Laccase-Responsive Biobased Nanocarriers from Lignin/Chitosan for Enhanced Foliar Adhesion and Targeted Pesticide Delivery

The inefficient use of conventional pesticides leads to substantial resource waste and poses serious risks to the environment and human health. To address this challenge, we developed a biobased, laccase-responsive nanodelivery system by fabricating pyraclostrobin (Pyr)-loaded lignin nanoparticles (Pyr@LNPs) through self-assembly followed by coating with chitosan (CS) to form Pyr@CS/LNPs. This water-based formulation, free of harmful solvents, demonstrated a high pesticide loading capacity (LC) of 46.66%. Compared to a commercial Pyr suspension concentrate (Pyr SC), Pyr@CS/LNPs significantly enhanced the photostability of Pyr, with a half-life under UV irradiation 2.65-fold longer. Under laccase stimulation simulating Botrytis cinerea (B. cinerea) infection, Pyr@CS/LNPs enabled rapid Pyr release. Additionally, Pyr@CS/LNPs exhibited superior retention and adhesion performance on strawberry leaves, with foliar retention being 3.15 times that of Pyr SC after simulated rain washout. Bioassays confirmed enhanced control efficacy against B. cinerea and bidirectional translocation in strawberry plants. Biosafety evaluations revealed that Pyr@CS/LNPs reduced acute toxicity to earthworms by 3.04-fold compared to Pyr SC and had no adverse effects on strawberry growth. Collectively, this work establishes an eco-friendly and sustainable nanoplatform for precision agrochemical delivery, offering a promising solution for advancing green agricultural technologies.