Christopher A. Lemmon, Ph.D., Inez Caudill, Jr. Distinguished Professor in Biomedical Engineering, will receive a National Science Foundation (NSF) grant to support his investigation into how cells respond to mechanical properties of soft tissues in the human body, which could shed light on cell behavior in illness such as cancer and fibrotic diseases.
Lemmon, an associate professor and associate department chair in the Department of Biomedical Engineering, will receive a $442,709, three-year grant from the Biomechanics and Mechanobiology program in Civil, Mechanical and Manufacturing Innovation at the NSF.
Lemmon’s lab focuses on cell-generated traction forces and extracellular matrix biology, including how cells respond to their surroundings and sense the stiffness of tissues.
One cell behavior that has previously been studied is how cells respond when they sit on stiff tissue. The cell will muster a stronger force pulling into itself, and then “starts making thicker, denser tissue,” Lemmon said. Nearby cells also sense this stiffness and in turn start generating bigger pulling forces of their own. “You get stuck in this loop where the cells make more and more of the tissue and the whole thing spirals out of control.”
This cycle results in the development of tough scar tissue in wound healing and solid tumors. Increased tissue stiffness is often seen in cancer and fibrotic disease, which includes cystic fibrosis, cirrhosis and keloid scars. However, studies on these diseases haven’t accounted for another property of tissue.
Soft tissues, including the skin, lung and liver, are viscoelastic, which means they behave both like a thick liquid (like syrup) and a stretchable spring.
Imagine grabbing Silly Putty, the stretchy toy, which is also viscoelastic. “If I stretch Silly Putty really slowly, I can stretch it out pretty easily,” he said. But if you stretch it quickly, you will feel more resistance from the substance.
In his lab, Lemmon has been creating novel polymer surfaces that have varying degrees of stiffness in order to investigate how cells respond to such variations.