Polydopamine-coated matchstick-like mesoporous silica carriers for improving foliar retention and responsive pesticide release

Intelligent responsive pesticide delivery systems have gained extensive interest in enhancing utilization efficiency of pesticides and relieving environmental hazards. Herein, we developed a novel matchstick-like mesoporous silica (mSiO 2 ) nanocarriers for pesticide delivery. The asymmetric matchstick-like mSiO 2 carriers were composed by a spherical dendritic silica (SiO 2 ) head (300 nm) and a rod-shaped tail (90 nm in length). This asymmetric structure would improve foliar retention by increasing contact area and forming topological effect between the carriers and the leaves surface. The prepared mSiO 2 carriers possessed a high loading content for the insecticide dinotefuran (DNF) (23.7 %). Subsequently, polydopamine (PDA) was utilized to seal the DNF-loaded mSiO 2 (DNF@mSiO 2 @PDA). The foliar affinity and adhesion properties of the mSiO 2 @PDA were enhanced due to the introduction of the hydrophilic PDA layer. The DNF@mSiO 2 @PDA exhibited pH-responsive release performance and the anti-UV property of loaded DNF was improved by about 10 times. Additionally, the DNF@mSiO 2 @PDA also exhibited high insecticidal activity due to the improving foliar wetting and affinity. Therefore, this work provides a promising strategy to increase pesticide retention on leaves and reduce pesticide chemical usage.