title: Design of super-elastic biodegradable scaffolds with longitudinally oriented microchannels and optimization of the channel size for Schwann cell migration.
abstract: We newly designed super-elastic biodegradable scaffolds with longitudinally oriented microchannels for repair and regeneration of peripheral nerve defects. Four-armed poly(ε-caprolactone-co-D,L-lactide)s (P(CL-co-DLLA)s) were synthesized by ring-opening copolymerization of CL and DLLA from terminal hydroxyl groups of pentaerythritol, and acryloyl chloride was then reacted with the ends of the chains. The end-functionalized P(CL-co-DLLA) was crosslinked in a cylindrical mold in the presence of longitudinally oriented silica fibers as the templates, which were later dissolved by hydrofluoric acid. The elastic moduli of the crosslinked P(CL-co-DLLA)s were controlled between 10-1and 102MPa at 37 °C, depending on the composition. The scaffolds could be elongated to 700% of their original size without fracture or damage ('super-elasticity'). Scanning electron microscopy images revealed that well-defined and highly aligned multiple channels consistent with the mold design were produced in the scaffolds. Owing to their elastic nature, the microchannels in the scaffolds did not collapse when they were bent to 90°. To evaluate the effect of the channel diameter on Schwann cell migration, microchannels were also fabricated in transparent poly(dimethylsiloxane), allowing observation of cell migration. The migration speed increased with channel size, but the Young's modulus of the scaffold decreased as the channel diameter increased. These findings may serve as the basis for designing tissue-engineering scaffolds for nerve regeneration and investigating the effects of the geometrical and dimensional properties on axonal outgrowth.
authors.affiliation: Biomaterials Unit, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Uto
authors.affiliation: Biomaterials Unit, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan.
authors.forename: Takanari
authors.initials: T
authors.lastname: Muroya
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan.
authors.forename: Michio
authors.initials: M
authors.lastname: Okamoto
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Murase
authors.affiliation: Biomaterials Unit, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Ebara
authors.affiliation: Biomaterials Unit, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan; Department of Materials Engineering, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Aoyagi
keywords: D,L-lactide (DLLA); biodegradable polymers; microchannels, Schwann cells; scaffolds; ε-caprolactone (CL)