Always wear sunscreen

Always wear sunscreen

But what if you can't? An Ottawa chemist tackles sunblock allergies - and more.
July 21, 2014

As the summer signals hot weather and long days at the beach, doctors, cosmeticians and mothers everywhere rally to proffer their standard warning: “Always wear sunscreen.”

But for people who are allergic to sunblock, like Elda Scaiano, it is impossible to wear commercial sunscreens. Fortunately for Elda, her husband, Juan Cesar “Tito” Scaiano, is a world-renowned chemist at the University of Ottawa who was inspired by her predicament to research sunscreens.

Scaiano, who holds a Canada Research Chair in Applied Photochemistry, found a solution by encapsulating the active ingredients in sunscreen that cause allergic reactions. Encasing the sunscreen molecules within the cavities of a non-toxic mineral called zeolite ensured that they wouldn’t directly touch the skin but would still absorb light and protect the skin.

Although the concept was simple, the formulation was tricky. Scaiano had to actually build the sunscreen molecules within cavities in the zeolite and fellow chemist Ann English of Montréal’s Concordia University tested them. “We called them ‘ship-in-the-bottle sunscreens,’” says Scaiano. The sunscreens produced by Scaiano and English successfully blocked the sun’s damaging ultraviolet rays without producing a harmful reaction on the skin.

There is a growing concern over the toxicity of chemicals in sunscreens with high SPF ratings and the technology developed by Scaiano and English can also potentially protect people from cancer.  

Members of Scaiano and English’s laboratories published several papers about the work, and in the early 2000’s, companies eventually commercialized the concept using different encapsulating materials. “There were other materials that grew more commercially viable,” says Scaiano.

His research on filling zeolite compartments with molecules and his questions about the effect sunscreen molecules could have on proteins spawned much of his current work with nanomaterials. Scaiano is now studying the antibacterial properties of silver nanoparticles to see whether they can be stabilized with collagen, a protein that is found in the skin.  

Scaiano and his team are working with colleagues at the University of Ottawa’s faculty of medicine to create a cream for diabetics who are prone to infections in their extremities. Encapsulating silver nanoparticles in collagen could harness silver’s antibacterial properties without damaging the skin. The research group is now testing a compound in Sweden.

“This is an area where, clearly, collaboration is the only way to reach an application that hopefully will have medical or health applications,” says Scaiano. The process of moving from sunscreens to biomedical creams and even industrial applications of nanotechnology is not a straight line, he adds, but is often the way scientific discoveries are made. “Where you’re going is important, but the journey in itself is important too.”

Scaiano, who moved to Ottawa from his native South America in 1975, has always been fascinated with the interaction between light and matter and the interaction of light with molecules and materials.

“It’s a fun field,” says Scaiano. “I always know that every day we are going to do something new and to find something new. And every now and then, you have a moment when you suddenly understand something you’ve been struggling with, and that is very rewarding.”

Originally posted: July 20, 2011