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S.A. Pilyugina, A. Lavoie, P. Huie, K. Derr, A.J. Smith, J. Noolandi, R.M. Waymouth, C. Ta; In Vitro Epithelialization of a Synthetic Polymer for Generation of Corneal Onlay/keratoprosthesis . Invest. Ophthalmol. Vis. Sci. 2003;44(13):1344.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To achieve epithelialization of a collagen I-coated synthetic polymer surface. Methods: Poly (2-hydroxyethyl methacrylate) (PHEMA) hydrogel lenticules (synthesized within our laboratories; composition: 6 % methacrylic acid, 93 % HEMA, and 1% EGDMA = ethyleneglycol dimethacrylate) and commercially available Vifilcon-A® contact lenses (American Optical; composition: HEMA and PVP = poly (vinyl pyrrolidone)) were used as test materials. Test surfaces were modified to aldehyde groups by TEMPO/H2O2 oxidation and subsequently functionalized with collagen I. Non-modified contact lens and polymer lenticules served as controls. Surface epithelialization was tested in vitro using a bovine corneal organ culture model: corneal wound was induced by debriedment of central corneal epithelium. Test lenticules (8 mm diameter ) were implanted into a corneal stromal pocket and maintained in air/liquid organ culture system. Epithelialization rate was monitored clinically using fluorescein over a period of 1 week. Epithelial architecture was examined histologically by light microscopy. Electron microscopy was used to examine the tissue-polymer interface for evidence of hemidesmosomal adhesion complex formation. Results: Clinical observation of the epithelialization process demonstrated complete re-epithelialization of the sham wound and collagen I-coated modified contact lens by Day 5. Collagen I-coated PHEMA lenticule re-epithelialized at a slower rate by Day 7. Aldehyde-modified contact lens (no collagen I present) only partially re-epithelialized by Day 7. Non-modified PHEMA lenticule and contact lens did not exhibit any epithelial overgrowth. Histological evaluation of the sham wound and collagen I-coated contact lens revealed the presence of architecturally-intact epithelium with a basal cell layer and 2-3 layers of epithelial cells. Aldehyde-modified contact lens demonstrated a single layer of epithelial cells, with no evidence of basal cell differentiation. Conclusions: Collagen I-coated PHEMA hydrogel surface appears to support epithelialization in vitro. This polymer shows potential for further use in development of a corneal onlay or keratoprosthesis device that requires epithelialization.
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