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Core‐shell silk hydrogels with spatially tuned conformations as drug‐delivery system
Author(s) -
Yan LePing,
Oliveira Joaquim M.,
Oliveira Ana L.,
Reis Rui L.
Publication year - 2017
Publication title -
journal of tissue engineering and regenerative medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.835
H-Index - 72
eISSN - 1932-7005
pISSN - 1932-6254
DOI - 10.1002/term.2226
Subject(s) - self healing hydrogels , fibroin , silk , chemical engineering , fourier transform infrared spectroscopy , drug delivery , shell (structure) , random coil , core (optical fiber) , materials science , tissue engineering , chemistry , swelling , composite material , nanotechnology , polymer chemistry , biomedical engineering , crystallography , circular dichroism , medicine , engineering
Hydrogels of spatially controlled physicochemical properties are appealing platforms for tissue engineering and drug delivery. In this study, core‐shell silk fibroin (SF) hydrogels of spatially controlled conformation were developed. The core‐shell structure in the hydrogels was formed by means of soaking the preformed (enzymatically crosslinked) random coil SF hydrogels in methanol. When increasing the methanol treatment time from 1 to 10 min, the thickness of the shell layer can be tuned from about 200 to about 850 μm as measured in wet status. After lyophilization of the rehydrated core‐shell hydrogels, the shell layer displayed compact morphology and the core layer presented porous structure, when observed by scanning electron microscopy. The conformation of the hydrogels was evaluated by Fourier transform infrared spectroscopy in wet status. The results revealed that the shell layer possessed dominant β‐sheet conformation and the core layer maintained mainly random coil conformation. Enzymatic degradation data showed that the shell layers presented superior stability to the core layer. The mechanical analysis displayed that the compressive modulus of the core‐shell hydrogels ranged from about 25 kPa to about 1.1 MPa by increasing the immersion time in methanol. When incorporated with albumin, the core‐shell SF hydrogels demonstrated slower and more controllable release profiles compared with the non‐treated hydrogel. These core‐shell SF hydrogels of highly tuned properties are useful systems as drug‐delivery system and may be applied as cartilage substitute. Copyright © 2016 John Wiley & Sons, Ltd.