Edward F. Leonard | Developing an Artificial Kidney

Edward F. Leonard
Professor of Chemical Engineering and
of Biomedical Engineering
This profile is included in the publication Excellentia, which features current research of Columbia Engineering faculty members.
Photo by Eileen Barroso

Nearly 500,000 Americans depend for their lives on thrice-weekly, in-clinic kidney dialysis to remain alive. The treatment is costly ($23 billion a year—or about $46,000 per person), very demanding, and provides only a low quality of life. Some 80,000 Americans are on waiting lists for kidney transplants, with 4,000 dying each year before they get one. A steadily operating, ambulatory blood purification system would decrease patients’ burdens and increase quality of life for all of these patients.

Chemical Engineering Professor Edward Leonard and his team have been working with government and investor support to devise such an ambulatory system based on microfluidics. The device spreads a small flow of blood into a layer only 30 microns thick. Water and toxins migrate between this layer and two layers of cell-free fluid flowing beside it in direct contact, with contact times less than a second. The cell-free fluid layers are collected and purified by a mini-dialyzer/ultrafiltrator that is part of the device. Flows are maintained by a small pump originally developed for NASA.

The system, which is expected to be about 4 inches square and 1 ½ inches high, is designed to be worn by the patient at all times. It will remove water nearly continuously and remove other wastes whenever the patient is stationary. A newly-developed nanopore filter formed of silicon nitride keeps the cells in the bloodstream. This novel blood-cleansing system will not require anticoagulants and will have operating costs well within current, federally mandated cost-containment limits. First trials on patients are expected in 2011.

Leonard directs Columbia’s Artificial Organs Research Laboratory, a component of the Department of Chemical Engineering since 1968. Its mission has grown with the evolution of modern biology and with the increasing sophistication available for the construction of medical devices. Thus, current projects have a wide range: innovations to traditional artificial organs effecting transport (kidney, liver, lung, cardiovascular implants) with special emphasis on the artificial kidney, to regenerative medicine, especially the development and study of methods for introducing stem cells into adult tissue.

Leonard, who directs the NSF-sponsored course cluster in Genomic Engineering and is a member of the Columbia Genome Center, is one of the first Columbia Engineering faculty members to engage in bioengineering research. He has worked in the dialysis field for more than 50 years and has been on the Columbia faculty since 1958. His principal medical collaborator is Dr. Stanley Cortell, Professor of Clinical Medicine and Chief of Nephrology at St. Luke’s-Roosevelt Hospital.

B.S., Massachusetts Institute of Technology, 1953; M.S., Pennsylvania, 1955; Ph.D., 1960

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