Effect of Polymer Concentration and Surface Charge on Controllable Nanopesticides Delivery

The efficacy of polymer-based nanopesticides (NPs) is strongly governed by carrier concentration and surface charge, which affect shell thickness, drug release kinetics, and photostability. However, the influence of these two factors in pesticide release and delivery performance remains unclear. This study introduces a NIR-II fluorescence dye-tracing strategy to enable high-resolution monitoring of NP behavior in model plants. By systematically varying polymer concentration and copolymer blocks, we investigate their impact on release behavior, photostability, and stem uptake. As the polymer concentration increased, NPs demonstrated a controlled slow release and better photostability, yet a lower pesticide loading capability. In model plants, PISNPs transport quickly and can accumulate at wound sites, effectively offering antifungal properties. This work provides experimental evidence for optimizing polymer carrier design to achieve efficient, controlled release while minimizing photodegradation risks, offering practical guidelines for developing high-performance, low-risk nanopesticide formulations.