A 3D-printed vision for the future

Research on track to develop the first bio-engineered cornea fit for human transplants

A research team led by the University of Sydney’s Professor Gerard Sutton, with researchers from the University of Wollongong (UOW) has scored an early goal in efforts to develop a 3D bio-engineered cornea to revolutionise sight-restoring transplants.

A research team led by the University of Sydney’s Professor Gerard Sutton, with researchers from the University of Wollongong (UOW) has scored an early goal in efforts to develop a 3D bio-engineered cornea to revolutionise sight-restoring transplants.

The UOW team, led by bio-engineering pioneer Professor Gordon Wallace and supported by the Medical Research Future Fund (MRFF) Frontiers Phase 1, has produced a prototype with the structural strength that has eluded similar attempts.

“We’ve hand-assembled a cornea in the lab…the breakthrough was assembling the stroma (the strength component of the structure) with aligned collagen fibrils and living cells,” says Professor Gordon Wallace, Director of the UOW Intelligent Polymer Research Institute (IPRI).

About 2000 corneal transplants are performed in Australia each year to treat eye disease that cause the cornea to become cloudy, lose transparency or change shape, leading to blindness.

Corneal transplants are the only treatment for these conditions which include bullous keratopathy, Fuchs’ endothelial dystrophy and keratoconus, as well as eye trauma.

However, the tissue needed for transplants can only be sourced from people who have bequeathed their corneas to eye banks before death.

Demand for that tissue is now exceeding supply worldwide, with 12.7 million people awaiting a transplant and less than 1500 donors in Australia in 2022, sparking urgency in the medical realm for a more innovative approach.

“Australia doesn’t do too badly, but there is a need to make sure we can generate more cornea if we are to keep up with demand – especially in developing countries,” says Professor Wallace.

Building for the future

The 3D bio-printing process builds layer by layer, using a digital file as a blueprint rather than traditional fabrication. Using this approach, the aim is to build a bio-engineered cornea using a technology that will eventually morph into a commercial entity.

The cornea build starts with collagen molecules in a solution.

“We then apply an electric field that causes those molecules to assemble into aligned collagen fibrils to replicate that complex structure that we find naturally in the stroma,” says Professor Wallace.

“The process introduces living cells, so of course that means you need materials to accommodate and protect those cells to make sure they survive and develop.

“We work closely with the NSW Organ and Tissue Donation Service, and we estimate the bio-engineering process will allow us to generate at least 30 bio-engineered corneas from one donated cornea,” says the professor.

The hand-assembled cornea produced on the lab bench at IPRI has taken more than three years to design and develop.

Benchwork is considered crucial preparation for successful outcomes because it provides the knowledge foundation for the applied science that follows.

A man in is standing in a lab wearing a lab coat and safety goggles. He is holding a white device connected to a 3D printer.

Dr Johnson Chung working the 3D printer

The average cornea is only as wide as a shirt button and as thick as sheet of paper, but it produces more than half of the eyes focusing power. It does that through its precise shape for refraction, and a chain of processes performed in its three main layers.

The epithelium is the clear, top layer which allows light into the eye. It also provides protection and cell regeneration.

The middle layer, the stroma, provides structural stability and durability, and the third layer the endothelium, pumps excess water out of the stroma to maintain transparency in the cornea.

“The stroma was always going to be one of the main challenges to ensure it maintains the cornea’s exquisite shape for clear sight, and we also need to ensure it can withstand the suturing process during transplants,” says Professor Wallace.

He is mindful that similar projects by other researchers have failed due to this issue.

Collagen can be derived from several sources including bovine and marine collagen. There is also human collagen produced from tissue sourced through the NSW Organ Tissue Donation Service, which the team will use throughout the project’s next phase.

One of the potential advantages of a bio-engineered cornea is that it could reduce the risk of rejection and infection that has dogged conventional transplants.

Immunosuppressive drugs are used to reduce the risk of that happening, but they are not always successful.

However, bioengineered cornea can be modified to be less immunogenic by removing or modifying certain cell surface markers that trigger immune responses. By reducing the recognition of the tissue as foreign, the chances of rejection could be minimised.

Multi-skilling for success

The team comprises an impressive line-up of highly skilled researchers and clinicians, including prominent eye surgeon, Professor Gerard Sutton, from the University of Sydney and Professor Mark Daniell from the Centre for Eye Research Australia in Melbourne.

It also includes one of Professor Wallace’s former PhD students and now research fellow, Dr Zhi Chen.

Dr Chen’s thesis topic, electro-compacted collagen for corneal bio-engineering, laid the foundation for the project’s fabrication method.

“My role is to optimise the manufacturing process to improve the physical performance of the product – such as transparency and mechanical toughness,” he says.

The young scientist’s plan growing up in China, where he did his undergraduate degree in clinical medicine, was to become a doctor.  However, over time he developed an interest in bio-engineering research.

“I have this dream to develop a device or material that could relieve suffering from disease,” says Dr Chen.

He says so far the research has been both challenging and exciting.

“Gordon has so much knowledge in this field and he’s always willing to share it with others - I’ve learned so much this from this scientific rock star, as well as from my clinical mentor, Professor Sutton,” he adds.

Two men in a science lab. They are both wearing lab coats and safety goggles. The man in the foreground is wearing blue latext gloves, holding tweezers to place a 3D printed film in place while the man in the background supervises.

Dr Zhi Chen and Professor Gordon Wallace in the IPRI lab. Photo: Martin Weaver

Keratoplasty and the need for innovation

Franz Reisinger initiated experimental animal corneal transplantation in 1818, coining the term ‘keratoplasty’, according to a paper on the history of corneal transplants by Alexandra Crawford from the New Zealand National Eye Centre.

But it was not until 1905 that Austrian ophthalmologist, Eduard Zirm, performed the first full-thickness bilateral corneal transplant surgery on a 45-year-old farm labourer.   

It restored sight in one eye, and allowed the labourer enough sight to return to light duties.

Since then, technique has been vastly refined but the push towards bio-engineering is accelerating.

Ageing populations have also increased the urgency for a different transplant approach.

Although there is still at least four years before the project is expected to reach the stage of human trials, Professor Wallace is confident his team will turn corneal 3D bio-printing into reality.

And it all comes down to brain power and military-style planning.

“On some other projects, we have identified the path of translation along the way, so therefore we took a lot of wrong turns,” says Professor Wallace.

“This has been a really well-planned project right from the very start.”

UOW will host a webinar as part of the Luminaries Series on the 3D bio-engineered cornea on 20 July. This is a free online event, however registrations are essential.