Treatment of silk fibroin with poly(ethylene glycol) for the enhancement of corneal epithelial cell growth

Suzuki, Shuko, Dawson, Rebecca A., Chirila, Traian, Shadforth, Audra, Hogerheyde, Thomas, Edwards, Grant, & Harkin, Damien G. (2015) Treatment of silk fibroin with poly(ethylene glycol) for the enhancement of corneal epithelial cell growth. Journal of Functional Biomaterials, 6(2), pp. 345-366.

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Abstract

A silk protein, fibroin, was isolated from the cocoons of the domesticated silkworm (Bombyx mori) and cast into membranes to serve as freestanding templates for tissue-engineered corneal cell constructs to be used in ocular surface reconstruction. In this study, we sought to enhance the attachment and proliferation of corneal epithelial cells by increasing the permeability of the fibroin membranes and the topographic roughness of their surface. By mixing the fibroin solution with poly(ethylene glycol) (PEG) of molecular weight 300 Da, membranes were produced with increased permeability and with topographic patterns generated on their surface. In order to enhance their mechanical stability, some PEG-treated membranes were also crosslinked with genipin. The resulting membranes were thoroughly characterized and compared to the non-treated membranes. The PEG-treated membranes were similar in tensile strength to the non-treated ones, but their elastic modulus was higher and elongation lower, indicating enhanced rigidity. The crosslinking with genipin did not induce a significant improvement in mechanical properties. In cultures of a human-derived corneal epithelial cell line (HCE-T), the PEG treatment of the substratum did not improve the attachment of cells and it enhanced only slightly the cell proliferation in the longer term. Likewise, primary cultures of human limbal epithelial cells grew equally well on both non-treated and PEG-treated membranes, and the stratification of cultures was consistently improved in the presence of an underlying culture of irradiated 3T3 feeder cells, irrespectively of PEG-treatment. Nevertheless, the cultures grown on the PEG-treated membranes in the presence of feeder cells did display a higher nuclear-to-cytoplasmic ratio suggesting a more proliferative phenotype. We concluded that while the treatment with PEG had a significant effect on some structural properties of the B. mori silk fibroin (BMSF) membranes, there were minimal gains in the performance of these materials as a substratum for corneal epithelial cell growth. The reduced mechanical stability of freestanding PEG-treated membranes makes them a less viable choice than the non-treated membranes.

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ID Code: 84584
Item Type: Journal Article
Refereed: Yes
Keywords: Cornea, Silk fibroin, Poly(ethylene glycol), Cell therapy, Corneal transplantation
DOI: 10.3390/jfb6020345
ISSN: 2079-4983
Subjects: Australian and New Zealand Standard Research Classification > ENGINEERING (090000) > BIOMEDICAL ENGINEERING (090300) > Biomaterials (090301)
Australian and New Zealand Standard Research Classification > TECHNOLOGY (100000) > MEDICAL BIOTECHNOLOGY (100400) > Regenerative Medicine (incl. Stem Cells and Tissue Engineering) (100404)
Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300) > Ophthalmology (111301)
Divisions: Current > Schools > School of Biomedical Sciences
Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Funding:
Copyright Owner: Copyright 2015 The Author(s), licensee MDPI, Basel, Switzerland
Copyright Statement: This article is an open access article
distributed under the terms and conditions of the Creative Commons Attribution license
(http://creativecommons.org/licenses/by/4.0/).
Deposited On: 31 May 2015 23:24
Last Modified: 02 Jun 2015 01:30

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