Considering how excrementally bad the movie is, getting the science wrong is no surprise, but what a shame it decided to impart such a dangerously misguided view of nanotechnology.
The premise in "Ballistic" is some German research group created a killer nanorobot. If injected into a victim, it would float through the bloodstream until the assassin hits the proverbial little red button, triggering the injection of something to cause a heart attack or stroke.
We can start with the matter of scale. One scene has Lucy Liu's character, Sever, examining some computer files about the robot. The image zooms in on a single blood vessel and finds the little killer.
Well, if the robot is floating freely through arteries or veins without blocking even a capillary, then it has to be the size of a blood cell. No problem here, since nanotech, the science of manipulating individual atoms and molecules, already deals with structures at a sub-celluar level.
The snag comes in terms of the robot's supposedly lethal payload. The "needle" portion of the device is a small fraction of the whole, so it could hold no more than a couple dozen molecules and there simply isn't a drug or toxin powerful enough to kill with such a minuscule dose.
That fact is part of the reason for research into nanomedicine -- designing devices to find and deal with disease without affecting healthy parts of the body.
It's also a bit sad the computer effects folks behind the "Ballistic" robot didn't pay more attention to their throwaway images.
When Antonio Banderas' character, Ecks, is first shown the robot, there's a small piece of animation in the corner of the screen, showing what appears to be gears made out of atoms. Such devices are exactly what researchers are working on, and in fact could have been a much more effective "engine" for the movie's robot.
Scientists at UCLA have constructed a molecular "propeller" by attaching a nano-sized metal rod to the business end of a subcelluar structure that rotates as it metabolizes ATP, the basic energy source for the human body. Rotating the rod is equivalent of a human spinning a telephone pole about 2 kilometers long at eight revolutions per second in a swimming pool -- sounds powerful enough to propel a nanobot through the bloodstream, doesn't it?
You know, putting such a propeller on the "Ballistic" bug probably would have looked cooler than the frog-leg sort of arrangement the animators chose. Blaming the techies for the robot's pincers and syringe, however, would simply be unfair, since such imagery is likely the only way the audience would understand what the robot was doing.
Actual research for those sorts of tasks involves such visually boring ideas as having specific protein strands bond with celluar surfaces to "grab" the desired target. Injections at that scale involve heat or electricity driving the liquid, not a plunger.
The bottom line here is to understand nanotechnologists are indeed considering ways to have little helpers floating through your body, but there's nothing sinister about it.