Biogenic ZnO nanoparticles derived from the Luprops tristis beetle exhibit broad spectrum activity, including DPPH radical scavenging, antibacterial, anticancer effects, and sensitive glucose detection

In the present study, zinc oxide nanoparticles (ZnO NPs) were synthesized using the defensive gland secretion of the beetle Luprops tristis as a natural stabilizing and functionalizing agent. This work presents a biologically assisted approach that explores the underutilized potential of insect-derived biomolecules for nanomaterial synthesis. The formation of ZnO nanoparticles was confirmed through UV–visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and zeta potential analysis. The UV–visible spectrum exhibited a characteristic absorption band at approximately 378 nm, corresponding to the intrinsic band-gap absorption of ZnO. FTIR analysis revealed the presence of functional groups such as hydroxyl, amine, and carbonyl moieties, indicating the involvement of biomolecules from the beetle secretion in nanoparticle stabilization. The synthesized nanoparticles exhibited a predominantly spherical morphology with an average particle size of approximately 26 nm. The crystalline nature and phase composition of the biosynthesized ZnO nanoparticles were examined using X-ray diffraction (XRD) analysis. The biological performance of the biosynthesized ZnO nanoparticles was evaluated through antioxidant, antibacterial, cytotoxic, and electrochemical studies. The nanoparticles demonstrated dose-dependent free radical scavenging activity in the DPPH assay, with an EC₅₀ value of 26 μg/mL. Antibacterial studies revealed concentration-dependent inhibitory effects against Staphylococcus aureus and Klebsiella pneumoniae , with maximum inhibition zones of 19 ± 0.05 mm and 13 ± 0.05 mm, respectively. Cytotoxicity analysis using Dalton’s lymphoma ascites (DLA) cells showed a concentration-dependent reduction in cell viability, indicating preliminary cytotoxic potential. Electrochemical analysis revealed a glucose detection limit of 15 mM, indicating preliminary glucose-responsive behavior rather than a fully optimized biosensing platform. Furthermore, environmental toxicity assessment using the Allium cepa assay indicated minimal genotoxic effects at the tested concentrations, highlighting the relative biocompatibility of the synthesized nanoparticles. Overall, this study demonstrates that L. tristis -mediated ZnO nanoparticles possess multifunctional biological activities, including antioxidant, antibacterial, and cytotoxic properties, while also exhibiting preliminary electrochemical responsiveness. These findings highlight the potential of insect-derived biomolecules in sustainable nanomaterial synthesis and provide a foundation for future optimization toward biomedical and environmental applications.