PH/redox/α-amylase triple responsive metal-organic framework composites for pest management and plant growth promotion

Abstract

The development of stimuli-responsive controlled release formulations is a promising strategy to enhance the utilization efficiency and reduce the environmental pollution of pesticides. In this work, a smart pH/redox/α-amylase triple stimuli-responsive pesticide delivery system was constructed by bonding carboxymethyl starch (CMS) with metal-organic frameworks (MIL-101(Fe)–NH2 nanoparticles) which loaded with CAR (CAR@MIL-101(Fe)-CMS nanoparticles). The results indicated that the loading capacity of CAR@MIL-101(Fe)-CMS nanoparticles for CAR was approximately 18.3% and the CMS attached on the surface of CAR@MIL-101(Fe)–NH2 nanoparticles could protect CAR from photolysis effectively. Meanwhile, the coated CMS and metal-organic framework structure of the nanoparticles could be decomposed and consequently release pesticide active ingredients on demand when CAR@MIL-101(Fe)-CMS nanoparticles were metabolized by glutathione and α-amylase in the insect alkaline midgut. The bioactivity survey confirmed that CAR@MIL-101(Fe)-CMS nanoparticles had a longer duration in controlling Spodoptera frugiperda larvae compared to CAR suspension concentrate. In addition, the MIL-101(Fe)-CMS nanocarriers were safe for the growth of maize and could be used as fertilizer to promote the growth and development of crops. Thus, this smart stimuli-responsive pesticide-fertilizer all-in-one combination strategy has great potential in pest management.