Synthesis of a Reactive Oxygen Species Responsive Star Polymer for the Controlled Release of Carbendazim

An intelligent responsive pesticide delivery system has been applied in agriculture to improve the utilization rate of pesticides. When plants are affected by fungi, a large number of reactive oxygen species (ROS) are produced rapidly on the wound surface. Based on this, a ROS responsive star polymer micellar slow-release system was constructed to load carbendazim (MBC) and improve its bioavailability. The star polymer was synthesized by using 3-mercaptopropionic acid, acetone, pentaerythritol (PER), ε-caprolactone (ε-CL), and methoxypolyethylene glycols (mPEG5000, Mw = 5000) and named PER-PCL-TK-mPEG5000. By loading MBC, the drug loading micelle MBC-loaded PER-PCL-TK-mPEG5000 was obtained. The cumulative release amount of MBC-loaded PER-PCL-TK-mPEG5000 containing H2O2 is 1.64 times of that without H2O2 after 120 h release. The inhibitory rate of MBC-loaded PER-PCL-TK-mPEG5000 containing H2O2 against Rhizoctonia solani (R. solani) was 91.6%. The critical micelle concentration (CMC) of PER-PCL-TK-mPEG5000 is 4.37 mg/L, and the result showed that PER-PCL-TK-mPEG5000 and MBC-loaded PER-PCL-TK-mPEG5000 have good stability at 4 °C for 14 d. This study proved that the strategy of designing pesticide vectors according to the target environment can be widely used to protect crops, improve pesticide utilization rate, and protect the environment.