环状组装体的形成机理、表面图案化及其细胞膜成孔行为的研究

环是自然界中重要的结构。聚合物自组装可以制备环状结构，但是通常与棒等其它结构共存。目前尚未掌握聚合物自组装成环的控制规律和内在机理。在前期研究中，申请人发现了棒状胶束弯曲环化制备规整环状结构以及聚合物直接自组装形成螺旋表面环状结构的新现象。基于这些环状组装体制备的研究，本项目拟系统开展环状组装体的制备、表面图案结构调控及其在细胞膜上内嵌成孔行为的研究。采用直接组装和间接组装两种方法制备表面图案化环状组装体。在直接方法中，聚肽嵌段共聚物与聚肽均聚物共混自组装，形成表面图案化环状组装体；在间接方法中，先由聚肽接枝共聚物自组装形成环，然后聚肽嵌段共聚物在环表面自组装形成不同纳米图案。在掌握环状组装体的可控制备以及表面图案调控规律的基础上，开展环状组装体与细胞相互作用的研究，探索环状组装体在细胞膜上成孔的条件和规律。另外，结合实验研究开展理论模拟计算，深化实验观察并指导实验研究。

The toroid is a fundamental geometrical structure in nature. Polymers are capable of assembling into toroidal structures, however, they usually coexisted with rod-like and other morphological structures. Currently, the formation mechanism for the toroids has not been explored. In the previous work of the applicant, toroidal structures have been prepared through a supramolecular cyclization of rod-like micelles (producing toroid exclusively) and self-assembly of a mixture of block copolymers and homopolymers (coexisting with rod-like structures). In this proposal, based on the applicant’s previous work, we aim to systematically study the formation of the toroids and surface patterning of the toroids, and seek the possibility of these surface-patterned toroids as a hole-formation agent on the cell membrane. Two approaches, i.e., direct and indirect approaches will be applied to construct the surface-patterned toroidal nanostructure. In the direct way, the toroids with various surface patterns are self-assembled from polymer mixtures containing polypeptide block copolymers and polypeptide homopolymers. In the indirect way, toroidal nanostructures are first self-assembled from polypeptide graft copolymers through a rod-like micelle-toroid route as reported in our previous work. Subsequently, polypeptide block copolymers self-assemble with the toroids constructing various surface patterns on the toroids. Through these researches, the formation mechanism for the toroidal nanostructures as well as the surface patterns will be revealed, and the method for constructing the surface patterned toroidal nanostructures will be governed. On the basis of the controlled preparation of the surface patterned toroidal nanostructures, we intend to investigate the interactions between the toroids and cells focusing on the hole-forming property of the toroids. By studying, the structure characters of the toroids and the surface patterns facilitating the hole forming on the cell membrane will be summarized. In addition to the experimental studies, theoretical simulations will be carried out to explore both the self-assembly mechanisms and the insertion and hole-forming behavior of the toroidal nanostructures. The results gained from the studies could provide valuable information and guidance for the controllable preparation of surface patterned toroidal structures as well as the further applications.