clusters of gold atoms can detect and kill cancer cells usually left behind after tumor removal surgery, according to a study of a new technical nanotechnology. For now, the approach has been tested in a mouse handle. But the researchers are designing a clinical trial that could begin testing in humans therapy over the next two years. If the technique proves effective in people, it could significantly improve the chances of cancer patients, especially in cases where surgical removal of an entire tumor is impossible.
When surgeons operate on patients with cancer, they do their best to eliminate every last diseased cell, because everything left behind can develop into new tumors or metastases in the body. Oncologists then usually follow up with surgery or radiation treatment or chemotherapy to increase the chance of eliminating all residual tumor cells. But this standard approach to fighting cancer is all but foolproof.
In recent years, doctors and scientists have turned to nanotechnology help. A pioneering approach over the last decade by researchers at Rice University in Houston, Texas and elsewhere has shown that atoms of gold clusters known as nanoparticles can serve as a powerful weapon against cells cancerous. solid tumor cancers generally have leaky blood vessels. Therefore, when gold nanoparticles are injected into the bloodstream, they tend to ooze out of the openings of the container and gather around tumors. To clean their environment, these cells then often engulf the nanoparticles. But once inside the cells, the nanoparticles can act as Trojan horses. When the researchers struck gold atoms with infrared laser light, which can travel through centimeters of tissue, the particles heat up and kill cancer cells.
Unfortunately, heating of the nanoparticle strategy has two problems, says Dmitri Lapotko, a physicist formerly with Rice and now head of the science of laser Masimo Corporation, a medical nanotechnology company in Irvine, California . The first is that some gold nanoparticles invariably end up in and around the normal cells, so that healthy tissue may be damaged when lasers go after cancers. Additionally, lasers that are normally used for heating the fire particles continuous beams of infrared light. It propagates both beyond the heat of cancer cells and in normal tissue. In cases where tumors develop and tissues around the civil state, such as nerve or artery walls, collateral damage to healthy tissue can be debilitating or dangerous.
In an effort to reduce the development of therapy, Lapotko and colleagues sought to change the approach to zapping nanoparticles. They started with mice that had been implanted with human squamous cell carcinoma, common cancerous cells in tumors and head of the human neck that are particularly difficult to treat with standard therapies. They have decorated their gold nanoparticles with proteins of immune antibodies that specifically lock on receptors which are seated on the surface of squamous cells. Which concentrates the particles, creating clusters of dozens of them in and around the cancer cells. And instead of pulling continuous laser beams, researchers fired only infrared ultrashort pulse.
As we expected, which prevented heat from spreading to surrounding normal tissues. But the approach has had an even more important effect: It caused temperatures to rise more where there were large clusters of gold nanoparticles. This vaporized adjacent water molecules, creating tiny bubbles that grow rapidly and burst, tear cancer cells. The key, Lapotko said, is that "nanoparticle clusters nanobubbles occur in cancer cells and not normal tissue."
online today Nature Nanotechnology , Lapotko and colleagues report that these mini explosions possible not only to retrieve sound where the tumor cells were located and thus detect the presence of only three cancer cells but it also destroys the cells in the process. in cases where it was possible to surgically resect most cancer tissues, 100% of animals survived, thanks to the fact that there is no residual tumor cells remained alive. And where the partial surgical removal of a tumor was an option, the survival rate for animals has doubled.
"This is very, very interesting," said Mien-Chie Hung of the University of Texas MD Anderson Cancer Center in Houston, which explores the treatment of tumors with nanoparticles. Hung noted that the approach fits very well with conventional surgery that is able to remove large tumors, but is unable to identify the cancer cells left behind. The new technique, he says, acts like microscopic surgery to target residual cells. Hung stressed that many approaches in oncology working in animals also found to be effective in humans. But if it does, it could open a new window in spots and the elimination of residual cancer cells left after surgery.
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