For instance, copper ions (derived from sulfates or iodide salts) have been widely used as antiviral agents because of their activity on several kinds of enveloped and non-enveloped viruses including influenza virus,49−51 herpes simplex virus52−54 and hepatitis A virus.55 Their mechanism of action relies on the formation of Cu+ ions (from soluble salts or nanoparticles) that generate hydroxyl radicals.56 The use of metallic copper nanostructures in the form of particles or sheets has shown only a moderate efficiency due to the low concentration and low release of Cu+.56 For these reasons, Cu+ salts, where the copper ions are readily present in their active monocationic form, have been favored.