Stimuli-responsive polymeric micelles based on cellulose derivative containing imine groups with improved bioavailability and reduced aquatic toxicity of pyraclostrobin

The low bioavailability of pesticides has resulted in serious resource waste, environmental pollution, and potential threats to human health. Polymeric micelles for the delivery of pesticides can obviously reduce the drift, and photolysis as well as the risks of poisoning during the application of pesticides. Herein, an amphiphilic polymer, octaneacylhydrazone propylcellulose pyruvate (OPP), was prepared by conjugating octanehydrazide with propylcellulose pyruvate and used as a micellar carrier to improve the utilization efficiency of pyraclostrobin (PYR). The results showed that OPP exhibited a lower critical micelle concentration (9.99 mg/L) than classical surfactant Tween. The prepared PYR-loaded OPP micelles (POM) exhibited excellent pH and cellulase dual responsive release properties with a pesticide loading rate of 8.94%, which could efficiently prevent PYR from photolysis to prolong the effective duration. The fungicidal activities of POM against Sclerotinia sclerotiorum and Botrytis cinerea were better than that of PYR in vitro and in vivo. Furthermore, the acute toxicity of POM to zebrafish was decreased more than eleven-fold compared with that of PYR technical. Therefore, the prepared POM with excellent fungicidal activities may be a potential alternative to conventional formulations of PYR, and OPP would be used as a promising polymeric carrier for the highly efficient delivery of pesticides.