Dual stimuli-responsive fungicide carrier based on hollow mesoporous silica/hydroxypropyl cellulose hybrid nanoparticles

The controlled release of pesticides based on nanoparticle platforms has emerged as a new technology for increasing the efficiency of pesticides and for reducing environmental pollution because of their size-dependent and target-modifying properties. In the present study, pH/cellulase dual stimuli-responsive controlled-release formulations (PYR-HMS-HPC) were designed by grafting hydroxypropyl cellulose onto pyraclostrobin-loaded hollow mesoporous silica nanoparticles via an ester linkage. The PYR-HMS-HPC formulations were characterized by Fourier transform infrared spectroscopy, thermogravimetric analyzer, transmission electron microscope and scanning electron microscope. The results demonstrated that PYR-HMS-HPC with a loading capacity of 12.1 wt% showed excellent pyraclostrobin release behaviors in response to acidic environments and the introduction of cellulase, could effectively prevented pyraclostrobin from photolysis. Compared with commercial pyraclostrobin formulations, the PYR-HMS-HPC formulations showed much stronger and statistically significant fungicidal activity against Magnaporthe oryzae from 7 to 21 days. Furthermore, the Allium cepa chromosome aberration assay demonstrated that the PYR-HMS-HPC formulations reduced the genotoxicity of pyraclostrobin. These pH/cellulase dual stimuli-responsive controlled-release formulations are of great interest for sustainable on-demand crop disease protection.