Multifunctional ?-Cyclodextrin-Based Metal-Organic Frameworks as Avermectins Carriers for Controlled Release and Enhanced Acaricidal Activity

A controlled pesticide delivery system has attracted considerable attention in recent years. Metal-organic frameworks (MOFs), which are one of the most rapidly developing porous materials, have been used as pesticide carriers. However, the inherent toxicity of reported metal nodes or the expensiveness of organic ligands is not desirable, which limits the practical application of such pesticide-loaded MOF delivery systems. gamma-Cyclodextrin-based MOFs (gamma-CD-MOFs) are considered as a green renewable framework material; however, it has been less exploited as a multifunctional pesticide carrier in agricultural applications. In this study, avermectins (AVM) were loaded into gamma-CD-MOFs (AVM-gamma-CD-MOFs) with a loading content of 20.41% by physical absorption. AVM-gamma-CD-MOFs exhibited pH-responsive release profiles and had better stability under photoirradiation. Moreover, it could promote the growth of cotton roots and stems, improve the chlorophyll content, and decrease malondialdehyde content to a certain extent by facilitating the activities of peroxidase. Compared with AVM technical concentrate wettable powder, the AVM-gamma- CD-MOF wettable powder exhibited a better acaricidal activity against Panonychus citri (McGregor). In short, this research explores the feasibility of gamma-CD-MOFs as a platform for potential application in sustainable plant protection.