Japanese researchers have built a miniature pump that's driven by living cells cultured from a rat's heart muscles. Instead of batteries, the pump is powered by a nutrient bath. Someday, this kind of bio-mechanical pump could be integrated into medical implants or labs-on-a-chip. According to the scientists from the University of Tokyo and the Japan Science and Technology Agency, the next step is to integrate chambers and valves to better control the liquid being pumped. From New Scientist:
The main part of the pump is made from a flexible polymer sphere 5 millimetres in diameter. Teflon capillary tubes measuring 400 microns in diameter are inserted into opposite sides of this sphere.Link
A cell-friendly protein coating is then added to the sphere followed by a sheet of pulsing cultured heart cells. After just an hour the cells are firmly attached and begin driving the pump.
To test the pump, the researchers placed it in a nutrient medium at human body temperature (37°C). They watched through a microscope as small polystyrene balls contained with a fluid moved through the pump's tubes. The pump operated continuously for six days in testing.