Self-assembled membranes constructed

Self-assembled membranes constructed from phospholipids and other surfactants have been extensively investigated to understand their formation, encapsulation and release, and templating properties (7-25). Lipids and surfactants are amphiphilic molecules with hydrophilic, polar headgroups and nonpolar tails. As a result of the hydrogen bonding and electrostatic interactions of the hydrophilic headgroups and the van der Waals interactions between the hydrophobic tails, amphiphiles form organized membrane microstructures when dispersed in water or oil. When... 

The lipid molecule is the main constituent of biological cell membranes. In aqueous solutions amphiphilic lipid molecules form self-assembled structures such as bilayer vesicles, inverse hexagonal and multi-lamellar patterns, and so on. Among these lipid assemblies, construction of the lipid bilayer on a solid substrate has long attracted much attention due to the many possibilities it presents for scientific and practical applications [4]. Use of an artificial lipid bilayer often gives insight into important aspects ofbiological cell membranes [5-7]. The wealth of functionality of this artificial structure is the result of its own chemical and physical properties, for example, two-dimensional fluidity, bio-compatibility, elasticity, and rich chemical composition. 

We will discuss here applications of polyelectrolyte-modified electrodes, with particular emphasis on layer-by-layer self-assembled redox polyelectrolyte multilayers. The method offers a series of advantages over traditional technologies to construct integrated electrochemical devices with technological applications in biosensors, electrochromic, electrocatalysis, corrosion prevention, nanofiltration, fuel-cell membranes, and so on. 

Molecular organization and self-assembly into layers, membranes, vesicles etc., construction of multilayer films [7.1-7.5], generation of defined aggregate morphologies [4.74, 4.75, 7.6-7.8J etc., make it possible to build up specific supramolecular architectures. The polymerization of the molecular components has been a major step in increasing control over the structural properties of such assemblies [7.9-7.13]. 

Finally, zeolite nanoparticles have been used as building blocks to construct hierarchical self-standing porous stmctures. For example, multilayers of colloidal zeolite crystals have been coated on polystyrene beads with a size of less than 10 p,m [271,272]. Also, silicalite-1 membranes with a thickness ranging from 20 to several millimeters and controlled mesoporosity [273] have been synthesized by the self-assembly of zeolite nanocrystals followed by high-pressure compression and controlled secondary crystal growth via microwave heating. These structures could be useful for separation and catalysis applications. 

In this study, we report a very effective and widely applicable method for fabricating of nanostructures of an inert material for the biomolecular nanoarrays. The stable nanostructures of the PEG and PVA hydrogels were directly fabricated on gold substrates by UV-NIL (Fig. la). The site-selective nanoarray of various biomolecules such as protein and tethered lipid bilayer raft membrane (tLBRM) was constructed from a nanoimprinted inert materials by stepwise molecular self-assembly (Fig. lb and Ic). 

Lipids are building blocks of model and real membranes, which can be combined with proteins and some other important biomolecules to simulate real membranes. The simplest model is hence the self-assembly of only one component of the complex membrane, in this case the lipids. These mono-component lipidic models are often employed in studies as their interaction with small molecules mimics the actual relationship between the cell membrane and a substrate. A commonly employed amphiphatic lipid, dipalmitoyl phosphatidylcholine (DPPC) (Figure 4.6.2), has been widely used to construct these cell membrane motifs, due to its high content in animal cells, and thus its tendency to mimic a valid animal ceU. The supramolecular organization of these (a) DPPC amphiphatic molecules lead to a (b) Langmuir monolayer, (c) bilayer, (d) micelle, and (e) vesicle, which are the available levels of modeling to mimic the cellnlar membrane. 

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