# Antiviral Filtering Capacity of GO-Coated Textiles
## 4 Discussion  
GO-coated fabrics are attracting great interest from researchers because of the ever-increasing demand for protective materials with antiviral capabilities. GO nanoparticles' antiviral properties are attributed to their capacity to bind viruses preventing them to enter and infect target cells [20].  
In this study, we demonstrated that GO combined with textiles exhibits antiviral activity towards the HHV-6 virus in a concentration-dependent manner as it prevented its infection of U373 cells. HHV6 virus is an enveloped DNA virus that is ubiquitous in the worldwide population. One of the receptors used mainly by HHV6A to infect cells is CD46 (complement inhibitor receptor), expressed on surfaces of almost every cell type [21]. Apart from specific receptors, infection of cells by herpes viruses depends upon  
Figure 6: Filtering effect of textiles coated with GO. q-RT PCR on U 373 cells infected with HHV-6A. The virus was allowed to infect cells after passing through different filters. Values are mean of **n. 1**: CTRL (NO FILTER NEG.CTRL); **2**: CTRL (T); **3**: GO-T 0.5; **4**: GO-T 5; **5**: GO-T 10; **6**: 0.2 \(\upmu\)m filter.  
Figure 7: SEM microscopy of textiles used as filters. (**A**) 10% GO-coated fibers covered with a thick layer of the virus; (**B**) GO sheets (arrow) emerging from fiber surface, surrounded by virus particles; (**C**) GO sheets (arrow) surrounded by viral aggregates.  
the initial attachment of virions to cell surface heparan sulfate, followed by receptor-ligand recognition [22].  
GO nanoparticles have been studied for virus detection and disinfection applications [23] given their versatility in binding different molecules and their potential to interfere with viral integrity, especially in the case of enveloped viruses.  
Because of the highly reactive ionic groups, GO can bind cotton fabrics [24]. Graphene oxide nanostructures modify multifunctional cotton fabrics [25] in a stable and easy way. The antibacterial efficacy of GO-treated fabrics has been previously demonstrated against both gram-positive and gram-negative bacteria [26].  
In this study, GO bound to textiles prevented viral passage through the filter by partially filling the pores of the fabric. However, even when the viral particles passed through low percentage GO-coated filters, they remained attached to the lower surfaces of them, suggesting other mechanisms of interaction.  
Apart from its mechanical action on fabric pores, the interaction of GO with viruses has been attributed to factors such as the negative charge of GO as opposed to the positive Z potential of viral capsids. Our study has shown an increase in Z potential after binding GO with fabric and a further increase after viral interaction; this may mean that both electrostatic interactions and bio-reduction processes may occur at the same time. On the nanocomposite side, one factor that must be taken into account is the size of GO, which may interfere with viral entry into cells. [PERSON] et al. [27] have shown that the size of carbon-based nanoarchitectures must adapt to the size of viral particles to inhibit cellular infection. Authors investigating carbon-based viral sensors or direct inhibitors of viral infections have functionalized nanomaterials with substances that lower cytotoxicity and can bind viruses directly [28]. Synthesized GO samples, which consisted of bi-three-layer nanosheets, of \(5\times 10^{-2}-0.2\) (\(\upmu\)m\({}^{2}\)), seem a useful size for avoiding viral contact with cells.