A cross-disciplinary team of researchers and doctors at the University of Waterloo (UW) are developing a new contact lens material that could change the way eyecare providers treat corneal wounds. The team, from the Centre for Ocular Research and Education (CORE), located within the School of Optometry & Vision Science and the Department of Chemical Engineering at the University, believe the new material, acting as a bandage for corneal wounds, could release drugs in a controlled manner to help the eye heal faster.

Lyndon Jones, PhD, DSc, a professor at UW’s School of Optometry & Vision Science and director of (CORE), said the new technology will mark a significant improvement in corneal wound treatment. “It’s a targeted-release, drug delivery system that is responsive to the body. The more injured you are, the more drugs get delivered, which is unique, and, potentially, a game changer,” he said.

There is a growing market for drug-delivering, bandage contact lenses that could simultaneously treat the eye and allow it to heal, Dr. Jones said.

 Lyndon Jones, PhD, DSc.
Current treatment of corneal abrasion patients involves wearing a clear, oxygen-permeable bandage contact lens for seven to 10 days. The bandage is infused with eye drops containing antibiotics. This approach, however, can make it difficult to ensure enough drugs are administered to the eye to sustain treatment.

Researchers found that collagen, a protein in the eye that’s often involved in the wound healing process, was too soft and weak to be used as a contact lens material. Dr. Evelyn Yim, an associate professor of chemical engineering at Waterloo University, discovered a way to transform gelatin methacrylate, a collagen derivative, into a biomaterial that is 10 times stronger than collagen. The team's research also found that one unique property of collagen-based materials is that they degrade when exposed to an enzyme called matrix metalloproteinase-9 (MMP-9), which is found naturally in the eye.

“These enzymes are very special because they’re involved in wound healing, and when you have a wound, they’re released in greater quantities,” according to Dr. Chau-Minh Phan, a research assistant professor at the UW’s School of Optometry & Vision Science. “If you have a material that can be degraded in the presence of this enzyme, and we add a drug to this material, we can engineer it so it releases the drug in a way that is proportional to the amount of enzymes present at the wound. So, the bigger the wound, the higher the amount of drug released.”

In addition to Dr. Phan and Dr. Yim, the research team included Dr. Susmita Bose, whose research spearheaded the project; Dr. Muhammad Rizwan, a former postdoctoral fellow; and John Waylon Tse, a former graduate student.

To conduct their research, the team used bovine lactoferrin, which has shown anti-infective, and anti-inflammatory effects, as a model wound-healing drug and entrapped it in the material. In a human cell culture study, the researchers achieved complete wound healing within five days of using the drug-releasing, novel contact lens material. The team also found that the material only becomes activated at eye temperatures, providing a built-in storage mechanism. The hope is that this research can be applied to the treatment of other injuries, such as large skin ulcers.

Dr. Chau-Minh Phan.

“Certainly, the enzymes' matrix metalloproteinases (MMPs) that are used to activate the drug-release technology are not only present in corneal wounds but are also present in other types of tissue damage throughout the body, including burns, bed sores, diabetic ulcers and venous ulcers,” Dr. Phan said.

“This has led us to consider the potential of adapting our bandage material technology for the treatment of various skin wounds,” he said, noting that the next steps in bringing this technology into daily practice is to optimize the material’s properties, specifically modulus, wettability and optical clarity, that are important for contact lens wear. He also shared that there are still significant challenges when it comes to integrating small molecular-weight drugs within the material, a crucial area of ongoing research.

“Realistic timelines are always hard to give, as the speed at which we can do research is dependent on funding availability,” he said. “But optimistically, we would target two years to reach animal trials, with an additional four years before we could do clinical trials, provided everything progresses favorably.”

Dr. Phan believes the first advantage of this technology is that it will provide clinicians with a more effective tool to treat corneal wounds that is superior to current bandage lenses, which do not deliver any drugs. He reiterated the benefit of the technology, in that it is activated by enzymes released when the eye is in a wounded state and that the dosage of drugs released is tailored to the severity of the wound.

“This is important as it ensures an effective dose of drugs is released for healing while minimizing any potential for side effects of the drug,” he said, emphasizing that they would not want a lot of drugs released when the wound is small. “In other words, by ensuring that the release of drugs or therapeutics is proportional to the severity of the condition, we enhance therapeutic efficacy and reduce drug-related side effects. This concept could also extend beyond just eyecare and the treatment of eye injuries, with the potential for applications in other sites of the body where enzymes are present.”

The contacts will be able to include a prescription, depending on the patient's needs. The treatment window using the new technology would be one to two weeks.

“Over time, the material is designed to degrade and release the drugs within this timeframe when exposed to the MMP9 enzyme at physiological temperatures,” he said. “The longer the treatment duration, the more difficult it becomes to manage precise drug release and dosage.”

He added that the interactions between the material, the eye and the surrounding environment become harder to test and predict for longer-term studies. “From a technology development standpoint, these materials could be developed for long-term injury treatment, but there will be new challenges that need to be overcome,” he concluded.

A complete study outlining the researchers’ work was recently published in the journal Pharmaceutics.