When he contemplates the human lung, Samir Ghadiali sees a mechanical wonder.
Millions of tiny alveoli, or air sacs, transfer oxygen from the breath to the bloodstream, while drawing carbon-dioxide from the blood to be exhaled.
Lining the alveoli, more millions of even tinier epithelial cells keep the blood separated from the passing air.
Like the branches of a tree, the alveoli spread out, or bifurcate, in elaborate patterns to maximize the amount of incoming oxygen they can pull in.
So intricate is this network that if each of the alveoli were bisected and laid flat, the combined surface area of all the air sacs would cover two tennis courts.
Ghadiali, an assistant professor of mechanical engineering and mechanics, recently received a Parker B. Francis Fellowship in Pulmonary Research to study the mechanics of lung function.
This competitive three-year award, intended to enhance the early career development of promising young faculty members, is similar to the Sloan Research Fellowships in Science and Technology. The Francis fellowship is specifically designed to support young researchers who plan to study pulmonary disease and lung biology.
Ghadiali, a member of Lehigh’s bioengineering and life sciences program, will conduct lab experiments and mathematical simulations to determine the effects of injury and disease on lung mechanics.
A traumatic injury or infection, Ghadiali says, can degrade the epithelial lining of the alveoli and cause fluid to build up inside the air sacs, which greatly impedes their ability to facilitate the transfer of air from blood to breath.
"When this happens," he says, "you can't get any air in your lungs; you're literally drowning."
Patients suffering from fluid-filled lungs are often hooked to a machine that forces air into their lungs. But the presence of the fluid makes the lungs more prone to injury, leading to what Ghadiali calls a Catch-22.
"Your lungs are damaged," he says, "but the only viable treatment is provided by a machine that causes further damage to your lungs."
Ghadiali is seeking to shed light on the fluid-mechanical forces which, during this process of mechanical ventilation, cause further injury to the lung.
"I want to understand these (injurious) fluid mechanical forces better. We hope that the information we gain will help others develop new ventilation therapies that minimize the lung injury caused by these machines."
In the lab, Ghadiali will grow cells on protein-coated glass slides and will expose these cells to oscillatory fluid forces at different frequencies and magnitudes to simulate inhalation and exhalation.
He has a mentor - Daniel Ou-Yang, professor of physics and co-director of the bioengineering program. Ou-Yang has done pioneering research using lasers as "optical tweezers" to manipulate cells. Ghadiali will utilize the optical tweezer method to study how cells react to the oscillatory fluid forces and to investigate how the mechanical properties of these cells influence the injuries they sustain.
Ghadiali earned a Ph.D. in 2000 in biomedical engineering from Tulane University, where he studied the mechanics of the surfactant therapy that is used to help premature infants breathe.
Before joining Lehigh's faculty in 2003, Ghadiali was a research assistant professor in the department of pediatric otolaryngology at Children's Hospital of Pittsburgh, where he continues to serve as an adjunct research professor. At CHP, Ghadiali studied the mechanics of how the Eustachian tube opens and closes in hopes that his research helps lead to the development of new treatments for middle-ear infections.
Posted on Saturday, March 05, 2005