Scientists at Case Western Reserve University in Cleveland have designed an artificial lung that uses air instead of pure oxygen as a ventilating gas--an advance that could turn accompanying oxygen cylinders into relics of the past.

Joseph Potkay

What's more, the device for use in humans could come in at just 6x6x4 inches, which is roughly the volume of the real human lung, meaning it could conceivably pave the way for implantable artificial lungs.

"Current technology involves complex systems that are limited to intensive care units, so [the] device has the potential to provide clinically relevant oxygenation levels using ambient air, opening the door to portable systems," says Jeffrey Borenstein, an expert in microsystems technology and biomedical devices at the Charles Stark Draper Laboratory in Cambridge, Mass., in a news release.

Joseph Potkay, an electrical engineering and computer science professor and the lead author of the paper describing the lung, estimates that based on current performance the unit could be powered by the heart instead of a mechanical pump.

The team first built a miniature-feature mold, layered a liquid silicone rubber over it that hardened into artificial capillaries and alveoli, and then separated the air and blood channels with a gas diffusion membrane. By building a small unit, they were able to maximize the surface-area-to-volume ratio and shrink the distance for gas diffusion to improve efficiency.

Because their initial tests using pig blood showed three to five times improvement in oxygen efficiency over current artificial lungs, the unit works using plain old air instead of pure oxygen as the ventilating gas.

The team anticipates testing human artificial lungs in clinical trials within a decade. In the meantime, they're working with the university's departments of biomedical and chemical engineering to build a durable unit large enough to test in rodent models of lung disease, and to develop a coating that will prevent clogging in the narrow capillaries.