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Subject:
From:
Brian Ellis <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Brian Ellis <[log in to unmask]>
Date:
Thu, 24 Apr 2008 11:09:06 +0300
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Joe

Nanotechnology generally, not just silver, is scary and we know 
bugger-all about the long-term effects, especially when nanoparticles 
enter the lungs and straight into the bloodstream, unmetabolised. In 
particular (no pun intended), nanocarbon, with its high reactivity, in 
an organic environment could result in all sorts of molecules being 
formed. Are we playing the sorcerer's apprentice with them?

Brian


Joe Fjelstad wrote:
>  
> Silver tongues
> Apr 17th 2008 | NEW YORK
>>From The Economist print  edition 
> Regulators are looking more closely at nanotechnology claims 
> 
> ANCIENT Phoenicians stored their drinking water in silver vessels, but not  
> for aesthetic reasons. They discovered that by doing so they remained 
> healthier.  The reason for that is now understood: silver has antimicrobial properties. 
>  
> In the 21st century people have realised that if you fortify Phoenician  
> wisdom with a dash of nanotechnology, silver can be made into a far more potent  
> bactericide. Companies have quickly seized on this idea to produce a wide  
> variety of products, from clothes to soap and even chopsticks, containing silver  
> nanoparticles. The claim is that they destroy germs. 
>  
> 
> 
> But silver can also accumulate in the environment and, at certain levels,  
> prove toxic. Nor is the general safety of nanoparticles fully understood, not  
> least because they can react in novel ways. Some scientists think more research 
>  is needed and perhaps more regulation too. A move in that direction now 
> seems to  be under way. 
> Silver's natural germ-killing ability stems from its extremely slow release  
> of silver ions (electrically charged atoms, or groups of atoms). When made 
> into  particles only a few nanometres big�a nanometre is a billionth of a metre�
> they  shed a lot more ions and so become more potent. 
> America's Environmental Protection Agency (EPA) is  worried about a large 
> number of products claiming antimicrobial abilities. One  is �Silver Wash�, a 
> washing machine made by Samsung, which claims to employ  nanotechnology to 
> release hundreds of billions of silver ions during a wash to  sanitise fabrics.  
> The EPA has ruled that ion-generating devices that  claim to kill germs must 
> be registered as a pesticide and tested to show they  pose no unreasonable 
> risk. The EPA says its intention  is to regulate ion-generating devices rather 
> than nanotechnology itself. But it  is hard to draw a distinction. Andrew 
> Maynard, chief science adviser for the  Project on Emerging Nanotechnologies at the 
> Woodrow Wilson International Centre  for Scholars in Washington, DC, says 
> functionality is  an important part of the definition. Turning silver into tiny 
> particles that  behave in new ways (for example, by shedding more ions) and 
> putting those  particles into new places (such as fabrics) qualifies�or so he 
> thinks. 
> One consequence of dividing a substance into nanoparticles is that the  
> surface area of the material greatly expands. �Nanosilver is so tiny it can go  
> right to the surface of an organism and essentially shoot ions into the  organism,
> � says Sam Luoma, a research scientist at the John Muir Institute of  the 
> Environment at the University of California, Davis. Although this makes  silver 
> nanoparticles an extremely effective antimicrobial agent, it also raises  
> concerns about humans' ability to withstand relatively high exposures. 
> Despite the unknowns, Dr Luoma and others believe there is enormous potential 
>  for good from nanosilver. It can, for example, be used in small amounts to 
> coat  medical catheters to reduce the possibility of infection without causing  
> environmental worries. �We need to separate out the truly beneficial uses,� 
> he  adds. 
> The EPA will not look at benefit or necessity, but  is determined to make its 
> registration stick. It has fined one company more than  $200,000 for making 
> unsubstantiated claims about unregistered nanosilver-coated  computer mice and 
> keyboards. Firms making claims about nanotechnology need to  watch out
> 
> 
> 
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> 
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