Nanoparticle technology being developed at the University of Waterloo could come to the rescue of individuals taking cyclosporin eye drops to treat dry eye syndrome. Users — who sometimes find they must administer the medication several times a day — could ultimately wind up applying the drops just once a week, which would be not just more convenient but would also significantly reduce the risk of toxic exposure to this powerful drug.

PhD student Sandy Liu is leading a team working on nanoparticles to improve the effectiveness of a medication that combats dry eye syndrome.

PhD student Sandy Liu is leading a team working on nanoparticles to improve the effectiveness of a medication that combats dry eye syndrome. Photo Credit: Tim Leshuk

Shengyan Liu, a doctoral candidate in Waterloo’s Faculty of Engineering, was an undergraduate when he began exploring the possibility of using nanoparticles to improve how drugs are delivered to the body. He wound up in the laboratory of Frank Gu, who holds a Canada Research Chair in Advanced Targeted Delivery Systems at Waterloo, which is dedicated to linking biology and engineering at the nano scale to improve medical treatment.

Liu now leads a team of university researchers addressing the shortcomings of eye drops used to treat dry eye syndrome. This condition is a more common problem for individuals over the age of 50, affecting as much as six percent of the population. The challenge in treating this ailment is caused by the eye’s ability to continuously cleanse itself, which means medicinal eye drops are also washed out.

The results of this work are described in an article for Nano Research that included Gu and Liu among the authors. It describes a key innovation in the use of a pair of polymers: dextran, which is an established eye lubricant and polylactic acid, a biologically compatible molecule that eventually degrades into lactic acid for easy absorption into the body. With phenylboronic acid on the surface of these nano-scale polymers, Liu explains, they serve as anchors in the surface of the eye. “They’re able to integrate the gel structure of that mucous membrane,” he says, adding that this means the pharmaceutical compounds attached to those polymers also stay put. “Instead of having to use eye drops several times during the day, this nanoparticle staying on the surface of the eye is doing the same thing — slowly.”

This research originated within a national research network called 20/20, which was established in 2008 by the Natural Sciences and Engineering Research Council in collaboration with the Ontario Centres of Excellence Centre for Materials and Manufacturing. This initiative brought together researchers at four universities with eight industrial partners to study new materials that could address challenges associated with vision loss.

More specifically, network researchers examined the prospect of introducing composite or hybrid materials that would be compatible with the makeup of the eye and its tissues. The results included microgels, microemulsions and other agents that could have practical ophthalmic applications, such as the nanoparticles developed by Liu’s team.

The design of Waterloo’s product is under patent protection and Liu’s team is now studying ways of making larger batches of this material so that it can be produced in commercial quantities. At the same time, they have also completed pre-clinical trials of this product and are looking forward to setting up formal clinical trials in humans.