Co-assembled nano-herbicide of bentazone with a hydrophilic-lipophilic diblock polymer: Enhanced foliar delivery, synergistic herbicidal activity, and environmental safety

Although herbicides like bentazone (BTZ) remain indispensable for weed control, their practical application is severely constrained by poor foliar affinity and high groundwater leaching risks. While escalating dosages are often used to compensate for these losses, such practices frequently accelerate the evolution of weed resistance. To address these, a hydrophilic-lipophilic diblock polymer (HLDP) nanocarrier was co-assembled with BTZ to develop the high-loading nano-herbicide BTZ@HLDP. These results demonstrated that BTZ@HLDP was successfully constructed via hydrogen bonding and hydrophobic interactions, and its amphiphilic nature significantly reduced droplet surface tension and contact angle to facilitate robust foliar adhesion and enhance herbicidal activity without compromising environmental safety. Compared with BTZ, BTZ@HLDP more effectively disrupted photosynthetic electron transport at the photosystem II (QB) binding site, triggering massive reactive oxygen species (ROS) bursts and irreversible metabolic dysfunction. Furthermore, the nano-formulation displayed favorable biosafety toward non-target organisms, and its strong soil electrostatic complexation minimized vertical leaching risks with negligible impacts on the soil microbiome. This work applied HLDP to comprehensively enhance the performance of BTZ via multifaceted synergistic mechanisms, offering a feasible strategy to bridge the gap between theoretical nano-carrier design and practical weed management.