Temperature-Induced Hydrogels Through Self-Assembly of Cholesterol-Substituted Star PEG-b-PLLA Copolymers: An Injectable Scaffold for Tissue Engineering

Authors

  • Koji Nagahama,

    1. Department of Chemistry and Materials Engineering & High Technology Research Center, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka (Japan)
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  • Tatsuro Ouchi,

    Corresponding author
    1. Department of Chemistry and Materials Engineering & High Technology Research Center, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka (Japan)
    • Tatsuro Ouchi, Department of Chemistry and Materials Engineering & High Technology Research Center, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka (Japan).===

      Yuichi Ohya, Department of Chemistry and Materials Engineering & High Technology Research Center, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka (Japan).===

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  • Yuichi Ohya

    Corresponding author
    1. Department of Chemistry and Materials Engineering & High Technology Research Center, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka (Japan)
    • Tatsuro Ouchi, Department of Chemistry and Materials Engineering & High Technology Research Center, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka (Japan).===

      Yuichi Ohya, Department of Chemistry and Materials Engineering & High Technology Research Center, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka (Japan).===

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  • The authors thank NOF Co. for the supply of 8-arm PEG and funding support. This research was financially supported in part by a Grant-in-Aid for Scientific Research (B) (17300163) from the Japan Society for the Promotion of Science (JSPS) and by Research for Promoting Technological Seeds from Japan Science and Technology Agency (JST). A part of this work was carried out as a study in the High-Tech Research Center Project supported by the Ministry of Education, Culture, Sports, Science and Technology, Japan. Supporting Information is available online from Wiley InterScience or from the author.

Abstract

Partially cholesterol-substituted 8-arm poly(ethylene glycol)-block-poly(L-lactide) (8-arm PEG-b-PLLA-cholesterol) has been prepared as a novel star-shaped, biodegradable copolymer derivative. The amphiphilic 8-arm PEG-b-PLLA-cholesterol aqueous solution (polymer concentration, above 3 wt%) exhibits instantaneous temperature-induced gelation at 34 °C, but the virgin 8-arm PEG-b-PLLA does not, irrespective of concentration. Moreover, an extracellular matrix (ECM)-like micrometer-scale network structure has been created with favorable porosity for three-dimensional proliferation of cells inside the hydrogel. This network structure is mainly attributed to specific self-assembly between cholesterol groups. The 10 and 20 wt% hydrogels are eroded gradually in phosphate buffered saline at 37 °C over the course of a month, and after that the gel becomes completely dissociated. Moreover, L929 cells encapsulated into the hydrogel are viable and proliferate three-dimensionally inside the hydrogels. Thus, in-vitro cell culture studies demonstrate that 8-arm PEG-b-PLLA-cholesterol is a promising candidate as a novel injectable cellular scaffold.

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