Carboxymethyl chitosan-encapsulated sulfur-functionalized cubic silica: enhanced leaf adhesion and stimuli-responsive pesticide delivery

Smart controlled-release nanopesticide systems offer enhanced pesticide efficiency through targeted delivery. In this study, we prepared sulfur-containing square mesoporous silica (S-MSN) carriers, combined them with carboxymethyl chitosan (CCS) to build a dual-responsive pesticide delivery platform (DNF@S-MSN@CCS) for sustained pesticide release. The S-MSN carriers demonstrated a high drug loading capacity of 21.3 %, excellent biocompatibility, responsive degradation and improved pesticide retention on hydrophobic leaves. Compared with spherical carriers, the cubic drug-loaded system shows a 33 % improvement in resistance to rain wash and a 38.8 % increase in liquid-holding capacity. Superior foliar adhesion and UV-shielding properties reduced photodegradation, extending DNF's UV half-life 6-fold compared to pure dinotefuran (DNF). Bioassays showed equivalent mortality against Plutella xylostella larvae as conventional formulations at reduced dosages. This work presents an effective strategy for sustainable pest management.