Development of Multifunctional Avermectin Poly(succinimide) Nanoparticles to Improve Bioactivity and Transportation in Rice

Avermectin (AVM) as a nonsystemic pesticide possesses a low effective utilization rate. Studies of the multifunctional pesticide delivery system for improving biological activity are developing prosperously. In this study, multifunctional avermectin/polysuccinimide with glycine methyl ester nanoparticles (AVM-PGA) were prepared by the self-assembly process. The AVM loading capacity was up to 23.7%. After 24 h of UV irradiation, there was still about 70% of AVM remaining in PGA₄₂ nanocarriers, as opposed to less than 5% of the free-form AVM. The rising ambient pH promoted the release of AVM using an in vitro releasing test, revealing a favorable pH-responsively controlled-release property. The mortality rate of Plutella xylostella with 2.5 μg/mL of AVM content of AVM-PGA₄₂ was 96.3% after 48 h, while that of free AVM was only 51.5%. In addition, the AVM could be detected in stems and all leaves treated with AVM-PGA₄₂ nanoparticles, whereas rare AVM was detected only in treated leaves for the free-form AVM, which achieved the transportation of nanocarriers carrying AVM in rice for the first time. Furthermore, the PGA nanoparticles performed a good growth promoting effect on rice. These results show that the AVM-PGA₄₂ nanopesticides have a great potential application prospect to control the pest and improve the drug utilization efficiency on agriculture.