Diepoxide-Triggered Conformational Transition of Silk Fibroin: Formation of Hydrogels


BIOMACROMOLECULES, vol.13, no.4, pp.1122-1128, 2012 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 13 Issue: 4
  • Publication Date: 2012
  • Doi Number: 10.1021/bm300006r
  • Title of Journal : BIOMACROMOLECULES
  • Page Numbers: pp.1122-1128


Silk fibroin hydrogels with tunable properties could be obtained from aqueous fibroin solutions (4.2 w/v %) in a short period of time. This was achieved by the addition of ethylene glycol diglycidyl ether (EGDE) into the reaction solution. Introduction of EGDE cross-links between the fibroin molecules decreases the mobility of the chains, which triggers the conformational transition from random-coil to beta-sheet structure and hence fibroin gelation. Dynamic rheological measurements conducted at 50 degrees C show the formation of strong to weak hydrogels depending on the pH of the reaction solution. Although EGDE attacks the amino groups of fibroin and forms interstrand cross-links, beta-sheets acting as physical cross-links dominate the elasticity of the hydrogels. Mechanical response of low-modulus fibroin hydrogels formed above pH 9.7 is highly nonlinear with strong strain hardening behavior (700%) arising from the alignment of the crystallizable amino acid segments.