Dual-Responsive Diatomite Microcarriers for Biocompatible Targeted Delivery of Emamectin Benzoate Against Plutella...

Agricultural sustainability is significantly threatened by pesticide residues. Carrier-mediated delivery technology promising as versatile tool enhances pesticide delivery efficiency, reduces pesticide residues and biological toxicity. However, conventional carriers often penetrate crop tissues and are not directly ingested by pests, thereby posing potential risks to food security. In this study, a multi-functionalized diatomite-based microcarrier was developed, which improved delivery accuracy to midgut of pests and reduce biological toxicity of pesticides for management of Plutella xylostella. The microcarriers can load emamectin benzoate with loading efficiency of 17.2% (w/w) and functionalize with capping materials (β-cyclodextrin and tannic acid-iron), which exhibit dual-responsive properties to alkalinity and α-Amylase. After 72 h of stimulation, the loaded pesticide can be released with a release rate of 70%, and this release process follows first-order release kinetics. Owing to micro-size and functionalization, the dual-responsive microcarriers were ingested by Plutella xylostella on the leaves of Brassica oleracea var. capitata L., responding to the midgut condition (alkalinity and α-Amylase) with a LC₅₀ value of 17.4 mg L^-1. Zebrafish experiments indicated that the microcarriers are biocompatible and reduce biotoxicity of loading emamectin benzoate by 20 times. This microcarrier approaches offer an efficient delivery strategy and improve integrated pest management for agricultural sustainability.