层层自组装修饰脂质体的结构特性变化与摄取释放的关系

Liposome as a deliver system is an nternational advanced technique and research hotspot in biological medicine, foodstuff chemical and other fields. However, there are still issues including membrane structure modification, drug control release, efficient drug targeting greatly needed to be further studied. Thus, in this work, layer-by-layer self-assembly coated liposome (LCL) will be prepared based on our previous work by large scale-small scale-large scale technique together with alternate coating strategy with positive and negative polyelectrolytes, in which physical and chemical stability of liposome have been significantly improved by layer-by-layer self-assembly coating. Structure properties (spectral structures, microstructure, the properties of particles and membrane), and theoretical stability ratio will be analyzed by modern instruments and classical DLVO theory, which aim to discuss variation of structure properties and mechanical behavior. In addition, cellular uptake properties including cellular compatibility, cellular uptake kinetics, cellular mechanism, and cellular intracellular distribution will be determined. Then, dissipative particle dynamics (DPD) method will be introduced to simulate the process of endocytosis of LCL, which aim to establish the relationship between structure properties and cellular uptake properties. Release properties of LCL during in vitro environment (simulated gastrointestinal tract, physical and chemical inducing) and cellular environment will be measured. Then, release model will be further to establish, which plant to illuminate the relationship between structure properties and release characteristic. It aims to provide new idea and theoretic reference for in-depth liposomal researches including effective approaches to adjust membrane structure, drug control release and efficient drug targeting.

脂质体作为运载体系是生物医药和食品化工等领域的国际前沿技术和研究热点，但膜结构修饰、药物控释和有效靶向性等问题有待深入。本项目在前期制备层层自组装修饰脂质体有效提高其物化稳定性的基础上，拟采用大尺寸－小尺度－大尺寸制备技术和正负聚电解质静电沉积作用修饰策略制备层层自组装修饰脂质体（LCL），采用现代分析手段表征其结构（光谱结构、微观结构、粒子特性、膜特性），以经典DLVO理论计算其理论稳定性，探讨LCL结构特性和力学行为的变化影响；通过测定其细胞摄取性质（细胞相容性、摄取动力学、途径、定位和内分布等），以耗散动力学模拟LCL内吞过程，探讨LCL结构特性变化与细胞摄取性质的关系；通过测定模拟胃肠道、物理和化学诱导环境及细胞环境下释放的变化，构建动力学释放模型，探讨LCL的结构特性变化与其体内体外释放性质的关系，为深入研究脂质体膜结构的有效调控、细胞靶向性和药物控释行为提供新的思路和理论参考。

脂质体技术在食品、化妆品和医药领域中有广阔的应用前景，能有效的提高活性成分的溶解度和生物利用率，然而脂质体本身存在物理稳定性差，在热处理和贮藏过程中易发生融合、破裂、药物泄漏等问题。脂质体修饰技术能有效改善脂质体的稳定性，然而其膜结构修饰与其控释和靶向性尚不清晰。本项目采用膜层修饰结合表面修饰技术，利用疏水作用力和静电作用力将壳聚糖、植物甾醇、Pluronic、叶酸等修饰剂结合到脂质体膜层或脂质体表面，降低脂质体膜流动性，提高其稳定性，控制活性成分的释放速率和释放位点。研究结果如下：（1）膜层修饰对脂质体结构和释放特性的影响：磷脂酰胆碱是脂质体的主要组成部分，磷脂酰乙醇胺能降低脂质体膜流动性，降低脂质体的粒径，提高稳定性；鼠李糖脂和火龙果茎植物甾醇在疏水作用力的驱动下，能镶嵌到脂质体膜层中，能替代胆固醇，降低脂质体膜流动性，提高脂质体稳定性，并改善姜黄素在脂质体中的释放特性；（2）聚电解质表面修饰对脂质体稳定性和细胞摄取率的影响：叶酸-壳聚糖通过静电作用能吸附到脂质体表面，显著提高姜黄素的理化性质和细胞摄取，叶酸壳聚糖能显著提高姜黄素脂质体在Hela细胞的特异性摄取。双亲性嵌段聚合物Pluronic则能吸附在脂质体膜层表面，从而提高其在不同理化环境下的稳定性，提高姜黄素在脂质体中的缓释性能及细胞摄取率；（3）层层自组装修饰对脂质体稳定性和释放的关系：在膜层修饰的基础上，采用壳聚糖层层修饰能进一步降低脂质体膜层的泄漏率，实现姜黄素等活性物质在脂质体膜层中的缓慢释放；（4）在本基金的资助下，本团队还研究了一种新型姜黄素等多酚类物质的包埋方法，即pH驱动法，该方法基于多酚类物质在不同pH条件下的溶解度不同，从而实现多酚类物质自组装形纳米粒子，成该方法具有简单快速，无需引入有机试剂，易于工业化应用等优点。该项目现已圆满完成预期目标，在Food Hydrocolloids, Food Chemistry、Journal of Agricultural and Food Chemistry等期刊发表17篇论文（SCI文章15篇，其中一区7篇）；培养博士生2名、硕士生3名。