Probing the physics behind biological systems

There’s an old adage that physicists like to tell their students: “Assume the cow is a sphere.” The idea is that the real world is complicated, but to do physics, many of those complexities don’t matter. So you ignore the cow’s legs and the head and treat it as a giant beach ball. 

A spherical cow sounds silly, but the underlying principle is sound, and it’s something that Aidan Brown, a professor in the Department of Physics and part of the Complex Systems research group, takes full advantage of. Brown’s specialty is the physics of biological systems, especially the workings of living cells, which can be incredibly complex. And yet, beneath that complexity are physical structures that obey well-understood laws, and whose behaviour can be modelled mathematically and simulated on a computer.

“Everything in biology is built of atoms, molecules, proteins - those things are not alive on their own. But you put them together in the right way, you add energy in the right way, and you get something that’s alive,” says Brown. “So how do these components that aren’t alive keep the overall system alive? That’s a big mystery.”

Brown is particularly interested in the workings of mitochondria, the organelles that provide the chemical energy to keep cells functioning. And while his research is rooted in basic science, a better understanding of mitochondria has enormous practical applications. “Understanding the fundamentals of how mitochondria are able to remain healthy in cells over long periods could help us investigate the root causes of nerve cell degeneration over time,” he says. A better knowledge of those processes may shed light on the mechanisms behind neurodegenerative diseases and even cancer. “I really want to understand how living things use physical principles to stay alive.”

Brown is one of four researchers at the heart of TMU’s interdisciplinary Complex Systems initiative.