title: The effect of sterilization on silk fibroin biomaterial properties.
abstract: The effects of common sterilization techniques on the physical and biological properties of lyophilized silk fibroin sponges are described. Sterile silk fibroin sponges were cast using a pre-sterilized silk fibroin solution under aseptic conditions or post-sterilized via autoclaving, γ radiation, dry heat, exposure to ethylene oxide, or hydrogen peroxide gas plasma. Low average molecular weight and low concentration silk fibroin solutions could be sterilized via autoclaving or filtration without significant loses of protein. However, autoclaving reduced the molecular weight distribution of the silk fibroin protein solution, and silk fibroin sponges cast from autoclaved silk fibroin were significantly stiffer compared to sponges cast from unsterilized or filtered silk fibroin. When silk fibroin sponges were sterilized post-casting, autoclaving increased scaffold stiffness, while decreasing scaffold degradation rate in vitro. In contrast, γ irradiation accelerated scaffold degradation rate. Exposure to ethylene oxide significantly decreased cell proliferation rate on silk fibroin sponges, which was rescued by leaching ethylene oxide into PBS prior to cell seeding.
authors.affiliation: Department of Biomedical Engineering, Tufts University, Medford, Massachusetts, USA.|Graduate School of Biomedical Engineering, UNSW Australia, Sydney, New South Wales, Australia.
authors.forename: Jelena
authors.initials: J
authors.lastname: Rnjak-Kovacina
authors.affiliation: Department of Biomedical Engineering, Tufts University, Medford, Massachusetts, USA.|KIYATEC, Inc., Greenville, South Carolina, USA.
authors.forename: Teresa M
authors.initials: TM
authors.lastname: DesRochers
authors.affiliation: Department of Biomedical Engineering, Tufts University, Medford, Massachusetts, USA.|Department of Chemical and Biomolecular Engineering, University of Connecticut, Storrs, Connecticut, USA.
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Burke
authors.affiliation: Department of Biomedical Engineering, Tufts University, Medford, Massachusetts, USA. david.kaplan@tufts.edu.
authors.forename: David L
authors.initials: DL
authors.lastname: Kaplan
mesh_terms: D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D005349:Fibroins / Q000737:chemistry*; D006801:Humans; D008297:Male; D008422:Materials Testing; D013242:Sterilization / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D005349:Fibroins
keywords: biomaterial; scaffolds; silk fibroin; sterilization; tissue engineering