Bimetallic MOF-Based Hybrid Platform with Dual Stimuli-Responsiveness for Sustained Release and Enhanced Retention

Pesticide delivery carriers provide protection against pathogens but face significant challenges, including limited loading capacity, rapid release rates, and inconsistent performance. To address these issues, this study develops a dual-stimuli-responsive pesticide delivery carrier, featuring an iron-copper bimetal-organic framework (Fe-Cu MOF) supported on diatomaceous earth (DE) and coated with lauric acid (LA). Here, DE serves as a biocompatible scaffold, enhancing the adhesion and retention of MOF particles at target sites, thereby improving the pesticide localization and delivery efficiency. The carrier exhibits a high thiabendazole (Tbz) loading capacity of 38.14% owing to its nanoporous structure. The LA coating functions as a pH- and temperature-responsive barrier, regulating pesticide release to prolong the treatment duration and minimizing the need for repeated applications. The carrier demonstrates controlled release rates of 80.73% at pH 5 and 96.55% at 40 °C, confirming its dual-stimuli responsiveness. In vitro assays reveal 92.26% inhibition of Botrytis cinerea at 1 μg mL-1, while in vivo experiments on tomato plants and fruits show complete inhibition at 200 μg mL-1. Additionally, the developed composites adhere strongly to leaves through electrostatic and hydrogen-bonding interactions, reducing the loss of pesticide due to rain erosion. Overall, DE-MOF-Tbz-LA presents a promising and efficient alternative to conventional pesticide applications.