Virucidal Effect of a Silver Nanocluster against Coronavirus SARS-CoV-2

Individual protective equipment do not possess an intrinsic antimicrobial/virucidal action. Masks, filters for air conditioning and for medical respiratory devices are susceptible to microbial/viral colonization. An article by Cristina Balagna et al in the Journal Open Ceramics discuss the virucidal effect of materials and methods used to deposit a silver nanocluster composite on a facial FFP3 mask.

Virucidal effect of Silver Nanoparticles

Individual protection measures do not completely mitigate the risk of contagion for healthcare staff and patients and the remaining population. All air filtering media are subject to microbial/viral colonization, and may limit microorganisms in the air. Air filtering media do not inactivate them or avoid their proliferation.

A more efficient approach to air filtering is needed to increase people protection. This will help to reinforce our health infrastructure and to protect the health of workers and patients.

Several studies have demonstrated the antibacterial and antifungal behaviour of silver ions and nanoparticles. A preliminary evaluation of a silver nanocomposite in the antiviral effect towards Coronavirus SARS-CoV-2 (COVID-19) of a silver nanocomposite cluster was studied.

A silver nanocomposite was deposited on a disposable facial FFP3 mask consisting of non-woven fabric. Subsequent tests proved to have an interesting virucidal effect in the two experiments undertaken. The infectivity of the viral particles was reduced or removed using a 200 nm thick nanocomposite.


Of the two tests performed, the Ag5W test demonstrated that the titre of the virus was reduced to zero. It was demonstrated that the cytopathic effect (See note 1) was completely removed using this test. In conclusion, a silver nanocluster composite coating deposited on facial masks possessed a virucidal effect against SARS-CoV-2 (See note 2).


  1. Cytopathic Effect (CPE) refers to structural changes in a host cell resulting from viral infection. CPE occurs when the infecting virus causes lysis (dissolution) of the host cell or when the cell dies without lysis because of its inability to reproduce.
  2. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the strain of coronavirus that causes coronavirus disease 2019, the respiratory illness responsible for COVID-19.
  3. The ability of very small amounts of several metal ions to inhibit or kill microorganisms, known as the oligodynamic effect, was first discovered in 1893 by von Nageli.


C.Balagna, S. Perero, E Percivalle, E.V. Nepita, Virucidal effect against coronavirus SARS-CoV-2 of a silver nanocluster/silica composite sputtered coating, Journal of Open Ceramics, Volume 1, May 2020, 100006,

Virucidal effect of Silver Nanoparticles. Open Ceramics Journal
Open Ceramics Journal


The outcome of this study may come as no surprise to users of colloidal silver, since colloidal silver consists of silver nanoparticles and silver ions. So why does the oligodynamic effect (See note 3) of silver go unnoticed, when in fact silver is set to be increasingly added to medical equipment and hospital furniture as a way of preventing hospital-based infections? Much of the discussion is based on the assumption that nanosilver is something new that has not been seen until recently. Advances in nanotechnology give the impression of a completely new application for silver. However, analysis shows that nanosilver in the form of colloidal silver has been used for more than 100 years. Also, colloidal silver has been registered as a biocidal material in the United States since 1954.

Pharmaceutical companies use business models when manufacturing medicines, and rely on patents to protect their interests. This would seem sensible from a business point of view, but what is the impact on public health? For one thing, traditional remedies take a back seat, and in extreme cases legislation emerges to prevent people from using plants from their own garden to make herbal remedies. ‘Take control of your own health’ would now seem to be the call to action for many people who are dissatisfied with the forces behind modern ‘medicine’. If ‘medicine’ has become synonymous with manufactured drugs, and the prescribing of drugs, then this discourages people from studying the beneficial effects of herbal medicine and home remedies since they have become conditioned by mechanistic science. A classic example is colloidal silver. When colloidal silver is made using steam distilled water and pure silver electrodes, and with a controlled concentration, it becomes a powerful ally as a germ killer. The discussion in scientific texts has honed in on home brews made using batteries, tap water and silver wire of unknown purity, when advances in colloidal silver manufacture have radically improved using modern microcontroller methods, high purity silver and countertop water distillers


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