High-performance delivery capsules co-assembled from lignin and chitosan with avermectin for sustainable pest management.

Inexpensive biomass materials hold great potential for the development of green delivery systems aimed at improving the extremely low utilization efficiency of pesticides. However, current systems face challenges in achieving both high encapsulation rates and drug loading capacities. This study introduces a novel method using chitosan (CS) and sodium lignosulfonate (SL) to co-assemble with avermectin (AVM), a widely used hydrophobic pesticide, forming AVM-CS-SL micro-nano capsules. Engineered under optimized conditions of pH 5 and 40 °C, the capsules exhibit an AVM encapsulation efficiency of 84.27 % and a loading capacity of 90 %. The AVM-CS-SL capsules demonstrate multifunctional attributes that enhance pesticide application. The capsules, with an average diameter of 356 nm, facilitate stable embedding in leaf grooves and enable effective adhesion to leaf surfaces, thereby improving their resistance to wash-off by rain compared to conventional formulations. Their core-shell structure protects AVM from photodegradation, ensuring long-term stability and efficacy. The capsules also exhibit enhanced bioactivity, with higher mortality rates in Plutella xylostella larvae and low genotoxicity to Vicia faba plants. These findings highlight the strategy of developing multifunctional delivery systems by the co-assembled carrier materials with active ingredients, offering an effective solution for the sustainable development of society and environment.