Gelation of Helical Polypeptide-Random Coil Diblock Copolymers by a Nanoribbon Mechanism
Autor: | Chiyoung Park, Mitchell A. Winnik, Kyoung Taek Kim, Ian Manners, Guido W. M. Vandermeulen, David A. Rider, Chulhee Kim |
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Rok vydání: | 2005 |
Předmět: |
chemistry.chemical_classification
Materials science Molecular Structure Polymers Supramolecular chemistry General Chemistry Polymer General Medicine Microscopy Atomic Force Catalysis Random coil Crystallography chemistry Liquid crystal Phase (matter) Helix Copolymer Nanotechnology Self-assembly Organic Chemicals Peptides Gels |
Zdroj: | Angewandte Chemie. 117:8178-8182 |
ISSN: | 1521-3757 0044-8249 |
DOI: | 10.1002/ange.200502809 |
Popis: | The polypeptide poly(g-benzyl-l-glutamate) (PBLG) serves as a model rod-like polymer in solution and in the solid state because of its rigid a-helix conformation. The stiff rod-like conformation of the PBLG helix is a crucial prerequisite for its unique solution behavior such as liquid crystalline ordering and thermoreversible gelation. Nematic ordering (orientational order of rod-like molecules) is responsible for the thermoreversible gelation of PBLG in dilute solution. Diblock copolymers of PBLG and flexible organic polymers are unable to form a nematic phase due to the presence of a block with a bulky random-coil conformation. Here we report the discovery of thermoreversible gelation of diblock copolymers of PBLG in dilute solution which has not been observed previously despite many studies of such materials. We also explain the gel formation of PBLG-based diblock copolymers in solution by a mechanism which is distinct from the current understanding of PBLG self-assembly. Based on our findings, we describe the formation of self-assembled functional scaffolds with precisely aligned fluorescent labels. The results illustrate a novel and general mode of self-assembly for block copolymers of PBLG and presumably other helical polypeptides and demonstrate an attractive new approach to nanostructured supramolecular materials derived from biological and synthetic polymers. Our initial studies involved the synthesis of poly(ferrocenylsilane)-b-poly(g-benzyl-l-glutamate) (PFS-b-PBLG), conjugates of an organometallic polymer and polypeptides with narrow molecular weight distributions (Figure 1a, Table 1). |
Databáze: | OpenAIRE |
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