Charged Bodies: Ferroelectricity Discovered
in Mammalian Tissue
By Hannah Hickey
THE HEART'S INNER WORKINGS are mysterious, perhaps even more so with a new finding. UW engineers have discovered an electrical property in arteries not seen before in mammalian tissues.
The researchers found the wall of the aorta, the largest blood vessel carrying blood from the heart, exhibits ferroelectricity, a response to an electric field known to exist in inorganic and synthetic materials.
"The result is exciting for scientific reasons," said lead author Jiangyu Li, associate professor of mechanical engineering. "But it could also have biomedical implications."
A ferroelectric material is an electrically polar molecule with one side positively charged and the other negatively charged, whose polarity can be reversed by applying an electrical field. Ferroelectricity is common in synthetic materials and used for displays, memory storage, and sensors.
Li collaborated with co-author Katherine Zhang at Boston University to explore the phenomenon in biological tissues. The only previous evidence of ferroelectricity in living tissue was reported in seashells. Others had looked in mammal tissue, mainly in bones, but found no signs of the property.
The new study shows clear evidence of ferroelectricity in a sample of a pig aorta. Researchers believe the findings will also apply to human tissue.
Pinpointing the source of the ferroelectricity may answer questions about how or whether it plays a role in the body. "The elastin network is what gives the artery the mechanical property of elasticity, which of course is a very important function," Li said.
Ferroelectricity may therefore play a role in how the body responds to sugar or fat. Diabetes is a risk factor for hardening of the arteries, or atherosclerosis, which can lead to heart attack or stroke. The team is investigating the interactions between ferroelectricity and charged glucose molecules, in hopes of better understanding sugar’s effect on the mechanical properties of the aortic walls.
Another possible application is to treat a condition in which cholesterol molecules stick to the inside of the channel, eventually closing it off.
"We can imagine if we could manipulate the polarity of the artery wall, if we could switch it one way or the other, then we might, for example, better understand the deposition of cholesterol which leads to the thickening and hardening of the artery wall," Li said.
NAE Honors David Stahl
UW Engineering's newest member of the National Academy of Engineering (NAE) is David Stahl, professor of civil and environmental engineering.
The NAE honored Stahl for his application of molecular microbial ecology to environmental engineering. Stahl's research concerns microbes and the role they play in processing nutrients. He also studies evolution and competition among microbial communities, and how to harness microbes for the bioremediation of polluted sites. Election to the Academy is among the highest professional distinctions accorded an engineer.
Stahl is author of more than 220 academic papers and is co-author of a NASA and Jet Propulsion Laboratory report on handling samples from Mars; a National Research Council task group report on possible human contamination of Jupiter's moon Europa; and an American Academy of Microbiology report titled "Microbial ecology and genomics: A crossroads of opportunity."
Also elected this year are UW affiliate professor Henrique Malvar and UW alumnus Peter Farrell.
Junior Faculty Win Coveted NSF CAREER Awards
Three junior faculty have been awarded National Science Foundation CAREER Awards. The grants typically provide funding of $400,000 to $500,000 over four to five years. Two of this year’s recipients, Marco Rolandi and Xiaodong Xu, are assistant professors in materials science and engineering. James Pfaendtner, an assistant professor in chemical engineering, is the other recipient.