Potential of graphene-based materials to combat COVID-19: properties, perspectives, and prospects
[MEK Note: It seems toxic Graphene oxide has been used in Face Masks and Covid test nose swaths]
Mater Today Chem. 2020 Dec; 18: 100385.Published online 2020 Oct 21. doi: 10.1016/j.mtchem.2020.100385PMCID: PMC7577689PMID: 33106780Author informationArticle notesCopyright and License informationDisclaimerThis article has been cited by other articles in PMC.Go to:
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a new virus in the coronavirus family that causes coronavirus disease (COVID-19), emerges as a big threat to the human race. To date, there is no medicine and vaccine available for COVID-19 treatment. While the development of medicines and vaccines are essentially and urgently required, what is also extremely important is the repurposing of smart materials to design effective systems for combating COVID-19. Graphene and graphene-related materials (GRMs) exhibit extraordinary physicochemical, electrical, optical, antiviral, antimicrobial, and other fascinating properties that warrant them as potential candidates for designing and development of high-performance components and devices required for COVID-19 pandemic and other futuristic calamities. In this article, we discuss the potential of graphene and GRMs for healthcare applications and how they may contribute to fighting against COVID-19.Keywords: Materials, Microbe, Virus, SARS-CoV-2Go to:
1. Introduction
The recent outburst of coronavirus disease-19 (COVID-19) is devastating for global health systems . COVID-19 is a fatal disease that is caused by a newly born severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Due to its severity and reach to most of the nations across the world, the world health organization (WHO) has declared it a pandemic. As of June 11, 2020, there are more than 7.597 million confirmed cases with about 3.841 million recoveries and about 0.423 million deaths for COVID-19 affecting 215 countries. To date, there is no medicine or vaccine available for COVID-19 treatment, though the research, development, and clinical trials for both medicines and vaccines are under progress at an unbelievable pace.
Over the past few years, graphene and graphene-related materials (GRMs) have attracted huge attention of the researchers owing to their wide spectrum properties such as high surface area, high electrical mobility and conductivity, excellent mechanical, electrochemical, and piezoelectric properties, and efficacy against microbes and viruses. Recently, few good reviews appeared in the literature revealing the authors’ views and projections on the possible contribution of graphene-based materials in the global fight against COVID-19. For example, Palmeri and Papi have emphasized over the various modes of interactions among graphene materials and different virions that can help in blocking or destroying the viruses. The authors also briefed over the plausible role of the graphene textiles and filters in controlling the epidemiological spread of COVID-19 and the implications of graphene materials for the development of environmental sensors. Udugama et al. focused on discussing the emerging diagnosis technologies for COVID-19 detection. These technologies include reverse transcription recombinase polymerase amplification (RT-RPA), loop-mediated isothermal amplification method (LAMP), nucleic acid sequence-based amplification (NASBA), rolling circle amplification, enzyme-linked immunosorbent assay (ELISA), magnetic biosensor, magnetic ELISA, and DNA-assisted immunoassay, which all mainly used nucleic acid and protein biomarkers for viral and bacterial diagnosis. Cordaro et al. compiled the literature on the contribution of graphene-based materials and strategies in liquid biopsy and the diagnosis of viral diseases and discussed the potential of graphene in COVID-19 diagnosis. In general, most of the recent reports briefly reviewed the literature related to the implications of graphene-related materials in virus diagnosis and their role in designing personal protective equipment with special reference to COVID-19. In the present review, we have discussed in detail the various functional properties of graphene and related materials and their plausible role in the global fight against viral diseases including COVID-19 by designing highly sensitive electrochemical, piezoelectric, field-effect transistor-based biosensors, and surface plasmon resonance-based diagnostic systems. The article further covers the importance of graphene oxide and related materials in controlling the virus spread and transmission including COVID-19 due to their potential role in (i) development of antiviral surfaces/coatings, (ii) designing of nanofoams for face masks and other PPEs, and (iii) fabrication of 3D printed medical components. Fig. 1 illustrates different possible applications of graphene and GRMs to combat different problems related to viral infections including COVID-19 spread.
