新型结构材料的可控制备一直是高分子材料科学研究的重中之重。这里,采用超分子结合策略开发具有新结构和功能的共价有机框架(COFs)。基于此,二维冠醚环螺纹共价有机框架(COF),表示为具有固有光热(PTT)和光动力(PDT)治疗能力的Crown-COPF,以冠醚螺纹轮烷和卟啉为基础,很容易开发。在开孔中具有离散的机械互锁块的Crown-COPF可以用作分子机器,其中冠醚作为车轮在激光刺激下沿着轴滑动。因此,Crown-COPF与冠醚的杀菌力结合显示出对革兰氏阴性(大肠杆菌)和革兰氏阳性(金黄色葡萄球菌)的显着光热和光动力抗菌活性,远远超过传统的无冠COF。值得注意的是,通过与多个配位位点(冠醚,联吡啶,和卟啉),它不仅赋予骨架正电荷,增强其与细菌膜结合的能力,还要介绍锌离子的杀菌能力。值得注意的是,对背部感染小鼠的体内实验表明,具有自适应多核锌中心的Crown-COPF-Zn,能有效促进伤口的修复。本研究为有效制备具有全新结构的多孔聚合物开辟了一条新途径,这为COF和机械互锁聚合物(MIP)的研究和应用提供了机会。
Controllable preparation of materials with new structure has always been the top priority of polymer materials science research. Here, the supramolecular binding strategy is adopted to develop covalent organic frameworks (COFs) with novel structures and functions. Based on this, a two-dimensional crown-ether ring threaded covalent organic framework (COF), denoted as Crown-COPF with intrinsic photothermal (PTT) and photodynamic (PDT) therapeutic capacity, was facilely developed using crown-ether threaded rotaxane and porphyrin as building blocks. Crown-COPF with discrete mechanically interlocked blocks in the open pore could be used as a molecular machine, in which crown-ether served as the wheel sliding along the axle under the laser stimulation. As a result, Crown-COPF combining with the bactericidal power of crown ether displayed a significant photothermal and photodynamic antibacterial activity towards both the Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus), far exceeding the traditional Crown-free COF. Noteworthily, the bactericidal performance could be further enhanced via impregnation of Zn2+ ions (Crown-COPF-Zn) flexible coordinated with the multiple coordination sites (crown-ether, bipyridine, and porphyrin), which not only endow the positive charge with the skeleton, enhancing its ability to bind to the bacterial membrane, but also introduce the bactericidal ability of zinc ions. Notably, in vivo experiments on mice with back infections indicates Crown-COPF-Zn with self-adaptive multinuclear zinc center, could effectively promote the repairing of wounds. This study paves a new avenue for the effectively preparation of porous polymers with brand new structure, which provides opportunities for COF and mechanically interlocked polymers (MIPs) research and applications.