Killing bugs with gold and laser beams

ICONN, Media releases

Scientists have been able to kill an infectious parasite using non-toxic gold nanoparticles and laser beams.

“Our first target is Toxoplamosis gondii, a parasite that infects one in three people and causes problems especially in the young and old, and people with a compromised immune system says Michael Cortie from the University of Technology Sydney, speaking on behalf of his team at ICONN 2010 the international nanotechnology conference in Sydney.

“We chose a parasite because no one’s succeeded in using this technology on parasites before,” says Cortie, “And if we can kill toxoplasmosis, we could probably also take out malaria and all the other kinds of infectious parasites.”

Changing the shape and size of gold nanoparticles changes the wavelength of light they absorb. So by matching a nanoparticle and a laser of the same wavelength, nanoparticles are obliterated when you shine a laser beam at them.

In pre-clinical trials, Cortie engineered gold nanoparticles with several hundred parasitic antibodies on the surface so they stuck to the parasite. “Within 2 to 3 minutes of exposure, the toxoplasmosis was covered with gold particles. Then we shone a low-powered laser which targeted the gold nanoparticles and we killed the parasite.”

“This is great because healthy cells won’t be killed because the gold particles never stuck to them. With this, we can localise disease treatment,” says Cortie.

They have now started targeting multi-drug resistant bacteria like Staphylococcus which is a common cause of food poisoning and infected over 6,000 Australians last year.

Another plus: because the particles are so small, the treatment only uses about $4 worth of gold.