Building machines for better health

By Emily Leighton, MA’13

Turn on your cellphone’s flashlight and hold your finger over it. What do you see?

As the light passes through your finger, it should turn red.

Because red has the highest wavelength on the visible electromagnetic spectrum, it is weakly absorbed by tissue and therefore transmitted deeper into your finger. By comparison, wavelengths associated with blue and green fall in a lower range and are more strongly absorbed.

Mamadou Diop, PhD, assistant professor with the Department of Medical Biophysics, is using this optical property to investigate tissue health – developing non-invasive technologies to measure specific biomarkers, such as tissue blood flow and oxygen saturation, at the bedside.

One way to measure these biomarkers is through a method called near-infrared spectroscopy, which applies the same concept illustrated by the flashlight experiment – transmitting high wavelength light deep into tissue.

“By doing this, we can measure the concentration of blood, water, fat and other important tissue components,” Diop explained. “We then use mathematical modelling of light propagation in tissue to extract information.”

When using this clinically, an important application is measuring cerebral perfusion, or blood flow in the brain. The brain needs a continuous supply of oxygen due to high metabolic demand and no storage capabilities, and any disruption to the blood supply can have devastating effects.

“With high-risk procedures, such as heart surgery, it is important to know what is happening to the brain,” said Diop. “This non-invasive technology will help monitor blood flow and inform clinicians right away should problems arise.”

Diop is also applying this work to other areas as well, such as joint inflammation.

Born and raised in Senegal, Diop graduated from Université Cheikh Anta Diop of Dakar with an undergraduate and master’s degree. He also completed teachers college during his studies, and taught high school physics part-time.

The researcher moved to Canada to pursue PhD training at Université Laval. As a native French speaker, he says the transition to a new continent and culture was exciting. “I was very open-minded, and hungry to read, learn and discover new things,” he said.

After adjusting to Quebec City’s famously cold winters, he journeyed westward to Ottawa, joining the National Research Council of Canada’s Institute for Microstructural Sciences for a two-year postdoctoral position.

In 2006, he landed in London for a second postdoctoral position, based at Lawson Health Research Institute with Keith St. Lawrence, PhD. Diop has continued this affiliation with Lawson, becoming a scientist with the Institute in 2013.

As a faculty member at Schulich Medicine & Dentistry, he says teaching and working with students is an essential part of his role. “Mentoring students is part of doing research,” he said. “We are tackling problems together as colleagues, and they are an integral part of the team.”

Diop’s lab is called the Translational Biophotonics Lab, reflecting the complex technical work he oversees, as well as the important connection to clinical application. “We build machines and algorithms,” he said. “But our goal is to improve health care for patients. We embark on a project because we foresee its application for better health.”