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Download fileDiepoxide-Triggered Conformational Transition of Silk Fibroin: Formation of Hydrogels
journal contribution
posted on 09.04.2012, 00:00 authored by Ilknur Karakutuk, Fatih Ak, Oguz OkaySilk 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 β-sheet
structure and hence fibroin gelation. Dynamic rheological measurements
conducted at 50 °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, β-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.