Systems, methods, and devices relating to a cellularized nephron unit

A bioartificial device comprising:

• a microfabricated blood flow layer having a first microfluidic channel formed therein for carrying blood, the first microfluidic channel including a loop, and wherein portions of the loop in the first microfluidic channel are separated by a porous medium;
• a microfabricated filtrate layer having a second microfluidic channel formed therein for carrying a filtrate flow, the second microfluidic channel including a loop having an ascending limb seeded with salt-pumping cells and a descending limb seeding with water permeable cells;
• and
• a permeable membrane positioned between the blood flow layer and the filtrate layer coupling the blood flow layer to the filtrate layer.