Enzyme- and GSH-responsive gelatin coated magnetic multi-shell hollow mesoporous organosilicon nanoparticles for avermectin controlled-release

To enhance the utilization of pesticides and reduce environmental risks, we constructed the magnetic recyclable and dual stimulus-responsive nanoparticles to achieve on-demand pesticide release. Magnetic multi-shell hollow mesoporous organosilicon nanoparticles (mMSN) were prepared by one-step hydrothermal method and loaded with pesticide avermectin (A@mMSN), afterwards A@mMSN were coated with gelatin through emulsification and chemical cross-linking to prepare A@mMSN@G microspheres (21.5 ± 9.7 µm). After being absorbed by the pests, the gelatin layer was hydrolyzed with the neutral protease, and the disulfide bonds within mMSN framework were decomposed by glutathione (GSH), endowing A@mMSN@G microspheres with enzyme and GSH responsiveness to achieve sustained avermectin release till 7 days (about 3.5 times that of the commercial avermectin emulsion). Importantly, the A@mMSN@G microspheres containing Fe₃O₄ nanoparticles could be easily magnetically collected from soil with a recovery rate of 41.7%, to reduce the environmental risks. With excellent biosafety, A@mMSN@G microspheres showed outstanding pest control effects till two weeks and the growth of cabbage was not affected by it. Therefore, based on the recyclability and dual stimulus-responsive controllable release, the fabricated A@mMSN@G microspheres have broad application potential in pesticide delivery.