Multipurpose β-Cyclodextrin-Involved nanospherical Aggregates: Self-Assembly Process, foliar Adhesion, and promising applications for kiwifruit and rice Protections

Abstract

Biofilm-interrelated bacterial diseases are a major challenge for global agriculture. However, existing agrochemicals often have bactericidal activity but rarely exhibit simultaneous biofilm eradicating effects. Moreover, traditional formulations suffer from droplet off-target motions during spraying, leading to inferior utilization and serious environmental pollution. To create versatile green bactericides, here, we devise a bioactive small molecule—adamantane-modified amide (AAd15) and employ host–guest supramolecular techniques to optimize it with a macrocyclic oligosaccharide—β-cyclodextrin (β-CD), thereby achieving a multifunctional supramolecular bactericide (AAd15@β-CD). Such inclusions self-assemble into biocompatible nanospheres and exhibit better wetting and deposition properties on target leaves. Importantly, AAd15@β-CD was highly effective in inhibiting Pseudomonas-biofilm formation by 77.6 % at 11.8 μg/mL, surpassing the single AAd15 (55.4 %). Also, AAd15@β-CD showed good removal activity against pre-existing biofilms by 73.0 % at 23.7 μg/mL, markedly higher to AAd15 (41.7 %). Besides, more ascending functions are granted to this carbohydrate-coated supramolecular bactericide, including limiting bacterial motility and impairing bacterial virulence. In vivo experiments at 200 μg/mL, AAd15@β-CD achieved enhanced efficacies (75.1 %∼83.1 %) against Pseudomonas-infected kiwi branches and leaves, overtopping those of commercial thiodiazole-copper-20 %SC (38.7 ∼ 42.9 %) and AAd15-0.1 %Tween-20 (64.9 ∼ 66.0 %). Furthermore, the designed carbohydrate-involved bactericide shows biosafety profiles to earthworms and zebrafishes. Thus, this study has significant implications in creating multifunctional, eco-friendly agrochemicals.