Understanding the effects of retinal scaffold mechanical properties on surgical handling and cellular response

Retinal degenerative diseases currently result in irreversible vision loss. Advancements in tissue engineering have enabled a promising treatment approach: retinal cell therapy, in which vision is restored by replacement of lost photoreceptor cells. Directly injecting these new rods and cones is ineffective; the cells need a supporting structure, or scaffold, to increase the survival of the procedure. However, full design constraints and recommendations for these scaffolds have not yet been established. In this study, we determined the effect of retinal scaffolds’ stiffness on their performance during mock retinal transplantation procedures. We identified a lower mechanical property limit for the scaffolds, below which the scaffolds were too fragile for surgeons to handle effectively. We also created a small device in which to place retinal scaffolds during culture with rods and cones. After several iterations, the final device was not toxic to retinal cells, enabled easy loading of both scaffold and cells, and kept the scaffold submerged as desired. This device sets the groundwork for studying the effects of scaffold stiffness on photoreceptor survival and function on the material. Coupling these two outcomes, a stiffness range for feasible surgical handling and for cell viability, these results help to better understand and control the performance of cellular scaffolds for future use in the treatment of retinal degeneration.