Author Topic: Optimum Particle Sizes of colloidal silver  (Read 1546 times)

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Offline kephra

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Optimum Particle Sizes of colloidal silver
« on: April 04, 2016, 08:30:17 AM »

Optimum Particle Size of Silver Nanoparticles


There is a lot of disinformation on the internet about particle sizes and why smaller is better.

Particle size plays a big part in the efficacy of silver nanoparticles.  However smallest does not mean best.  There are literally hundreds of research papers published in the scientific journals which show that silver nanoparticles (not ionic silver) is very effective against a wide range of pathogens including bacteria, viruses, and fungus,   All of these papers show the effective size in the range of 10 to 20 nanometers in diameter.  There are also research papers which show that particles smaller than this range become toxic to healthy human cells. 

Since particle size influences the number of particles in a colloid at a given ppm concentration, we should also expect that particle sizes larger than the optimum would be less effective simply because there are less particles available for a given ppm to attack the pathogens. 

So the optimum particle size seems to be within the 10 to 20 nanometer diameter range.  Below this and the silver becomes toxic to healthy human cells2, and above this becomes less effective.

Colloidal silver produced by the methods presented on this site has particles averaging about 14 nanometers in diameter as determined by their surface plasmon resonance1.  20 ppm solutions with 14 nanometer average particle size are clear yellow in color, about the color of Johnson's baby shampoo.  At higher ppm, the 14nm particles appear brownish in color.   At slightly larger size, the color shifts slightly to orange, and at slightly smaller size, it shifts very slightly to having a green tint.

As average particle size decreases from the optimum 14 nm, the color shifts toward green below 10nm, to clear at less than 5nm.  Clear colloidal silver is toxic and will cause argyria, the blue discoloration of the skin.

Its not possible to make colloidal silver products with only one particle size.  There will always be a spread.  Even commercial labs cannot make a product where every particle is exactly the same size without resorting to extreme measures like ultra filtration. 

The human eye has cones in its retina which detect blue, green, and red wavelengths.  If the brain perceives yellow color, its because the eye detected green and red together.  Because of this, yellow colloidal silver with a slight green tint does not mean that all the particles are smaller.  It means that there are fewer larger particles that would resonate with and remove green or appear red. 

Because of the way the eye/brain perceives color, it cannot distinguish among samples with different amounts of size distributions.  IE: A sample with sizes ranging from 12 to 16nm particle sizes will look the same color as a sample with sizes ranging 10 to 18nm.  The eye sees the average, but not the size distribution.

The conclusion regarding optimum particle size is that current research shows that particles sizes in the 10 to 20 nanometer size range are optimum for safety and effectiveness against pathogens.  Larger particles are less effective, and smaller particles are toxic to healthy body cells.

1) Surface plasmon resonance is the absorption of light by nanoparticles which causes their specific color.  14nm particles absorb blue light, leaving red and green, which the eye sees as yellow.  So the color is determined by particle size.

2) http://jnanobiotechnology.biomedcentral.com/articles/10.1186/s12951-016-0214-9


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