Comparative generation and characterization of probiotic-derived bacterial ghosts from gram-negative and...

Bacterial ghost (BG) are empty bacterial cell envelopes that retain native surface architecture and antigenic structures, making them promising platforms for vaccine delivery and immunotherapy. This study aimed to develop a simple, scalable chemical method for generating probiotic BG using representative Gram-negative and Gram-positive bacterial strains.

BG were produced by Tween-80-mediated lysis followed by acidic treatment. Structural and morphological integrity was assessed using scanning and transmission electron microscopy. Particle size and zeta potential were determined by physicochemical characterization, while biochemical assays were performed to confirm the release of intracellular proteins and nucleic acids.

Electron microscopy demonstrated evacuation of cytoplasmic contents while preserving the structural integrity of the bacterial cell envelopes. The generated BG exhibited hydrodynamic diameters of 1.18 μm and 1.14 μm, with zeta potentials of -38.4 mV and - 30.4 mV for Escherichia coli Nissle 1917 and Lactobacillus paragasseri ATCC 19992, respectively, indicating favorable colloidal stability. Biochemical analyses further supported effective ghost formation by detecting released intracellular proteins and nucleic acids.

Tween-80-mediated chemical induction provides a simple, reproducible, and scalable strategy for generating probiotic bacterial ghosts while preserving structural integrity. Unlike gene-based lysis systems, this approach applies to both Gram-negative and Gram-positive bacteria, offering a safer alternative to pathogen-derived BG and expanding the potential of probiotic bacterial ghost platforms for vaccine delivery and other biomedical applications.