The proof-of-concept research, published today in Experimental Eye Research, reports how stem cells (human corneal stromal cells) from a healthy donor cornea were mixed together with alginate and collagen to create a solution that could be printed, a 'bio-ink'.

　　Using a simple low-cost 3-D bio-printer, the bio-ink was successfully extruded in concentric circles to form the shape of a human cornea. It took less than 10 minutes to print.

　　The stem cells were then shown to culture—or grow.

3D printer for cornea with co-author Dr. Steve Swioklo. Credit: Newcastle University, UK

　　Che Connon, Professor of Tissue Engineering at Newcastle University, who led the work, said: "Many teams across the world have been chasing the ideal bio-ink to make this process feasible.

　　"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 3-D 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 thecells separately."

　　The scientists, including first author and Ph.D. student Ms Abigail Isaacson from the Institute of Genetic Medicine, Newcastle University, also demonstrated that they could build a cornea to match a patient's unique specifications.

　　The dimensions of the printed tissue were originally taken from an actual cornea. By scanning a patient's eye, they could use the data to rapidly print a cornea which matched the size and shape.

(L-R) Dr Steve Swioklo and Professor Che Connon with 3D printer. Credit: Newcastle University, UK

　　Professor Connon added: "Our 3-D 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."

　　Explore further: Curve-eye-ture: How to grow artificial corneas 

　　More information: 3D Bioprinting of a Corneal Stroma Equivalent. Abigail Isaacson, Stephen Swioklo, Che J. Connon. Experimental Eye Research.