One-Step Construct Responsive Lignin/Polysaccharide/Fe Nano Loading System Driven by Digestive Enzymes of Lepidopteran for Precise Delivery of Pesticides.

Abstract

A strategy that relies on the differences in feeding behavior between pests and natural enemies to deliver insecticides precisely was proposed. After proving that the digestive enzymes in Lepidopteran pests can act as triggers for lignin-based controlled-release carriers, a novel multiple-enzyme-responsive lignin/polysaccharide/Fe nanocarrier was constructed by combining the electrostatic self-assembly and chelation and loaded with lambda-cyhalothrin (LC) to form a nanocapsule suspension loading system. The nanocapsules were LC@sodium lignosulfonate/chitosan/Fe (LC@SL/CS/Fe) and LC@sodium lignosulfonate/alkyl polyglycoside quaternary ammonium salt/Fe (LC@SL/APQAS/Fe). LC@SL/APQAS/Fe was more stable than LC@SL/CS/Fe because it adsorbs more Fe3+, and the half-lives of LC in LC@SL/APQAS/Fe under UV irradiation were prolonged at 4.02- and 6.03-folds than those of LC@SL/CS/Fe and LC emulsifiable concentrate (LC EC), respectively. Both LC@SL/APQAS/Fe and LC@SL/CS/Fe have responsive release functions to laccase and cellulase, and the release rate of the former was slower. The insecticidal activity of LC@SL/APQAS/Fe against Agrotis ipsilonis was similar to those of LC@SL/CS/Fe and LC EC, while the toxicity of LC@SL/APQAS/Fe to the natural enemy was 2-3 times less than those of LC@SL/CS/Fe and LC EC. Meanwhile, the organic solvent component in the nanocapsule suspension was 94% less than that in the EC preparation. Therefore, the nano loading system based on SL/APQAS/Fe is a promising nanoplatform with the advantages of high efficiency, low toxicity, and environmental friendliness.