Regulation of Lipid Bilayer Ion Permeability by Antibacterial Polymethyloxazoline‐Polyethyleneimine Copolymers

Abstract

Amphiphilic antimicrobial polymers display activity against the outer bacterial cell membrane, triggering various physiological effects. We investigated the regulation of ion transport across the lipid bilayer to understand differences in biological activity for a series of amphiphilic polymethyloxazoline – polyethyleneimine copolymers. The results confirmed that the tested structures were able to increase the permeability of the lipid bilayer (LB) membrane or its rupture. Black lipid membrane (BLM) experiments show that the triggered conductance profile and its character is strongly correlated with the polymer structure and zeta potential. The polymer exhibiting the highest antimicrobial activity promotes ion transport by using a unique mechanism and step‐like characteristics with well‐defined discreet openings and closings. The molecule was incorporated into the membrane in a reproducible way, and the observed channel‐like activity could be responsible for the antibacterial activity of this molecule.

Influence of PEG Subunit on the Biological Activity of Ionenes: Synthesis of Novel Polycations, Antimicrobial and Toxicity Studies

“…Zeta-potential of polymeric aggregates was measured using the dynamic light scattering (DLS) technique. This property influences the membrane lytic mechanism of polymers, [55,71] particularly at the stage of initial electrostatic interactions between a polycation and negatively charged phospholipid bilayer. Obtained results indicate that aggregates of C8-D-PEG and C12-D-PEG are characterized by a substantially lower surface charge than their nonPEGylated counterparts.…”

Changes in Ion Transport across Biological Membranes Exposed to Particulate Matter

“…One of the best methods for the evaluation of membrane quality changes and their bioelectric properties is the black lipid membrane technique. In recent decades, this well-established method has been extensively used to study a plethora of antibacterial copolymers, ionophoric agents and ion channels, including those found in intracellular membranes [ 16 , 27 , 28 ]. To our knowledge, a study on the interactions between PM and biological membranes has not been reported yet, leaving some open questions: Does PM permeabilize biological membranes?…”