New Approach Cooks Cancer Cells

A new approach to killing tumors uses the beam from a near-infrared laser to heat carbon nanotubes that have been selectively directed to the cancer cells.

While biologic systems are highly transparent to 700-1,100 nm near-infrared (NIR) light, a solution of carbon nanotubes exposed to NIR light warms to about 70oC within two minutes. Investigators at Stanford University (Palo Alto, CA, USA) have exploited this property of carbon nanotubes to selectively destroy cancer cells.

They coated nanotubes with folate molecules that directed the nanotubes to folate receptors on the cancer cell membranes. After the cells took up the nanotubes, the tumors were exposed to NIR laser light. The light caused the nanotubes to heat up, and the heat killed the cells. Nearby normal cells with no nanotubes were not damaged by the laser treatment. These findings were published in the August 8, 2005, online edition of the Proceedings of the [U.S.] Academy of Sciences.

"One of the longstanding problems in medicine is how to cure cancer without harming normal body tissue,” explained senior author Dr. Hongjie Dai, associate professor of chemistry at Stanford University. "We are using an intrinsic property of nanotubes to develop a weapon that kills cancer.”




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