Nonequilibrium lipid domain growth in the gel-fluid two-phase region of a DC16PC-DC22PC lipid mixture investigated by Monte Carlo computer simulation, FT-IR, and fluorescence spectroscopy
K. Jorgensen et al., Nonequilibrium lipid domain growth in the gel-fluid two-phase region of a DC16PC-DC22PC lipid mixture investigated by Monte Carlo computer simulation, FT-IR, and fluorescence spectroscopy, J PHYS CH B, 104(49), 2000, pp. 11763-11773
The nonequilibrium ordering dynamics of lipid domains in the gel-fluid coex
istence region of an equimolar DC16PC-DC22PC lipid mixture has been studied
by means of Monte Carlo computer simulation, fluorescence, and Fourier tra
nsform infrared spectroscopy. The results reveal that the nonequilibrium ph
ase separation process after a sudden temperature or pressure quench of the
binary mixture from the one-phase fluid region into the two-phase gel-flui
d coexistence region has a strong influence on the lateral membrane organiz
ation on different length scales. This is manifested as the formation of a
heterogeneous lateral bilayer structure composed of long-living gel and flu
id lipid domains characterized by a relaxation time on the order of hours.
In the early time stage of the phase separation process a distinct local li
pid structure of ordered DC16PC lipids is formed at the dynamically changin
g network of domain boundaries. Our combined theoretical and experimental i
nvestigations suggest that nonequilibrium effects may be a strong modulator
of lateral membrane heterogeneity and lead to the formation of local lipid
structures on various length and time scales. Such results are of importan
ce for a deeper understanding of properties that control membrane compartme
ntalization which in turn might be of relevance for membrane processes that
take place in localized membrane regions.