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Gold Nanorods May Permit Heat Treatment of Tumors

Scientists at MIT, together with collaborators, have developed gold nanorods that can home in on tumors and then, by absorbing energy from near-infrared light and emitting it as heat, destroy the tumors with minimal side effects. The light heats the nanorods, but passes harmlessly through tissue. Although it has long been known that heat can kill tumor cells, it has previously been difficult to heat the tumor cells specifically while leaving the surrounding tissue undamaged. In designing the nanorods, the researchers took advantage of the fact that blood vessels located near tumors have tiny pores just large enough for the nanorods to enter. The team developed a polymer coating for the particles that allows them to survive in the bloodstream longer than any other gold nanoparticles. In experiments in mice with tumors, the nanorods were injected into the bloodstream and accumulated in the tumors. With near-infrared laser treatment, the tumors disappeared in 15 days. The treated mice survived for three months with no evidence of recurrence, until the end of the study, while mice that received no treatment or only the nanorods or laser, did not. The researches noted that the gold nanorods also have potential in the detection and diagnosis of tumors, because the particles can be imaged by a technique known as Raman scattering. This work was reported in two recent papers, one in Cancer Research and the other in Advanced Materials. [MIT release]