Green synthesis of ZnOCuO nanocomposites for dengue vector control and antibacterial applications

Mosquito-borne diseases, particularly dengue fever, pose a significant global health challenge, with Aedes aegypti serving as a primary vector. Conventional chemical insecticides have led to the emergence of resistance in mosquito populations, necessitating the development of sustainable and effective alternative control measures. In this study, biogenic zinc oxide (ZnO) - copper oxide (CuO) nanocomposite was synthesized using Aegle marmelos aqueous leaf extract (Am-NCs) and evaluated for its dual-action: larvicidal efficacy and resistance management potential against Ae. aegypti. The novelty of this research lies in the synergistic combination of ZnO and CuO nanoparticles, which exhibit enhanced toxicity through oxidative stress induction and enzymatic pathway interference. Characterization of the Am-NCs was carried out with advanced technical instrumentations, which confirmed the structural integrity, crystalline nature and nanoscale morphology of nanocomposites (NCs). The synthesized Am-NCs demonstrated significant larvicidal activity, achieving an LC₅₀ value of 5.429 µg/mL in IV-instar larvae and 5.695 µg/mL against pupae. The biochemical assays revealed substantial inhibition of key detoxification enzymes, including acetylcholinesterase (AChE), α-carboxylesterase, and β-carboxylesterase, exhibiting its potential for mitigating insecticide resistance. Histopathological analysis further confirmed severe neurotoxicity and midgut disruption in treated larvae, revealing the mode of action of Am-NCs. Additionally, Am-NCs exhibited effective antibacterial activity against Staphylococcus aureus and Escherichia coli, demonstrating their broad-spectrum efficacy. The present study showed inhibitory effects of Am-NCs on mosquito resistance-associated enzymes, offering a promising biopesticide alternative for integrated vector management strategies.