Hydrophilic and lipophilic diblock polymer-based nanoplatform improves the bioactivity of insect growth regulator via inhibiting chitin synthesis

Insect growth regulators (IGRs) have shown great potential in green pest management, but their low control efficacy and delayed action limit their widespread application. In recent years, various nanodelivery systems have revolutionized pesticides by enhancing bioavailability, reducing dosage requirements, improving environmental compatibility, etc. Herein, a hydrophilic and lipophilic diblock polymer (HLDP) was designed and developed to construct an efficient nanoplatform for an IGR diflubenzuron (DFB). The HLDP could spontaneously assemble with DFB into DFB/HLDP complex via electrostatic interactions, and this self-assembly formed uniformly sized spherical nanoparticles (136.06 nm), with the substantial increase in zeta potential (48.27 mV). Compared to DFB alone, the DFB/HLDP complex exhibited remarkably higher stomach and contact toxicity against a major migratory pest oriental armyworm. RNA-seq analysis revealed that the oral feeding of DFB/HLDP complex upregulated several crucial genes involved in metabolism, delivery and chitin synthesis. Meanwhile, the DFB/HLDP complex could further decrease the chitin content and ATP level, which amplified the inhibitory effects of DFB on chitin biosynthesis. Overall, our study successfully constructed a HLDP-based nanodelivery system for IGRs, which offered an innovative and sustainable strategy for green pest management.