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US-12616206-B2 - Graphene-silver nanocomposites and uses for same as an antimicrobial composition

US12616206B2US 12616206 B2US12616206 B2US 12616206B2US-12616206-B2

Abstract

The present invention relates to antimicrobial compositions comprising graphene-silver cation nanocomposites and uses for same as an antimicrobial agent. The antimicrobial agent is particularly useful as a disinfectant or for use as a coating to confer antimicrobial activity to a substrate. The antimicrobial agent can further be used to enhance filtration efficiency in PPE, face masks, and filters in air filtration (HVAC) systems, and other airflow membranes and filters to reduce the transmission of microbial pathogens.

Inventors

  • Seyyedarash HADDADI
  • Colin VAN DER KUUR
  • Joseph KORKIS
  • Deepak Sridhar

Assignees

  • ZENTEK LTD.

Dates

Publication Date
20260505
Application Date
20210920

Claims (17)

  1. 1 . An antimicrobial nanocomposite comprising graphene oxide (GO) and silver cations (Ag + ) bound to the GO as Ag(1)-complexes, wherein the silver cations (Ag + ) are bound to the GO by complex bonds, and wherein the nanocomposite is effective at killing coronavirus.
  2. 2 . The nanocomposite according to claim 1 wherein the complex bonds are chelated bonds or coordinate covalent bonds.
  3. 3 . The nanocomposite according to claim 1 , wherein the nanocomposite comprises between 3-80% w/w, 10-20% w/w, or 4-8% w/w of silver cations bound to the GO.
  4. 4 . The nanocomposite according to claim 1 , further comprising silver nanoparticles covalently bound to the GO of the nanocomposite.
  5. 5 . The nanocomposite according to claim 4 , wherein the silver cation and silver nanoparticles are present in a ratio of 10:1 to 15:1.
  6. 6 . The nanocomposite according to claim 4 wherein the silver cations bound to the GO comprises about 90-99% silver cations (Ag + ) in an Ag(1)-complex form and about 1-10% silver nanoparticles in a clustered Ag(0)-nanoparticle form.
  7. 7 . The nanocomposite according to claim 1 , further comprising copper cations (Cu 2+ ), or zinc cations (Zn 2+ ).
  8. 8 . The nanocomposite according to claim 1 , wherein the nanocomposite has a particle size ranging from 2 to 10 μm.
  9. 9 . The nanocomposite according to claim 1 , wherein said coronavirus is Covid-19 coronavirus, SARS coronavirus, MERS coronavirus, or SARS-CoV-2 virus.
  10. 10 . An antimicrobial formulation comprising the nanocomposite according to claim 1 , and a solvent, a carrier, a diluent, and/or a dispersant.
  11. 11 . The antimicrobial formulation according to claim 10 , wherein the formulation has a nanocomposite concentration of 40 mg/L to 5 g/L.
  12. 12 . The antimicrobial formulation according to claim 10 , wherein the formulation is a liquid spray, mist, foam, dip-coat bath, wipe, or coating.
  13. 13 . The antimicrobial formulation according to claim 10 , wherein the formulation is applied to a face mask, personal protective equipment (PPE), environmental cleaning wipes, counters, door handles, walls, or airflow membranes and filters to provide a coating thereon.
  14. 14 . The antimicrobial formulation according to claim 12 , wherein the coating has a thickness from about 5 nm to about 5 μm, from about 100 nm to about 3 μm, from about 200 nm to about 2 μm, from about 300 nm to about 1.5 μm, or from about 500 nm to about 1.0 μm.
  15. 15 . A method for conferring antimicrobial activity to a substrate, comprising: dispersing the nanocomposite of claim 1 in ethanol, or deionized water, or a mixture of deionized water and ethanol to provide a nanocomposite dispersion; applying the nanocomposite dispersion to a substrate to provide the nanocomposite dispersed on the substrate; and fixing the nanocomposite dispersed on the substrate by air or heat drying.
  16. 16 . The method according to claim 15 , wherein the nanocomposite dispersion is applied to the substrate by spray coating or dip coating.
