If you were riding a bike and happened to fall and hit your head, you might sustain a concussion—even if you were wearing a helmet.
Whether the impact leads to brain cell loss depends on the amount of physical force that rattles the brain.
“If you get hit hard enough, brain cells will die—but there’s a lot we don’t know about concussions,” says Christian Franck. “For example, how much force is too much for the brain cells to tolerate before they start shutting down?”
Franck, who joined the UW-Madison mechanical engineering faculty as an associate professor in fall 2018, is shedding light on how concussions, a mild form of traumatic brain injury, originate in the brain at the cellular level.
With his cellular biomechanics research, Franck studies how physical forces from an impact cause trauma in the brain and lead to cell loss. He ultimately wants to help inform new guidelines and medical protocols for traumatic brain injuries, and to enable new head protection technologies that could prevent brain cell loss from happening in the first place.
Franck points out that the helmets we have today are designed and evaluated based on standards from the 1970s meant to prevent skull fractures.
“Incidents of skull fractures are now less than 1 percent, but we don’t have a current helmet standard for concussions,” he says. “My goal is to help develop a new standard—to do the same thing we did in the 1970s—but targeted at preventing concussions.”
Franck, whose work is supported by major grants from the U.S. Office of Naval Research, will use the findings from his research to help develop helmets that are much more effective at preventing concussions. The new helmet design would keep the amount of stress and strain entering the brain below the threshold for cell damage.
For his project with the Navy, Franck is currently collaborating with a company that makes helmets for the military. However, he says other companies could apply his findings to develop better football and bike helmets. “I want everyone to have access to this protective technology, particularly in youth sport leagues, because the adolescent population is especially at risk,” he says.
But first things first. To realize such a helmet, Franck says, it’s essential to understand the mechanical thresholds for brain damage. A large portion of his research is focused on quantifying key parts of the concussion puzzle—such as exactly how much stress and strain it takes to damage cells and generate a concussion, and how long it takes for cells to die after the initial trauma.
To take these measurements, Franck develops and applies new experimental techniques at the micro and nanoscale. For example, he pioneered a technique for delivering a mechanical stimulus to neurons in a petri dish—essentially, he gives the neurons a concussion, then uses a powerful microscope to capture 3D images of how those neurons deform under stresses and strain in real time.
Franck and his research group leveraged these cutting-edge techniques to make a significant advance: They discovered that it took approximately six hours following a traumatic impact for the neurons to die. Understanding that time component is crucial, he says, because it establishes a window for therapeutic intervention before the damage becomes irreversible.
Franck didn’t set out to study cellular biomechanics and brain trauma. His love of airplanes and flying led him to study aerospace engineering as an undergraduate at the University of Virginia. Then, as a graduate student at the California Institute of Technology, he focused on mechanical engineering (while also earning his pilot’s license). During this time, he became interested in the many ways that mechanical forces can affect cell biology, and he saw opportunities to work closely with neuroscientists to bring his expertise in mechanics to the study of brain.
“I’ve maintained my persona as an aerospace mechanical engineer, but I love to collaborate with people in the biological disciplines to help address societally important problems like traumatic brain injuries,” he says.
Franck, who came to UW-Madison from Brown University, says the rich opportunities for interdisciplinary collaboration attracted him to the university. “The exceptional faculty here and UW-Madison’s excellence in research were a big draw,” he says.
Franck’s long-term goal for his brain trauma work is to establish a center at UW-Madison that brings together researchers from diverse areas to focus on the prevention, diagnosis and treatment of traumatic brain injuries to benefit society.
“At the end of the day, if I can help improve even just one person’s life with my research, I’m going to feel really good about it,” he says.