Construction of on-demand lignin-based nano-delivery system via microfluidic technology: Enabling low-cost transportation and storage of pesticide formulations.

Nanopesticides represent a significant direction in the development of agricultural nanotechnology. The traditional solvent-antisolvent method is a classic preparation technique characterized by its simplicity and broad applicability. However, this approach suffers from low product concentration, high transportation costs, and poor stability of the resulting nanoparticles, which are prone to Ostwald ripening, thereby limiting their large-scale field application. In this study, we propose a novel "production-for-immediate-use" nanopesticide preparation technology based on a simplified microfluidic device. Using prometryn (PMT) as a model drug and leveraging the electrostatic-driven self-assembly between sodium lignosulfonate (SL) and cationic surfactants, drug-loaded nanospheres were continuously prepared in a single step within the microfluidic channel. The microfluidic process parameters and environmental conditions were systematically optimized to establish the optimal preparation protocol. The stability, adhesion, and sustained-release properties of the prepared nanopesticides were evaluated to identify the optimal cationic surfactant system. Petri-dish-based bioassays demonstrated that the selected nanoformulation exhibited herbicidal efficacy against barnyard grass comparable to that of the commercial formulation, while showing less inhibitory effect on the early-stage growth of corn seedlings relative to the commercial product, preliminarily suggesting its potential advantage in reducing phytotoxicity to non-target crops. The developed green, continuous, and integrated nanopesticide technology enhances stability and convenience while lowering costs, offering key insights for on-demand pesticide production and smart agricultural equipment advancement.