ZnO nanoparticles
ZnO nanoparticles
Overview
zinc oxide nanoparticles (ZnO nanoparticles, ZnO NPs) are nanoscale forms of zinc oxide that are widely studied in materials science, nanomedicine, and environmental toxicology. In biomedical research, they are of interest because their surface chemistry, small size, and zinc ion release can contribute to antimicrobial, anticancer, catalytic, and redox-active properties. At the same time, these same features can also underlie cellular stress and developmental toxicity, making ZnO nanoparticles a dual-use nanomaterial with both therapeutic promise and safety concerns.
Recent studies have focused on green synthesis approaches, in which plant extracts act as reducing and capping agents to generate ZnO nanoparticles under relatively mild conditions. These studies often evaluate biological effects such as antioxidant activity, enzyme inhibition, cytotoxicity, antibacterial activity, anticoccidial activity, and interactions with oxidative stress pathways such as ferroptosis and ferritinophagy. ZnO nanoparticles have also been incorporated into nanobiotechnology platforms for controlled zinc release and catalytic or immunomodulatory applications.
Focus of Latest Publications
Recent publications on ZnO nanoparticles have focused heavily on green synthesis strategies and the resulting physicochemical and biological properties. Several studies used plant extracts as reducing and capping agents, including Hibiscus sabdariffa, green tea, pomegranate husk, pomegranate peel, Cucumis seed extract, Coriandrum sativum extract, and Datura stramonium leaf extract. These approaches were used to produce ZnO nanoparticles with confirmed crystallinity and nanoscale dimensions by UV-Vis spectroscopy, XRD, FTIR, SEM/FE-SEM, EDX, and zeta potential analysis. Reported particle sizes varied with synthesis conditions, with some green-synthesized ZnO nanoparticles reaching the low-nanometer range and showing stable surface charges.
A major theme was the development of bioactive materials for antimicrobial and preservation applications. ZnO nanoparticles were incorporated into chitosan-based nanocomposites and anthocyanin-containing smart dipping solutions for Nile perch packaging, where the system showed antioxidant and antibacterial activity against Escherichia coli and Staphylococcus aureus and extended refrigerated shelf life by up to six days while providing a visible color change as a freshness indicator. Other studies reported antibacterial activity of ZnO nanoparticles synthesized from Datura stramonium and Cucumis seed extract, with the latter also showing membrane-disruptive effects and anticancer activity against MCF-7 breast cancer cells. In a diabetic skin infection context, ZnO nanoparticles were included among eco-friendly antibacterial nanomaterials evaluated for activity against multidrug-resistant bacteria, although the in vivo healing results in that study were attributed to an AgNP-based combination rather than ZnO nanoparticles alone.
Additional publications examined ZnO nanoparticles for therapeutic and functional applications beyond antimicrobial use. Pomegranate husk-derived ZnO nanoparticles showed antioxidant activity, inhibition of pancreatic lipase and alpha-amylase, and high Vero-cell viability, supporting interest in obesity-related enzyme inhibition. Pomegranate peel-derived ZnO nanoparticles were also studied as dual-functional materials for photocatalysis and supercapacitors, with synthesis temperature and precursor concentration strongly affecting morphology, charge-transfer resistance, photocatalytic degradation of methylene blue, and specific capacitance. In contrast, one study identified ZnO nanoparticles as an environmental and developmental stressor in Caenorhabditis elegans, where exposure caused developmental delay through mitochondrial dysfunction, reactive oxygen species accumulation, ferritinophagy, and ferroptosis, with SLC-30A9 downregulation implicated as an initiating event.
Overall, the recent literature portrays ZnO nanoparticles as highly versatile materials whose properties depend strongly on synthesis route and surface chemistry. The studies collectively emphasize green fabrication, structural control, and multifunctional performance, while also highlighting that ZnO nanoparticles can be beneficial in antimicrobial, packaging, catalytic, energy-storage, and enzyme-inhibition settings, yet may also produce adverse biological effects under exposure conditions.