artificial kidney

Short definition from Wiktionary

Noun

1. 1
   A dialysis machine, an external device that cleans the blood of people with kidney failure; from the 1940s to the 2000s, not portable, but wearable versions now exist.
2. 2
   An implantable bionic device to replace the function of a natural kidney, long dreamed of but not yet feasible.
3. 3
   A bioengineered (laboratory-grown) biologic kidney (from cultured cells), still experimental.