Super Antibacterial Capacity and Cell Envelope-Disruptive Mechanism of Ultrasonically Grafted N-Halamine PBAT/PBF Films against Escherichia coli

Antibacterialmaterials are urgently needed to combatbacterialcontamination, growth, or attachment on contact surfaces, as bacterialinfections remain a public health crisis worldwide. Here, a novelultrasound-assisted method is utilized for the first time to fabricateoxidative chlorine-loaded AH@PBAT/PBF-Cl films with more superiorgrafting efficiency and rechargeable antibacterial effect than thosefrom conventional techniques. The films remarkably inactivate 99.9999% Escherichia coli and Staphylococcusaureus cells, inducing noticeable cell deformationsand mechanical instability. The specific antibacterial mechanism against E. coli used as a model organism is unveiled usingseveral cell envelope structural and functional analyses combinedwith proteomics, peptidoglycomics, and fluorescence probe techniques.Film treatment partially neutralizes the bacterial surface charge,induces oxidative stress and cytoskeleton deformity, alters membraneproperties, and disrupts the expression of key proteins involved inthe synthesis and transport of the lipopolysaccharide and peptidoglycan,indicating the cell envelope as the primary target. The films specificallytarget lipopolysaccharides, resulting in structural impairment ofthe polysaccharide and lipid A components, and inhibit peptidoglycanprecursor synthesis. Together, these lead to metabolic disorders,membrane dysfunction, structural collapse, and eventual death. Giventhe films' antibacterial effects via the disruption of keycell envelope components, they can potentially combat a wide rangeof bacteria. These findings lay a theoretical basis for developingefficient antibacterial materials for food safety or biomedical applications.

Automated summary

In this study, a novel ultrasound-assisted method was used to fabricate oxidative chlorine-loaded AH@PBAT/PBF-Cl films with superior grafting efficiency and rechargeable antibacterial effect. The films showed significant antibacterial activity against Escherichia coli and Staphylococcus aureus cells, inducing cell deformations and mechanical instability. The specific antibacterial mechanism against E. coli was revealed through various analyses, indicating the cell envelope as the primary target. The films can potentially combat a wide range of bacteria, laying a theoretical basis for developing efficient antibacterial materials for food safety or biomedical applications.