For the very first time, scientists from Newcastle University in the UK have 3D printed human corneas, the clear outer layer of the eye that plays a huge role in controlling and focusing the entry of light into the eye.
Over 5 million people suffer from total blindness due to burns, damage, or disease of their corneas, with a further 10 million people waiting for surgery to prevent corneal blindness. People can donate their corneas after they die, however, the demand currently outweighs the supply.
As documented in the journal Experimental Eye Research, the team used a low-cost 3D printer to craft these artificial corneas. It prints out layers of “bio-ink”, building them up in concentric circles, to form a cornea-shaped scaffolding. Stem cells are then added and left to grow to create a cornea ready for transplantation.
Don't worry, the finished product is crystal clear, not dark blue like the cornea in the photograph above, which was dyed to make it easy to see.
"Many teams across the world have been chasing the ideal bio-ink to make this process feasible," lead author Che Connon, Professor of Tissue Engineering at Newcastle University, said in a statement.
"Our unique gel – a combination of alginate and collagen – keeps the stem cells alive whilst producing a material which is stiff enough to hold its shape but soft enough to be squeezed out the nozzle of a 3D printer.
"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."
Corneas have no blood vessels, unlike most body tissues, making the process of transplantation ever so slightly easier.
To gauge the correct shape and dimensions of the printed eye part, the researchers first scanned the patient's eye. They say this method will allow them to create custom-made cornea transplants to suit the patient’s needs.
Professor Connon added: "Our 3D-printed corneas will now have to undergo further testing and it will be several years before we could be in the position where we are using them for transplants.
"However, what we have shown is that it is feasible to print corneas using coordinates taken from a patient eye and that this approach has potential to combat the world-wide shortage."