Tom, Sorry that I haven't had time to reply. Even this will be a little brief. One important point to note is that silver is not consumed when it kills a pathogen as chlorine dioxide or other chemicals would be. And the study below shows that it takes but a single ion to destroy a bacteria. Although it does take more silver to inactivate an HIV virus.
Here is a study relating to how low concentrations of Ag+ ions are able to kill bacteria: Chemiosmotic Mechanism of Antimicrobial Activity of Ag+ in Vibrio cholerae http://www.ncbi.nlm.nih.gov/pmc/articles/PMC127333/ “Although the antimicrobial effects of silver salts were noticed long ago, the molecular mechanism of the bactericidal action of Ag+ in low concentrations has not been elucidated. Here, we show that low concentrations of Ag+ induce a massive proton leakage through the Vibrio cholerae membrane, which results in complete deenergization and, with a high degree of probability, cell death.” "In summary, the addition of low micromolar concentrations of Ag+ to inside-out membrane vesicles of V. cholerae induced a total collapse of both ΔpH and Δψ irrespective of the presence of Na+ ions. This effect of Ag+ was independent of the presence of the Na+-translocating NQR, known as a specific target for submicromolar Ag+, suggesting that the other Ag+-modified membrane proteins (or perhaps the Ag+-modified phospholipid bilayer itself) can cause the H+ leakage, thus explaining the broad spectrum of the antimicrobial activity of Ag+ ions. ... Thus, finally, the controversy over the mechanism of the bactericidal activity of low concentrations of Ag+ ions has been clarified." Regarding silver particles vs ionic silver: Treatment of Various Surfaces with Silver and its Compounds for Topical Wound Dressings, Catheter and Other Biomedical Applications http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=ECSTF8000011000021000001000001&idtype=cvips&gifs=yes “The applications of surfaces treated with silver and its compounds include devices used as topical wound dressings, urinary catheters, endotracheal tubes, cardiac valves etc. Treatment of surfaces e.g. textile, polymers or metals with silver or its compounds is carried out to achieve the antimicrobial action of silver ions. Several approaches of surface treatment of medical devices for the antimicrobial purposes, such as electrodeposition, electroless deposition, physical vapor deposition, - radiation, etc. have been used in practice. It is clear that only silver ions are responsible for the antimicrobial activity. As confirmed experimentally, only samples containing silver compounds can deliberate silver ions in the tested media and exhibit antimicrobial activity both in vitro and in vivo. There is no evidence that elemental silver, even its so-called "nano-crystalline" state, exhibits an antimicrobial activity. Consequently, the devices coated with "nano-crystalline" silver should carefully be taken into consideration before the application.” From the full article in Google books: http://books.google.com/books?id=mWFylRiXV8cC&pg=PT9&lpg=PT9&dq=%22Treatment+of+various+surfaces+with+silver+and+its+compounds+for+topical+wound+dressings%22&source=bl&ots=ixGCz2qti9&sig=of-Mkcn3VyMVbo0syg6hZMiY788&hl=en&ei=-pMdS7rvN87anAfX2dzeAw&sa=X&oi=book_result&ct=result&resnum=2&ved=0CBIQ6AEwAQ#v=onepage&q=%22Treatment%20of%20various%20surfaces%20with%20silver%20and%20its%20compounds%20for%20topical%20wound%20dressings%22&f=false “Based on the observation that metallic silver may exhibit some antimicrobial activity, when sufficiently long in contact with interstitial fluids, and considering the fact that only silver ions, and not silver metal, are responsible for the antimicrobial activity. One can conclude that electrochemical or corrosion phenomena plays a significant role in the antimicrobial activity of pure silver.” I don't think the study above tells the whole story as is the case with so many studies. For example, below is a study showing an HIV-1 virus with each of its binding sites occupied by a silver particle, thereby preventing the virus from attaching to a host cell and rendering the HIV virus harmless. Interaction of silver nanoparticles with HIV-1 http://www.jnanobiotechnology.com/content/3/1/6 "HAADF images of the HIV-1 virus. a) HAADF image of an HIV-1 virus exposed to BSA-conjugated silver nanoparticles. Inset shows the regular spatial arrangement between groups of three nanoparticles. b) HAADF image of HIV-1 viruses without