Author/Editor		Cevc, G; Blume, G
Title		Rationale for the control of the biological properties of lipid membranes in vitro and vivo
Type		članek
Source		Acta Pharm
Vol. and No.		Letnik 42, št. 4
Publication year		1992
Volume		str. 263-71
Language		eng
Abstract		Lipid membranes are being used increasingly in many biotechnological and biological systems. For the success of such applications it is crucial to understand and quantify the interactions between bilid bilayers and soluble macromolecules, however. We argue that the efficiency of specific binding of any large molecule (e.g. an antibody) to its ligand attached to a lipid membrane is diminished by the proximity of the bilayer surface. This appears to be due to the same non-Coulombic, hydration dependent short-range force which also prevents the colloidal collapse of a stack of lipid membranes. The strength of this force, as a rule, decreases with decreasing polarity of the lipid headgroups. Nonspecific protein adsorption of the lipid bilayers, on the contrary, is little affected by the overall repulsion between a mucromolecule and the bilayer surface; rather, this adsorption is governed by the number of defects and/or by the available hydrophobic binding sites in a given membrane. Multiple nonspecific protein adsorption, which results in the macromolecular denaturation, is one of the main reasons for the rapid elimination of lipid vesicles fro the blood stream in vivo. To promote the longevity of liposomes it is therefore necessary to modify the surfaces of their constituent lipid bilayers. Increasing the surface density of the net charges and/or the bilayer surface hydrophilicity is of little use in this respect; to affect the nonspecific bilayer-protein interactions significantly, an optimal number of water solluble, short polymers should be attached to the lipid headgroups. These increase the repulsive barrier of the lipid membrane surface and often may prolong the life-time of the resulting lipid vesicles dramatically.(trunc.)
Descriptors		SYNAPTIC MEMBRANES MEMBRANE LIPIDS LIPID BILAYERS PROTEIN BINDING ADSORPTION PHOSPHOLIPIDS LIPOSOMES MICE