title: In situ cross-linked electrospun fiber scaffold of collagen for fabricating cell-dense muscle tissue.
abstract: Engineered muscle tissues used as transplant tissues in regenerative medicine should have a three-dimensional and cell-dense structure like native tissue. For fabricating a 3D cell-dense muscle tissue from myoblasts, we proposed the electrospun type I collagen microfiber scaffold of the string-shape like a harp. The microfibers were oriented in the same direction to allow the myoblasts to align, and were strung at low density with micrometer intervals to create space for the cells to occupy. To realize this shape of the scaffold, we employed in situ cross-linking during electrospinning process for the first time to collagen fibers. The collagen microfibers in situ cross-linked with glutaraldehyde stably existed in the aqueous media and completely retained the original shape to save the spaces between the fibers for over 14 days. On the contrary, the conventional cross-linking method by exposure to a glutaraldehyde aqueous solution vapor partially dissolved and damaged the fiber to lose a low-density shape of the scaffold. Myoblasts could penetrate into the interior of the in situ cross-linked string-shaped scaffold and form the cell-dense muscle tissues. Histochemical analysis showed the total area occupied by the cells in the cross section of the tissue was approximately 73 %. Furthermore, the resulting muscle tissue fabricated from primary myoblasts showed typical sarcomeric cross-striations and the entire tissue continuously pulsated by autonomous contraction. Together with the in situ cross-linking, the string-shaped scaffold provides an efficient methodology to fabricate a cell-dense 3D muscle tissue, which could be applied in regenerative medicine in future.
authors.affiliation: Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan. ntakeda@waseda.jp.
authors.forename: Naoya
authors.initials: N
authors.lastname: Takeda
authors.affiliation: Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Tamura
authors.affiliation: Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Mineguchi
authors.affiliation: Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Ishikawa
authors.affiliation: Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, TWIns, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Haraguchi
authors.affiliation: Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, TWIns, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan. shimizu.tatsuya@twmu.ac.jp.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Shimizu
authors.affiliation: Chemical Material Evaluation Group, Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8565, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Hara
mesh_terms: D000818:Animals; D002452:Cell Count; D002460:Cell Line; D003094:Collagen / Q000648:ultrastructure*; D005976:Glutaral; D051379:Mice; D018482:Muscle, Skeletal / Q000166:cytology*; D051381:Rats; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds
chemical_list: D003094:Collagen; D005976:Glutaral
keywords: Cell-dense muscle tissue; Electrospinning; In situ cross-link; String-shaped scaffold