Their potency to destabilize and kill microbes and viruses could lead to the application of graphene and GRMs, especially metal ions decorated GRMs, in the development of antiviral and antimicrobial materials and surfaces that may be used in hospital settings, high touch surfaces, and various consumer products. The excellent electrical, electrochemical, piezoelectric properties may enable their applications in the development of electrochemical biosensors, field-effect transistor (FET)-based biosensors, and piezoelectric biosensors for rapid, cost-effective, sensitive, and early-stage diagnosis of viruses. Graphene and GRM-based materials could be used as surface plasmon resonance (SPR) substrate to design highly sensitive viral diagnostic devices, their nanofoams could be used in the development of highly effective face masks with controlled porosity on nanoscale, and 3D printing of these materials may lead to design and development of a variety of PPEs and other healthcare components. We discussed in detail the possible technology development based on graphene and GRMs to fight against COVID-19 and other futuristic health calamities.
2. Graphene and graphene-related materials
Graphene is an atomically thin layer (single layer) of sp2 bonded carbon atoms arranged in a hexagonal pattern. Single-layer graphene (SLG) displays outstanding properties. In SLG, the π and π∗ bands touch at the Dirac point that makes it a zero-band gap material, and at Dirac point, the SLG electrons behave-like massless fermions. SLG displays high carrier mobility that can reach to about 105–106 cm2V−1s−1, two to three orders of magnitude higher than silicon; high mechanical strength of about 130 GPa (130 GPa = 13256310768.713 kg/m2), several times higher than steel; electrical and thermal conductivities higher than copper and diamond, respectively; high transmission of about 97.7%; excellent lubricity; broad-spectrum antimicrobial properties, etc. Graphene and GRMs can be produced by various top-down and bottom-up approaches. Dry and liquid exfoliations are among the common methods for the synthesis of graphene. Geim and Novoselov used the mechanical exfoliation method to peel off the graphite through the scotch tape to produce graphene. Thermal chemical vapor deposition (CVD) is one of the best methods for the synthesis of high-quality graphene with minimal defects that could be used in the development of graphene field-effect transistor (FET), electrochemical, and piezoelectric biosensors. The CVD process of graphene production requires the thermal decomposition of carbon-containing precursor gas, mainly methane, at a high temperature of about 1000 °C on a specific substrate viz. copper. Other materials such as Ni, Pt, Fe, and their alloys have also been employed as the substrates for the deposition of the graphene layer. Preconditioning of the substrate is also required before the deposition of high-quality graphene on copper. Once the synthesis of graphene has been done on a specific substrate, the transfer methods are employed to place the graphene on desired surfaces. Commonly, the transfer of graphene from Cu foil to the desired substrate requires the following steps: (i) coating of poly(methyl methacrylate) (PMMA) on graphene on copper, where PMMA acts as a support layer for graphene, (ii) etching of copper in FeCl3 solution, (iii) rinsing of PMMA/graphene film with ultrapure water, (iv) lifting off PMMA/graphene film on a desired substrate, (v) removal of PMMA, and cleaning and baking of the graphene to get good quality transferred graphene. Likewise, GRMs, such as bilayer graphene (BLG) and multilayer graphene, can be obtained by repeated transfer of the SLG on top of one another. Unlike SLG, the BLG has a greater feasibility to tune its bandgap and hence in recent past this material has attracted considerable interest for optoelectronic applications in particular. The engineering of the bandgap and other properties of BLG and MLG can be performed by the application of electric field, and chemical doping. The top-down approach is the simple, scalable, and fast method for the synthesis of GRMs such as graphene oxide, which is an oxide sheet of graphene. Hummer’s, Brodie, and Staudenmaier methods or modified versions of these methods are used for the synthesis of GO. Graphite is the starting material that is oxidized in an acidic environment, and then ultrasonication and purification steps are employed to reduce the number of layers of graphite oxide to a few layer GO, and even single-layer GO. Furthermore, GO possesses a bandgap due to the presence of functional groups but it shows inferior electrical and thermal properties than graphene. It is essential for many applications, in particular for electronics and bio-electronics like biosensors, to enhance the conductivity of GO to develop highly sensitive, selective, and fast sensing devices. Thus, the chemical reduction of GO is performed commonly using hydrazine, and the resultant reduced graphene oxide (rGO) demonstrates considerably improved electrical properties than GO. This is attributed to a reduced amount of oxygen-containing groups in rGO with respect to GO, but the electrical properties of rGO remain slightly inferior to pristine graphene. A detailed description of the synthesis and properties of graphene and GRMs can be found in Ref.
Open in a separate windowFig. 2
Schematic illustration of the graphene and GRMs. (a) Single-layer graphene, (b) energy-momentum diagram for one of the discrete points of graphene’s Brillouin zone showing conduction and valence bands touching at the Dirac point, (c) multilayer graphene, and (d) graphene oxide.
