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Author: Subject: Why is silver antibacterial?
Oanh
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[*] posted on 5-6-2017 at 06:19
Why is silver antibacterial?


Hi everyone – first post.
I’ve been looking into making colloidal silver solutions and got to wondering why is silver antibacterial. I’m not bio (just analytical chemist) so don’t go to complicated depths to explain it for me.

Thanks
Oanh
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Sulaiman
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[*] posted on 5-6-2017 at 07:00


First, I do not hve the answer,

'scientists' do not have all of the answers yet,
there is a lot of research into the antimicrobial properties of silver as modern antibiotics are becoming ineffective due to evolution of the bacteria,

my favourite aspect of this is the silver Zombie effect, e.g. http://www.sciencemag.org/news/2015/05/silver-turns-bacteria...




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Texium (zts16)
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[*] posted on 5-6-2017 at 08:59


Quote: Originally posted by Oanh  
Hi everyone – first post.
I’ve been looking into making colloidal silver solutions
You aren't planning on drinking those solutions, I hope! :P



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Sulaiman
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[*] posted on 5-6-2017 at 09:12


Quote: Originally posted by zts16  
Quote: Originally posted by Oanh  
Hi everyone – first post.
I’ve been looking into making colloidal silver solutions
You aren't planning on drinking those solutions, I hope! :P


Why not ?

If you are concerned about argyria https://en.wikipedia.org/wiki/Argyria
then do not worry, only excessive silver consumption causes it,
it is a very rare condition.

P.S. when experimenting with silver salts I keep a bottle of sodium thiosulphate solution handy to neutralise spills that would otherwise cause stains - especially on skin.
I commonly rinsed my hands in thiosulphate soln. after experimenting, before exposure to the sun, even if I think that I did not spill any silver salt/solution on my hands,
as a precaution against staining.




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Magpie
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[*] posted on 5-6-2017 at 12:49


Copper is also antibacterial.



[Edited on 5-6-2017 by Magpie]




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S.C. Wack
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[*] posted on 5-6-2017 at 14:55


It's been known for a very long time that copper is broadly toxic. It says something about who we are, that copper and brass are nearly absent in hospitals.



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[*] posted on 5-6-2017 at 19:22


Many heavy metals can substitute for other metals and mess up the function of enzymes. Mercury and Lead (arsenic also is bad) often substitute for other metals in enzymes such as zinc or others, but are not as active in the actions of the metals that they replace. There are many metalloproteins, so in some cases it is hard to tell which ones are most critical, but silver and copper can be bad in large amounts, but they are not nearly as toxic. Silver would mostly ppt in the stomach due to the large amount of chloride ions in the stomach, but could be bad in large amounts. Silver can dissolve in very small amounts and might be concentrated by some bacteria, which often are trying to find trace elements and have many proteins that try to scavenge iron and other minerals from the environment.
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Oanh
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[*] posted on 14-6-2017 at 04:03


Yes, I am going to make (have already made) colloidal silver and drink small amounts of it at times. I've already heard of 'the blue man' and I don't believe in drinking excessive amounts of anything . :)
Thanks everyone for your thoughtful answers. Especially you Dr.Bob, you put me on the right research track with metalloproteins.

oanh

ps. Sorry for the late reply - I had a little password problem.
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[*] posted on 13-11-2017 at 17:08


https://www.eurekalert.org/pub_releases/2014-09/scp-cib09291...

http://aem.asm.org/content/74/7/2171.full

It looks like the primary suspected mechanism is reacting with thiols in the bacterial cell wall, disrupting the cell wall. But there seems to be a lot more going on too. Great question; I'd never really thought about it.
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[*] posted on 22-11-2017 at 04:21


Silver is biocidal probably because of several factors:

1) It has a high oxydizing power for the couple Ag(+) --> Ag(0) and thus it reacts very fast with a lot of reducers causing injuries to biochemical pathways...

2) It mimicks some Na(+) or K(+) and enters their biochemical pathways

3) Ag(+) when reducing to Ag(0) via light or via oxydoredox produces nano-silver (the catalytic behaviour of a metal is directly linked to its surface area (thus the higher the mesh (fineness of the particles)) ... thus catalytic effect of nano-silver is several orders of magnitude higher than micro-silver

4) Also the counter anion often yield oxydising species...
Cl(-) will yield Cl2, Cl°
NO3(-) will yield NO2, NO3°, O2 (and eventually N2O5)
ClO3(-) will yield ClO2, Cl2O3, Cl2O, Cl2, O2
ClO4 will yield the same as ClO3(-) plus eventually Cl2O5




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URETHANE.FOAM
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[*] posted on 22-11-2017 at 04:55


Google search "Argyria" apparently if you consume large amounts over time you will turn blue.
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[*] posted on 22-11-2017 at 10:23


I suspect AKJOER has the answer to this question, although probably in a convoluted manner.

[Edited on 22-11-2017 by Sigmatropic]
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clearly_not_atara
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[*] posted on 22-11-2017 at 11:37


It disrupts thiols IIRC:

http://en.wikipedia.org/wiki/Oligodynamic_effect




[Edited on 04-20-1969 by clearly_not_atara]
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