Bio-printing of a three-layer retina
2Division of Ophthalmology, Tel-Aviv Medical Center, Israel
3Sackler Faculty of Medicine, Tel-Aviv University, Israel
4Department of Biomedical Engineering, Faculty of Engineering, Tel-Aviv University, Israel
5The Center for Nanoscience and Nanotechnology, Tel-Aviv University, Israel
6Sagol Center for Regenerative Biotechnology, Tel Aviv University, Israel
Age-related macular degeneration (AMD) is the leading cause of vision loss in the elderly worldwide. There are two types of AMD: non-exudative (dry) and exudative (wet). The dry form accounts for 90% of cases. Currently, there is no cure for dry AMD, which is characterized by retinal pigment epithelium (RPE) degeneration and photoreceptor atrophy. Transplantation of healthy RPE has been shown to support photoreceptor survival in human patients with dry AMD.
Recently, our group developed a personalized hydrogel, serving as a bioink for 3D printing of a thick, vascularized, and perusable cardiac tissue. As both the material and cells were from humans, the tissue matched the immunological, biochemical, and anatomical properties of the same individual. Here, we sought to exploit the technology to 3D print a three-layer retina, consisting of a blood vessel network, an RPE and a photoreceptor layer.
Using 3 distinct bioinks, an in vitro model with the morphology and function of the choroid, RPE, and photoreceptor layers of the retina was fabricated. The endothelial cells formed a perfusable blood vessel network, the RPE cells expressed mature RPE markers, perform phagocytosis and formed a barrier on the hydrogel. Finally, the photoreceptors could be sustained by the RPE monolayer.
Future in vivo experiments will be performed to evaluate the integration of the printed structure with the retina, and the function of the regenerated tissue.