title: Degradation of silk films in multipocket corneal stromal rabbit models.
abstract: BACKGROUND
  The need for human cornea tissues continues to grow as an alternative option to donor tissues. Silk protein has been successfully used as a substrate to engineer corneal epithelium and stroma in vitro. Herein, we investigated the in vivo response and the effect of silk crystalline structure (beta sheet) on degradation rate of silk films in rabbit multipocket corneal models.
  
  
  METHODS
  Three different surgical techniques (peripheral-median P-M, central-superficial C-S, central-deep C-D) were used to assess the in vivo response as well as the degradation profile of silk films with low, medium and high beta sheet (crystalline) content at 2 and 3 months after surgery.
  
  
  RESULTS
  Approach C-D showed signs of sample degradation without inflammation, with one single incision and a pocket created by flushing air two thirds deep in the corneal stroma. In comparison, approaches P-M and C-S with multiple incisions presented manually dissected surgical pockets resulted in inflammation and possible extrusion of the samples, respectively. Low beta sheet samples lost structural integrity at 2 months after surgery C-D, while medium and high beta sheet content films showed initial evidence of degradation.
  
  
  CONCLUSIONS
  The in vivo response to the silk films was dependent on the location of the implant and pocket depth. Crystallinity content in silk films played a significant role in the timing of material degradation, without signs of inflammation and vascularization or changes in stromal organization.
authors.affiliation: Department of Biomedical Engineering, Tufts University, Medford, Massachusetts - USA.
authors.forename: Chiara E
authors.initials: CE
authors.lastname: Ghezzi
authors.affiliation: Department of Ophthalmology, Chinese People's Liberation Army (PLA) General Hospital, Beijing - PR China.
authors.forename: Liqiang
authors.initials: L
authors.lastname: Wang
authors.affiliation: Molecular Biology and Microbiology and Ophthalmology, Tufts-Sackler Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts - USA.
authors.forename: Irmgard
authors.initials: I
authors.lastname: Behlau
authors.affiliation: Department of Biomedical Engineering, Tufts University, Medford, Massachusetts - USA.|Graduate School of Biomedical Engineering, UNSW Australia, Sydney, NSW - Australia.
authors.forename: Jelena
authors.initials: J
authors.lastname: Rnjak-Kovacina
authors.affiliation: Department of Biomedical Engineering, Tufts University, Medford, Massachusetts - USA.
authors.forename: Siran
authors.initials: S
authors.lastname: Wang
authors.affiliation: Tufts University School of Medicine, Boston, Massachusetts - USA.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Goldstein
authors.affiliation: Department of Biomedical Engineering, Cornell University, Ithaca, New York - USA.|Margaret M. Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, New York - USA.
authors.forename: Jingbo
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, Boston, Massachusetts - USA.
authors.forename: Jeffrey K
authors.initials: JK
authors.lastname: Marchant
authors.affiliation: Department of Biomedical Engineering, Cornell University, Ithaca, New York - USA.|Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois - USA.
authors.forename: Mark I
authors.initials: MI
authors.lastname: Rosenblatt
authors.affiliation: Department of Biomedical Engineering, Tufts University, Medford, Massachusetts - USA.
authors.forename: David L
authors.initials: DL
authors.lastname: Kaplan
mesh_terms: D000818:Animals; D003319:Corneal Stroma; D019573:Epithelium, Corneal; D006801:Humans; D008422:Materials Testing; D011817:Rabbits; D047011:Silk / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D023822:Tissue Engineering; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D047011:Silk