Shape-Directed Hydrothermal Design of Zinc Oxide Nanoparticles for Antimicrobial and Anticancer Applications

The emergence of antibiotic-resistant bacteria represents one of the most pressing challenges in global healthcare. In this study, metal oxide–based nanomaterials are gaining prominence due to their antimicrobial and anticancer potential. In the present study, six new zinc oxide nanoparticles (ZnO-NPs) synthesized via the hydrothermal method using different surfactants were characterized, and their biological activities were evaluated. ZnO-NPs, whose structural properties were determined by a range of analytical methods including BET, FT-IR, SEM-EDX, XRD, and XPS, exhibited significant antibacterial and antifungal effects on a range of bacterial and fungal strains. The study revealed that variations in the morphology and surface area had a direct impact on antimicrobial efficacy. In antimicrobial assays, the inhibition zones ranged from 10.5 mm to 25.5 mm, with ZnO-6 exhibiting the highest efficacy against S. epidermidis (25.5 mm). In cytotoxicity assays, ZnO-6 demonstrated the strongest anticancer potential against H460 cells with the lowest IC50 value of 31.9 µg/mL. Furthermore, a strong correlation was revealed between the physicochemical properties of ZnO-NPs and their anticancer activity, as evidenced by the results of tests conducted on H460 lung cancer cells. Specifically, ZnO-6, which possesses a flower-like morphology and the highest surface area, exhibited the strongest anticancer effect with an IC50 value of 31.9 µg/mL. The parallel enhancement in both antimicrobial and anticancer activities observed in ZnO-6 suggests a common underlying mechanism, likely driven by the high surface area and specific flower-like morphology that facilitates increased interaction with cell membranes and ROS generation. The findings demonstrate that the controlled design of ZnO-NPs in terms of morphology and surface area offers significant potential in both antimicrobial and anticancer applications.