RALEIGH, NC, May 27, 2008 – Researchers at North Carolina State University have discovered that gold nanoparticles are helping a once-failed drug to safely stop HIV from invading the body’s immune system.
The original drug, a compound known as TAK-779, was designed in the 1990s to combat HIV by binding to a specific location on human T-cells that block HIV from entering the immune system. This method was rendered useless when it was discovered that a major component, ammonium salt, caused harmful side effects.
According to Dr. Christian Melander, assistant professor of chemistry at NC State, and doctoral student T. Eric Ballard, the addition of gold nanoparticles to a modified version of the TAK-779 (minus the ammonium salt), creates a compound that prevents the virus from gaining a cellular foothold.
It is the first time gold nanoparticles have shown potential in therapies for HIV, and according to researchers associated with the study, the same technique has potential for use in the treatment of a variety of diseases.
The reason researchers turned to gold is because it is a non-reactive element in the human body, and would be the perfect "scaffold" to attach molecules of the drug to in the absence of the ammonium salt, holding the drug molecules together and concentrating their effect.
"It's the same idea as Velcro," said T. Eric Ballard, a scientist at North Carolina State University and a co-author on the new study, which was recently published online in the Journal of the American Chemical Society. "One interaction is weak, but if you have a lot of weak interactions together they make one strong interaction."
Researchers tested several ratios of drug molecules to nanoparticles and found that when each nanoparticle was equipped, on average, with 12 drug molecules, the drug appeared to be as effective against HIV as the original version, minus the side effects.
So far, the researchers have only tested the TAK-779 gold nanoparticle combination in cultured cells. But without the ammonium salt, the drug could be again considered as a potential therapy, though it would require extensive testing before it could be used on patients.
The next step, according to David Margolis, a study co-author at the University of North Carolina, is to try and fuse other drugs onto gold nanoparticles. Their next effort will be to attach an antiviral drug and a glucose molecule to the nanoparticles and see if they can be transported across the blood-brain barrier, creating a virus-killing drug in the brain, something that hasn't been possible before.
"We've discovered a non-harmful way to improve the strength and efficacy of an important drug," Melander says. "There's no reason to think that this same process can't be used with similar effect on other existing drugs."
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