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PH/temperature sensitive chitosan-g-(PA-PEG) aqueous solutions as new thermogelling systems

Title
PH/temperature sensitive chitosan-g-(PA-PEG) aqueous solutions as new thermogelling systems
Authors
Jang J.H.Choi Y.M.Choi Y.Y.Joo M.K.Park M.H.Choi B.G.Kang E.Y.Jeong B.
Ewha Authors
정병문
SCOPUS Author ID
정병문scopus
Issue Date
2011
Journal Title
Journal of Materials Chemistry
ISSN
0959-9428JCR Link
Citation
vol. 21, no. 14, pp. 5484 - 5491
Indexed
SCOPUS WOS scopus
Abstract
As a new thermal gelling polymer aqueous solution, we are reporting a poly(ethylene glycol)-poly(alanine) grafted chitosan (CS-g-(PA-PEG)) system. The sol-gel transition temperature and the modulus of the in situ-formed thermal gel at 37°C changed 17 → 27 →32°C and 396 → 241 → 43 Pa, respectively, as the pH increased from 3.0 to 6.5 and to 9.0. The mechanism of such a pH/temperature sensitive behaviour of the CS-g-(PA-PEG) aqueous solution was investigated by studying changes in the conformation of chitosan, polyalanine and PEG of the CS-g-(PA-PEG). As the temperature increased, ammonium groups of the chitosan partially deprotonated to a neutral form, the α-helical content of the polyalanine increased and molecular motion of the PEG decreased. Such changes cooperatively increase the hydrophobicity and viscosity of CS-g-(PA-PEG), resulting in the sol-gel transition of the polymer aqueous solution with increasing temperature. As the pH increased, ammonium groups of the chitosan deprotonated to a neutral form and the α-helical content of polyalanine decreased, which induce a change in the nanoassembly of the polymer. CS-g-(PA-PEG) significantly increased the gel modulus of a previously reported PEG grafted chitosan (CS-g-PEG) thermal gel by incorporating the α-helical polyalanine moieties between CS and PEG. The CS-g-(PA-PEG) could be a promising biomaterial as a new robust thermogel with pH and temperature sensitivity. © 2011 The Royal Society of Chemistry.
DOI
10.1039/c0jm03894f
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자연과학대학 > 화학·나노과학전공 > Journal papers
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