Fabrication and antibacterial properties of self-assembled lysozyme nanofilms induced by reduced glutathione

This study developed a self-assembled lysozyme nanofilm at the air-water interface using reduced glutathione (GSH) as an inducer, demonstrating broad-spectrum antibacterial activity and tunable functionality. Through thiol-disulfide exchange, GSH reduces the disulfide bonds in lysozyme, leading to protein unfolding and conformational transition from α-helix to β-sheet-rich structures. The assembly process, along with film morphology and surface properties, can be effectively modulated by varying lysozyme concentration and environmental pH, enabling the rational design of surface charge and hydrophobicity to optimize antibacterial performance. The resulting nanofilm demonstrates significant antibacterial efficacy against both Staphylococcus aureus (Gram-positive bacteria) and Escherichia coli (Gram-negative bacteria), attributed to a synergistic mechanism involving inherent enzymatic activity and membrane disruption mediated by exposed hydrophobic domains and positive surface charges. These findings provide a feasible strategy for designing eco-friendly protein-based antibacterial materials with potential applications in food packaging, biomedical coatings, and functional surfaces. • Green self-assembly of lysozyme nanofilms using biocompatible GSH. • Tunable morphology, structure, and function via controlled pH and concentration. • Broad-spectrum efficacy against both Gram-positive and Gram-negative bacteria. • Enhanced efficacy via membrane disruption by hydrophobic and cationic surfaces.