The World Health Organization has called for new effective and affordable alternative antimicrobial materials for the prevention and treatment of microbial infections. In this regard, calcium alginate has previously been shown to possess antiviral activity against the enveloped double-stranded DNA herpes simplex virus type 1. However, non-enveloped viruses are more resistant to inactivation than enveloped ones. Thus, the viral inhibition capacity of calcium alginate and the effect of adding a low amount of carbon nanofibers (0.1% w/w) were explored here against a non-enveloped double-stranded DNA virus model for the first time. The results of this study showed that neat calcium alginate films partly inactivated this type of non-enveloped virus and that including that extremely low percentage of carbon nanofibers (CNFs) significantly enhanced its antiviral activity. These calcium alginate/CNFs composite materials also showed antibacterial properties against the Gram-positive Staphylococcus aureus bacterial model and no cytotoxic effects in human keratinocyte HaCaT cells. Since alginate-based materials have also shown antiviral activity against four types of enveloped positive-sense single-stranded RNA viruses similar to SARS-CoV-2 in previous studies, these novel calcium alginate/carbon nanofibers composites are promising as broad-spectrum antimicrobial biomaterials for the current COVID-19 pandemic.

Due to the current COVID-19 situation caused by the spread of the new SARS-Cov-2 coronavirus, new alternative materials with antiviral activity are encouraged to be fabricated by the World Health Organization for present and future pandemics. Previous studies of low-cost alginate-based nanocomposite films produced with very low amounts (0.1% w/w) of carbon nanomaterials such as graphene oxide (GO) or carbon nanofibers (CNFs) have shown very low transparency reduction, enhanced mechanical performance, improved water diffusion and wettability, and similar biological properties than neat alginate in terms of cell adhesion and non-cytotoxicity. However, only the nanocomposite containing CNFs have shown antibacterial activity. Herein, the antiviral properties of these nanocomposite biomaterials are explored for the first time in literature using a double-stranded DNA viral model. The results of this study showed that neat calcium alginate films possess antiviral activity and the incorporation of that low percentage of CNFs significantly enhanced its antiviral action from ~55.6% to 96.33% inhibition after 48 hours. Nevertheless, the addition of this minuscule amount of GO did not improve the antiviral activity of calcium alginate. Nonetheless, both antiviral composite biomaterials possess excellent physical and biological properties with great potential in biomedical applications.