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Newly designed hydrogel with both sensitive thermoresponse and biodegradability

Authors

  • Takatsune Yoshida,

    1. Institute of Applied Biochemistry, University of Tsukuba, 1-1-1 Tennodai, Tsukuba-shi, Ibaraki-ken 305-8572, Japan
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  • Takao Aoyagi,

    Corresponding author
    1. Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
    Current affiliation:
    1. Department of Nanostructured and Advanced Materials, Graduate School of Science and Engineering, Kagoshima University, 1-21-40, Korimoto, Kagoshima 890-0065, Japan
    • Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
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  • Etsuo Kokufuta,

    1. Institute of Applied Biochemistry, University of Tsukuba, 1-1-1 Tennodai, Tsukuba-shi, Ibaraki-ken 305-8572, Japan
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  • Teruo Okano

    1. Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
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Abstract

The synthesis and characterization of thermoresponsive hydrogels on the basis of N-isopropylacrylamide (IPAAm) copolymers crosslinked with biodegradable poly(amino acids) are described. This hydrogel was prepared with two kinds of reactive IPAAm-based copolymers containing poly(amino acids) as the side-chain groups and activated ester groups. We introduced the graft chains by decarboxylation polymerization of amino acid N-carboxyanhydrides initiated from lateral amino groups in the PIPAAm copolymer. The hydrogels easily crosslinked with degradable poly(amino acid) chains by only mixing the copolymer aqueous solutions. The gelling method in this study would provide some of the following innovative features: (1) no necessary removal of unreacted monomers and so forth, (2) simpler loading of drugs into the hydrogels (only mixing when gelling), and (3) easier insertion into the body. On the basis of the swelling ratio measurement of the hydrogel, large volume changes dependent on temperature changes were observed. Moreover, the enzymatic temperature-dependent degradation was confirmed. The results suggested that these hydrogels could be used for an injectable or implantable matrix of temperature-modulated drug release. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 779–787, 2003

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