Design of biocompatible nanoformulation of dimethoate for pest control in the field condition

Abstract

The design of a dimethoate nanoformulation was carried out using biocompatible materials in order to reduce the risks associated with its traditional formulation. The optimal copolymers, developed in this study for encapsulating dimethoate, were synthesized using a polycondensation approach and the following precursors: Glycerol (Gly), Adipic acid (Ad), Maleic anhydride acid (Ma), and Polyethylene glycol (PEG) 1000. ZnO nanoparticles (ZnO-NPs) were synthesized through a chemical precipitation method and coupled with the aforementioned copolymers to introduce photodegradable properties. Nanocapsules containing dimethoate were characterized using spectroscopy, microscopy, and thermal analyses. TEM images after 50 days of synthesis confirmed the average particle sizes of 50 nm, 60 nm, 80 nm, and 100 nm for the Gly-Ad-Ma/DiM (Nano-DiM I), Gly-Ad-Ma-ZnO/DiM (Nano-DiM I/ZnO), Gly-Ad-Ma-PEG/DiM (Nano-DiM II), and Gly-Ad-Ma-PEG-ZnO (Nano-DiM II/ZnO) formulations, respectively. The results revealed that the loading capacity of dimethoate in the studied nanoformulations ranged from 60 to 80% and was dependent on pH. The formulations containing ZnO nanoparticles exhibited the lowest rate of release. Results of bioassay tests demonstrated that the use of nanoformulations (7%), in contrast to traditional formulation (EC, 40%), led to an increase in the rate of pest control over time. Notably, formulations containing ZnO nanoparticles exhibited the highest efficiency compared to other formulations. Using EC formulations leads to the direct leaching and leakage of a significant amount of solvent and active ingredient into the environment. Therefore, optimizing the formulation of dimethoate by preparing a water-based, pH-sensitive, and photodegradable nanoformulation can serve as a viable solution to mitigate these risks.