Dr Steve Swioklo and Prof Che Connon with a dyed cornea. Credit: Newcastle University, UK

The first human corneas have been 3D printed by scientists
at Newcastle University.

It means the technique could be used in the future to
ensure an unlimited supply of corneas.

The proof-of-concept research, published  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 3D 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.

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 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.”  

The scientists, including first author and PhD
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.

Prof 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.”

Source: https://www.ncl.ac.uk/press/articles/latest/2018/05/first3dprintingofcorneas/

Reference: Isaacson A et al. 3D Bioprinting of a
Corneal Stroma Equivalent. Experimental Eye Research. Published online ahead of
print 14 May 2018.