title: Optimization strategies for electrospun silk fibroin tissue engineering scaffolds.
abstract: As a contribution to the functionality of scaffolds in tissue engineering, here we report on advanced scaffold design through introduction and evaluation of topographical, mechanical and chemical cues. For scaffolding, we used silk fibroin (SF), a well-established biomaterial. Biomimetic alignment of fibers was achieved as a function of the rotational speed of the cylindrical target during electrospinning of a SF solution blended with polyethylene oxide. Seeding fibrous SF scaffolds with human mesenchymal stem cells (hMSCs) demonstrated that fiber alignment could guide hMSC morphology and orientation demonstrating the impact of scaffold topography on the engineering of oriented tissues. Beyond currently established methodologies to measure bulk properties, we assessed the mechanical properties of the fibers by conducting extension at breakage experiments on the level of single fibers. Chemical modification of the scaffolds was tested using donor/acceptor fluorophore labeled fibronectin. Fluorescence resonance energy transfer imaging allowed to assess the conformation of fibronectin when adsorbed on the SF scaffolds, and demonstrated an intermediate extension level of its subunits. Biological assays based on hMSCs showed enhanced cellular adhesion and spreading as a result of fibronectin adsorbed on the scaffolds. Our studies demonstrate the versatility of SF as a biomaterial to engineer modified fibrous scaffolds and underscore the use of biofunctionally relevant analytical assays to optimize fibrous biomaterial scaffolds.
authors.affiliation: Institute of Pharmaceutical Sciences, ETH Zurich, Department for Chemistry and Applied Biosciences, HCI J 390.1, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland. lorenz.meinel@pharma.ethz.ch
authors.forename: Anne J
authors.initials: AJ
authors.lastname: Meinel
authors.forename: Kristopher E
authors.initials: KE
authors.lastname: Kubow
authors.forename: Enrico
authors.initials: E
authors.lastname: Klotzsch
authors.forename: Marcos
authors.initials: M
authors.lastname: Garcia-Fuentes
authors.forename: Michael L
authors.initials: ML
authors.lastname: Smith
authors.forename: Viola
authors.initials: V
authors.lastname: Vogel
authors.forename: Hans P
authors.initials: HP
authors.lastname: Merkle
authors.forename: Lorenz
authors.initials: L
authors.lastname: Meinel
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D001696:Biomechanical Phenomena; D040761:Biomimetic Materials / Q000737:chemistry; D012831:Bombyx; D002448:Cell Adhesion; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D005349:Fibroins / Q000737:chemistry* / Q000648:ultrastructure; D005353:Fibronectins / Q000737:chemistry; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000737:chemistry / Q000166:cytology / Q000648:ultrastructure; D011487:Protein Conformation; D047011:Silk / Q000737:chemistry* / Q000648:ultrastructure; D017550:Spectroscopy, Fourier Transform Infrared; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds
chemical_list: D001672:Biocompatible Materials; D005353:Fibronectins; D047011:Silk; D005349:Fibroins