VTN and retinal degeneration: We successfully generated RPE cells from hiPSCs using one of the most suitable xeno-free peptide-grafted hydrogels, KVN2CK (KGCGGKGG-PQVTRGDVFTMP), which was derived from vitronectin, and confirmed the effect of these hiPSC-derived RPE cells in a rat retinal degeneration model (Royal College of Surgeons (RCS) rats) via subretinal transplantation, when we investigated functional improvements in vision in RCS rats after the transplantation of hiPSC-derived RPE cells.