Biomedical engineers have developed techniques to deliver tiny amounts of medicines like anticancer drugs to a specific target directly to a location in the body affected by, say tumors for example. Most of their work involves nanocapsules or hollow structures which carry the payload of medicines, the delivery of which can be controlled from outside the body. Like many nanoparticles, quantum dots can be conjugated to antibodies, ligands or other targeting moieties to mediate specific interactions with cancer cells.

Gold nanoparticles when irradiated with near-infrared light are capable of destroying tumors and particularly gold nanoshells are used to deliver little amount of heat to breast tumor cells already treated with radiation, boosting the destroying capacity of both therapies. The action is that nanoshells increase perfusion of tumors with oxygen and also focally disrupts the blood supply to tumors, both of which enhance the effectiveness of radiation. Nanoshells reduce the population of stem cells dramatically which were left without destroying by radiation alone. Gold nanoparticles and quantum dots are used to diagnose and treat cancer.

The nanocages are cubes of gold nanoparticles having sides of about 50-billionths of a meter made with holes at each corner made using silver particles as a mold. The holes are plugged with strands of a smart polymer. When the polymer strands are heated they collapse, opening the holes and allowing the drug inside nanocage to escape at the target. The polymer strands are heated using near-infrared rays from outside the body. Near-infrared wavelength rays are not greatly absorbed by the unaffected body tissues as they penetrate a couple of inches inside the body, but they are absorbed by nanogage made of gold.