Microbial colonization and proliferation have always attracted the attention of scientific research and the need to reduce them is growing, due to the presence of viruses, bacteria, and fungi in the environment and due to the continuous discovery of microorganisms resistant to traditional therapy or antibiotics.
Furthermore, widespread of viral diseases, such as the recent Corona Virus Disease, played an important role in this field.  For this reason, the development of new technologies in order to prevent risks to human wellness has crucial importance in the scientific world.
As it is well-known, silver nanoparticles have excellent antibacterial and antiviral properties, so they are often involved in antimicrobial devices.
Innovative composite coatings constituted by a ceramic or glass-ceramic matrix, with silver nanoclusters well embedded in it, were developed for application in air and water filtration systems. The coatings were deposited by the co-sputtering technique on different substrates. The filtration performances and the mechanical properties do not change after the coating deposition process.
To evaluate the effect of these coatings, they were tested towards gram-positive and gram-negative bacteria strains, such as Staphylococcus Epidermis and Escherichia Coli, and towards a fungus, Candida Albicans, founding that their adhesion and proliferation were slowed down or stopped. In addition, excellent antiviral activity was performed by the coatings on different viruses, such as Influenza A virus or Respiratory Syncyal virus. The coatings are not toxic to humans and the environment: it was demonstrated that the amount of silver ions released by the coatings is under the threshold allowed.