Tiny bacterial pumps have been grown that will take in nutrients and spin constantly for as long as they can.
Somehow it should be possible to use this to make the heart redundant. (Note that much of the difficulty in restarting a heart is lack of fluid in the chambers, which interferes with proper beating. note also that any bacterial pumps can work much better after youve fallen onto the floor) Some possible ideas how:
1) Put some sort of electronic component in the bacteria that will trigger the release of an anti-inhibitory chemical of some sort upon command (The command issuedautomatically by a monitoring-only pacemaker) Thus, the bacteria sit still in your bloodstream until you stop the inhibitory effect that is preventing them from spinning. They then pump blood for you, until your heart can be restarted, at which point inhibitory chemicals are injected again in large volume via injection by paramedics.
2) The bacteria always spin, but they are anaerobic and in the veins only. Since there is already a downward lag in the veins, this shouldnt hurt you while your heart is pumping (in fact, it might help by preventing vericose veins, etc.), but when it cuts out, the pumping action is still significant to at the very least keep your heart filled with fluid. If the pressure is too great while your heart pumps, then these bacteria could be installed in your body at the same time that your vein valves are surgically removed.
3) Make bacteria that simply naturally start spinning either when they encounter a lack of oxygen, or when they encounter some particular rare chemical that your monitoring pacemaker would inject into your blood as soon as anything went wrong. This is a low-tech version of #1, but is slower to respond.
4) As the link mentions, thermal changes can cause bacterial response too. Perhaps it is possible to make it so that they pump when they get too cold. This would help both with heart attacks AND with simple body heating in cold environments.-- Smurfsahoy, Mar 26 2007 Bacterial pumps http://www.nsti.org...ch2005v1/11/W907.04 [Smurfsahoy, Mar 26 2007] Three problems I see.
First how do the bacterial pumps know which way to pump? If half the pumps are pushing upstream and half are pushing downstream, you will get zero net effect.
Second, bacteria are typically smaller than blood cells, so all they are going to be able to pump is the plasma, which might do some good, as the cells should entrain.
Third, how are you going to power the bacteria? Pumping five liters of fluid takes a LOT of energy.-- Galbinus_Caeli, Mar 26 2007 It would probably make more sense to use an existing body structure rather than a bacterial motor. Just arrange for segments of a few key arteries to do peristalsis (a la intestine) when deprived of oxygen - they could probably keep you alive until help arrived.
Or surgically create a tough-walled aneurysm, plumb it into the aorta and put it somewhere soft (eg, near the surface of your abdomen). Then, when you have a heart attack, just massage your stomach (or get a friend to do it) to manually pump blood around as a stop-gap.
Or grow another heart and plumb it in as a backup. Lots of animals have >1 heart.-- MaxwellBuchanan, Mar 26 2007 Uh, well yeah sure, an additional heart, or genetically modified arteries are nice and all, but way more invasive and complicated. The idea is to make this all injectable, automatically growing, cheap, etc.
As for the first response - directionality is indeed sort of an issue. I'm thinking it should be possible to make it so that any pressure in the system will orient the bacteria in the right way. For instance, even while inhibited, they could spin verrry slightly, which would create a small resistance differential, such that they are generally flipped in the correct direction, being spun by the heart's pumping action. Then, if the monitoring pacemaker is good enough, it can make them spin faster BEFORE the natural flow has stopped completely, and thus they would be spinning in the right direction when their time comes. The flow creatd by the majority of the bacteria would then help flip any rogue bacteria that may have foundered in the lag period back to where they should be.
Only able to pump plasma? Nonsense. The propeller on an oil tanker is less than 1% the size of the tanker (im guessing), but it still moves it. it moves the very tiny water particles around the ship, which then create currents that carry the ship. Same thing for plasma and red blood cells. By pumping the plasma, they WILL pump the red blood cells indirectly, just like any outboard boat motor.
And power - Well, the whole point of these bacteria is that they keep the blood flowing and allow energy to reach where it needs to reach. So they provide their own energy, from the human blood stream, just like they use when the heart IS working. Their preservative effects apply to them too, not just the rest of the body's tissues.-- Smurfsahoy, Mar 26 2007 random, halfbakery