Abstract
Abstract: :
Purpose: Age–Related Macular Degeneration (ARMD) is the main cause of irreversible vision loss and registered blindness in people of 65 years and older in Europe and the USA. Despite recent advances in our understanding of its pathogenesis, at present there is very limited effective preventative or curative treatment. RPE transplant presents potential treatment of ARMD and RPE–specific retinal degeneration. Delivery of isolated cells has been shown to cause further complications including proliferative vitreoretinopathy. We therefore, aimed to investigate how to establish an intact functioning monolayer on an underlying artificial substrate that can substitute for the damaged native Bruch’s membrane. The artificial substrate we have investigated is silicon rubber (Si), which already has its uses in the eye, and its ability to maintain a healthy monolayer of RPE cells. Methods: Commercially available Si was cut to 3mm diameter discs. The discs were then surface modified by air and ammonia gas plasma treatment using Emitech K1050 X plasma Asher and a half–wave helical resonator plasma system, respectively. Following treatment, the samples were placed in distilled water for 24 hours. Dynamic contact angles were measured using the Wilhelmy plate technique to determine extent of hydrophilicity induced by the plasma treatments. ARPE 19 cells were seeded on to untreated, air and ammonia gas plasma treated samples and the samples then incubated. At set time intervals of 1, 4, 7, 10 and 15 days the samples were fixed and cellular morphology, monolayer formation, proliferation and cytotoxicity were assessed by immunofluorescent staining and fluorescent microscopy. Images were digitally captured using software Image Pro. Results: Air plasma treatment resulted in increased wettability with lower advancing and receding values exhibiting a relatively hydrophilic surface. This significantly enhanced cell adhesion and viability in comparison to ammonia plasma treatment (p<0.0001) and untreated samples (p<0.0003), reaching to confluent areas by day 4. Immunofluorescence revealed well–defined actin staining, monolayer formation and high cell viability on untreated and air plasma treated surfaces, and to a lesser extent on ammonia plasma treated. Conclusions: Si rubber can be surface modified to support intact RPE monolayer formation and with further work be considered for use in transplant.
Keywords: age-related macular degeneration • retinal pigment epithelium • transplantation