Zinc oxide microparticles in paint formulations for antimicrobial surface coatings

Surfaces in healthcare environments are highly susceptible to microbial contamination and biofilm formation, posing a risk for nosocomial infections. Functional coatings incorporating antimicrobial agents offer a potential strategy to mitigate this problem. Here we show that zinc oxide microparticles (ZnO-MPs), synthesized by chemical precipitation and thermally treated at 400 and 500 °C, effectively inhibit microbial growth when incorporated into paint formulations. The microparticles display antimicrobial activity against Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa. Paints functionalized with ZnO-MPs at 400 °C significantly reduce biofilm formation of S. aureus and K. pneumoniae on coated surfaces, showing a marked decrease in viable cell counts compared to unmodified paint. This enhanced activity results from the higher surface area, porosity, and structural defects of ZnO-MPs, which promote ion release and reactive oxygen species generation, confirming their potential for incorporation into paints as an effective, scalable, and sustainable antimicrobial strategy in healthcare environments in practice.