For neurosurgeons who are trying to distinguish the healthy from the unhealthy brain tissues around a tumor, the unique properties found in gold nanoparticles are a treasure hunter’s dream come true.
Since until now techniques to outline brain tumors have all had limitations as to how much they have been able to discern, such as the inability to perform real-time imaging without the use of extremely expensive equipment, or the limited lifespan and toxicity of some labeling agents. Gold nanoparticles are so minute that you could fit 500 of them end to end across a human hair. They are non-toxic, and relatively inexpensive to manufacture.
Researchers at Duke University’s Fitzpatrick Institute for Photonics and Biomedical Engineering Department are set to unveil their findings at the Optical Society’s (OSA) Annual Meeting of 2011 in San Jose, California in October.
Prof. Adam Wax’s team of researchers has been able to synthesize gold, rod-shaped nanoparticles with varying length-to-width ratios. “By controlling the nanorods’ growth we are able to ‘tune’ the particles to scatter a specific frequency of light,” says Wax. They then combine the tuned particles with antibodies that bind to growth factor receptor proteins found in unusually high concentrations on the outside of cancer cells. When the antibodies latched on to cancer cells, the gold nanoparticles mark their presence.
The team tested their theory by slices of a tumor-riddled mouse’s brain and bathing slices of it in a solution of antibodies merged with gold nanoparticles. Shining the specially tuned frequency of light on the sample revealed bright points where the tumors existed. “The tunability of the gold nanoparticles is important,” says team member Kevin Seekell, “because it allows researchers to choose from a window of light frequencies that are not readily absorbed by biological tissue. It might also allow researchers to attach differently tuned nanoparticles to different antibodies, providing a way to diagnose different types of tumors based the specific surface proteins the cancer cells display.”
Future work by the team will also focus on developing a surgical probe that can image gold nanoparticles in a living brain, Seekell says. This research will help neurosurgeons to isolate the areas in the brain that need to be cut out, while being able to leave healthy tissue that would otherwise have been cut out as a preventative measure.
This is Ron White, and I look forward to hearing more about this new technique to localize tumors from healthy tissue.
Sources:
Science Daily – Tagging Tumors With Gold: Scientists Use Gold Nanorods to Flag Brain Tumors: http://www.sciencedaily.com/releases/2011/10/111012113559.htm
