Smart nanoscale lamellated supramolecular assemblies overcome biofilm barriers and enhance foliar affinity for efficient control of bacterial diseases

Abstract

Agricultural infections arising from morbigenous biofilms and biofilm-dispersed bacteria have become a huge obstacle, threatening global food supply and security. Recalcitrant dense biofilms assist the embedded pathogens to efficaciously evade the host immune responses and bactericidal attack, thereby causing inferior antibacterial efficacy and severe bacterial resistance. However, currently available bactericides don’t proclaim any competencies in inhibiting or eliminating intractable biofilms. Facing this daunting challenge, here, we have developed nanoscale lamellated supramolecular assemblies (PtA22@β-CD) integrated by a bioactive isopropanolamine-modified thiophenol (PtA22) and β-cyclodextrin (β-CD). These smart lamellar materials exhibit multipurpose orientations: (1) Strongly damaging mature biofilms of Xanthomonas citri (Xac) with a higher eradication rate of 91.9 % at 25 μg mL−1, after aged Xac for 24 h; (2) Killing biofilm-enclosed pathogenic bacteria that markedly reduces colony-forming units by 87.3 % at 25 μg mL−1; (3) Significantly weakening the biofilm-involved pathogenicity; (4) Enhancing foliar adhesion and deposition of PtA22@β-CD droplets. More attractively, in vivo pot experiments, PtA22@β-CD displayed excellent control efficiencies (protection 81.4 %, remediation 69.4 %, low-dose: 200 μg mL−1) against citrus bacterial canker, markedly overtopping the commercial thiodiazole-copper. Besides, PtA22@β-CD demonstrates broad-spectrum bioactivities against Xanthomonas oryzicola. This study is bright for enhancing agrochemical bioavailability and circumventing the large-scale use of hazardous traditional adjuvants.