Towards a comprehensive assessment of functionalized ceramic tiles with antibacterial properties

The increasing demand for antimicrobial surfaces, particularly in hygiene-sensitive environments, has driven the development of ceramic tiles functionalized with bioactive agents. This study proposes the use of multiple and customized approaches to characterize functionalized ceramic tiles for antibacterial purposes. Tiles incorporating two silver-based formulations (named W-Ag and S-Ag) within different glaze matrices were characterized using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) to evaluate surface morphology and elemental composition. Antibacterial efficacy was assessed against four opportunistic pathogens ( Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, and Pseudomonas aeruginosa ) through minimum inhibitory and bactericidal concentration assays, ISO 22196 standard procedures, bacterial adhesion assays, and biofilm visualization. Results revealed that post-firing S-Ag-treated tiles exhibited superior antibacterial activity and anti-adhesive properties compared to pre-firing W-Ag tiles, achieving substantial bacterial reduction (R>2) against all strains after 24 hours, and early-stage inhibition after 4 hours. W-Ag tiles showed limited efficacy, primarily against E. coli , likely due to a decrease in silver availability after high-temperature firing. Tile morphology and glaze composition significantly influenced antibacterial performance, with smoother surfaces promoting reduced bacterial adhesion. Reduced concentrations of S-Ag maintained efficacy against S. aureus but were less effective against other strains, highlighting species-specific and concentration-dependent activity. These findings underscore the critical role of deposition methods, surface morphology, and material composition in determining the antimicrobial performance of ceramic tiles. Comprehensive evaluation combining standardized assays, early-stage adhesion testing, and structural characterization is essential for optimizing bioactive tiles for real-world applications, including infection/contamination prevention in healthcare and public settings.