Another successful approach relies on the reduction of ROS concentration in host cells. ROS scavenging is able to alleviate the toxicity of the infection enhancing cell viability, giving time to start its endogenous antiviral mechanisms. So, this approach may both block infection and ensure host cell survival. In this context, selenium NPs (SeNPs) have been extensively studied for their antiviral activity. The mechanism of action of these NPs relies on the quenching of the radicals into host cells due to the infection, stopping the mitochondria depolarization and the consequent apoptotic cascade.119 Additionally, SeNPs can also adsorb onto the viral capsid sensibly reducing their infectivity. SeNPs can be prepared via classical mixing of selenium salt precursors in the presence of a reducing agent. More recently, SeNPs have been instead biosynthesized from Actinobacteria showing good stability and capacity to inhibit Dengue virus in vitro.120 Moreover, SeNPs were used to carry different antiviral drugs including zanamivir,121 oseltamivir,122 amantadine,123 and ribavirin.119 Their functionalization with the desired drug can be easily achieved adding the molecule during their synthesis through the Se ion controlled reduction. These NMs have been applied for the treatment of H1N1 virus. Notably, SeNPs with ribavirin (administered via intranasal absorption every 24 h for 3 days) showed that infected mice had much less alveolar collapse and perivascular and peribronchiolar edema, compared to the group challenged with the virus (Figure 13).119