Abstract:
The construction of bacterial outer membrane
models with native lipids like lipopolysaccharide (LPS) is a barrier
to understanding antimicrobial permeability at the membrane
interface. Here, we engineer bacterial outer membrane (OM)-
mimicking giant unilamellar vesicles (GUVs) by constituting LPS
under different pH conditions and assembled GUVs with
controlled dimensions. We quantify the LPS reconstituted in
GUV membranes and reveal their arrangement in the leaflets of the
vesicles. Importantly, we demonstrate the applications of OM
vesicles by exploring antimicrobial permeability activity across
membranes. Model peptides, melittin and magainin-2, are
examined where both peptides exhibit lower membrane activity
in OM vesicles than vesicles devoid of LPS. Our findings reveal the
mode of action of antimicrobial peptides in bacterial-membrane-mimicking models. Notably, the critical peptide concentration
required to elicit activity on model membranes correlates with the cell inhibitory concentrations that revalidate our models closely
mimic bacterial membranes. In conclusion, we provide an OM-mimicking model capable of quantifying antimicrobial permeability
across membranes.
