Controlling the Supramolecular Polymerization of Squaraine Dyes by a Molecular Chaperone Analogue

ABSTRACT: Molecular chaperones are proteins that assist in the (un)folding and (dis)assembly of other macromolecular structures toward their biologically functional state in a non-covalent manner. Transferring this concept from nature to artificial self-assembly processes, here, we show a new strategy to control supramolecular polymerization via a chaperone-like two-component system. A new kinetic trapping method was developed that enables efficient retardation of the spontaneous self-assembly of a squaraine dye monomer. The suppression of supramolecular polymerization could be regulated with a cofactor, which precisely initiates self-assembly. The presented system was investigated and characterized by ultraviolet–visible, Fourier transform infrared, and nuclear magnetic resonance spectroscopy, atomic force microscopy, isothermal titration calorimetry, and single-crystal X-ray diffraction. With these results, living supramolecular polymerization and block copolymer fabrication could be realized, demonstrating a new possibility for effective control over supramolecular polymerization processes.摘要：分子伴侣（molecular chaperone）是一类以非共价方式辅助其他大分子结构完成（去）折叠与（解）组装，使其达到生物学功能状态的蛋白质。本研究将这一自然概念拓展至人工自组装领域，提出了一种基于类分子伴侣双组分体系调控超分子聚合的全新策略。本研究开发了一种新型动力学捕获方法，可有效延缓方酸菁染料（squaraine dye）单体的自发自组装过程。超分子聚合的抑制过程可通过辅因子进行调控，辅因子可精准触发自组装过程。本研究通过紫外-可见（ultraviolet–visible）光谱、傅里叶变换红外（Fourier transform infrared）光谱、核磁共振（nuclear magnetic resonance）波谱、原子力显微镜（atomic force microscopy）、等温滴定量热法（isothermal titration calorimetry）以及单晶X射线衍射（single-crystal X-ray diffraction）对该体系进行了表征与研究。基于上述研究结果，本研究成功实现了活性超分子聚合与嵌段共聚物的制备，为超分子聚合过程的精准调控提供了全新的可行路径。