pH-responsive poly(acrylic acid) coated mesoporous silica nanoparticles for controlled abamectin release: Synthesis, characterization, and agricultural application

Background

Smart pesticides, capable of responding to environmental stimuli, hold promise for achieving precise and on-demand release of pesticides, thereby reducing environmental risks and optimizing pesticide utilization.

Methods

Herein, we prepared a novel composite nanoparticle with a core-shell structure of poly(acrylic acid)-coated mesoporous silica by distillation precipitation polymerization method, which is simple and efficient. Then, abamectin was successfully loaded by impregnation adsorption, and a novel pH-responsive controlled-release pesticide formulation, Abamectin-MSN@PAA, was prepared.

Significant

Findings In this work, Abamectin-MSN@PAA exhibited a loading content of 23.79 % and an average particle size of approximately 272.1 nm. Notably, the formulation demonstrated acid-responsive release kinetics, with cumulative release percentages of 85.91 %, 69.03 %, and 53.44 % observed at pH values of 5, 7, and 9, respectively, after 96 h. Moreover, Abamectin-MSN@PAA effectively preserved abamectin from degradation under UV light exposure. In comparison with abamectin suspension, Abamectin-MSN@PAA exhibited superior adhesion to radish leaves and demonstrated increased aphid mortality in bioassay experiments. Following 7 days of drug spraying, the aphid survival rate was 26.67 % for Abamectin (40 mg L⁻¹) and only 18.3 % for Abamectin-MSN@PAA (40 mg L⁻¹). These findings underscore the potential of pH-responsive poly(acrylic acid)-coated mesoporous silica nanoparticles as a versatile platform for controlled pesticide delivery, thereby enhancing pesticide bioavailability and efficacy in agriculture.