Linear Supramolecular Block Copolymer Micelles for ROS-Responsive Release of Antimicrobial Pesticides

After cotton is invaded by cotton aphids and other pests,the functionof its defense system decreases, and it is more vulnerable to infectionby bacteria. When plants are invaded by external bacteria, they quicklyproduce reactive oxygen species (ROS). In this paper, ROS-responsivepesticide release carrier materials are designed and prepared forsolving bacterial infections in plants by ring-opening polymerizationof & epsilon;-caprolactone (& epsilon;-CL) and & beta;-cyclodextrin (& beta;-CD)to obtain a hydrophobic guest (& beta;-CD-PCL). Thioketal (TK) wasmodified by adamantane (Ad) and poly(ethylene glycol) monomethyl ether(mPEG(5000)-OH) to form a hydrophilic guest(mPEG(5000)-TK-Ad). & beta;-CD-PCL and mPEG(5000)-TK-Ad interact with each other to forman amphiphilic polymer (mPEG(5000)-TK-Ad@& beta;-CD-PCL),which is loaded with carbendazim (MBC) by self-assembly (MBC-mPEG(5000)-TK-Ad@& beta;-CD-PCL). The polymer hadROS response characteristics, and the release rate of C increasedfrom 30 to 57% after 120 h of ROS stimulation. The inhibition rateof Rhizoctonia S. was 92.23% when the effective concentrationof MBC was 30 mg/L. The critical micelle concentration (CMC) of thepolymer is 8.30 mg/L, and the micelle had storage stability for atleast 14 days, showing good storage stability. Therefore, this ROS-responsivepolymer carrier has great potential as a carrier for antimicrobialpesticides.