Smart dual-responsive Pickering emulsions engineered from functionalized cellulose nanocrystals: Enhanced targeted...

This study designed a novel environmentally responsive pesticide delivery system based on Pickering emulsion technology to improve pesticide utilization efficiency and achieve precise application. Specifically, pH/temperature dual-responsive nanoparticles CNC-P(NVCL-b-MAA-b-RG) (abbreviated as CNC/PNMR) were successfully prepared by grafting copolymerization on cellulose nanocrystal (CNC) surfaces via reversible addition-fragmentation chain transfer (RAFT) polymerization using N-vinylcaprolactam (NVCL), methacrylic acid (MAA), and self-assembling monomer (RG) as functional monomers, which were then employed to stabilize O/W Pickering emulsions. The emulsion exhibited reversible emulsification-demulsification switching under pH/temperature stimuli and maintained excellent re-emulsification capability even after multiple cycles. When abamectin (AVM) was encapsulated in the CNC/PNMR Pickering emulsion, the resulting AVM@CNC/PNMR-PE delivery system demonstrated a high pesticide encapsulation efficiency (82.61 %). Release kinetics studies revealed that this system exhibited excellent stimuli-responsive release behavior, with faster drug release rates under weakly alkaline (pH = 9) and elevated temperature (T = 40 °C) conditions. Compared with AVM technical, this system achieved a 2.09-fold enhancement in UV-shielding efficiency, effectively improving the photostability of the pesticide. Furthermore, in vivo bioactivity assays demonstrated that this system possessed excellent insecticidal activity against target pests. Therefore, the dual-stimuli-responsive Pickering emulsion delivery system based on CNC/PNMR nanoparticles showed great potential for achieving on-demand and targeted pesticide delivery.