Researchers from Newcastle University have successfully created viable corneas using a 3D printer loaded with a unique bio-ink. The printed tissue, which contains live stem cells, has the potential to address the chronic shortage of donor corneas worldwide.

The proof-of-concept research was published this month in Experimental Eye Research.

Led by Che Connor, PhD, the team first had to formulate a bio-ink that could sustain the growth of human corneal stromal cells. The final product—a combination of alginate and collagen—is both soft enough to squeeze through a 3D printer nozzle, yet stiff enough to maintain its printed shape.

Next, using dimensions obtained from a healthy cornea, the scientists employed a low-cost 3D printer to emit the bio-ink in concentric circles. Within 10 minutes, the printer produced a structure mirroring a human cornea.

The live cells inside the printed corneas survived for at least 1 week. After 1 day, cell viability was 92% and remained above 80% for 7 days.

“This builds upon our previous work in which we kept cells alive for weeks at room temperature within a similar hydrogel. Now we have a ready-to-use bio-ink containing stem cells allowing users to start printing tissues without having to worry about growing the cells separately,” explained Dr. Connor, adding that the corneas could be custom-printed to match each patient’s specific needs.

He anticipates it will be several years before these prototypes are cleared for human transplants. Questions remain regarding the ability of these printed corneas to facilitate epithelial cell growth, as well as biocompatibility and functional capacity.