Dual stimuli-responsive carriers based on pectin-coated organosilica nanoparticles for improved in planta...

The inefficient delivery of pesticides causes unpleasant side effects on the ecological environment. Stimuli-responsive controlled release formulations offer a promising avenue for increasing delivery to specific locations on demand. However, designing platforms that achieve efficiency, sustainability, and biocompatibility simultaneously remains a considerable challenge. Here, high-purity organosilica nanoparticles (OSiNPs) are extracted from rice husk biomass and engineered into nanocapsules with an average diameter of 42.59 nm by coating them with a pectin shell (Lam@OSiNP-Pec), which serves as a gatekeeper to regulate release. The platform has a high loading content of lambda-cyhalothrin (Lam) at 22.67% (w/w). Lam release is dual-responsive, triggered by pH changes and pectinase activity. Confocal microscopy demonstrates the translocation of fluorescein isothiocyanate-labeled OSiNPs within coconut palm tissues. The distribution profile of Lam@OSiNP-Pec in plants achieves markedly higher uptake, enhanced translocation, prolonged persistence, and superior insecticidal activity against the red palm weevil (Rhynchophorus ferrugineus). Following trunk injection, Lam@OSiNP-Pec induces 96.7% larval mortality at 25 cm and 90% at 100 cm from the injection site within seven days, whereas the conventional formulation achieves only 50% and 16.7% mortality, respectively. These findings demonstrate that pectin-coated, rice-husk-derived OSiNPs provide an efficient, targeted, and environmentally sustainable nanoplatform for precision pest management in agriculture.