Tackling COVID-19 Using Antiviral Nanocoating's-Recent Progress and Future Challenges

Abstract

In the current situation of the global coronavirus disease 2019 (COVID-19) pandemic, there is a worldwide demand for the protection of regular handling surfaces from viral transmission to restrict the spread of COVID-19 infection. To tackle this challenge, researchers and scientists are continuously working on novel antiviral nanocoatings to make various substrates capable of arresting the spread of such pathogens. These nanocoatings systems include metal/metal oxide nanoparticles, electrospun antiviral polymer nanofibers, antiviral polymer nanoparticles, graphene family nanomaterials, and etched nanostructures. The antiviral mechanism of these systems involves depletion of the spike glycoprotein that anchors to surfaces by the nanocoating and makes the spike glycoprotein and viral nucleotides inactive; however, the nature of the interaction between the spike proteins and virus depends on the type of nanostructure and a surface charge over the coating surface. In this article, the current scenario of COVID-19 and how it can be tackled using antiviral nanocoatings from the further transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), along with their different mode of action, are discussed. Additionally, it is also highlighted different types of nanocoatings developed for various substrates to encounter transmission of SARS-CoV-2, future research areas along with the current challenges related to it, and how these challenges can be resolved.

Keywords: coronavirus disease 2019; nanocoating; nanomaterials; pathogens; severe acute respiratory syndrome coronavirus 2.

Figure 1

Structure of virus and mechanistic action. a) Structure of a coronavirus. b) Surface addition of viruses via electrostatic interaction. c) The schematic diagram of the mechanism of SARS‐CoV‐2 entry, viral replication, and viral RNA packing in the cell. Reproduced with permission.^{[ 11 ]} Copyright 2021, MDPI.

Figure 2

Characteristics of PVP coated 10 nm AgNPs in SARS‐CoV‐2 infection. Immunofluorescence imaging comparing the effect of 10 nm and 100 nm AgNPs against SARS‐CoV‐2 infection in VeroE6/TMPRSS2 cells. Cell nuclei (blue) and SARS‐CoV‐2 nucleocapsid protein in cytoplasm (red). A) NC—Negative control; PVP‐coated 10 nm AgNPs protect VeroE6/TMPRSS2 cells from SARS‐CoV‐2 infection mediated cell death. B) Crystal violet staining reveals partial protection with visible plaques (red arrowheads) and complete protection with absence of plaques (black arrowheads); Pseudovirus entry assay. C) PVP‐coated 10 nm AgNPs inhibit entry of pseudovirus in VeroE6/TMPRSS2 cells. NC—Negative control, nAb—neutralizing antibody. Reproduced with permission.^{[ 32 ]} Copyright 2020, Elsevier.

Figure 3

Copper based inorganic antiviral coatings. A,D) The test mask composed of 2 external spunbond polypropylene layers containing 2.2% copper oxide particles (weight/weight), B) one internal meltblown polypropylene layer containing a) 2% copper oxide particles (w/w) and one polyester layer containing no copper oxide particles; b) Scanning electronic microscope picture and X‐ray analysis of external layer A; c) Scanning electronic microscope picture and X‐ray photoelectron spectrum analysis of internal layer B. Reproduced with permission.^{[ 46 ]} Copyright 2010, PLoS.

Figure 4

Virucidal performance of the multi‐functional anti‐pathogen coating. A) Transmission electron microscopy (TEM) image of the H1N1 virus; B) TEM image of the H1N1 virus after contact with the coating; C) plaque assay image of an H1N1 infected host cell; D) plaque assay image of the coating inactivated N1N1 virus. Reproduced with permission.^{[ 19 ]} Copyright 2018, Royal Society of Chemistry.

Figure 5

a) Macro‐photograph of an in‐use stainless steel push plate; b) copper coating on stainless steel push plate; c) polished copper coating; and d) copper‐coated push plate installed on a door. Reproduced with permission.^{[ 50 ]} Copyright 2020, Elsevier.

