Targeted release mechanism of λ-cyhalothrin nanocapsules using dopamine-conjugated silica as carrier materials.

Based on the specific binding between the receptors and ligands, novel targeted nanocapsules were prepared by using silica covalently bonded with dopamine to increase the insecticidal efficacy of λ-cyhalothrin. The targeted release mechanism of λ-cyhalothrin nanocapsules (NC) nanocapsules was verified by enzymatic analysis, fluorescent marking method and high performance liquid chromatograph. The results showed NC had uniform particle size (800 nm) and approximately 31% (w/w) loading efficiency of λ-cyhalothrin. The stability of λ-cyhalothrin in nanocapsuels was improved under different pH and temperature conditions. The NC showed sustainable release properties and the release kinetics mainly belonged to Fickian diffusion at all experimental conditions. Compared to λ-cyhalothrin emulsifiable concentrate and microcapsule suspension, the NC exhibited more excellent insecticidal activity. The micronucleus test indicated that NC significantly reduced the genotoxicity of λ-cyhalothrin to non-target organisms. This work offers a novel and efficient way to use targeted drug delivery system to improve the insecticidal activity, and may be extended to other pesticides in the future.