Gold nanoparticle could allow powerful alpha particles to join cancer fight
By Darren Quick
February 6, 2013
Gold nanoparticles have already shown promise in precisely highlighting brain tumors, “blowing up” individual diseased cells, and developing a lung cancer breath test. Now researchers have created gold nanoparticles that allow an alpha particle-emitting element to be directed to small cancer tumors. The researchers say the gold coating keeps the powerful radioactive particles in place at the cancer site so they do negligible damage to healthy organs and tissue.
Conventional radioactive cancer treatments typically rely on the use of low-energy radiation particles known as beta particles. However, of the three types of radiation – alpha, beta and gamma – alpha particles have the highest ionizing power. For this reason, scientists have been looking for ways to use them in cancer treatments.
But while they have the highest ionizing power, they also have the lowest penetration of ordinary objects. So the challenge has been to find a way to confine the powerful alpha particles, which are more than 7,000 times heavier than beta particles, at a specific location in the body to prevent damage to healthy organs and tissues.
J. David Robertson, director of research at the University of Missouri (MU) Research Reactor and professor of chemistry in the College of Arts and Science, says some success has been had in using radium-223 chloride, which emits alpha particles. The U.S. Food and Drug Administration has fast tracked radium-223 chloride but it has only been shown to be effective in treating bone cancer. This is because radium is attracted to the bone and stays there.
Robertson and researchers from Oak Ridge National Laboratory and the School of Medicine at the University of Tennessee in Knoxville have found a way that should allow alpha particles to be used to target other cancer sites in the body.
The research team started with the element “actinium,” which creates three additional elements that produce alpha particles as it decays. Around the actinium core, they added four layers of material before topping off the nanoparticle with a gold coating. The resulting nanoparticle is strong enough to contain the actinium and the elements created as it decays long enough for the alpha particles emitted to destroy nearby cancer cells.
“Holding these alpha emitters in place is a technical challenge that researchers have been trying to overcome for 15 years,” Robertson said. “With our nanoparticle design, we are able to keep more than 80 percent of the element inside the nanoparticle 24 hours after it is created.”
If the promising early-stage results are replicated in additional studies to be conducted within the next few years, MU officials plan to request authority from the federal government to begin conducting human clinical trials with the goal of developing new cancer treatments.
The team’s study appears in the journal PLOS ONE and Robertson explains the research in the video below.
Source: University of Missouri
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