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Issue 12, 2008
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Significance of secondary structure in nanostructure formation and thermosensitivity of polypeptide block copolymers

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Abstract

Well-defined nanostructural control from biological motifs is gaining attention among materials scientists. We are reporting that the β-sheet structure of L-polyalanine plays a critical role in developing a fibrous nanostructure as well as the sol-to-gel transition of amphiphilic poly(ethylene glycol)-L/or DL-polyalanine diblock copolymers. L-isomers underwent transitions from random coils to β-sheets, and to nanofibers as the polymer concentration increased, whereas the DL-isomer remained as a random coil structure without developing any specific nanostructure. At high polymer concentrations, the aqueous polymer solutions underwent a sol-to-gel transition as the temperature increased, a so called reverse thermal gelation. The L-isomer with a preassembled β-sheet secondary structure facilitates the sol-to-gel transition rather than the DL-isomer with a random coil structure. Thus, only the L-isomer showed a sol-to-gel transition in the physiologically important range of 20–40 °C. This report provides fundamental information on the relationship between hierarchical structures of polypeptides and the thermosensitive sol-gel transition of the polypeptide aqueous solution.

Graphical abstract: Significance of secondary structure in nanostructure formation and thermosensitivity of polypeptide block copolymers

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Publication details

The article was received on 29 May 2008, accepted on 10 Sep 2008 and first published on 21 Oct 2008


Article type: Paper
DOI: 10.1039/B809116A
Citation: Soft Matter, 2008,4, 2383-2387
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    Significance of secondary structure in nanostructure formation and thermosensitivity of polypeptide block copolymers

    Y. Y. Choi, M. K. Joo, Y. S. Sohn and B. Jeong, Soft Matter, 2008, 4, 2383
    DOI: 10.1039/B809116A

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