Facile, Smart, and Degradable Metal-Organic Framework Nanopesticides Gated with FeIII-Tannic Acid Networks in Response to Seven Biological and Environmental Stimuli

Nanopesticides were selected as one of the top 10 emerging technologies in chemistry that will change our world in 2019. Facile, smart, and degradable metal-organic framework MIL-101(Fe-III) nanopesticides gated with Fe-III-tannic acid (TA) networks are created using a universal strategy. The capping of the Fe-III-TA network gatekeepers is instinctively oriented by the coordinatively unsaturated FeIII sites on the surfaces of the MIL-101(Fe-III) nanocarriers; thus, their combination is perfectly matched. This is the first example that one smart gated nanoparticle is integrated with seven stimuli-responsive performances to meet the diverse controlled release of encapsulated cargos by the disassembly of the gatekeepers and/or the degradation of the nanocarriers. More importantly, each of the seven stimuli (acidic/alkaline pH, H2O2, glutathione, phosphates, ethylenediami-netetraacetate, and near-infrared light of sunlight) is closely related to the biological and natural environments of crops, and the biocompatible nanocarriers are eventually degraded against bioaccumulation even if the nanopesticides enter crops. These mechanisms of the stimuli-responsive controlled release are identified and clearly elaborated. It is found that the natural polyphenol can improve the wettability of aqueous droplets of nanopesticides on model hydrophobic foliage for pesticide adhesion and retention. The nanopesticides encapsulated with the fungicide tebuconazole show high fungicidal activities against pathogenic fungi Rhizoctonia solani (rice sheath blight) and Fusarium graminearum (wheat head blight); good safety on seed germination, seedling emergence, and plant height of wheat by seed dressing; and satisfactory control efficacy in wheat powdery mildew caused by Blumeria graminis in the greenhouse. The nanopesticides have potential applications in the field for high quality and yield of agricultural production.

Automated summary

Nanopesticides, selected as a top emerging technology in chemistry for 2019, are created with a facile, smart, and degradable metal-organic framework using a universal strategy. With seven stimuli-responsive performances, these nanopesticides can meet diverse controlled release needs for encapsulated cargos, potentially improving agricultural production quality and yield.