title: Control of in vitro tissue-engineered bone-like structures using human mesenchymal stem cells and porous silk scaffolds.
abstract: Natural bone consists of cortical and trabecular morphologies, the latter having variable pore sizes. This study aims at engineering different bone-like structures using scaffolds with small pores (112-224 microm) in diameter on one side and large pores (400-500 microm) on the other, while keeping scaffold porosities constant among groups. We hypothesized that tissue engineered bone-like structure resulting from silk fibroin (SF) implants is pre-determined by the scaffolds' geometry. To test this hypothesis, SF scaffolds with different pore diameters were prepared and seeded with human mesenchymal stem cells (hMSC). As compared to static seeding, dynamic cell seeding in spinner flasks resulted in equal cell viability and proliferation, and better cell distribution throughout the scaffold as visualized by histology and confocal microscopy, and was, therefore, selected for subsequent differentiation studies. Differentiation of hMSC in osteogenic cell culture medium in spinner flasks for 3 and 5 weeks resulted in increased alkaline phosphatase activity and calcium deposition when compared to control medium. Micro-computed tomography (microCT) detailed the pore structures of the newly formed tissue and suggested that the structure of tissue-engineered bone was controlled by the underlying scaffold geometry.
authors.affiliation: Institute of Pharmaceutical Sciences, HCI J 392, Wolfgang-Pauli-Strasse 10, ETH Zurich, 8093 Zurich, Switzerland.
authors.forename: Sandra
authors.initials: S
authors.lastname: Hofmann
authors.forename: Henri
authors.initials: H
authors.lastname: Hagenmüller
authors.forename: Annette M
authors.initials: AM
authors.lastname: Koch
authors.forename: Ralph
authors.initials: R
authors.lastname: Müller
authors.forename: Gordana
authors.initials: G
authors.lastname: Vunjak-Novakovic
authors.forename: David L
authors.initials: DL
authors.lastname: Kaplan
authors.forename: Hans P
authors.initials: HP
authors.lastname: Merkle
authors.forename: Lorenz
authors.initials: L
authors.lastname: Meinel
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D018786:Bone Substitutes; D018929:Cell Culture Techniques / Q000379:methods; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D006801:Humans; D008422:Materials Testing; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000502:physiology*; D010006:Osteoblasts / Q000166:cytology* / Q000502:physiology*; D010012:Osteogenesis / Q000502:physiology; D016062:Porosity; D047011:Silk / Q000737:chemistry*; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D001672:Biocompatible Materials; D018786:Bone Substitutes; D047011:Silk