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Updated: May 14, 2025
07:54
Fluorescence Recovery after Merging a Droplet to Measure the Two-dimensional Diffusion of a Phospholipid Monolayer
Published on: October 15, 2015
8.0K
Quantifying Ionic Liquid Affinity and Its Effect on Phospholipid Membrane Structure and Dynamics
Veerendra K Sharma1,2, Jyoti Gupta1,2, Harish Srinivasan1,2
1Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
Summary
Ionic liquids (ILs) disrupt lipid membranes, increasing fluidity and toxicity. Longer alkyl chains on ILs cause more significant membrane disorder and enhanced lipid diffusion.
Area of Science:
- Biomembrane science
- Physical chemistry
- Toxicology
Background:
- Understanding ionic liquid (IL) interactions with biomembranes is crucial for pharmaceutical applications and explaining IL-induced biological effects.
- Imidazolium-based ILs are widely studied for their potential in various applications, necessitating a clear understanding of their membrane interactions.
Purpose of the Study:
- To investigate how imidazolium-based ILs with varying alkyl chain lengths affect the viscoelasticity, dynamics, and phase behavior of dipalmitoylphosphatidylcholine (DPPC) model membranes.
- To elucidate the role of IL alkyl chain length in modulating membrane properties and lipid diffusion.
Main Methods:
- Utilized model membrane systems: lipid monolayers and unilamellar vesicles composed of DPPC.
- Employed Fourier transform infrared spectroscopy (FTIR) and quasielastic neutron scattering (QENS) to analyze membrane structure and dynamics.
- Performed molecular dynamics (MD) simulations to complement experimental findings and provide molecular-level insights.
Main Results:
- Both 1-decyl-3-methylimidazolium bromide (DMIM[Br]) and 1-hexyl-3-methylimidazolium bromide (HMIM[Br]) induced membrane disorder, altering area per lipid and viscoelastic properties.
- Longer alkyl chains on ILs led to stronger membrane interactions, increased disorder, lower phase transition temperatures, and more gauche defects.
- ILs significantly enhanced lipid lateral diffusion, with the effect being more pronounced in ordered membrane phases, at higher IL concentrations, and with longer IL alkyl chains.
Conclusions:
- Ionic liquids, particularly those with longer alkyl chains, disrupt lipid membrane organization, increasing fluidity and permeability.
- The enhanced membrane fluidity and permeability correlate with increased IL toxicity, providing a mechanistic link.
- These findings offer critical insights into IL-biomembrane interactions, informing their toxicological profiles and pharmaceutical development.
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