Monday, April 4, 2011

Abstract: Progress on artificial cornea development

Degradation studies and biological behavior on an artificial cornea material.

Objective:
Patients suffering from dry eye syndrome, Stevens-Johnson syndrome or have had recurrent transplant rejections are unsuitable to receive a keratoprosthesis. The present work aims at developing a highly biocompatible keratoprosthesis that could be successfully implanted in such patients. Methods and materials:

Methods and materials:
Glass-reinforced hydroxyapatite (GRHA) was used to construct this new artificial cornea. In order to grant the device an adequate porosity, a porogen agent was added in the following percentages, 10, 30 and 50 %. Samples were physicochemically analyzed in terms of density, porosity, roughness, degradation and surface imaging. Biological relevance was assessed by cell culture, MTT assays, and cell imaging.

Results:
Samples B (30 %porogen) and C (50 %porogen) were found to be the most porous and also had the roughest topography. Degradation studies showed that under simulated physiological conditions, no mass loss was observed. Conversely, under acidic conditions, a significant mass loss was observed. The biological performance of these samples was satisfactory when cultured with human fibroblasts. The MTT assay revealed that samples B and C had greater propensity to cell invasion and proliferation than the other tested materials. Cell imaging demonstrated that fibroblasts organized around the pore edges before colonizing it.

Conclusions:
A material with physical-chemical and biological characteristics close to an ideal artificial cornea has been fabricated. The GRHA cornea containing 30 % porogen is the most promising substitute material due to the biological performance, adequate porosity and low degradation propensity.


Invest Ophthalmol Vis Sci. 2011 Mar 18. [Epub ahead of print]
Santos L, Ferraz MP, Shirosaki Y, Lopes MA, Fernandes MH, Osaka A, Santos JD.
CEMUC, Departamento de Engenharia Metal├║rgica e dos Materiais, Faculdade de Engenharia, Universidade do Porto, Portugal.

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