title: Effect of sterilization on structural and material properties of 3-D silk fibroin scaffolds.
abstract: The development of porous scaffolds for tissue engineering applications requires the careful choice of properties, as these influence cell adhesion, proliferation and differentiation. Sterilization of scaffolds is a prerequisite for in vitro culture as well as for subsequent in vivo implantation. The variety of methods used to provide sterility is as diverse as the possible effects they can have on the structural and material properties of the three-dimensional (3-D) porous structure, especially in polymeric or proteinous scaffold materials. Silk fibroin (SF) has previously been demonstrated to offer exceptional benefits over conventional synthetic and natural biomaterials in generating scaffolds for tissue replacements. This study sought to determine the effect of sterilization methods, such as autoclaving, heat-, ethylene oxide-, ethanol- or antibiotic-antimycotic treatment, on porous 3-D SF scaffolds. In terms of scaffold morphology, topography, crystallinity and short-term cell viability, the different sterilization methods showed only few effects. Nevertheless, mechanical properties were significantly decreased by a factor of two by all methods except for dry autoclaving, which seemed not to affect mechanical properties compared to the native control group. These data suggest that SF scaffolds are in general highly resistant to various sterilization treatments. Nevertheless, care should be taken if initial mechanical properties are of interest.
authors.affiliation: Institute for Biomechanics, ETH Zurich, Wolfgang-Pauli-Str. 10, CH-8093 Zurich, Switzerland. Electronic address: sahofmann@ethz.ch.
authors.forename: Sandra
authors.initials: S
authors.lastname: Hofmann
authors.forename: Kathryn S
authors.initials: KS
authors.lastname: Stok
authors.forename: Thomas
authors.initials: T
authors.lastname: Kohler
authors.forename: Anne J
authors.initials: AJ
authors.lastname: Meinel
authors.forename: Ralph
authors.initials: R
authors.lastname: Müller
mesh_terms: D002470:Cell Survival; D055119:Elastic Modulus; D005349:Fibroins / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D059630:Mesenchymal Stem Cells / Q000166:cytology; D008855:Microscopy, Electron, Scanning; D016062:Porosity; D017550:Spectroscopy, Fourier Transform Infrared; D013242:Sterilization; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*; D055114:X-Ray Microtomography
chemical_list: D005349:Fibroins
keywords: Scaffold; Silk fibroin; Sterilization; Tissue engineering