“…Natural polymers could be more advantageous and are currently being purified and used to grow hESC-RPE and iPSC-RPE. ECM proteins secreted from RPE [120] and corneal endothelial cells [120,121], isolated gelatins and collagens [117,120,[122][123][124][125], alginates [108], hyaluronic acid [108], fibrinogens [126], vitronectin [117,118], laminins [117,118,121], and fibronectins [118,121] all can support RPE growth. In addition to human purified proteins, a combination of ECM proteins derived from the mouse Englebreth-Holm-Swarm tumor called Matrigel is also efficient for culturing RPE [124].…”