April 14, 2008 -- A new nanodevice loaded with powerful cancer-killing drugs can operate inside a living cell to zap cancer cells in response to light.
The nanomachine, created by researchers in California, is called a nanoimpeller and is the first of its kind.
"We have developed a machine to deliver the cancer drugs only in the cancer cells and not normal cells," said Fuyuhiko Tamanoi, a study author and scientist at the University of California, Los Angeles.
"Our research is the first demonstration of controlled and on-demand release of anticancer drugs using mechanized nanopartilces in living cells," said Tamanoi.
The nanoimpellers are actually tubes made of light-sensative silica. When light strikes the silica, tiny tails on the inside of the tubes wag back and forth, creating a current that propels the drugs out of their cyllindrical home.
The more light is directed at the silica, the more drugs they deliver.
For initial tests the researchers loaded their nanomachines with camptothecin, a chemotherapy drug commonly used to treat pancreatic and colon cancer. The nanoparticles were then injected into human cancer cells in vitro and taken up in the dark.
When a light source was turned on for five minutes, the drugs, which trigger cell suicide or apoptosis, were released and shrank the tumors.
Since the drug release is only activated in locations where the light is shining, scientists can direct the drug release within cancer cells. The researchers note that they could load other drugs into the nanoimpellers to treat other diseases that are specific to certain locations and not spread out across the entire body.
The nanoimpeller drug delivery system will take several years before it is approved for human use, but Tamanoi says he expects a "clear path" toward approval.
If it is approved, patients wouldn't need to worry about inadvertently activing the nanoimpellers by stepping outdoors. The devices only respond to a very specific wavelength of light.
"This is a highly significant application of these light activated materials," said Darren Dunphy, a nanomaterials scientist at the University of New Mexico who was not involved in the research.
''This is beyond proof of concept and at some point could be applied to people."
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