Figure 6

ZnO micro nano structures (MNSs). Synthesis of the ZnO material can be done in large quantities, please note the a) 23 mm diameter coin. b) Microscopic image, comparison between A) a standard powder and B) the material synthesized here. c) Electron micrograph showing the complex geometries. d,e) The powder contains a larger quantity of filopodia like structures, which have spikes down to the nanoscale. UV‐illumination on ZnO MNSs significantly enhances HSV‐1 binding. ZnO‐MNSs were exposed to UV illumination for 30 min. MNSs were stained as red via phalloidin treatment (panel f); UV untreated (panel g) and UV‐treated (panel h) ZnO MNSs were mixed with green fluorescent protein (GFP)‐tagged HSV‐1 (VP26); The UV exposed ZnO‐MNSs showing significant HSV‐1 trapping as indicated by strong yellow co‐localization signal (highlighted by arrows) compared to UV‐untreated red‐ZnOMNSs. i) Pre‐incubation of UV‐treated ZnO MNSs with HSV‐1 significantly blocks viral entry. In this experiment, b‐galactosidase‐expressing recombinant virus HSV‐1 (KOS) gL86 (25 pfu/cell) was pre‐incubated for 90 min with the UV pre‐treated (+) or untreated (−) ZnO‐MPs at 0.1 mg mL⁻¹. HSV‐1 KOS gL86 mock‐incubated with 1× phosphate buffer saline (PBS; black bar) was used as positive control. The uninfected cells were used as negative control (grey bar). After 90 min the soup was challenged to CF. After 6 h, the cells were washed, permeabilized and incubated with ONPG substrate (3.0 mg mL⁻¹) for quantitation of b‐galactosidase activity expressed from the input viral genome. The enzymatic activity was measured at an optical density of 410 nm (OD410). The value shown is the mean of three or more determinations (±SD). Reproduced with permission.^{[ 15 ]} Copyright 2011, Elsevier.

Figure 7

a) ROS generation of •OH and •O₂ ⁻ after UV light irradiation of TiO₂. b) Mechanism of photocatalytic inactivation of bacteria and viruses. Reproduced with permission.^{[ 63 ]} Copyright 2021, MDPI.

Figure 8

Antiviral effect of TiO₂ films‐reaction of cell cultures infected by virus HSV‐1. Control sample 1: A) virus on sample without TiO₂ film placed in dark. Control sample 2: B) virus on sample without TiO₂ film UV illuminated. C,D) Virus on two different TiO₂ samples (TiO₂ film from temperature series deposited on microscopic glass slides at a substrate temperature of 155 °C (sample X) and 280 °C (sample Y)) with TiO₂ film illuminated with UV light. Reproduced with permission.^{[ 14 ]} Copyright 2007, Willey.

Figure 9

Changes in SARS‐CoV‐2 virion morphology due to LED‐TiO₂ photocatalytic reaction. SARS‐CoV‐2 (1 mL) titer of 1.78 × 106 TCID₅₀ mL⁻¹ was placed on TiO₂‐coated sheet and subjected to photocatalytic reaction for 120 min before TEM imaging. a) Representative virion images in the TiO₂ + Light, Light, and control groups are shown. Bar = 100 nm. b) Number of S proteins on single virions in individual TEM images of the TiO₂ + Light, Light, and control groups was counted, and distribution and mean number of S protein/virion are shown; n = 50/group. c) Each dot represents a value of S protein of each virion in (b). d) Virion number in an area of 170 µm² in an individual TEM image is shown; n = 10. e) Diameter of single virion in an individual TEM image is shown; n = 40. f) Viral titer in each group was confirmed by TCID₅₀ assay. Each column and error bar represents the mean ± SD of results. All values were analyzed by two‐way ANOVA followed by Tukey's test. Asterisk indicates a statistically significant difference (*p < 0.05; **p < 0.01; ***p < 0.001). Reproduced with permission.^{[ 69 ]} Copyright 2021, MDPI.

Figure 10

A) Schematic for the antiviral mechanisms of graphene oxide (GO) against the enveloped virus. B) Graphene‐silver nanocomposites (GO‐Ag) against the enveloped virus. C) GO against the non‐enveloped virus. D) GO‐Ag against the non‐enveloped virus. Reproduced with permission.^{[ 83 ]} Copyright 2016, MDPI.