Human Antimicrobial Peptide Triggered Colloidal Transformations in Bacteria Membrane Lipopolysaccharides

Raw data for the paper entitled, "Human Antimicrobial Peptide Triggered Colloidal Transformations in Bacteria Membrane Lipopolysaccharides" published in Small in October 2021.

Abstract:

Growing concerns of bacterial resistance against conventional antibiotics has shifted the research focus towards antimicrobial peptide (AMP)-based materials. Most AMPs kill Gram-negative bacteria by destroying their inner membrane, but have to first pass the outer membrane covered with lipopolysaccharides (LPS). Their interplay with the LPS is crucial for bactericidal activity, but is yet to be elucidated in detail.

In this study, self-assemblies of Escherichia coli LPS with the human cathelicidin AMP LL-37, free and encapsulated into glyceryl monooleate (GMO) lipid nanoparticles, were analyzed using synchrotron small angle X-ray scattering, dynamic light scattering and cryogenic transmission electron microscopy. Circular dichroism spectroscopy was used to study modifications in LL-37’s secondary structure. LPS was found to form elongated micelles and the addition of LL-37 induced their transformation to multilamellar structures. LPS addition to GMO cubosomes triggered the swelling of the internal cubic structure; while multilamellar GMO/LL-37 nanocarriers transitioned into unstructured nanoparticles.

The insights on the interactions among LPS and LL-37, in its free form or encapsulated in GMO dispersions, may guide the design of LPS-responsive antimicrobial nanocarriers. The findings may further assist the formulation of antimicrobial nanomaterials with enhanced penetration of LPS layers for improved destruction of bacterial membranes.