Molecular recognition-driven engineering of electrospun cyclodextrin nanofibers: Pesticide structure modulates sustained release and mechanism

Conventional pesticides are often plagued by poor controlled-release performance, hydrophobic nature, posing risks to nontarget organisms. The development of nano-delivery carriers with hydrophilicity on crop surfaces and sustained-release function within crops remains challenging. Inspired by host-guest recognition in supramolecular chemistry, we developed a molecular recognition-driven engineering strategy that exploits the pesticide structure to modulate its release performance and mechanism. The two structurally distinct fungicides azoxystrobin (AZO) and dimethomorph (DIM) as guests were encapsulated in methylated β -cyclodextrin cavity (M β CD) towards preparing nanofibers using electrospinning techniques to target crop diseases. SEM, Zeta potential, molecular simulations, DFT calculations, release kinetics and mechanism collectively confirmed that pesticide structure affected the host-guest inclusion behavior, nanofiber morphology, and ultimately the sustained-release feature. Both pesticide/M β CD inclusion complex nanofiber (pesticide/M β CD-IF) displayed highly water-soluble and good antifungal efficacy against Rhizoctonia solani and Haematonectria haematococca relative to the corresponding free pesticides. The LC 50 value of DIM/M β CD-IF was higher than that of DIM SC, indicating improved safety for soil nontarget organisms. This study presents a pesticide architecture-centered paradigm for nanofiber design, aiming to provide a feasible method for sustainable crop protection. Download: Download high-res image (194KB) Download: Download full-size image