A great deal of work is presently taking place to develop targeted nanoparticles to kill very specific types of cell with no side-effects or collateral damage. This is good, as the applications of this technology range far beyond cancer: the aging immune system, for example, or cases of autoimmune disease could benefit from killing off malfunctioning immune cells. Many other potential uses exist. Here is another example of work in progress: "researchers synthesized nanoparticles - shaped something like a dumbbell - made of gold sandwiched between two pieces of iron oxide. They then attached antibodies, which target a molecule found only in colorectal cancer cells, to the particles. Once bound, the nanoparticles are engulfed by the cancer cells. To kill the cells, the researchers use a near-infrared laser, which is a wavelength that doesn't harm normal tissue at the levels used, but the radiation is absorbed by the gold in the nanoparticles. This causes the cancer cells to heat up and die. ... This is a so-called 'smart' therapy. To be a smart therapy, it should be targeted, and it should have some ability to be activated only when it's there and then kills just the cancer cells."