title: Silk fibroin sponges with cell growth-promoting activity induced by genetically fused basic fibroblast growth factor.
abstract: Transgenic silkworm technology has enabled the biological properties of silk fibroin protein to be altered by fusion to recombinant bioactive proteins. However, few studies have reported the fabrication of genetically modified fibroin proteins into three-dimensional spongy structures to serve as scaffolds for tissue engineering. We generated a transgenic silkworm strain that produces fibroin fused to basic fibroblast growth factor (bFGF) and processed the fibroin into a spongy structure using a simple freeze/thaw method. NIH3T3 mouse embryonic fibroblasts grown on bFGF-fused fibroin sponges proliferated and spread out well, showing half the population doubling time of cells cultured on wild-type fibroin sponges. Furthermore, the number of primary rabbit articular chondrocytes growing on bFGF-fused fibroin sponges was around five-times higher than that of the wild-type control at 3-days post cell-seeding. As the physical properties of wild-type and bFGF-fused fibroin sponges were almost identical, it is suggested that bFGF fused to fibroin retained its biological activity, even after the bFGF-fused fibroin was fabricated into the spongy structure. The bFGF-fused fibroin sponge has the potential for widespread application in the field of tissue engineering, and the method of fabricating this structure could be applicable to other recombinant bioactive fibroin proteins.
authors.affiliation: Silk Materials Research Unit, National Institute of Agrobiological Sciences (NIAS), 1-2 Owashi, Tsukuba, Ibaraki, 305-8634, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kambe
authors.affiliation: Silk Materials Research Unit, National Institute of Agrobiological Sciences (NIAS), 1-2 Owashi, Tsukuba, Ibaraki, 305-8634, Japan.
authors.forename: Katsura
authors.initials: K
authors.lastname: Kojima
authors.affiliation: Faculty of Textile Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano, 386-8567, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Tamada
authors.affiliation: Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku-Katsura, Nishikyo-Ku, Kyoto, 615-8540, Japan.
authors.forename: Naohide
authors.initials: N
authors.lastname: Tomita
authors.affiliation: Silk Materials Research Unit, National Institute of Agrobiological Sciences (NIAS), 1-2 Owashi, Tsukuba, Ibaraki, 305-8634, Japan.
authors.forename: Tsunenori
authors.initials: T
authors.lastname: Kameda
mesh_terms: D000818:Animals; D015153:Blotting, Western; D012831:Bombyx; D002358:Cartilage, Articular / Q000166:cytology; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology* / Q000187:drug effects; D004591:Electrophoresis, Polyacrylamide Gel; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D005347:Fibroblasts / Q000166:cytology* / Q000187:drug effects; D005349:Fibroins / Q000494:pharmacology*; D005818:Genetic Engineering; D005822:Genetic Vectors / Q000378:metabolism; D006801:Humans; D051379:Mice; D041681:NIH 3T3 Cells; D011161:Porifera / Q000737:chemistry*; D011817:Rabbits
chemical_list: D016222:Fibroblast Growth Factor 2; D005349:Fibroins
keywords: basic fibroblast growth factor; cell proliferation; scaffold; silk fibroin; transgenic technology