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Fluorescence Recovery after Merging a Droplet to Measure the Two-dimensional Diffusion of a Phospholipid Monolayer
Published on: October 15, 2015
Diffusion of 1,2-dimethoxyethane and 1,2-dimethoxypropane through phosphatidycholine bilayers: a molecular dynamics
Susruta Samanta1, Samira Hezaveh, Giuseppe Milano
1School of Engineering and Science, Jacobs University Bremen, Bremen, Germany.
The Journal of Physical Chemistry. B
|March 14, 2012
Summary
1,2-dimethoxyethane (DME) and 1,2-dimethoxypropane (DMP) show different behaviors at interfaces. DMP readily diffuses into lipid bilayers, while DME prefers aqueous solutions, impacting molecular interactions.
Area of Science:
- Computational chemistry
- Molecular dynamics simulations
- Interface science
Background:
- Understanding molecular behavior at interfaces is crucial for various applications.
- 1,2-dimethoxyethane (DME) and 1,2-dimethoxypropane (DMP) are relevant solvents.
- Phospholipid bilayers (DMPC) are key biological structures.
Purpose of the Study:
- To theoretically investigate the interfacial behavior of DME and DMP.
- To determine the free energy barriers for DME and DMP translocation.
- To analyze the spontaneous diffusion of DME and DMP at interfaces.
Main Methods:
- Umbrella sampling method for free energy calculations.
- GROMOS96/OPLS compatible models for DME and DMP.
- Unconstrained molecular dynamics simulations.
Main Results:
- Percolation free energy barriers: DME ~18.5 kJ/mol (water/n-heptane), ~20 kJ/mol (DMPC bilayer); DMP ~6 kJ/mol (water/n-heptane), ~12 kJ/mol (DMPC bilayer).
- DME spontaneously diffuses into aqueous solution from the lipid interior.
- DMP shows spontaneous diffusion within the DMPC layer, unlike DME.
Conclusions:
- DMP exhibits significantly lower free energy barriers for interface crossing compared to DME.
- DMP's ability to spontaneously diffuse into lipid bilayers is confirmed.
- DME's preference for aqueous environments over lipid interiors is established.
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