Deposition of bone-like apatite on modified silk fibroin films from simulated body fluid

Authors

  • Rikako Kino,

    Corresponding author
    1. Division of Frontier Research, Creative Research Initiative “SOUSEI” (CRIS), Hokkaido University, Kita 21, Nishi 10, Kita-ku, Sapporo 001-0021, Japan
    2. Faculty and Graduate School of Engineering, Hokkaido University, Kita 13, Nishi 9, Kita-ku, Sapporo, 060-8628, Japan
    • Division of Frontier Research, Creative Research Initiative “SOUSEI” (CRIS), Hokkaido University, Kita 21, Nishi 10, Kita-ku, Sapporo 001-0021, Japan
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  • Toshiyuki Ikoma,

    1. Biomaterials Center, National Institute for Materials Science, Namiki 1–1, Tsukuba, Ibaraki 305-0044, Japan
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  • Akira Monkawa,

    1. Biomaterials Center, National Institute for Materials Science, Namiki 1–1, Tsukuba, Ibaraki 305-0044, Japan
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  • Shunji Yunoki,

    1. Biomaterials Center, National Institute for Materials Science, Namiki 1–1, Tsukuba, Ibaraki 305-0044, Japan
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  • Masanobu Munekata,

    1. Faculty and Graduate School of Engineering, Hokkaido University, Kita 13, Nishi 9, Kita-ku, Sapporo, 060-8628, Japan
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  • Junzo Tanaka,

    1. Division of Frontier Research, Creative Research Initiative “SOUSEI” (CRIS), Hokkaido University, Kita 21, Nishi 10, Kita-ku, Sapporo 001-0021, Japan
    2. Biomaterials Center, National Institute for Materials Science, Namiki 1–1, Tsukuba, Ibaraki 305-0044, Japan
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  • Tetsuo Asakura

    1. Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
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Abstract

Silk fibroin films with various calcium chloride contents were prepared by a cast film method and subsequent MeOH treatment. The conformational changes from α-helix to β-sheet structure were analyzed by Fourier transformed infrared attenuated total reflection spectroscopy measurements. The films obtained were soaked in 1.5-times simulated body fluid (1.5 SBF) and the deposition of hydroxyapatite crystals were observed by scanning electron microscopy. The films with calcium chloride contents lower than 3 wt % relative to the silk fibroin were not mineralized under these conditions, while those with calcium chloride contents more than 5 wt % mineralized after 6 h. The X-ray diffraction patterns and inductive coupled plasma spectroscopy analyses indicated that the hydroxyapatite crystals were grown by hydrolysis of octacalcium phosphate, as indicated by differences in diffraction intensities and changes in concentrations of calcium and phosphate ions in 1.5 SBF. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006

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