Force-field dependence on the liquid-expanded to liquid-condensed transition in DPPC monolayers

Abstract

We have investigated using molecular dynamics simulations, the influence of the interaction cut-off and water model on the surface-pressure area isotherms of dipalmitoylphosphatidylcholine monolayers, where the phospholipids and the water molecules are modelled atomistically. We find that both the cut-off employed and the water model, influence the pressure area isotherms and the location of the liquid-expanded to liquid-condensed transitions. The combination of the Berger's et al. force field, with the TIP4P/2005 water model, and a long cut-off for the pair interactions ( ≥ 1.7 nm) provides a more accurate prediction of the surface pressure–area isotherm and reproduces the liquid condensed–liquid expanded transition observed in the experiments at 310 K.

Keywords::

• DPPC
• molecular dynamics simulation
• surface pressure isotherm
• liquid-expanded
• liquid-condensed
• phase transitions
• phospholipids monolayers

Acknowledgements

We would like to acknowledge the Imperial College High Performance Computing Service and the Shiraz University of Technology for providing computational resources.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

FB would like to thank the EPSRC for the award of a Leadership Fellowship (EP/J003859/1).