Retinal cells grown from stem cells can reach out and connect with neighbors, according to a new study, completing a “handshake” that may show the cells are ready for trials in humans with degenerative eye disorders. once they are separated from adjacent cells in their organoid, they can reach out toward new neighbors with characteristic biological cords called axons. “The last piece of the puzzle was to see if these cords had the ability to plug into, or shake hands with, other retinal cell types in order to communicate,” says Gamm, whose new results on successful connections between the cells was published today in the Proceedings of the National Academy of Sciences.