Gold Nanoshells Help Visibly Heat and Destroy Cancer

July 29, 2008 - Most cancer tumors that have clear borders and are well defined have traditionally been treated successfully by surgical removal.

But not all cancers respond to conventional surgery. More importantly, conventional surgery brings risks of complications and long recovery periods that can negatively impact a person's quality of life.

To overcome these treatment limits, a group of researchers based at the University of Texas' M.D. Anderson Cancer Center, turned to lasers and nanotechnology. They explored an emerging minimally-invasive approach to treating tumors that delivers a lethal dose of laser-generated heat to tumors, known as thermal ablation. To improve thermal ablation,they added a nano-twist that precisely guides and concentrates heat in targeted tumors.

Working with Nanospectra Biosciences, Inc., researchers injected nanoshells made of gold silica into canine models of brain cancer. The nanoshells homed to the target tumors, where they were taken in by the tumor cells. Next, researchers irradiated the nanoparticle-filled tumor

with low-power laser light to selectively heat the tumor-but not the surrounding, healthy tissue. M.D. Anderson researchers added iron-oxide cores to the nanoshells to make them visible by magnetic resonance imaging so researchers could observe the process.

Results from these experiments were supported by numerical modeling studies, and by scanning electron microscope data showing destructive thermal increases near the tumors’ blood supplies.

"Based on these encouraging early results, we conclude that the use of magnetic resonance temperature imaging and gold nanoshells hold the very real possibility of meeting the long-sought goal of improving the precision of thermal ablation, while sparing healthy tissue," explains M.D.
Anderson Cancer Center's R.J. Stafford, Ph.D. "Temperature imaging and guidance is an invaluable tool furthering this approach as it moves from feasibility studies to future use in human clinical trials."

For more information: www.aapm.org

Source: American Association of Physicists in Medicine