A patient may undergo intense chemoradiation and surgery, only to have the tumor grow up within a short period of time. We haven't found a way to stop the tumors from recapitulating. The culprit of this regeneration of tumor bulk is a group of cells with exquisite traits: cancer stem cells. Researchers have now aimed at destroying tumors by targeting cancer stem cells within the tumor via nanoparticle killing machines. The researchers packaged the anti-cancer drug doxorubicin into nanoparticles coated with chitosan, a natural polysaccharide that can specifically target CSCs.