Simon Fraser University Professor Pursues Photo-Switches For Cancer Treament

By Kim Gunnerson

There are major challenges in administering chemotherapy to cancer patients. The most common mode of dispensing chemotherapy–systemically–leads to unwanted side effects caused by the drug's destruction of healthy cells throughout the body.

Designing and administering drugs that are specifically targeted to destroy cancerous cells only is one approach to solve this problem. The dream of turning the drug on and off "where and when you want it" is the goal of Neil Branda, a professor at Simon Fraser University in Vancouver, B.C.

Branda is a recent recipient of the National Sciences and Engineering Research Council of Canada (NSERC) Steacie Fellowship, which is awarded to six young outstanding Canadian university faculty each year. Recipients of this fellowship are released from teaching duties for a two-year period to allow them to devote more time to research.

Finding the time necessary to expand research into a new field is a major obstacle for a scientist. The award is giving Branda the chance "to devote the next two years of my life to exploring how molecular switching strategies can benefit health sciences, specifically drug delivery in treating prostate cancer," he says.

Treating cancer with a molecular switch involves attaching an organic molecule to a drug, trapping it in a complex that prevents the drug from interacting with tissues. The complex is then administered to the patient. The area of the body where the cancer is located is then exposed to a laser, whose light frees the drug, allowing it to destroy the cancer cells. This type of treatment is called photodynamic therapy (PDT) and the organic molecule is called a photo-switch.

Branda studies molecules that change from colorless to colorful when radiated with light. In addition, Branda's research group has been able to design combinations of these photo-switches to produce colors all across the color spectrum.

One of the problems with current examples that use light to release therapeutics is that they often rely on UV light, says Branda. "So our strategies are all using photo-switching where the photo-switch is triggered by visible light.” The use of this lower energy radiation in cancer treatments may decrease the damaging effect of UV light in photodynamic therapy.

Kim Gunnerson is a physical chemistry doctoral degree candidate at the University of Washington.

Images

Top: Neil Branda, Professor and Canada Research Chair in Materials Science Department of Chemistry at Simon Fraser University in Vancouver B.C. Photo: SFU

Middle: A series of vials filled with different combinations of photo-switches illustrating the different portions of the visible spectrum interacting with the molecules. Photo: Neil Branda