The Huh lab's eye-on-a-chip attached to a motorized, gelatin-based eyelid. Blinking spreads tears over the corneal surface, and so was a critical aspect to replicate in the researchers' model of dry eye disease. cells. The cells of the cornea grow on the inner circle of scaffolding, dyed yellow, and the cells of the conjunctiva grow on the surrounding red circle. Artificial tears are supplied by a tear duct, dyed blue.