双重仿生生物大分子口服纳米载体的结构要素研究

Insufficient mucus permeability and cellular uptake of conventional nanoparticles are the main bottlenecks that restrict their application in the field of oral mucosal delivery. The design of nano-carriers that are stable, with high mucus penetrating capacity and meanwhile can be efficiently absorbed by epithelial cells is the key to solve this problem. However, the relationship between the structural characteristics of nanoparticles and the permeability of mucus, uptake of epithelial cells is unclear. In order to solve the above problems, insulin is used as a biological macromolecular model drug. Through the functional bionic of virus capsid and mucus bionic of the capsid composition, the structure-activity relationship between the structural characteristics of nanoparticles and their mucus permeability and epithelial cell uptake is clarified. Firstly, bionic virus capsid nanoparticles were constructed based on the highly specific non-covalent binding property of biotin - avidin. Thereafter, multiple polymeric viroid capsid nanoparticles were constructed by combining chitosan or its derivatives with polyanionic polymers of different structures. The effects of polyanionic structural elements and polycationic structural elements on the mucus-penetration and cellular uptake of the nanoparticles were systematically elucidated. Furthermore, the correlation between the surface structural elements of the nanoparticles and their mucus-penetration and epithelial cell uptake were also clarified from cellular and animal level. The completion of this project will lay a solid theoretical foundation for the design of biomacromolecule mucosal delivery system based on nanotechnology. The research results are also applicable to the design of other mucous delivery systems.

常规纳米粒子黏液渗透性不足及细胞摄取障碍是制约其在口服等黏膜递药领域应用的主要瓶颈。稳定、高黏液渗透且能被肠上皮细胞有效摄取的纳米载体设计是解决该问题的关键。但纳米粒结构特性与其黏液渗透性及细胞摄取间关系尚不清楚。本项目拟针对上述问题，以胰岛素作为生物大分子模型药物，通过病毒衣壳的功能仿生及衣壳组成的黏液仿生, 阐明纳米粒结构特性与其黏液渗透性、上皮细胞摄取间构效关系。首先基于生物素-亲和素的高特异非共价结合特性构建生物仿病毒衣壳纳米粒，继而分别以壳聚糖或其黏液仿生衍生物与不同结构聚阴离子聚合物构建多元聚合物双重仿生衣壳纳米粒，系统阐明聚阴离子及聚阳离子的结构要素对纳米粒黏液渗透及细胞摄取的影响, 并从细胞和整体动物水平阐明纳米粒的表面结构要素与黏液渗透、细胞摄取间相关性。本项目的完成将为基于纳米技术的生物大分子黏膜递送系统设计奠定坚实的理论基础。其研究成果同样适用于其他黏液递药系统设计。

常规纳米粒子黏液渗透性不足及细胞摄取障碍是制约其在口服等黏膜递药领域应用的主要瓶颈。稳定、高黏液渗透且能被肠上皮细胞有效摄取的纳米载体设计是解决该问题的关键。但纳米粒结构特性与其黏液渗透性及细胞摄取间关系尚不清楚。本项目针对上述问题，以胰岛素作为生物大分子模型药物，通过病毒衣壳的功能仿生及衣壳组成的黏液仿生, 阐明了纳米粒结构特性与其黏液渗透、上皮细胞摄取间的关系。首先基于生物素-亲和素的高特异非共价结合特性，在优化了壳聚糖-生物素接枝度的基础上构建了生物仿病毒衣壳纳米粒，同时构建了分别以壳聚糖、壳聚糖接枝苯丙氨酸、壳聚糖接枝脯氨酸、壳聚糖接枝丝氨酸、壳聚糖接枝苏氨酸、壳聚糖接枝叶酸等与不同结构聚阴离子聚合物如透明质酸、海藻酸钠等的多元聚合物仿病毒衣壳纳米粒。结果表明，聚阴离子及聚阳离子的结构组成和接枝度对纳米粒黏液渗透及细胞摄取产生重要影响，其中，包衣外壳分子结构中包括酯键、负电性基团、糖单元结构可影响其黏液渗透性，聚阴离子多糖中如含有与黏蛋白中多糖相同的N-乙酰半乳糖胺结构，可显著降低与黏液的相互作用力，从而表现出更好的黏液渗透增强作用。从生物仿生角度模拟病毒蛋白衣壳结构的纳米粒相比聚合物仿生病毒衣壳结构具有更好的黏液和肠渗透性，且不同于聚合物仿生以网格蛋白主导的肠细胞内吞方式，生物仿生纳米粒主要涉及小窝蛋白介导的能量依赖型多种转运途径。同时，纳米载体的体内吸收是表面性质依赖的，经过适当调控的亲水性优于疏水性修饰。此外，黏液渗透性纳米粒中药物的释放速度对其体内吸收影响显著。将黏液渗透纳米粒子与主动跨肠细胞转运相结合，可更好促进其肠道吸收。但基于相同内核的黏液渗透型和黏液黏附型纳米粒子的研究表明，黏附型和渗透型纳米粒在促进胰岛素体内吸收方面表现出了相当的效果，只是体内吸收机制不同，渗透性纳米粒起效略快于黏附型。希望该研究成果可为生物大分子口服纳米递送系统的设计提供参考借鉴。