Durable SiO2-ZrO2-Ag coatings produced via co-sputtering method for sustained antimicrobial activity on air filtration media

The development of multifunctional antimicrobial surfaces is critical for healthcare, air filtration, and hygienesensitive applications. In this work, innovative SiO₂–ZrO₂–Ag composite coatings were obtained via physicalvapor deposition (PVD) co-sputtering, and successfully applied on both cotton fabrics and high-efficiency particulate air (HEPA) H14 filters. The coatings consist of a robust silica–zirconia matrix embedding silver nanoclusters, providing simultaneous chemical stability, controlled silver release, and broad-spectrum antibacterial activity. Morphological, compositional, and structural analyses confirmed uniform deposition, amorphous matrix formation, and nanoscale silver cluster incorporation. Antibacterial performance was evaluated through inhibition halo assays, CFU counting, and a bioaerosol contamination test, demonstrating effective suppression of both Gram-positive (Staphylococcus epidermidis) and Gram-negative (Escherichia coli) bacteria, as well as reduced surface colonization under realistic conditions. Durability tests revealed sustained antibacterial efficacy after repeated washing cycles, highlighting the long-term stability of the coatings. Overall, the results suggest a versatile and potentially scalable strategy for producing antimicrobial surfaces with tunable properties, offering a promising solution for textiles, filtration systems, and other applications requiring long-lasting microbial control.