The Mechanics of Hearing

Losing his hearing isn’t what made Rice bioengineer Robert Raphael begin researching possible cures. It all began with the Grand Unified Theory. . . .

Robert Raphael, the T.N. Law Assistant Professor of Bioengineering, is severely hearing impaired. His research investigates the molecular forces driving the ear’s outer hair cells, the tiny sensors in the cochlea responsible for the uniquely mammalian ability to resolve high-frequency sound.

Cue inspiring soundtrack: In a quest to help himself and others, Raphael has dedicated his life’s work to researching the root causes of some of the most common forms of hearing loss and deafness.

Cut to reality: Raphael’s hearing loss, which began while he was in high school, had no initial influence on his academic choices. “I started out wanting to be a particle physicist and work on the Grand Unified Theory,” says Raphael, who earned a double major in physics and philosophy from the University of Notre Dame. “It was very practical,” he notes wryly. “My senior thesis was on philosophical implications of quantum theory.”

Now a popular professor who teaches bioengineering thermodynamics, Raphael can’t resist analogies referencing the field—he jokes that it was engineers who converted him to doing “useful” work. The conversion began during his PhD studies at the University of Rochester, where Raphael applied his physics background to become an expert in the mechanical and thermodynamic properties of cellular membranes.

Then coincidence landed him in postdoctoral research in a Johns Hopkins’s lab studying the action of outer hair cells in the cochlea. Even here, Raphael continued to focus more on the physics of the system than on its potential relationship to him. The wake-up call came three months into his work while Raphael was taking a course titled Structure and Function of the Auditory System.

“A doctor was talking about mechanisms of hearing loss, and one of the things he mentioned was deficiencies in outer hair cells,” Raphael remembers. “And I asked, ‘Are you telling me that what’s wrong with me could have something to do with this outer hair cell that I’m working on?’ and he said, ‘There’s a good chance.’”

Today, students in Raphael’s lab are well aware that their research could one day lead to new therapies for hearing loss. Raphael has assembled a diverse team of undergraduate and graduate students that is rapidly amassing new knowledge to explain how outer hair cells work to supercharge mammalian hearing. But it’s not just about hearing, despite Raphael’s personal connection to his model system. The research is just as likely to spawn tiny, nanoscale sensors or other miniature devices modulated by tweaking membrane properties just so.

“Bionanotechnology is fast becoming the next big thing,” Raphael notes. “But if it’s going to grow beyond the hype into actual tools and devices, it’s very likely to happen because of inspiration provided by the delicate workings of the inner ear.”