Preparation and characterization of enzyme-responsive emamectin benzoate microcapsules based on a copolymer matrix of silica-epichlorohydrin-carboxymethylcellulose

Controlled release formulations of pesticides is highly desirable for maximising the utilization of the pesticide, as well as remarkably reducing environmental pollution. A stimuli-responsive controlled release formulation can intelligently respond to the stimuli produced by pests and trigger the release of the active ingredients to control pests effectively. In this work, a novel enzyme-responsive emamectin benzoate microcapsule was prepared using silica cross-linked with carboxymethylcellulose using epichlorohydrin. The results showed that the obtained microcapsules had a remarkable loading ability for emamectin benzoate (about 35% w/w) and could protect emamectin benzoate against photo-and thermal degradation effectively. The silica-epichlorohydrin-carboxymethylcellulose microcapsules displayed excellent cellulase stimuli-responsive properties and a sustained insecticidal efficacy against Myzus persicae. Allium cepa chromosome aberration assays demonstrated that the microcapsules had less genotoxicity than the technical grade emamectin benzoate (referred to throughout the manuscript as the technical). Given these advantages, the enzyme-responsive emamectin benzoate microcapsules are worth extending as a novel safe strategy for sustainable crop protection.