Building the bioengineered cornea
The decade-long mission to create a bioengineered cornea is taking its next steps with a new national collaboration.
For the millions of people around the world with corneal blindness, an alternative to waiting for donor tissue is closer than ever before.
In a first of its kind project, researchers from CERA, the University of Melbourne, and other institutions across Australia are working together to create a fully bioengineered cornea.
A clear cornea, the window that lets through light at the front of the eye, is crucial to good vision. However, injury and disease can damage one or more of its five layers, and it will not always heal on its own.
“The endothelial layer of the cornea is made up of cells that don’t divide normally after birth, so if they become damaged, they cannot heal effectively and you end up with a swollen, opaque cornea,” says Professor Mark Daniell, Head of Corneal Research at CERA.
For people with a damaged cornea, the only option is to wait for a corneal transplant using donor tissue from an eye bank.
“That’s a very well-organised, expensive and highly regulated system that works well in Australia, America and Europe, but not so well in the rest of the world,” says Professor Daniell.
Many countries do not have their own eye bank or have a lack of donors, leaving millions, particularly in the developing world, unable to receive the surgery.
It’s estimated that 53 per cent of the world’s population do not have any access to corneal transplants.
Announced in December 2021, the BIENCO consortium aims to create a fully artificial cornea that can be use instead of donor tissue.
Professor Daniell’s team at CERA, alongside the University of Melbourne School of Engineering led by Professor Greg Qiao, are building two layers of the cornea: the epithelium and the endothelium.
The epithelium is the surface layer of the cornea, and the endothelium is the delicate single layer of cells lining the back of the cornea.
Professor Gerard Sutton at the University of Sydney, Professor Gordon Wallace at the University of Wollongong and Professor Damien Harkin at the Queensland University of Technology are leading development on the other layers, in conjunction with SESLHD – NSW Organ and Tissue Donation Service.
Professor Daniell says that a bioengineered cornea has major benefits, the first being unlimited supply.
“You could just order a cornea off the rack, and you wouldn’t have to require a single donor for each surgery.
“Also, if the operation fails you won’t have wasted any precious donor tissue.”
The second major benefit would be increased patient safety.
“The surgery would be safer, with no risk of transplanted viruses and potentially reduced rates of rejection,” says Professor Daniell.
“Rejection rates can be an issue when you put donor tissue into another person. With a synthetic cornea you should be able to reduce the chance of rejection.”
As well as a fully bioengineered cornea, the group is also collaborating on developing partial transplants for individual layers.
BIENCO is being funded by a Medical Research Future Fund Grant under the Australian Government Frontier Health and Medical Research Initiative.
The road to develop a bioengineered cornea has been over a decade long and led to significant achievements along the way.
Professor Daniell says he first started discussing the idea of a tissue-engineered cornea with Professor Qiao ten years ago.
Rather than work on the full cornea from scratch, they approached the final goal step-by-step.
“The interactions between corneal surgery, chemical engineering, polymer science and cell biology are much more complicated than they initially appear,” says Professor Daniell.
“Some cells like growing on surfaces that others don’t. We know a lot about the cells, but finding the best ways to grow the cells on the novel polymers and making hydrogels more biocompatible, as well as transparent and tough enough to withstand surgery, has been a real challenge.”
Based on this work and in collaboration with EverSight, the US’ largest non-profit community-based eye bank network, they are also developing CorGel.
CorGel is a scaffold that affixes to the donor corneal tissue that makes endothelial keratoplasty, a transplant of the endothelial layer of the cornea, easier to perform.
“You just take a disc of endothelium, which has several properties that are not good for surgery, and we attach that onto our CorGel hydrogel scaffold, and then you can very easily use that to attach to the eye,” says Professor Daniell.
Without CorGel, the donor endothelium can curl up, making transplants a significant challenge for surgeons to perform.
It is also a good material for growing cells for transplants, stretching eye bank donations further than ever before.
CorGel is funded through the Victorian Medical Research Acceleration Fund, and it is hoped that human trials could begin as soon as next year.