A Star Polycation Acts as a Drug Nanocarrier to Improve the Toxicity and Persistence of Botanical Pesticides

The excessive use of chemical pesticides brings many environmental problems. Botanical pesticides seem to be a good alternative to control pests, but their slow action and lack of residual action constrain their further application. Here, we developed a star polycation (SPc) as the drug nanocarrier that could combine matrine into a complex to decrease its particle size to the nanoscale. The combination of SPc and matrine increased the zeta potential and the noncovalent molecular interaction, such as hydrogen bonds and hydrophobic interactions playing an important role in the complex formation. The nanosized matrine/SPc complex exhibited a higher cytotoxicity and an enhanced lethal effect on insect pests compared to those of matrine alone. As a botanical pesticide adjuvant, the SPc could increase the control efficacies of matrine, d-limonene, and pyrethrin against insect pests, achieving a great improvement in toxicity and persistence. The construction of SPc provides a powerful tool for delivering pesticides to increase their control efficacies and decrease their application amounts and rates, showing great potential for sustainable pest management.