Salicylaldehyde and D-(+)-galactose functionalized chitosan oligosaccharide nanoparticles as carriers for sustained release of pesticide with enhanced UV stability

Sustainable food consumption is intertwined with sustainable agriculture development, which focuses on the production and protection of agricultural crops in a safe and effective fashion. Herein, amphiphilic functionalized chitosan oligosaccharide nanoparticles (CSD) were formed by a Schiff base reaction grafted with salicylaldehyde and D-(+)-galactose (D-Gal). Avermectin (AVM) was used as a model pesticide and self-assembled onto CSD to obtain AVM@CSD nanoparticles with an encapsulation efficiency of 74.94%. AVM@CSD nanocarrier exhibited excellent anti-UV property to retain more AVM, due to their Schiff base structure and salicylaldehyde for UV shielding. Compared with bare AVM and commercial AVM emulsifiable concentrates, AVM@CSD preserved high insecticidal activity after UV irradiation. Additionally, CSD carrier promoted cucumber seed germination and seedling growth. These data suggested the potential utilization of the amphiphilic chitosan oligosaccharide as carriers for pesticides to improve their delivery and release properties and opens a novel avenue towards the application of water-dispersible and biological CSD in the field of pest management and plant growth.