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New Silver-Copper Nanolayer-based Antimicrobial Mask Inactivates SARS-CoV-2

Published on 2021-08-31. Edited By : SpecialChem

TAGS:  Medical     Nanotechnologies    

sakcu-mask ORn group from the Materials Research Institute, led by Sandra Rodil, created an antimicrobial mask with a material registered as SakCu. The SakCu mask is made of three layers. The outer and inner ones are made of cotton and the middle one is made up of silver-copper nanolayers deposited in polypropylene. Silver and Copper were used for their proven antiviral, antibacterial, and even antifungal properties.

Testing Virus on Silver-Copper Nanolayers

In collaboration with the Hospital Juárez de México, the team from the National University demonstrated that the silver and copper nanolayer inactivates SARS-CoV-2.

As seen at the beginning of the pandemic copper surfaces are the ones that most rapidly reduce the virus that causes the Covid 19 infection. By using a silver-copper mixture forming a nanolayer between 30 and 40 nanometers thick, it offers double protection against viruses and bacteria.

Drops with the virus taken from Covid-19 positive patients were placed on the silver-copper film deposited in polypropylene and it was observed that, depending on the viral concentration, if it was high, the virus disappeared by more than 80 percent in a few eight hours and if the viral load was low, in two hours none of the virus RNA was detected. Upon contact with the silver-copper nanolayer, the SARS-CoV-2 membrane breaks and its RNA is damaged.

With the same hospital, the viability of a group of five bacteria of hospital origin, grouped under the acronym ESKAPE and causing nosocomial infections, was tested on a surface of silver-copper nanolayers. "Almost all of them after four hours were eliminated one hundred percent."

No Cytotoxic Effect on Skin

In collaboration with the National Rehabilitation Institute (INR), cytotoxicity tests were also carried out on the surface of polypropylene with silver-copper deposit. Any risk for the people who will use this mask, especially due to direct contact with the skin, had to be ruled out.

The INR measured the effect of the silver-copper nanolayer on the viability of abundant cells in the skin (fibroblasts and keratinocytes), and the response of these cells was the same as observed in commercial masks. There was no cytotoxic effect or risk.
No particles are simply impregnated on the surface, but a continuous silver-copper layer is formed well adhering to the polypropylene. To ensure that there is no detachment, the synthetic fabric was subjected to intense air flow for 24 hours and there was no release of silver or copper.

There is also no greater risk with humidity. When put in water for 24 hours, the amount of silver and copper released is minimal.

Fine-tuned Filtration and Disposability

With the certainty that it is antiviral and there is no cytotoxic risk, a face mask made of natural and reusable fabrics was elaborated to reduce the problem of the continuous disposal of masks. The mask has outer and inner layers of cotton and a polypropylene filter interlayer coated with SakCu, which can be washed up to 10 times without losing its biocidal properties.

They also have a filtration efficiency of 50 percent for the smallest aerosol-like particles and between 80 and 90 percent for 2.5 micron particles. Although the filtering is still being fine-tuned, the protection offered by the SakCu mask is quite good. In addition, if drops with viruses or bacteria fall on it, in a few hours they will be inactivated.

Thus, even if the SakCu is disposed of improperly, it will not be a problem as it does not remain contaminated, like many of the masks that are thrown away. Another advantage is that, by withstanding 10 washes without degrading the nanolayer and can be reused, the impact on the environment generated by so many disposable or single-use masks is reduced.

They have a filtration efficiency of 50 percent for the smallest aerosol-type particles and between 80 and 90 percent for those of 2.5 microns; Even if they are disposed of improperly, they will not be a problem because they do not remain contaminated, like many of those that are thrown away.

Future Development of Mask Suitable for Surgeries

In addition to the SakCu triple-layer mask (sewn in a maquiladora), it is planned to manufacture a surgical-type mask that can be washed “three to five times”. Its manufacture would be with heat sealing systems to reduce costs. The silver-copper nanolayer will be deposited on polyester, which would be the outer layer and the inner layer would be “SMS type”, like the one that comes with a surgical mask.

Thanks to the support of Carlos Ramos, academic technician from the IIM, the deposit equipment was modified and now, instead of small samples, 20 meters of silver-copper nanolayers can be made continuously and in several deposits enough material is produced to produce at least 200 masks a day.

Source: National Autonomous University of Mexico (UNAM)


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