Surface modification of layered double hydroxides nanocomposites with dopamine for pH-responsive delivery of tebuconazole to improve antifungal activity and biological safety

The effectiveness of conventional fungicides is often limited by poor bioavailability and unacceptable toxicity. Owing to their high loading capacity, long-term validity, and anti-photodegradation, the pH-sensitive layered double hydroxides (LDHs) nanocomposites for controlled release of fungicide is a promising candidate in agricultural protection. As the interfacial regulated modifier, dopamine (DA) with bountiful phenolic hydroxyl group is an ideal synergistic agent to improve interaction with the target organisms. The DA modified tebuconazole (TEB)-LDHs nanocomposites was fabricated for enhancing the antifungal efficacy and biological safety. The cumulative release rates of TEB from TEB-LDHs and TEB-LDHs-DA nanocomposites indicated the pH-sensitive controlled release behavior with a higher cumulative release rate under acid condition. Based on the bioactivity assay, the TEB-LDHs-DA nanocomposites was endowed with a pH responsive stimulus nano-fungicide and exhibited a superior antifungal activity against Fusarium pseudograminearum , for improving delivery capability, inducing intracellular excessive reactive oxygen species, reducing membrane potential and inhibiting ergosterol biosynthesis. The biosafety assay suggested that DA grafted onto TEB-LDHs nanocomposites could effectively reduce the acute toxicity of TEB to zebrafish. Overall, these results demonstrated that DA successfully grafted onto TEB-LDHs nanocomposites was able to provide a nanocomposites platform for responsive stimulus strategy of crop disease control in cost-effective and ecological manner.