Oligodynamy

The term oligodynamy goes back to the Swiss botanist Carl Wilhelm von Nägeli and describes the damaging effects of metal cations (positively electrically charged metal ions) on living cells .

Mode of action

The ions of some metals have a (sometimes only weak) damaging effect on various pathogens, including bacteria , viruses and fungi . The metals for which this effect has been observed so far are sorted in descending order by effect:

Mercury - silver - copper and its alloys brass a . Bronze - tin - iron - lead - bismuth .

Even gold and osmium show this effect. Among the bacteria, the gram-positive bacteria may be slightly more sensitive than the gram-negative bacteria. The exact mechanism of action has not yet been fully clarified, a disruption of the bacterial metabolism was found, reactions with cytochromes and complexes with DNA and RNA were involved .

It is also known that silver ions can influence the permeability of cell membranes , that they can bind to sulfur bridges of proteins and cause a disruptive effect on enzymes there (silver can form sulfides with thiol groups of enzymes and react with amino and carboxy groups of enzymes and these thereby inactivate.) Lactate dehydrogenase and glutathione peroxidase are inhibited in their activity, for example (Shinogi, 1993). The majority of the reports on the in vitro effect of silver against microorganisms after sufficient exposure time in the range of hours are positive, i.e. to be seen as effective. A slight antiviral effect of metal ions on viruses is also described, which can hardly be increased even by increasing the ion concentration.

Critical voices also emphasize that the biocidal effect of silver (especially as colloidal silver ) is not always reliable. For example, silver in colloidal form failed completely in a study at various concentrations against various microorganisms (P. van Hasselt, 2004). Hasselt literally: "As the tested colloidal silver solutions did not show any antimicrobial effect in vitro on the microorganisms, claims of colloidal silver's antimicrobial potency are misleading and there is no place for it as an antiseptic." ("Because the examined colloidal silver solutions in In vitro, did not show any antimicrobial activity against microorganisms, claims that colloidal silver has antimicrobial properties are misleading and therefore there is no place for it as an antiseptic . ")

There have also been reports of damaging effects on algae and plant cells. A typical feature of oligodynamy is the relatively long exposure time (in the range of hours) that is required to achieve the full antimicrobial effect. Silver-sensitive bacteria can become resistant over time, i.e. insensitive to silver ions. The highest silver concentrations that silver-resistant microorganisms tolerated were 10 g / l and this corresponds to about 500 times the value for silver-sensitive germs.

application

The oligodynamic effect is used with some disinfectants , mostly in combination with chlorine compounds or hydrogen peroxide . Oligodynamy can also be used to preserve drinking water in mobile water tanks (on ships, airplanes, camping). In medicine, catheters , plasters and textiles are also equipped in such a way that they can release silver ions. Silver-containing agents are used in wound treatment (mainly burn wounds), for example silver sulfadiazine . The low incidence of caries in the edge area of ​​gold cast fillings (inlays) is also attributed to the oligodynamic effect of dental gold alloys.

Doorknobs in hospitals are sometimes made of brass. Coronavirus SARS-CoV-2 applied to stainless steel or plastic was active for up to three days, on copper it only took 4 hours before the virus became inactive. Copper also has an effect on influenza viruses: after six hours, in contrast to stainless steel, only a minimal number of viruses have survived.

literature

• Carl Wilhelm von Nägeli (1893): About oligodynamic phenomena in living cells. In: New memoranda of the Swiss natural research society. Vol. 33, pp. 1-51.
• Phyllis J. Kuhn: Doorknobs: a Source of Nosocomial Infection? In: Diagnostic Medicine . November / December, 1983, pp. 62–63 ( online [PDF]).
• Mohankandhasamy Ramasamy, Jintae Lee: Recent Nanotechnology Approaches for Prevention and Treatment of Biofilm-Associated Infections on Medical Devices . In: BioMed Research International . tape 2016 , October 2016, p. 1–17 , doi : 10.1155 / 2016/1851242 , PMID 27872845 , PMC 5107826 (free full text).
• Aerosol and surface stability of HCoV-19 (SARS-CoV-2) compared to SARS-CoV-1 Neeltje van Doremalen1 *, Trenton Bushmaker1 *, Dylan H. Morris2 *, Myndi G. Holbrook1, Amandine Gamble3, Brandi N. Williamson1, Azaibi Tamin4, Jennifer L. Harcourt4, Natalie J. Thornburg4, Susan I. https://www.medrxiv.org/content/10.1101/2020.03.09.20033217v1.full.pdf

Individual evidence

1. ↑ Harald Remke: Hospitals: door handles made of brass . aerzteblatt.de. Retrieved March 23, 2020.
2. ↑ Gene Emery: Coronavirus can persist in air for hours and on surfaces for days: study ( English ) reuters.com. March 17, 2020. Accessed March 30, 2020.
3. ↑ JO Noyce, H. Michels, CW Keevil: Inactivation of Influenza A Virus on Copper versus Stainless Steel Surfaces ( English ) reuters.com. January 26, 2007. Accessed March 31, 2020.

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