Systems and methods utilize semipermeable nanotubes in conjunction with application of controlled electrical potentials across semipermeable nanotube walls allow selective transport of charged impurities (e.g., charged impurities, ions, etc.) from a fluid into these nanotubes. Impurities collected in these nanotubes can then be removed from the fluid, (e.g., blood) as a waste stream. A collection of semipermeable nanotubes each carrying a waste stream can be aggregated and merged into a ureter for excretion thereby providing an artificial kidney system. Sensors that detect/measure various impurities may be included in the system to feed information to a microprocessor to inform on concentrations of impurities, and thereby control electrical potentials applied to the system.
