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" Both King Midas and Goldfinger knew how deadly gold can be. But turning everything you touch into gold and coating Bond girls in glistening body paint aren&amp;#039;t the only ways this precious metal can be used for deadly purposes. Scientists are revealing the power of microscopic gold nanoparticles to kill bacteria. Tiny gold particles no bigger than a speck of dust can kill bacteria in several ways, says Hong Liang, a professor of materials science and engineering at Texas A&amp;amp;amp;M University. Gold nanoparticles can damage a cell wall from the outside, pass through the wall and attack the bacterium from within, or damage the bacterial docking process and disrupt the supply of nutrients and energy to the cell. Whichever way they attack, these flecks are bad news for even the most dangerous bugs, such as Escheria coli and drug-resistant Staphococcus aureus, known as MRSA. Metallic Teamwork For decades we&amp;#039;ve been reliant on penicillin and other antibiotics to stave off infections. But some strains of bacteria, like MRSA, are evolving resistance to these drugs faster than we can find new ones. &amp;quot;The problem is that people use antibiotics too much and they make bacteria very resistant,&amp;quot; Liang says. &amp;quot;Nanoparticles don&amp;#039;t have that problem.&amp;quot; Nanoparticles disrupt physical processes, rather than biological ones, so microbes are less likely to be able to find workarounds to the damage they cause, Liang argues. To see what kind of difference gold nanoparticles could make, consider the problem of preventing infections from implanted medical devices. Implants are a major cause of infection, partly because they provide a foreign surface for bacteria to adhere to. Some bacteria, like MRSA, can form &amp;quot;biofilms&amp;quot; on these surfaces\u2014congregations of organisms that are all but impenetrable even to the most powerful antibiotics. Titanium dioxide nanotubes sprayed onto the surface of medical devices can make them inhospitable to bacteria\u2014but only in the presence of light, which kicks off a process that drains electrons from the bacteria&amp;#039;s energy supply system. To fight these biofilm-forming bacteria in the darkness of the body cavity, the titanium dioxide rods need help.  Destructive electron extraction from bacterial membranes by plasmonic gold nanoparticles.  (Photo by Jinhua Li/SICCAS) This is where gold nanoparticles come in. For their new study published this month in the journal Applied Physics Letters, a team of Chinese scientists designed a coating for implanted devices pairing gold nanoparticles with titanium dioxide that kills bacteria on contact. The combined metals siphon off electrons from the bacteria, with gold spurring the titanium dioxide into action. Unable to sustain their basic respiratory functions with out the electrons, the bacteria die.  This is the first study to show this electron stealing mechanism with gold nanoparticles, according Xuanyong Liu, a researcher at the Shanghai Institute of Ceramics and a co-author on the study. Silver and Gold It&amp;#039;s not just gold that can spell doom for bacteria, Liang says. Silver nanoparticles are equally lethal and have been used in common products like diapers for years. But gold may be better than silver for certain cases, like inside the human body. &amp;quot;The potential toxicity of silver exposure should not be neglected, mainly due to the possible release of silver ions, causing cytotoxicity and tissue and organ damages,&amp;quot; Liu tells PM. Gold is more chemically stable, he says, but further studies should be done before gold should be put inside the human body.  While you can make gold and silver nanoparticles in your kitchen microwave, as Liang does in her lab at Texas A&amp;amp;amp;M, she doesn&amp;#039;t recommend using them as a home remedy. Ingesting them won&amp;#039;t turn you yellow with the Midas touch, but there is the possibility that they can change your skin tone. One study from Brown University suggests that ingesting silver nanoparticles could cause a condition called argyria, which turns the skin a much different color: blue. "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.popularmechanics.com/science/health/a12986/to-kill-superbacteria-bring-on-the-bling-16988989/>