In particular, CuI nanoparticles (stable at room temperature) have been extensively studied for deactivation of feline calicivirus56 and H1N1 pandemic influenza virus.57 However, the use of copper salts at high concentrations can irreversibly alter reactive oxygen species (ROS) homeostasis of healthy cells, provoking a general toxicity for the organism, limiting their applications to disinfection.56 Nanostructured cuprous and cupric oxides have been also extensively employed as antiviral agents for in vitro applications.