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

Abstract

Antibacterial materials are urgently needed to combat bacterial contamination, growth, or attachment on contact surfaces, as bacterial infections remain a public health crisis worldwide. Here, a novel ultrasound-assisted method is utilized for the first time to fabricate oxidative chlorine-loaded AH@PBAT/ PBF-Cl films with more superior grafting efficiency and rechargeable antibacterial effect than those from conventional techniques. The films remarkably inactivate 99.9999% Escherichia coli and Staphylococcus aureus cells, inducing noticeable cell deformations and mechanical instability. The specific antibacterial mechanism against E. coli used as a model organism is unveiled using several cell envelope structural and functional analyses combined with proteomics, peptidoglycomics, and fluorescence probe techniques. Film treatment partially neutralizes the bacterial surface charge, induces oxidative stress and cytoskeleton deformity, alters membrane properties, and disrupts the expression of key proteins involved in the synthesis and transport of the lipopolysaccharide and peptidoglycan, indicating the cell envelope as the primary target. The films specifically target lipopolysaccharides, resulting in structural impairment of the polysaccharide and lipid A components, and inhibit peptidoglycan precursor synthesis. Together, these lead to metabolic disorders, membrane dysfunction, structural collapse, and eventual death. Given the films' antibacterial effects via the disruption of key cell envelope components, they can potentially combat a wide range of bacteria. These findings lay a theoretical basis for developing efficient antibacterial materials for food safety or biomedical applications.

Chickpea-Derived Modified Antimicrobial Peptides KTA and KTR Inactivate Staphylococcus aureus via Disrupting Cell Membrane and Interfering with Peptidoglycan Synthesis

“…To further confirm this phenomenon, HADA in situ labeling was employed to ascertain the effect of AMPs on peptidoglycan biosynthesis . As shown in Figure c, AMP-treated cells exhibited a significantly weak fluorescence intensity, and the appearance of some unlabeled cells was observed.…”

“…Among them, KTR induced more severe damage to the membrane components of S. aureus and MRSA cells, including amide bands at 3314 cm –1 (amide A), 1657 cm –1 (amide I), and 1546 cm –1 (amide II); saturated lipids at 2966, 2930, 2851, and 1458 cm –1 (CH 2 antisymmetric stretching or CH 3 umbrella symmetric bending vibration); and sugar bands at 1245, 1074, and 962 cm –1 (stretching vibrations of C–O, COH, and C–C glycosidic bonds) . The attenuated intensity of all these peaks provided sufficient evidence for the disintegration of membrane components, including peptidoglycan, phospholipids, and membrane proteins.…”

“…Fourier transform infrared spectroscopy (FTIR) (Nicolet 5700; Thermo Fisher Scientific, MA, USA) was applied to characterize the conformational changes in the functional groups of bacterial membrane components . The bacterial pellets of S.…”

Synthesis of γ-Cyclodextrin-Reduced Fe(III) Nanoparticles with Peroxidase-like Catalytic Activity for Bacteriostasis of Food

“…Foodborne diseases are a growing global health concern, with approximately 70% of cases being caused by foodborne pathogens (WHO, 2015) . Common pathogens responsible for food poisoning include Escherichia coli , Staphylococcus aureus , Salmonella , Shigella , and others .…”