SAN ANTONIO, Dec. 8 /PRNewswire/ -- Nanotechnology, using particles as small as 100 nanometers in size, is offering exciting new possibilities for finding and treating breast tumors, according to speakers at the 28th Annual San Antonio Breast Cancer Symposium being held this week. Two researchers from Rice University in Houston, Texas, offered enticing insights into how these minute particles can be manipulated to have different properties, and tagged with antibodies to target them specifically at cancer cells. Jennifer West, PhD, has studied the unique optical properties of nanoshells. These particles consist of a nonconducting core (for example, silicon) surrounded by a metal shell of varying thickness. They are "tunable," in that their ability to respond to light varies with the thickness of the shell and core size. Nanoshells can be designed so that they either scatter or absorb light that hits them. Nanoshells designed to absorb incident light heat up and can potentially be used to kill cells. Nanoshells that scatter incident light may improve our ability to image breast cancer. Dr. West is particularly interested in gold nanoshells, because they respond to near-infrared light, a wavelength that is easily transmitted through biological tissue. In a series of preliminary experiments in tissue culture cells and animals, she has demonstrated that nanoshells will accumulate in tumors, especially when they are coated with tumor-specific antibodies. Once accumulated, the nanoshells can be used to treat the tumor with heat or, when designed to scatter light, act as highly effective contrast agents to improve imaging. Near infrared light can penetrate biological tissue to a depth of 15 cm, and can also be delivered via catheter-based fiber-optic cable, so that although this technology has not yet been applied in humans, clinical application seems feasible and promising. Lon Wilson, PhD, also from Rice University, has looked at the therapeutic and imaging possibilities of carbon-based molecular scaffolds, specifically fullerenes (bucky balls) and carbon-based nanotubes. Although these structures are easily absorbed into cells, when properly constructed they are nontoxic and nonimmunogenic in mammals, and are excreted from the system quickly. Both fullerenes and nanotubes can have metals inserted into them, and Dr. Wilson has looked specifically at structures into which gadolinium has been inserted as potential contrast agents for high resolution magnetic resonance imaging. Other gadolinium-complexed contrast agents are routinely used for MRI, but are quite toxic. Gadofullerenes are five times as efficient as these agents, making them more effective as contrast agents. Gadolinium carbon nanotubes are even more powerful as contrast agents, some of the highest efficacies every recorded. In addition, by cycling magnetic fields in cells containing gadolinium carbon structures, sufficient thermal energy can be generated to kill targeted cells.
SOURCE San Antonio Breast Cancer Symposium