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.