Eco-friendly-synthesized chitosan-zinc oxide-selenium nanocomposites: characterization and insecticidal activity

In this work, the chitosan-zinc oxide-selenium nanocomposites (Ch-ZnO-Se NCs) were prepared in an affordable and eco-friendly way. Throughout the synthesis stage, chitosan served as reducing and stabilising agent. Different analytical techniques were employed to characterize the resulting nanocomposites. The findings demonstrated that irregular spherical-nanoparticles with a mean diameter of 73.95 nm were the predominant feature of the generated Ch-ZnO-Se NCs. The present study demonstrates that the mosquito vector Culex pipiens exhibit larvicidal and adulticidal effects upon exposure to the generated Ch-ZnO-Se NCs. The 23.308, 57.167 μg/ml and 30.632, 52.063 μg/ml were the recorded LC₅₀ and LC₉₀ values, respectively. Adult mortality reached 97.33% at the same dose, whereas the maximum larval mortality reached 100% at 60 μg/ml. As applied doses rose, the glutathione S-transferase (GST) enzyme increased but the acetylcholinesterase (AChE) enzyme declined. Molecular docking studies were conducted on concentrations of Ch-ZnO-Se NCs against acetylcholinesterase (AChE, PDB: 5x61) and glutathione S-transferase (GST, PDB: 1pn9) using MOE 2015. Concentrations (10, 20, 30, 40, 50, and 60 μg/ml) of Ch-ZnO-Se NCs exhibited stronger binding affinities than the controls, with 40 μg/ml showing the highest interaction (- 8.4233 kcal/mol) for AChE and 30 μg/ml (- 6.6624 kcal/mol) for GST. The results align with in-vitro assays, suggesting these compounds as potential inhibitors.