柔性可通过制备材料、交联和表面修饰来调节，易于构建柔性可调控的纳米载体。本项目通过改变制备材料，制备了结构柔性差异化的纳米柔性脂质体，采用荧光偏振技术和荧光共振能量转移技术量化了产物的结构柔性，探讨了结构柔性变化和制备材料种类、用量的关系。进一步系统研究了在柔性改变和调控下，纳米脂质体粒径大小、形态、包封率和载药量的变化，系统深入研究了纳米脂质体结构柔性变化对体循环时间、脑肿瘤靶向效率的影响。.在此基础上，通过改变制备工艺和处方调整，结合功能磷脂tLyp-1-PEG2000-DSPE，制备了内水相可调控的具有脑肿瘤靶向的纳米脂质体，对脂质体内水相的影响因素进行了广泛考察，对内水相大小进行了表征。对产物的体内、外性质进行了系统研究，对产物的脑肿瘤靶向效率进行了研究和确认。