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Polymer-induced flip-flop in biomembranes
Alexander A Yaroslavov1, Nikolay S Melik-Nubarov, Fredric M Menger
1School of Chemistry, M. V. Lomonosov Moscow State University, Moscow 119899, Leninskie Gory, Russian Federation. yaroslav@genebee.msu.ru
Accounts of Chemical Research
|October 18, 2006
Summary
Amphiphilic polymers and polycations accelerate lipid flip-flop in membranes. These polymers, even at low surface coverage, significantly impact membrane dynamics and drug permeation.
Area of Science:
- Polymer science
- Membrane biophysics
- Drug delivery
Background:
- Amphiphilic polymers and polycations interact with lipid bilayer membranes.
- Understanding polymer-membrane interactions is crucial for biomaterial and drug delivery applications.
Purpose of the Study:
- To investigate the ability of amphiphilic polymers and polycations to accelerate lipid flip-flop in vesicle bilayer membranes.
- To elucidate the distinct driving forces and mechanisms for nonionic and cationic polymers in catalyzing lipid translocation.
- To explore the correlation between polymer-mediated membrane dynamics and drug permeation.
Main Methods:
- Utilized amphiphilic polymers (EO/PO/EO block copolymers) and polycations (quaternized poly(4-vinylpyridine)).
- Investigated polymer binding mechanisms: hydrophobic incorporation for nonionics, electrostatic interactions for cationics.
- Assessed polymer effects on lipid flip-flop and membrane dynamics, even at low surface occupancy (<1%).
Main Results:
- Nonionic polymers accelerate flip-flop via hydrophobic block insertion, influenced by hydrophobicity and block volume.
- Cationic polymers accelerate flip-flop through electrostatic binding with anionic lipids, promoting anionic domain formation.
- A significant correlation was observed between polymer-induced "flippase" activity and enhanced drug permeation through biomembranes.
Conclusions:
- Amphiphilic polymers and polycations are potent catalysts for lipid flip-flop in membranes.
- The distinct binding modes of these polymers lead to different mechanisms of membrane perturbation.
- These findings suggest potential applications in modulating membrane permeability for drug delivery.
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