Supported Membranes with Well‐Defined Polymer Tethers—Incorporation of Cell Receptors

Abstract

We report the design of supported lipid membranes attached to the surface by tailored lipopolymer tethers. A series of well-defined lipopolymers were synthesized by means of living cationic polymerization of 2-methyl-2-oxazolines. The polymers were equipped with a silane coupling group on the proximal, and lipid anchors on the distal chain ends. The length of the intermediate hydrophilic polymer tether was varied (n = 14, 18, 33) to change the distance between the membrane and the substrate. Supported membranes have been prepared in two-steps. First, a suitable lipopolymer/lipid mixture was deposited by Langmuir-Blodgett transfer, and annealed to establish the covalent coupling to the surface. On the dry lipopolymer/lipid monolayer, the upper leaflet was deposited by vesicle fusion. Optimization of both preparation steps resulted in the formation of stable and defect-free membranes. Impacts of the spacer length and the lipopolymer fraction upon the lateral diffusivity of the lipids were systematically compared by fluorescence recovery after photobleaching (FRAP). First experiments on the incorporation of a large transmembrane cell receptor (integrin alpha IIb beta 2) into the polymer-tethered membrane suggested that the length of the polymer tether plays a crucial role in distribution of the proteins on the surface.

Nonionic polyoxazoline surfactants based on renewable source: Synthesis, surface and bulk properties

“…Castor oil CO is unique among all oils since it is the only one containing about 90% of C 18 Methine groups bearing alcohol oxygen atom were observed at 3.6 ppm. Methylene groups in  position of alkene or of carbonyl ester appeared at 2.3-2.05 ppm.…”

“…The large demand for surfactants urgently calls for sustainable surfactants made from renewable raw materials to reduce the impact on the environment and to save fossil resources [13]. In this sense few nonionic polyoxazoline surfactants based on vegetable biomass have been synthesized from glycerol [14] and lipopolymers [15][16][17][18]. Schubert et al have recently reported the synthesis of amphiphilic poly(2-ethyl-2-oxazoline-block-2-"soyalkyl"-2-oxazoline) copolymers from soybean fatty acid [19,20].…”

How Does the Mobility of Phospholipid Molecules at a Water/Oil Interface Reflect the Viscosity of the Surrounding Oil?

“…12, 13 However, the effects of bulk viscosity on the membrane fluidity remain unclear, because the various undefined physicochemical factors are included in these systems. In the present study, we adapted a monolayer at a water/oil interface to shed light on this unsolved problem.…”

Structural characterization of an elevated lipid bilayer obtained by stepwise functionalization of a self-assembled alkenyl silane film

“…23 Similarly, grafting of 2-methyl-2-oxazoline based lipopolymers using LB transfer followed by thermal annealing to induce covalent coupling of the silane to the surface was reported. 24 In a recent work, a tetra͑ethylene glycol͒-lipid silane has been grafted to an oxide surface without LB transfer. 25 In all cases, tethered bilayer lipid membranes have been successfully accomplished.…”