  17. 17 . The method according to claim 15 , wherein the nanocomposite dispersion is applied to said substrate to provide a coating that ranges in thickness from about 5 nm to about 5 μm, from about 100 nm to about 3 μm, from about 200 nm to about 2 μm, from about 300 nm to about 1.5 μm, or from about 500 nm to about 1.0 μm.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is the U.S. national phase of PCT/CA2021/051308 filed on Sep. 20, 2021, which claims the benefit of U.S. Patent Application No. 63/161,873, filed Mar. 16, 2021; U.S. Patent Application No. 63/128,993, filed Dec. 22, 2020; and U.S. Patent Application No. 63/081,301, filed Sep. 21, 2020, the disclosure of each of which is expressly incorporated herein by reference in its entirety. FIELD OF THE INVENTION The present invention relates to the field of antimicrobial agents and, in particular, to graphene-silver nanocomposites and compositions thereof for use in conferring antimicrobial activity to a substrate. BACKGROUND OF THE INVENTION Microorganisms (or microbes) are single cell, cell cluster, or multicellular microscopic (or macroscopic) organisms including but not limited to, bacteria, fungi, and viruses. Pathogenic microbes have the potential to cause a multitude of infectious diseases through various modes of transmission including by contact, touch, or airborne transmission. For example, contamination of surfaces with one or more types of microorganisms, the transfer of microorganisms between surfaces, and/or the aerosol transfer of microbes in the air, can lead to transmission of illness and disease. Infectious diseases caused by pathogenic microbes continue to be a global issue. In recent years, there have been widespread outbreaks of Swine Flu, Ebola virus, Zika virus, norovirus, severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and most recently coronavirus disease 19 (COVID-19) which has been declared a pandemic by the World Health Organization. Pathogenic microbes are most commonly spread throughout a community by host-to-host transfer, including through respiratory droplets; close, prolonged personal contact; and touching an infected area, then touching the mouth, nose or eyes before washing hands. Efforts to stop the transmission of infection have required the use of antimicrobial disinfectants, physical distancing from infected hosts, and physical protective barriers such as the wearing of face masks, gloves, and protective clothing, otherwise known as personal protective equipment (PPE). Pathogenic microbes have also been shown to spread as aerosols and can spread through airborne transmission. Studies of pathogen transmission in enclosed spaces have shown that recirculated air may further result in the spreading of pathogenic microbes. Current PPE are typically single-use, or re-usable, materials that are designed to create a physical barrier to protect the wearer of the PPE from exposure to the pathogenic microbe. Similarly, current air filtration systems rely on materials that physically filter out dust, pollen and other airborne agents. Materials that filter out a pathogenic microbe, or altogether physically block exposure to the pathogenic microbe, have had limited effectiveness and have raised new issues in transmission. For example, it has been found that many disease-causing pathogenic microbes are smaller in size than the filtering-size of most filter media used for face masks. In this regard, the virus causing COVID-19 (SARS-CoV-2 virus) has been identified as having a particle size of 0.125 μm, which is much smaller than the size of the particles that are filtered by most face mask materials including N95 masks. Reducing the filtering-size of the filter media is further not possible without compromising air flow and exchange to allow the wearer to breathe. A further risk of transmission also exists from contact with contaminated substrate surfaces and materials. Disease-causing microbes typically remain viable on filter media and other substrate materials for a period of time that can range between hours to days. For example, the SARS-CoV-2 virus has been shown to remain viable on materials for 3 days, and the H1N1 virus was shown to remain on protective materials for 6 days. As a result, substrate surfaces or protective materials that have been used and discarded, can remain contaminated for relatively long periods of time and, therefore, carry the risk of leading to the secondary transmission of the pathogen into the environment. A need exists for compositions and/or materials that protect against pathogen transmission on multiple levels, namely, compositions and/or materials that physically block, trap, or immobilize the pathogen, as well as being able to destroy the pathogen to prevent secondary transmission. Moreover, a need exists for antimicrobial compositions and/or materials that are amenable to being applied to substrate surfaces, or processed into, functional products such as PPE and filter membranes in ventilation systems, to confer antimicrobial activity. This background information is provided for the purpose of making known information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that