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A silver ion (also called a cation) is a positively charged atom that has lost one electron from oxidizing in the presence of moisture. Elemental silver carries the atomic number 47, which indicates an equal number of protons and electrons, and therefore has no electrical charge. Of all the metals, it has the whitest color, the highest electrical and thermal conductivity and the highest optical reflectivity.
Antimicrobials are substances, natural or synthetic, that kill micro-organisms. Antimicrobials are often described as broad or narrow spectrum, which means the particular substance either kills a wide/broad variety of micro-organisms or only a limited/narrow spectrum of micro-organisms. 6
According to the Heads of Medicines Agencies in Europe, antimicrobial is the general term for natural or synthetic compounds which, at certain concentrations, inhibit growth of, or kill, micro-organisms. Antibacterial (anti=against, bacterial against bacteria). Antiviral (anti=against), viral (viruses) are examples.
Silver dressings most commonly refer to antimicrobial power based on how many silver ions are present in parts per million (ppm) notation. One part per million = 1/1,000,000 or one part in 106 total parts or 1 x 10-6. This is equivalent to four drops in a 55 gallon drum of liquid.11
Antimicrobial activity is measured by the increase or decrease in the number of bacteria present, and is measured in colony forming units. If you start with a 10 5 bacterial load, you have 100,000 cfus per gram of tissue (colony forming units). If you have a load of 106, you have 1,000,000 cfus - i.e. 10 times more. This is the nature of logarithmic math. If you have a load of 107, 10,000,000 cfus are present – 100 times larger than 105.
Similarly, reducing the bacterial load from 107 to 106 is termed a one log reduction. This reduces the load from 10,000,000 cfus to 1,000,000 cfus (i.e., 9,000,000 cfus are killed), and represents a 90% reduction. A two log reduction would take the bacterial burden down to 105 means 100,000 cfus remain (9,900,000 cfus were killed) and represents a 99% reduction.
In dry metallic form, silver is inert and exhibits no biocidal action. However, silver ionizes in the presence of moisture (e.g. blood, water or tissue fluids) and releases the positively charged silver ion known as Ag1 (or Ag+). This positively charged ion will attach to negatively charged microbes.
Silver ions are believed to kill bacteria, virus, and fungi in four different ways:
Silverlon releases silver ions within minutes of contacting moisture. Within the first 24 hours all Silverlon substrates (except the calcium alginate) show a highly effective minimum of five log reductions against E. coli, P. aeruginosa, and MRSA.
Silverlon has been independently tested against over 360 isolates. Silver ions safely kill more microbial species than any other antimicrobial wound treatment.
Separately, Silverlon also has been tested and shown effective against these common wound pathogens.