From Scientific American:
Fighting cancer is currently a messy war. Modern chemotherapies attack tumors with the equivalent of a machinegun approach: cover the area widely with deadly fire and hope to destroy the tumor with a minimum of collateral damage. Doctors have long sought a way to precisely target tumors with their chemical therapies. Now researchers may have found it in a nanoparticle laced with a cancer-combatting drug.
Omid Farokhzad of Harvard, Robert Langer of the Massachusetts Institute of Technology and their colleagues created the nanoparticle out of a previously FDA-approved polymer that has been shown to dissolve inside cells. This nanoparticle–one-thousandth the width of a human hair–carries a load of a lethal chemical: docetaxel, which is currently used to treat prostate cancer. In addition, the scientists studded the outside of the particle with so-called aptamers–tiny proteins that link directly to cancer cells while avoiding regular cells. Finally, they equipped the nanoparticles with polyethylene glycol molecules, which allow them to resist the internal defenses of a tumor cell.
More here.