Kidney
Like healthy kidneys, dialysis machines filter out unneeded urea as well as useful
sugars, salts, and water. But unlike the real thing, the machines don't recycle
the useful materials into the blood. Nephrologist David Humes of the University
of Michigan is developing a bioartificial kidney that routes those beneficial
elements through tubes lined with kidney cells, which reabsorb the good stuff
and send it back through the tubes' porous walls into the blood. Tested so far
only on dogs, Humes' device may enter human trials soon. (20)