Expanded polytetrafluoroethylene as a substrate for retinal pigment epithelial cell growth and transplantation in age-related macular degeneration

Background Retinal pigment epithelial (RPE) transplantation presents a potential treatment for age-related macular degeneration (AMD). A suitable transplant membrane that can support an intact functioning RPE monolayer is required. Expanded polytetrafluoroethylene (ePTFE) possesses the physical properties required for a transplanting device; however, cells do not attach and spread on ePTFE. This study investigated the ability of surface-modified ePTFE to optimise the growth and function of healthy RPE monolayers. Methods ePTFE discs were modified by ammonia gas plasma treatment. ARPE-19 cells were seeded on the membranes and maintained in media supplemented with retinoic acid and reduced serum. Cell number, morphology and proliferation were analysed. RPE monolayer function was investigated through formation of cell–cell junctions and phagocytosis of photoreceptor outer segments (POS). Results Ammonia gas plasma treatment resulted in enhanced cell growth and good monolayer formation with evidence of cell–cell junctional proteins. Furthermore, RPE monolayers were able to phagocytose POS in a time-dependent manner. Conclusions ePTFE can be surface-modified to support an intact functional monolayer of healthy RPE cells with normal morphology and the ability to perform RPE-specific functions. Following further investigation ePTFE may be considered for use in transplantation.