Surface modification using nanostructures and nanocoating to combat the spread of bacteria and viruses: Recent development and challenges

Apart from transmission through the respiratory droplet, the surface contact route is another major mode of viral transmission. The recent pandemic is neither the first nor the last; hence, it is a big challenge for a surface engineer to combat the transmission of microbes and viruses through the contact route. In this topical review, we have comprehensively summarized the possible techniques of surface modification for making surfaces antiviral and the respective antiviral mechanisms. Will the anti-biofouling, superhydrophobic, structured surfaces be enough to roll down viruses with water droplets? If so, there could be critical dimensions of nanostructures that need to be fabricated using a precise micro-nano manufacturing method, and the same has been discussed in this review. The surface structuring using functional nanomaterials (copper and copper alloy, gold nanoparticles, silver nanoparticles, titanium dioxide, zinc dioxide, etc.) against different types of viruses and viruses belonging to the coronavirus family has been compared in detail with their merits and demerits. Finally, we foresee that among these surface modification techniques, the nanospike structures combined with an antiviral coating could be the most effective way to combat the transmission of viruses (e.g., COVID-19) through the contact route.