Hydrophilic Spacer Groups in Polymerizable Lipids: Formation of Biomembrane Models from Bulk Polymerized Lipids

Article abstract of DOI:10.1021/ja00300a007

A variety of polymerizable lipids containing a hydrophilic spacer group between the reactive group and the main amphiphilic structure have been synthesized.They were investigated in monolayers, liposomes, and multilayers.When the spacer concept was used, efficient decoupling of the motions of the polymeric chain and the amphiphilic side groups is achieved.Thus, the often found loss of the important fluid phases by polymerization is avoided.Polymeric monolayers of the spacer lipid, prepared either by polymerization in the monolayer or by spreading of prepolymerized lipid, exhibit nearly identical surface preassure-area diagrams.Most distincly, the successful decoupling of the motions of the polymer main chain and the membrane forming amphiphilic side groups is demonstrated by the self-organization of bulk polymerized spacer lipids to polymeric liposomes.In addition, spacer lipids are able to build polymeric Langmuir-Blodgett multilayers.The decoupling of the polymer main chain and the membrane-forming amphiphilic side groups enables the deposition of already polymeric monolayers onto supports to form defined multilayers.If, alternatively, monomeric monolayers are deposited and polymerized on the support, defects in the layers due to structural changes during the polymerization are avoided by the flexible spacer group.