Linear-dendritic copolymers/indoxacarb supramolecular systems: biodegradable and efficient nano-pesticides

Abstract

Photodegradable and biocompatible nano-indoxacarb was prepared successfully by encapsulation of indoxacarb with poly(citric acid)–poly(ethylene glycol)–poly(citric acid) (PCA–PEG–PCA) ABA type linear-dendritic copolymers both with (nano-IND/TiO₂) and without (nano-IND) TiO₂ nanoparticles via supramolecular interactions. Preparation of nano-indoxacarb by both formulae was confirmed using spectroscopy and microscopy analyses. TEM images showed small particles with average sizes of 10 nm for nano-IND and 12 nm for nano-IND/TiO₂. Interestingly, the rate of degradation of indoxacarb in both nano-IND/TiO₂ and nano-IND exposed to UV and natural light was higher than that for free indoxacarb in the presence of TiO₂ nanoparticles. Furthermore, results of bioassay experiments on the model pest showed that the essential dosage of pesticide for pest control significantly decreased when nano-IND and nano-IND/TiO₂ were used. Because of the higher loading capacity and slower release rate for indoxacarb from nano-IND than from nano-IND/TiO₂, and because TiO₂ nanoparticles show toxicity in bioassay experiments, nano-IND is introduced as a promising and eco-friendly pesticide system.