by: Jack Williams, January 4, 2010 3:01:13 am
Dr. Naomi Halas, a professor at Rice University, knows her nanoshells. She invented the tiny particles, with a glass core and gold covered shell, in the 1990's. Now Halas and her colleagues have figured out a way to make nanoshells smarter. They've attached a bright fluorescent dye to the particles that make them glow under infrared light. They've also added a magnetic shell that makes the particles visible to MRI. In addition, researchers can now attach antibodies to the nanoparticles that help them hone-in on a variety of cancer cells.
"If you try to do the same thing with molecules or with drugs, it's very difficult, if not impossible, to attach several different functions to the same drug without disrupting its first function. But with nanoparticles you have a nice platform that you can add several different things to it and still preserve the primary function of the nanoparticle itself."
Which at this point, is to harvest laser light, convert that light to heat, and then kill tumor cells with that heat. Halas says being able to watch the progress of the nanoparticles, both optically and magnetically, is crucial.
"In terms of being able to facilitate medical treatments with this approach, this type of tool is going to be very good. It gives eyes to the medical research. It gives two sets of eyes to the medical research, the optical eyes and the magnetic eyes. Those in combination complement each other so more information will be available using this approach."
"This is the unique advance, because nanoshells have been around for a decade, but no one was able to see them like this."
At his desk inside the radiology department at Baylor College of Medicine, Amit Joshi is pointing to the image of a small animal on his computer screen. Fluorescent nanoparticles slowly collect around a tumor in the animal.
"So they're going into the heart and lung region. Gradually, this thing is going to trap..."
Joshi says the important part of the imaging is that nanoparticles could eventually be used as much more directed treatments that affect only specific cancer cells, unlike chemotherapy that affects the entire body. Researchers are still studying what they call biodistribution, why nanoparticles end up where they do in the body.
"Next step is to do exhaustive studies on hundreds of animals and optimize the shape and the surface properties of these nanoshells so that we get favorable biodistribution where most of the stuff retains in the tumor and its clear of the liver and kidneys to the body. Once that is done, we should be ready for pursuing the FDA approval process for these agents and talking to clinicians and planning for trial."
At this point, Joshi says human trials are still a few years away. He says in a decade, nanoparticles could be one of the leading tools in the fight against cancer.