Just think what this technology would do to the pharmaceutical industry's advertisement war on television. Can the drug companies come up with an ad campaign clever enough to make people go back to pills after seeing these bad boys in action? I think that somewhere, an ad exec is crying.

"The nanoparticles remain dormant until activated by an external magnetic field, which causes them to cluster together, mimicking the effect of drugs, thereby triggering a cascade of biochemical signals inside the cell."