Additionally, it is possible to extend the therapeutic index of liposomal carriers over that of the corresponding conventional formulations by optimizing the lipid composition, liposomal size, membrane fluidity, surface charge, steric stabilization, and so forth.
These phospholipids contribute an important structural role to the membrane and, in addition, determine membrane fluidity and cell-surface charge.
Apart from changes in the pattern of the surface charge, membrane fluidity also appears to be altered in tumorigenic cells, though it is not clear if this alteration is uniform throughout all carcinomas.
The use of lipid-based mimics, usually synthetic liposomes, has provided a wealth of information based on the ability to introduce guest lipids to modulate surface charge, lateral pressure and membrane fluidity and to examine their effect on OMP folding and stability.
A more cationic analog of AmphoB, DS-AmpB-020, was more potent against IFITM3, which likely arises from its improved hydrogen-bonding ability, which could augment either channel formation or interactions with negatively charged phospholipids to increase membrane fluidity.
For example, activity of the reconstituted sugar transporter of the human erythrocyte increases with magnitude of surface charge in a manner suggesting it protects the catalytic domain against changes in membrane fluidity [ 96].
Recently, it was reported that smoking decreases RBC membrane fluidity.
Membrane fluidity and polarity were studied using fluorescence spectroscopy.
Changes in membrane fluidity are measured by the membrane polarization index, p, an inverse indicator of membrane fluidity (Sangwan et al. [2002]).
PAMPA membrane fluidity was inferred from anisotropy measurements in liposomes.
