近年來科學家致力於發展具有超分子自組裝形成高分子聚合物特性的建構單元 (monomer) 以及操控階級式 (hierarchical) 的超分子結構。啟發於自然界,建構單元能透過協同性非共價作用力 (cooperative non-covalent interactions) 聚合,進而達到設計的型態及功能。然而操控由合成的巨分子 (macromolecule) 作為超分子聚合 (supramolecular polymerization) 單體仍然是具挑戰性的研究,因為監測以及控制主導超分子聚合過程的二級作用力有實務上困難。因此本研究發展以具有螢光訊號輸出特性的皇冠醚修飾聚胜肽高分子 (polypeptide) 偵測超分子聚合過程,同時發展經由活化氨酯 (activated-urethane) 衍生物以原位 (in situ) 生成N - 羧酸内酸酐 (N-carboxyanhydride) 並聚合功能性聚胜肽高分子。所合成的高分子能夠以高度協同性作用力與金屬離子 (Na(I), Hg(II)) 或氨鹽類 (n-butylammonium) 結合,透過電子顯微鏡以及螢光共軛焦顯微鏡觀察觀測到作用後的高分子能自組裝形成直徑在微米等級的球狀物。經過長時間靜置,此與金屬離子或氨鹽類結合的巨分子能進一步進行超分子聚合成核 (nucleation) 並延展 (elongation) 成螺旋狀絲帶。
Supramolecular assembly draws attempts in developing building blocks and manipulating hierarchical suprastructure. Inspired by natural system, constituents can be polymerized through cooperative non-covalent interactions to achieve designed morphologies and programmed functions. However, controlled supramolecular polymerization from synthetic macromolecules still remains a challenge because of the difficulty in monitoring and controlling the underlying interactions. Herein we report a crown ether fabricated polypeptide with fluorescence readout to probe the non-covalent interactions. A facile approach to functionalize polypeptide by in situ generated NCA from corresponding precursor-activated urethane derivatives is developed. The resulting polymer exhibits highly cooperative interactions with either metal ions (Na(I) or Hg(II)) or ammonium salt (n-butylammonium) and further assembles to well defined spherical particles with micrometer in diameter based on the observation via transmission/scanning electron microscopy and fluorescence confocal microscopy. Prolonged incubation of the supramolecular polymeric macromolecules triggers time dependent nucleation and elongation to supramolecular twisted ribbon.