Ag nanoparticles loaded on filter surfaces were found to effectively suppress bacteriophage MS2 activity. Ag nanoparticles may be an effective antiviral material against SARS-CoV-2 in healthcare settings, or to air filters or face masks. However, further study is needed.

Smith College

Nanomaterials can be used to increase the performance and safety of PPE, such as air filters and masks. They may be used to not only capture aerosol droplets but also inactivate the virus upon contact with the surfaces of PPE. 

Opportunities for nanotechnology-based solutions to increase the efficiency and safety of air filter and mask devices include (i) improving particle capture and retention characteristics, particularly, in the 300 nm diameter size range; (ii) reducing the effects of exhaled humid air on particle redistribution; (iii) rapid inactivation of membrane-bound microbes including enveloped viruses upon capture; and (iv) thin, high-efficiency filtration media for personal masks that are able to be reused repeatedly without loss of efficiency (e.g., novel electrospun nanofibers). 


Nanomaterials for Personal Protective Equipment (PPE)

Definition: Ag and Au nanoparticles and nanorods can induce heating when illuminated at optimal wavelength, corresponding to the plasmon resonance condition, in a process called plasmonic photothermal treatment. The proposed underlying mechanism is plasmon-enhanced shockwave generation, which alters virus membrane and/or surface groups and, therefore, reduces virus binding and fusion with the host cell. 

Plasmonic nanoparticles for photothermal inactivation of the virus include but are not limited to the following:

- Ag nanoparticles

- Au nanoparticles


Photothermal Inactivation of SARS-CoV-2 with Nanomaterial

Weiss C, Carriere M, Fusco L, et al. Toward Nanotechnology-Enabled Approaches against the COVID-19 Pandemic. ACS Nano. 2020;14(6):6383-6406. doi:10.1021/acsnano.0c03697

Toward Nanotechnology-Enabled Approaches against the COVID-19 Pandemic

Electrospun nylon nanofibers sprayed with TiO2 nanoparticles allow photocatalytic and bactericidal activities when illuminated under UV light. 


Advantages of TiO2:

- considered inert

- low toxicity

- not susceptible to photocorrosion


 If effective, the use of TiO2 photocatalysis for SARS-CoV-2 inactivation would be particularly useful for surface decontamination using TiO2-doped paints, aerosol decontamination using air filtration filters and ventilation systems impregnated with TiO2 that can be exposed to UV light, and for wastewater treatment.


TiO2 NPs can be coupled with other components (e.g., metals) to increase efficiency of bacteria and/or viruses inactivation However, the toxicity levels of these combined materials have not been tested.


TiO2 nanoparticles

Ag nanoparticles

Graphene has become an engineering material with a variety of uses. For instance, graphene can serve as an effective barrier for masks, gloves, and gowns for medics against bacteria and viruses larger than 300 nm. Graphene has been used for effective photodynamic inactivation of viruses, including Semliki Forest virus, vesicular stomatitis virus, HSV-1, HIV-1, mosquito iridovirus, influenza A virus, and phage mS2.




Graphene 

MXenes are emerging as a promising tool to capture and degrade viruses, such as SARS-CoV-2. MXenes are light-to-heat converters that are capable of adsorbing virus and inactivating it by applying light. Some MXenes are antibacterial as well, likely due to their combined hydrophilic property and charge transfer ability. They are particularly promising for the development of coatings that are capable of capturing and inactivating viruses on face masks and other PPE. MXenes can also regenerate dialysate by removing toxins that build up in the setting of kidney failure - they may be able to address key limitations of current ambulatory dialysis systems by offering efficient urea adsorption, small size, and lightweight. 

- Biocompatible MXenes




2D Carbides and Nitrides (MXenes)

One study found that the "filter showed effective inactivation of SARS-CoV when exposed for 6 h to UV light." Additional studies on the effectiveness of titanium apatite are recommended.

Titanium apatite filter (PTAF)

Au NPs are much less toxic than Ag NPs. Au NPs can emit intense heat under the sunlight to inactivate viruses. One study found that Au NPs can inactivate bacteriophages MS2 and PR772 through photothermal process. Another study found that Au NPs can kill pathogens by generating an effective plasmon-enhanced shockwave and altering virus membranes.

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