Dialdehyde carboxymethyl cellulose-zein conjugate as water-based nanocarrier for improving the efficacy of pesticides

Abstract

In order to increase insecticidal activity by generating zein nanoparticles, zein was modified by dialdehyde carboxymethyl cellulose (DCMC), making a conjugate (Z-DCMC) that is more hydrophilic than zein. The conjugate was used as a water-based nanocarrier for pesticides. Specifically, in this study the model drug avermectin (AVM) was encapsulated though hydrophobic interactions with the conjugate. The oxidation of carboxymethyl cellulose to form DCMC, and the reaction between zein and DCMC were confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis, and SDS-PAGE. Scanning electron microscopy and dynamic light scattering showed that the drug-loaded nanoparticles have an average particle size of 68 nm. The release of AVM was found to be responsive to pH, with the release rate in neutral conditions being faster than in acidic or alkaline conditions. AVM encapsulated in Z-DCMC (Z-DCMC@AVM) exhibits higher wettability, with leaf retention increasing from 11.44 to 16.15 mg/cm2 compared to non-encapsulated AVM. Z-DCMC protects AVM from UV light, with 81.23 % of the encapsulated AVM remaining intact after exposure to UV for 195 min, compared to less than 20 % for the bare AVM. More importantly, Z-DCMC@AVM enhances the insecticidal activity, with the LC50 decreasing from 199.89–106.41 mg/L after encapsulation.