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Scientists are hoping to one day target cancer at the cellular level, by-passing the need for radiation and chemotherapy. That dream may be getting closer through the use of nanotechnology. This ScienCentral News video has more.
Nanoshells vs. cancer cells
Tiny particles called nanoshells may one day provide cancer treatment that packs the same punch as chemotherapy, without the nausea, fatigue, hair loss and other side effects. Nanoshells do this by scorching cancer tumors from within the tumor itself, without leaking out and damaging the healthy tissue around them.
“If we compare nanoshell-assisted cancer therapy to conventional cancer therapy, for example chemotherapy, there’s a very high likelihood that the type of side effects that people see in conventional therapies would be greatly reduced,” says Naomi Halas, professor of chemistry and electrical and computer engineering at Rice University.
Nanoshells stick to the surface of cancerous cells in the body.
Naomi Halas created a nanoshell one-1000th the width of a single strand of hair that would capture only infrared light and convert it into heat. Halas and her colleague, biomedical engineer Jennifer West, then coated the nanoshell with a material that makes it stick only to cancer cells when it is injected into the patient. An infrared light shone on the patient would get captured only at the cancer site. The nanoshell then heats up, destroying the cancer cells while leaving the healthy tissue unharmed.
The nanoshell is made up of a core and a shell. Their sizes can be controlled relative to each other in order to absorb specific wavelengths of light – in this case near infrared light, above the absorption level of body tissue and below that of water. “So, because there’s nothing in the human body that can be absorbed at these wavelengths, light can pass very deeply into tissue and not cause any damage,” says West.
The nanoshell converts the light into heat so that it increases the tumor’s temperature to 55 degrees Celsius – the threshold – enough to kill the cancer but not enough to leak out into the healthy neighboring cells.
Mouse MRI - nanoshells collect in areas with tumors. image: Rice University
Halas reported in the journal Cancer Letters that in lab tests on mice with colon cancer, nanoshells injected into the mice then heated with the infrared light destroyed tumors in 10 days and did not recur. “We saw that those animals continued to survive cancer-free months afterwards, we never saw any rebirth of a tumor,” West explains. In the mice not treated with nano shells however, the cancer continued growing.
West says that they haven’t seen any adverse effects from the nanoshells in the mice and they have done a lot of testing showing that they’re very safe, non-toxic and biocompatible. The next step in their research is to test nanoshells in humans.
West and Halas are particularly hopeful about their potential in hard to treat or inoperable cancers like brain cancer.
Their research appeared in the June 25, 2004 issue of the journal Cancer Letters and was funded by the National Science Foundation.
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