silver nanoparticle treatment. Inset highlight the regular spatial arrangement observed on the surface of the untreated HIV-1 virus. c) EDS analysis of image a) confirming the presence of Ag. The C signal comes from both the TEM grid and the virus, O, and P are from the virus, and Na, Cl, and K are present in the culture medium. Ni and Si come from the TEM grid, while Cu is attributed to the sample holder. d) Composite size distribution of silver nanoparticles bound to the HIV-1 virus, derived from all tested preparations. In Figure 3, we present HAADF images of the HIV-1 virus with (3a) and without (3b) silver nanoparticles. For complete experimental details, refer to Methods Section. The presence of silver was independently confirmed by Energy Dispersive X-ray Spectroscopy (EDS), shown in Figure 3c. Interestingly, the sizes of nanoparticles bound to the virus (Figure 3d) were exclusively within the range of 1-10 nm. In the case of the silver nanoparticles released from the carbon matrix, the fact that no nanoparticles greater than 10 nm in diameter were observed to interact with the virus is significant, since the size of ~40% of the overall population is beyond this range. This provides strong evidence for the size-dependence of interaction. Additionally, the nanoparticles seen in Figure 3a are not randomly attached to the virus, as regular spatial relationships are observed among groups of three particles. Both the spatial arrangement of nanoparticles and the size dependence of interaction can be explained in terms of the HIV-1 viral envelope, and can provide insight into the mode of interaction between the virus and nanoparticles. The exterior of the HIV-1 virus is comprised of a lipid membrane interspersed with protruding glycoprotein knobs, formed by trimers consisting of two subunits: the gp120 surface glycoprotein subunit is exposed to the exterior, and the gp41 transmembrane glycoprotein subunit spans the viral membrane and connects the exterior gp120 glycoprotein with the interior p17 matrix protein[32]. The main function of these protruding gp120 glycoprotein knobs is to bind with CD4 receptor sites on host cells. Numerous cellular proteins are also embedded within the viral envelope[33]. However, the protruding gp120 glycoprotein knobs are more exposed to the exterior, and should be more accessible for potential nanoparticle interactions. Leonard and coworkers[34] reported that the gp120 subunit has nine disulfide bonds, three of which are located in the vicinity of the CD4 binding domain. These exposed disulfide bonds would be the most attractive sites for nanoparticles to interact with the virus. As mentioned previously, the nanoparticles in Figure 1a appear to be located at specific positions, with regular spatial relationships observed among groups of three particles. The observed spatial arrangements correlate with the positions of the gp120 glycoprotein knobs in the structural model for HIV-1 proposed by Nermut and coworkers[32]. Regular spatial relationships are also found on the surface of the untreated virus, as seen in the inset of Figure 1b. The observed darker contrast at these sites could indicate the locations of the glycoprotein knobs." Here is another study you may find interesting: Bactericidal Actions of a Silver Ion Solution on Escherichia coli, Studied by Energy-Filtering Transmission Electron Microscopy and Proteomic Analysis http://aem.asm.org/cgi/reprint/71/11/7589.pdf - Steve N From: poast [mailto:[email protected]] Sent: Saturday, February 06, 2010 1:52 PM To: [email protected] Subject: Re: CS>moon on fingernails? -- how much do you use? Hello Steve, I am begining to realize that the exact mechanism of how silver works inside the body is still a "little" theoritical... Let's jump outside the body for just a moment. Other sanatizers require a concentration of the product to be in contact with the pathogen for a period of time. With chlorine dioxide, for example, the CT values allow you to adjust the process time for the concentration you are using. When disinfecting wilderness water, I use a CT of 1000 mg-minutes/liter. When I mix up a 4 PPM chlorine dioxide solution, I know that to sanatize a liter of water it is going to take 250 minutes. If I have lots of time, and am concerned with better taste, I can reduce the concentration to 2 PPM chlorine dioxide, and extend the time out to 500 minutes. Does anything like this exist for EIS? 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