Wetting and dewetting of extracellular matrix and glycocalix models

Abstract

In this paper, we study wetting and dewetting of hydrated biopolymer layers mediating cell-cell and cell-tissue contacts, called the extracellular matrix and cell surface glycocalix, by the combination of various physical techniques. Here, the sum of the net effects of the various interfacial forces, which is referred to as the disjoining pressure, is used as a semi-quantitative measure to describe the thermodynamics of hydrated interlayers. The disjoining pressure can be measured by applying external forces to maintain the equilibrium distance between two parallel surfaces (in biology, two neighbouring plasma membranes). Using artificial models of the extracellular matrix and glycocalix, we describe stable cell-cell contacts in terms of the wetting (or spreading) of complex fluids on polymer surfaces. In fact, the adjustment of the wetting interaction via thin hydrating layers enables us to transform three-dimensional cell membranes into quasi-two-dimensional films on macroscopically large surfaces. Fine-tuning of local wetting conditions at the interface further allows for the selective wetting of native cell membranes on microstructured polysaccharide films, which has a large potential for individual detection of biological functions in confined geometries.

Lipid Nanotechnology

“…Polyethylene glycol (PEG), cellulose and dextran are among the most commonly used polymers for making polymer cushioned SLB [69–74]. A hydrated polymer cushion acts as a spacer and a lubricating layer between the lipid bilayer and the substrate and assists self-healing of local membrane defects [75,76]. In addition to a cushioning polymer film, alternative strategies include self-assembled monolayers (SAMs) [77,78] and the use of adsorbed or bound proteins as a cushioning layer [79–83].…”

α,ω‐Functionalized Poly(2‐Oxazoline)s Bearing Hydroxyl and Amino Functions

“…[4,[15][16][17] The concept of such ''polymer-supported'' membranes can be realized by intermediate ''polymer cushions'' [15,[18][19][20][21] or ''polymer-tethered'' membranes (PTM). In the latter, lipids with hydrophilic polymer head groups (lipopolymers) are incorporated into the lipid bilayer, acting as spacer to define the distance between membrane and substrate.…”

Influence of length and conformation of saccharide head groups on the mechanics of glycolipid membranes: Unraveled by off-specular neutron scattering

“…At thermal equilibrium, the disjoining pressure counterbalances the osmotic pressure. 18,41 For the measurements in bulk buffers, 19,20 a self-built liquid cell consisting of two Si wafers with a gap of 0.17 mm was used. To guarantee that the sample reaches the equilibrium state, the sample was held at each temperature and humidity condition for at least 90 min before measurement.…”

“…15,16 As the surface of eukaryotic and prokaryotic cells is coated with saccharide chains that serve as a) Authors to whom correspondence should be addressed. Electronic addresses: ayamamoto@icems.kyoto-u.ac.jp and tanaka@uni-heidelberg.de protectors to sustain the structural integrity as well as specific ligands for proteins and complementary saccharides, 17,18 we have previously proposed more realistic model systems based on synthetic and natural glycolipids. [19][20][21] We demonstrated that the introduction of finite size effects, the so-called "cut-off radius," 22 allows full calculation of the scattering functions in reciprocal space and quantification of the vertical compression modulus B and the bending rigidity κ of the membranes.…”