Green Delivery System: Lignin-Derived Nanospheres Significantly Improve Azoxystrobin Foliar Retention and Fungicidal Efficiency

Traditional pesticides, owing to their large particle size and poor leaf adhesion, are unable to adhere effectively to plant leaves. This leads to waste and environmental pollution. To tackle this problem, we developed a nanocarrier system based on alkaline lignin (AL) and tea saponin (TS) (AZO@AT) to enable efficient loading and intelligent delivery of the fungicide azoxystrobin (AZO). This system enhances leaf surface deposition and adhesion, achieves controllable release, and lessens the environmental impact. Nanoparticles with an average size of 183.87 ± 1.52 nm were prepared via the hydrophobic self-assembly method. In these nanoparticles, AL-AZO serves as the core, and TS acts as the stable shell layer. Characterization verified high drug loading and temperature-responsive release. The leaf wettability test revealed that, in comparison with pure AZO, the contact angles of osmanthus leaves (8.41°) and ivy leaves (15.55°) were significantly decreased. Simulated rainfall experiments demonstrated that the nanoparticles exhibit strong adhesion on the leaf surface. Moreover, AZO@AT demonstrated synergistic effects, increasing UV shielding by 5.74 times and reducing zebrafish toxicity by 4.65 times. This research offers a novel approach for efficient and environmentally friendly pesticide delivery.