Microfabrication of a three-dimensional polycaprolactone thin-film scaffold for retinal progenitor cell encapsulation.

Retinal degenerations are the leading cause of irreversible visual disability among the adult population. Stem-cell-based therapy has the potential to preserve and restore vision in these conditions. In addition to replacing lost or diseased cells, transplanted cells may be able to rescue dying photoreceptors of the host retina. To fully realize the potential of these cells, improved methods for cell delivery are needed. Utilizing microfabrication processes, a novel biodegradeable thin-film cell encapsulation scaffold was developed in polycaprolactone (PCL) as a possible cell transplantation vehicle. Individual thin-film 2-2.5-D PCL layers (<10 μm thin) were structured with varying micro- and nano-geometries (protrusions, cavities, pores, particles) utilizing a modified spin-assisted solvent casting and melt templating technique. Thin-film layers were aligned and thermally bonded to form the 3-D cell encapsulation scaffold (<30 μm thin) and these were found to promote retinal progenitor cell (RPC) retention and provide appropriate permeability. The resulting scaffolds provide a novel platform for the delivery of cells to the outer retina that addresses critical biological constraints related to transplantation to this anatomical location.