A review on zinc oxide nanostructures as antimicrobial agent: mechanism and applications.

The escalating threat of multidrug-resistant (MDR) pathogens has intensified the search for alternative antimicrobial strategies, with zinc oxide (ZnO) nanostructures (NSs) emerging as a promising solution due to their unique physicochemical properties. This review critically examines recent advances in the development and application of ZnO NSs as antimicrobial agents, with a focus on addressing the limitations of conventional antibiotics. It highlights the underlying mechanisms of action such as membrane disruption, reactive oxygen species generation, and ion release, and how these are influenced by NS size, morphology, and surface properties. The review also analyses key factors affecting antimicrobial efficacy, including environmental conditions, particle concentration, and synergistic effects with other materials. Applications discussed range from biomedical coatings and wound dressings to food packaging and water purification systems. By outlining current challenges in synthesis optimization, mechanistic understanding, and safety assessment, this review identifies critical knowledge gaps and provides a roadmap for future research. The paper is organized to first introduce the global context of MDR infections, followed by sections on antimicrobial mechanisms, influencing parameters, practical applications, and emerging perspectives in ZnO-based antimicrobial technologies.