Modification of face masks with zeolite imidazolate framework-8: A tool for hindering the spread of COVID-19 infection

Abstract

The worldwide spread of the SARS-CoV-2 virus has continued to accelerate, putting a considerable burden on public health, safety, and the global economy. Taking into consideration that the main route of virus transmission is via respiratory particles, the face mask represents a simple and efficient barrier between potentially infected and healthy individuals, thus reducing transmissibility per contact by reducing transmission of infected respiratory particles. However, long-term usage of a face mask leads to the accumulation of significant amounts of different pathogens and viruses onto the surface of the mask and can result in dangerous bacterial and viral co-infections. Zeolite imidazolate framework-8 (ZIF-8) has recently emerged as an efficient water-stable photocatalyst capable of generating reactive oxygen species under light irradiation destroying dangerous microbial pathogens. The present study investigates the potential of using ZIF-8 as a coating for face masks to prevent the adherence of microbial/viral entities. The results show that after 2 h of UV irradiation, a polypropylene mask coated with ZIF-8 nanostructures is capable of eliminating S. Aureus and bacteriophage MS2 with 99.99% and 95.4% efficiencies, respectively. Furthermore, low-pathogenic HCoV-OC43 coronavirus was eliminated by a ZIF-8-modified mask with 100% efficiency already after 1 h of UV irradiation. As bacteriophage MS2 and HCoV-OC43 coronavirus are commonly used surrogates of the SARS-CoV-2 virus, the revealed antiviral properties of ZIF-8 can represent an important step in designing efficient protective equipment for controlling and fighting the current COVID-19 pandemic.

Keywords: Anti-viral/bacterial coating; COVID-19 pandemic; Face masks; MOFs; ZIF-8.

Graphical abstract

Fig. 1

Schematic representation of the ZIF-8-based mask antiviral and antibacterial mechanism.

Fig. 2

Schematic representation of a modification of face masks with ZIF-8 photocatalyst using (a) Method A and (b) Method B.

Fig. 3

SEM images of ZIF-8 deposited on (a) non-woven material (Teho Filter), and (b) woven material (LUT-branded cloth mask), morphology of ZIF-8 photocatalyst synthesized by (c) Method A, and (d) Method B, and (e) example of elemental mapping.

Fig. 4

Comparison of ZIF-8-modified and uncoated mask materials by (a) XRD analysis and (b) EDX analysis, and recorded XRD patterns after chemical stability tests by (c) boiling, and (d) steaming.

Fig. 5

Results of anti-bacterial/viral efficacy tests and corresponding log reduction after 2 h of contact time of ZIF-8-modified mask materials with (a–b) S. Aureus and (c–d) MS2 bacteriophage.

Fig. 6

Results of antiviral efficacy of ZIF-8-modified mask materials against low-pathogenic HCoV-OC43 coronavirus after 1 h of contact time: (a) mean results for the antiviral activity, (b) cytotoxicity of samples.(For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)