Effects of polydepsipeptide side-chain groups on the temperature sensitivity of triblock copolymers composed of polydepsipeptides and poly(ethylene glycol)

Authors

  • Yuichi Ohya,

    Corresponding author
    1. Department of Chemistry and Materials Engineering, Faculty of Chemistry Materials and Bioengineering, Kansai University, Suita, Osaka 564-8680, Japan
    2. High Technology Research Center, Kansai University, Suita, Osaka 564-8680, Japan
    • Department of Chemistry and Materials Engineering, Faculty of Chemistry Materials and Bioengineering, Kansai University, Suita, Osaka 564-8680, Japan
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  • Hidetoshi Yamamoto,

    1. Department of Chemistry and Materials Engineering, Faculty of Chemistry Materials and Bioengineering, Kansai University, Suita, Osaka 564-8680, Japan
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  • Koji Nagahama,

    1. Department of Chemistry and Materials Engineering, Faculty of Chemistry Materials and Bioengineering, Kansai University, Suita, Osaka 564-8680, Japan
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  • Tatsuro Ouchi

    1. Department of Chemistry and Materials Engineering, Faculty of Chemistry Materials and Bioengineering, Kansai University, Suita, Osaka 564-8680, Japan
    2. High Technology Research Center, Kansai University, Suita, Osaka 564-8680, Japan
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Abstract

To develop new types of biodegradable polymers possessing predictable responses to changes in temperature, ABA-type and BAB-type triblock copolymers composed of various polydepsipeptides (PDP) and poly(ethylene glycol) (PEG) (PDP-PEG-PDP and PEG-PDP-PEG) were synthesized. The specific focus of this study was on the effect of the different side-chain groups of various amino acids on the temperature-responsive behavior of the triblock copolymers. An ABA-type triblock copolymer containing the less hydrophobic glycine (PGG-PEG-PGG) did not exhibit any temperature-responsive behavior; however, ABA-type triblock copolymers containing the hydrophobic α-amino acids, L-leucine and L-phenylalanine (PGL-PEG-PGL or PGF-PEG-PGF), did exhibit temperature-responsive behavior. The cloud point of PGF-PEG-PGF was 10 °C lower than that of PGL-PEG-PGL. It can be possible to control temperature-sensitivity by changing not only PDP segment length but also kind of α-amino acid in PDP segment. Moreover, BAB-type triblock copolymer containing L-leucine (PEG-PGL-PEG) showed temperature-responsive sol-gel transition. Because polydepsipeptides are biodegradable polymers, the information obtained in this study is useful to design biodegradable injectable polymers having controllable temperature-sensitivity for biomedical use.© 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3892–3903, 2009

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