3. Graphene-based anti-viral surfaces and coatings
Unveiled in December 2019, a new fatal SAR-CoV-2 virus starts circulating among humans. Transmission through sub-micron size respiratory droplets is the common pathway for COVID-19 spread. Moreover, a person can also catch this virus by coming in contact with the contaminated objects or surfaces and then touching their mouth, nose, or eyes. A recent study reported the variable stability of the SAR-CoV-2 virus on different surfaces. The SARS-CoV-2 is found to have a higher survival time on plastic (72 h) and stainless steel (48 h) surfaces compared to copper (4 h) and cardboard (24 h). Moreover, the virus is confirmed to be more stable on smooth surfaces compared to rough surfaces such as printing/tissue papers (3 h), wood (2 h), and cloths (2 h). Unfortunately, the detectable level of the virus is reported to be available on the external layer of the surgical masks even on day 7. Thus, contaminated high touch surfaces that offer high virus stability can enhance the chances of COVID-19 spread. In the present pandemic situation, where the COVID-19 cases are exponentially increasing each day globally, the development of efficient anti-SARS-CoV-2 protective surfaces/coatings can play a significant role in controlling the viral spread through high touch components, products, and systems.
Graphene-based materials have been explored extensively for their antimicrobial potentials. Reported studies provided evidence about the broad-spectrum inhibition activity of graphene oxide and its derivatives against bacteria and fungi. In 2014, Sametband et al. reported the antiviral properties of GO and partially reduced sulfonated GO against Herpes Simplex Virus Type-1 (HSV-1) through competitive inhibition mechanism. Similar to cell surface receptor heparan sulfate, GO and rGO-SO3 contain multiple negatively charged groups and thus both moieties compete with each other in binding with HSV-1. Blocking of the virus binding sites with the nanomaterial was the main inhibitory factor to safeguard Vero cells from infection. Ye et al. have compared the antiviral potency of GO, rGO, GO-polyvinylpyrrolidone (PVP) composite, GO-poly(diallyldimethylammonium chloride) (PDDA) composite with precursors graphite (Gt), and graphite oxide (GtO). The study revealed broad-spectrum antiviral activity of GO against Pseudorabies virus (PRV, a DNA virus) and porcine epidemic diarrhea virus (PEDV, an RNA virus). Results also suggest that the antiviral properties of GO are attributed to its negatively charged, sharp-edged structure. The GO conjugated with polyvinylpyrrolidone (PVP, non-ionic polymer) showed potent antiviral activity; however, PDDA (cationic polymer) bound GO revealed no virus inhibition, suggesting negative charge as a prerequisite for antiviral properties.
Song et al. have reported the GO-based label-free method to detect and disinfect environmental viruses such as Enterovirus 71 (EV71) and endemic gastrointestinal avian influenza A virus (H9N2) that have great environmental stability and low sensitivity for organic disinfectants and soaps. The report suggests that the physicochemical interactions (hydrogen bonding, electrostatic, redox reactions) among GO and viruses, under thermal reduction of GO, play a critical role in capturing and destruction of the viruses. The viricidal properties of GO are found to be enhanced under elevated temperature conditions (56 °C). In another report, GO sheets are reported to exhibit significant antiviral inhibition potentials toward enveloped feline coronavirus (FCoV), and incorporating silver particles into GO structure broadens its antiviral potential toward non-enveloped infectious bursal disease virus (IBDV) as well. Yang et al. have prepared multifunctional curcumin loaded β-CD functionalized sulfonated graphene composite (GSCC) and investigated its antiviral potential against negative sense respiratory syncytial virus (RSV) which like SARS-CoV-2 infects both the lower and upper respiratory tracts with children and elderly as their easy targets. The results revealed that GSCC could inhibit RSV from infecting the host cells by inactivating the virus directly and prohibiting the attachment of the virus and have prophylactic and therapeutic effects toward the virus. In a recent study, authors have attempted to investigate the antiviral effect of GO-Silver nanoparticles composite on the replication of porcine reproductive and respiratory syndrome virus (PRRSV). The results suggest that the exposure of virus with GO-AgNPs composite obstruct the virus to enter the host cell with 59.2% efficiency and also promotes the production of IFN-stimulating genes (ISGs) and interferon-α (IFN-α) that inhibits the virus proliferation. More
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Coronavirus Covid-19 Research History – Index
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