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A new cancer treatment could kill cancer cells without the painful side effects of chemotherapy. As this ScienCentral News video reports, using nanotechnology, scientists may now be able to destroy tumors without killing healthy cells at the same time.
For people with cancer, chemotherapy, with its painful side effects, is often the worst part of the treatment process. What if there was a noninvasive cancer treatment that could target a tumor and leave the healthy tissue alone?
Now, nanotechnology may be on the way to providing just that. Naomi Halas, professor of chemistry and electrical and computer engineering at Rice University created tiny particles called nanoshells, which are 1/1000th the size of a human hair. "If you could see them they would look a lot like malted milk balls, except they are made of different materials," says Halas, "The crunchy core would instead be made of glass and the chocolate coating would instead be made of gold. And that's very important geometry because being able to control the relative size of the two parts of the nanoshell, the core and the shells, allows us to tune the optical properties of that nanoparticle such that we can control what wavelength of light it absorbs, what color of light it absorbs."
Halas reported in the journal Cancer Letters that the nanoshells' ability to capture light and convert it to heat has, in lab tests on mice, destroyed tumors. She and Rice biomedical engineer Jennifer West coat the nanoshells with a substance that binds them to cancer cells, and inject them into tumors. A harmless near-infrared light heats only the nanoshells, which convert the light into heat that destroys tumor cells, without affecting healthy tissue near the tumor.
Nanoshells are coated with a substance that binds them to cancer cells.
Halas and West studied 25 mice with tumors that were divided into three groups: one that received no treatment; one that received saline injections and three minutes of exposure to the near-infrared light; and one that received nanoshell injections and a laser applied on the skin above each tumor.
While tumors in the other two groups of mice continued to grow, the tumors in the group that got the nanoshell treatment disappeared within ten days, and those mice remained cancer-free afterwards. "So far we have never seen any adverse reaction to nanoshells in animals," says West. "We've done a lot of testing at this point and all of the results to date look like they're very safe, non-toxic, and bio-compatible."
Halas says nanoshells would have virtually no side effects because they're not interacting with the organism. "They only are active once they're in place at the tumor site and once one shines light through the skin to the actual tumor site and heats that localized region," she says. "So we feel that is something might make a huge difference in terms of the invasiveness—not just the side effects but the overall lack of invasiveness of this sort of treatment. When nanoshells are directly injected into the bloodstream, the body doesn't recognize them. They're coated with specific molecules that essentially make them stealth particles, so they're not recognizable as a foreign object. Also…they're gold and gold is not recognized as a foreign substance by the human body. If we compare nanoshell-assisted cancer therapy to conventional cancer therapy for example, like chemotherapy, there's a very high likelihood that the type of side effects that people see in conventional therapies would be greatly reduced."