Pest Invasion-Responsive Hollow Mesoporous Silica-Linked Carboxymethyl Starch Nanoparticles for Smart Abamectin Delivery

Interactive release formulations are one of the best strategies for enhancing pesticides usage. A 112 nm α-amylase enzyme-responsive nanosystem loaded with abamectin (ABM) was synthesized by attaching carboxymethyl starch (CMS) to the surface of hollow mesoporous silica (HMS) to improve ABM insecticidal activity and photostability. ABM-loaded HMS–CMS characteristics were tested. ABM release behavior under different pH levels and in the presence or absence of α-amylase enzyme was investigated. The ultraviolet (UV) protection ability and the insecticidal activity against one of the model insects, Spodoptera littoralis, were examined. The adhesion properties of ABM-loaded HMS–CMS on corn leaves have been tested. The prepared ABM-loaded HMS–CMS presented a high loading efficacy of up to 24.77% and enzymatic release dependency of up to 88.34% after 17 days of adding α-amylase enzyme. After 60 h of UV radiation, only 17.7% of the loaded ABM into HMS–CMS has deteriorated. ABM-loaded HMS–CMS showed better insecticidal activity against S. littoralis than abamectin commercial formulation (ABM-EC). After 14 days, the LC50 of ABM-loaded HMS–CMS was 51.7% lower than that of ABM-EC. The prepared ABM-loaded HMS–CMS showed excellent adhesion on corn leaves. We recommend using such formulations to achieve better and sustainable farming.