Evaluation of Zinc Oxide Nanoparticles Against Bacterial Biofilms
This study explores the synthesis and application of green‑synthesized zinc oxide nanoparticles (ZnO‑NPs) coated with polysaccharide stabilizers for eradication of mature bacterial biofilms formed by Pseudomonas aeruginosa and Staphylococcus aureus. Nanoparticles were produced using plant extract reduction, yielding a mean diameter of approximately 50 nm. In vitro assays on static and dynamic biofilm models revealed a >95% reduction in total biomass after 24 hours of exposure to 100 µg/mL ZnO‑NPs.
Scanning electron microscopy (SEM) demonstrated extensive disruption of the extracellular polymeric matrix, supporting a combined mechanical and oxidative antimicrobial mechanism. Reactive oxygen species (ROS) generation was confirmed via dichlorofluorescein assays, with maximal ROS release observed at pH 6.5—suggesting pH-dependent biofilm targeting.
Cytotoxicity tests on mammalian fibroblasts showed >80% viability at treatment concentrations. The results underscore the promise of ZnO‑NPs as antibiofilm coatings in catheter and wound-care devices, with the caveat that future in vivo toxicity studies are warranted.
