Enhancement of retinal pigment epithelial culture characteristics and subretinal space tolerance of scaffolds with 200 nm fiber topography.

Tissue engineered retinal pigment epithelial (RPE) transplantation is a promising cell-based therapy for age-related macular degeneration. The aim of this work is to develop a supportive scaffold with a favorable topography to aid functional RPE monolayer maintenance while being tolerated underneath the retina. To this end, films and electrospun substrates with fiber diameters ranging from 200 to 1000 nm were made of polyethylene terephthalate or poly(L-lactide-co-ε-caprolactone), and then tested using human fetal RPE cells in vitro and transplanted subretinally in rabbits. The results indicated that RPE on both 200 nm fiber variants showed the highest cell densities, adherent monolayers achieved deeper pigmentation, and more uniform hexagonal tight junctions. Facile subretinal implantation of flat 200 nm fiber membranes was achieved by electrospinning them onto a porous rigid-elastic carrier. Spectral-domain optical coherence tomography showed a reattached, slightly thinned retina overlying the implants over 2 weeks observation. Histology demonstrated native RPE variably migrated onto the nanofibers, and a reactive gliosis with some photoreceptor degeneration. In conclusion, scaffolds with 200 nm fiber topography enhanced RPE culture, showed subretinal biocompatibility, and should thus be considered for future cell-based therapies in blinding retinal diseases.