la0c00475_si_001.pdf (2.19 MB)
Mechanical Properties Determination of DMPC, DPPC, DSPC, and HSPC Solid-Ordered Bilayers
journal contribution
posted on 2020-03-24, 12:11 authored by Dominik Drabik, Grzegorz Chodaczek, Sebastian Kraszewski, Marek LangnerLipid
bilayers are active participants in many crucial biological processes.
They can be observed in different phases, liquid and solid, respectively.
The liquid phase is predominant in biological systems. The solid phase,
both crystalline and gel phases, is under investigation due to its
resilience to mechanical stress and tight packing of lipids. The mechanical
properties of lipids affect their dynamics, therefore influencing
the transformation of cell plasma and the endomembrane. Mechanical
properties of lipid bilayers are also an important parameter in the
design and production of supramolecular lipid-based drug delivery
systems. To this end, in this work, we focused on investigating the
effect of solid phases of lipid bilayers on their structural parameters
and mechanical properties using theoretical molecular dynamics studies
on atomistic models of whole vesicles. Those include area per lipid,
membrane thickness, density vesicle profiles, bending rigidity coefficient,
and area compressibility. Additionally, the bending rigidity coefficient
was measured using the flicker noise spectroscopy. The two approaches
produced very similar and consistent results. We showed that, contrary
to our expectations, bending rigidity coefficients of solid-ordered
bilayers for vesicles decreased with an increase in lipid transition
temperature. This tendency was reverse in planar systems. Additionally,
we have observed an increase of membrane thickness and area compressibility
and a decrease of area per lipid. We hope these results will provide
valuable mechanical insight for the behavior in solid phases and differences
between spherical and planar confirmations.