Iron-based porous metal-organic frameworks with crop nutritional function as carriers for controlled fungicide release

Abstract

Metal-organic frameworks (MOFs) are an emerging class of hybrid inorganic-organic porous materials used in various fields. Considering their excellent performance, MOFs have a considerable application potential in sustainable agriculture. Research projects of MOFs-based platforms for plant protection and nutrition have just started. Environmental stimuli-responsive pesticide release is highly desirable for improved efficacy and decreased side effects. Iron-based MOFs (Fe-MOFs) have a considerable prospect in agriculture as multifunctional materials both for pesticide delivery and plant nutrient replenishment because iron is an essential micronutrient for crop growth. In this work, a simple octahedral Fe-MOFs built from trimers of iron octahedra linked by 1, 3, 5-benzenetricarboxylate (Fe-MIL-100) have been prepared as carriers for fungicide azoxystrobin. Due to the high surface area of 2251 m²/g, the loading content of azoxystrobin into Fe-MIL-100 is satisfactory up to 16.2%. Azoxystrobin-loaded Fe-MOFs (AZOX@Fe-MIL-100) exhibit a pH-responsive initial burst and a subsequent sustained release pattern. Moreover, AZOX@Fe-MIL-100 exhibits good fungicidal activities against two pathogenic fungi-wheat head scab (Fusarium graminearum) and tomato late blight (Phytophthora infestans). The nutritional function of Fe-MIL-100 as iron micronutrient for the enhanced wheat growth was also observed. This research explores the feasibility of MOFs as a platform for potential application in sustainable plant protection.

Keywords: Controlled release; Fungicidal activity; Metal–organic framework; Micronutrient; Pesticide.