Light-activated material could repair damaged corneas

An injectable biomaterial activated by pulses of low-energy blue light has “tremendous potential” for repairing the outer layer of the eye, a team of University of Ottawa researchers and their collaborators have claimed.

Guided by biomimetic design – innovation inspired by nature – the multidisciplinary researchers’ results showed that the light-activated material can be used to effectively reshape and thicken damaged corneal tissue, promoting healing and recovery.

The technology is a “potential game-changer in corneal repair”, a research announcement said. Tens of millions of people across the globe suffer from corneal diseases, and only a small fraction are eligible for corneal transplantation. Transplant operations are the current gold standard for ailments resulting in thinning corneas, such as keratoconus, which results in loss of vision for many people.

“Our technology is a leap in the field of corneal repair. We are confident this could become a practical solution to treat patients living with diseases that negatively impact corneal shape and geometry, including keratoconus,” said Dr Emilio Alarcon, an associate professor at the uOttawa Faculty of Medicine and senior author of a paper on the work.

The cornea is the protective, dome-like surface of the eye, in front of the iris and pupil. It controls and directs light rays into the eye and helps achieve clear vision. It is normally transparent, but injury or infection can result in scarring.

The biomaterials devised and tested by the team are comprised of short peptides and naturally occurring polymers called glycosaminoglycans.

In the form of a viscous liquid, the material is injected within corneal tissue after a tiny pocket is created surgically. When pulsed with low-energy blue light, the injected peptide-based hydrogel hardens and forms into a tissue-like 3D-structure “within minutes”, the announcement said. It then becomes a transparent material, with similar properties to those measured in pig corneas.

In vivo experiments using a rat model indicated that the light-activated hydrogel could thicken corneas without side effects. The research team – which reportedly used a “much smaller” blue light dosage compared to what has been used in other studies – also successfully tested the technology in an ex vivo pig cornea model. Testing in large animal models will be necessary before clinical human trials.

“Our material was engineered to harvest the blue light energy to trigger the on-the-spot assembling of the material into a cornea-like structure. Our cumulative data indicates that the materials are non-toxic and remain for several weeks in an animal model. We anticipate our material will remain stable and be non-toxic in human corneas,” said Dr. Alarcon.

The research took over seven years to reach the publication stage.

“We had to engineer each part of the components involved in the technology, from the light source to the molecules used in the study. The technology was developed to be clinically translatable, meaning all components must be designed to be ultimately manufacturable following strict standards for sterility,” said Dr Alarcon.

The research findings are also the focus of a patent application, which is presently under negotiations for licensing.

Interdisciplinary collaborators included University of Montreal scientists Dr May Griffith, an expert in cornea regeneration, and Dr Isabelle Brunette, an ophthalmology and corneal transplant expert.

The project was supported by a Collaborative Health Research Projects grant, an NSERC Discovery grant, the Government of Ontario, and the University of Ottawa Heart Institute.

The research was published in Advanced Functional Materials.