Functionalized Ionic Liquids at Bacterial Membrane Interfaces: A Multiscale Perspective from Tensiometry, Microscopy,...

Area of Science:

• Biochemistry
• Materials Science
• Medicinal Chemistry

Background:

• Ionic liquids (ILs) are emerging as potential antibacterial agents due to increasing antibiotic resistance.
• Their tunable structures allow for balancing antimicrobial efficacy and toxicity.

Purpose of the Study:

• To investigate the membrane interaction mechanisms of two monoterpene-based functionalized ionic liquids (FILs).
• To compare the antibacterial activity and membrane disruption capabilities of ammonium- and imidazolium-based FILs.

Main Methods:

• Utilized a multiscale approach including Langmuir monolayers, Brewster angle microscopy, atomic force microscopy, and molecular dynamics (MD) simulations.
• Examined FIL interactions with model bacterial membrane interfaces, focusing on lipid packing and interfacial organization.

Main Results:

• Both FILs integrated into lipid monolayers, disrupted lipid packing, and altered interfacial organization, particularly in anionic lipid-rich systems.
• Comparable antibacterial activity was observed for both FILs, despite differences in their cationic core.
• MD simulations indicated that electrostatic interactions between FIL cations and lipid phosphate oxygens are the primary drivers of membrane association.

Conclusions:

• Monoterpene-based FILs effectively interact with and disrupt bacterial membranes via electrostatic interactions.
• These FILs demonstrate significant antibacterial potential, offering a promising avenue for developing novel antimicrobial agents.
• The study provides key insights into designing ILs with targeted activity at biological surfaces.