Bacteria harnessed as Micro Propellar Motors

[Vargha Poralli]

Bacteria harnessed as micro propeller motors (http://www.newscientisttech.com/article/dn11037-bacteria-harnessed-as-micro-propeller-motors.html)

Great news for medical field I belive.


(from article)
"In the future, such hybrid swimming micro-robots could even be used to deliver drugs inside the liquid environments of the human body, such as the urinary tract, eyeball cavity, ear and cerebrospinal fluid," Sitti told New Scientist. "They could also be employed to monitor toxic or pathogenic biochemical agents in the environment as well for inspection and maintenance of liquid filled pipes in spacecraft and nuclear plants."

[Kia]

Impressive. However getting the bacteria to go exactly where one wants seems a bit more complicated then they say. Wouldn't they have to continually regulate the on/off switch inside the bacteria using copper sulphate and EDTA (word is too damn long)?
This is the exact quote:

To stop the bacteria's motion, the researchers add copper sulphate to the solution. The copper ions bond to the rotor of the flagella motor and prevent it from moving. To restart the motion, another chemical called ethylenediaminetetraacetic acid (EDTA) is added. The EDTA traps the copper ions attached to the rotor, allowing it to move again. The rotors can be switched off in this way an unlimited number of times.
Would this mean building some kind of mechanism inside the "robot" or would this mean injecting some kind of substance into the human body to do so? And if does mean injecting the substance into the body would that be dangerous? Someone with a better understanding of the human body and this kind of science have an idea?