细胞穿膜肽-聚合物偶联物的合成、组装与载药机制研究

Cell-penetrating peptides (CPP) are short peptides with outstanding ability to translocate the plasma membrane and they play vital roles in many critical biological processes, such as those involved in the invasion of viruses to cells and in vivo delivery of many biomacromolecules. In order to improve the stability of CPP in vivo as well as the ability to target special cells, we carry out research on the design and synthesis of CPP-polymer conjugates. The self-assembly behaviour, drug delivery ability and cell-penetrating mechanism of CPP-polymer conjugates and relative assemblies were also discussed. CPP macroinitiators were first synthesized via chemical modification of certain functional groups and well-defined polymers with controlled molecular weight (MW), narrow MW distribution and multiblock structures were then in-situ grafted from CPP by single electron transfer living radical polymerization (SET-LRP) efficiently. Through particular selection of functional monomers, the synthesized CPP-polymer conjugates could have environmental responsive property and recognition behaviour with special proteins. Following that the effect of the structure and composition of CPP and polymer as well as the environmental factors on the self-assembly behaviour of the conjugates was discussed. The drug delivery ability and cellular uptake mechanism of the CPP-polymer conjugates and relative assemblies were further explored. It’s proposed that this research will be able to develop novel strategies in the synthesis of CPP-polymer conjugates and promote the research on relative self-assembly and cell-penetrating mechanism.

细胞穿膜肽是一类具有优异的细胞膜穿透能力的短肽，在病毒对细胞的入侵以及生物活性大分子的体内转运等生命过程中发挥着重要作用。针对穿膜肽的稳定性及细胞特异性相对较差的特点，本项目开展穿膜肽-聚合物偶联物的结构设计与分子合成，系统研究偶联物的组装行为，并探索偶联物及其组装体的载药和跨膜传递机制。在设计制备出特定位点修饰的穿膜肽大分子引发剂的基础上，利用单电子转移活性自由基聚合，高效地从穿膜肽主链原位接枝一系列界定良好的具有可控分子量、窄分子量分布和多嵌段结构的聚合物，并通过功能性单体的选择赋予偶联物环境响应特性和对特定蛋白的靶向识别能力。进一步研究偶联物在水中的自组装行为，系统分析穿膜肽和聚合物的结构、组成以及外界环境因素对其自组装行为的影响，并初步探索偶联物及其组装体的载药行为和相关的细胞摄取机制。本项目可为穿膜肽-聚合物偶联物的合成、组装及载药传递机制的研究提供思路和理论支撑。

项目执行期间，首先建立了一系列单电子转移自由基聚合方法，用于合成儿茶酚端基功能聚合物，并实现了对二氧化钛等无机纳米材料的表面接枝。发展的方法能够实现在儿茶酚、强极性溶剂等竞争性条件下的活性/可控自由基聚合，得到具有儿茶酚端基、设定分子量和窄分子量分布的聚合物。对无机纳米材料的表面接枝采用了“接枝到表面”和“从表面接枝”两种不同的策略，均取得了成功的表面修饰，得到了具有多重环境响应行为的智能纳米材料，并用于蛋白质的偶联和表面固定。在此聚合方法基础之上，发展了新型的蛋白质-聚合物偶联物合成策略，利用漆酶这一天然铜蛋白作为酶催化“点击化学”反应，实现了蛋白质与聚合物的高效偶联；利用水体系中进行的单电子转移自由基聚合，从蛋白质表面原位引发聚合，获得了具有环境响应行为的蛋白质-聚合物偶联物。项目最后开展了含糖聚合物型纳米海绵的合成研究，制备了具有有机污染物高效萃取和硼酸可逆螯合两种功能的多孔纳米海绵，这是具有硼酸吸附能力的环糊精聚合物材料的首次报道。