Figure 21.

Mechanisms that stabilize or destabilize phase separation in ternary bilayers. (A) Aromatic and aliphatic compounds have different effects on phase separated membranes. Cholesterol is shown in yellow, DPPC headgroups in blue, DLiPC headgroups in red, and hydrophobic compounds in gray. Aromatic benzene partitions to the L_d phase and stabilizes separation (panel ii), whereas aliphatic hexadecane partitions at the phase boundary and destabilizes separation (panel iii). Note that in panel iii, cholesterol is not fully shown to reveal the presence of hexadecane in the L_o phase. Adapted with permission from ref (590). Copyright 2014 Barnoud et al. (https://creativecommons.org/licenses/by/4.0/legalcode). (B) Effect of chloroform on domain registration. DSPC is shown in red, DLiPC in blue, cholesterol in orange, and chloroform in green. In the absence of chloroform (panel i), the phases are unaligned, whereas in the presence of chloroform (panel ii), the alignment is present. Adapted with permission from ref (591). Copyright 2015 Reigada et al. published by the Royal Society. (C) Mechanism of disruption of phase separation induced by surface-bound molecules. Sucrose has fewer sufficiently large defects as biding sites in the L_o phase (panel i) than in the L_d phase (panel ii). Therefore, the presence of sucrose favors lipid mixing. A similar effect is not observed for smaller glucose, which binds the L_o and L_d phases with equal magnitudes. Adapted from ref (592). Copyright 2014 American Chemical Society.