Multilamellar arrangement

The mechanism of transfection by cationic lipids is not known, but cationic lipids probably form stable complexes with anionic DNA molecules to facilitate entry into the cell. Physical studies of DNA/DOTAP/DOPE complexes suggest that DNA molecules are arranged in a regular pattern between layers of lipid bilayer [54]. This multilamellar arrangement permits the charged lipid-head groups to interact with the charged DNA molecules. When mixtures... 

In the typical setup, the lipids are arranged in a bilayer, with water molecules on both sides, in a central simulation cell, or box, which is then replicated by using three-dimensional periodic boundary conditions to produce an infinite multilamellar system (Fig. 2). It is important to note that the size of the central cell places an upper bound on the wavelength of fluctuations that can be supported by the system. 

Liposomes, also known as lipid vesicles, are aqueous compartments enclosed by lipid bilayer membranes [56,57]. Figure 10.11 shows how lipid bilayers are arranged in the liposome and the lipid structures in large unilamellar vesicles and multilamellar vesicles. Lipids consist of two components ... 

Multilamellar Crystals, Hedrites, and Spherulites. Upon crystallization from the quiescent melt (or concentrated solution), polymers exhibit higher order supramolecular structures, including stacks of lamellae, hedrites, and finally spherulites (167). Hedrites (177) are entities composed of multiple lamellar crystals and as such correspond to intermediate stages of spherulitic growth. SFM in various modes was used to determine spherulite sizes and details of lamellar arrangement within spherulites for a wide variety of polymers and polymer processing conditions. SFM data acquired at free surfaces, at the surface of microtomed... 

The systems described above formed linearly extended, fibrous self-assemblies, although the morphological structures depended on amphiphiles. The molecular arrangement in fibers were maintained by the formation of concentric multilamellar bilayer, besides hydrophobic interaction and hydrogen bonding, except C Asp fibers with chiral character. The assemblies underwent temperature-dependent fibril-vesicle transition. The fibril-vesicle transition resulted from the rearrangement of bilayers. Generally, multilamellar layers were diminished in ves-... 

FIGURE 3.9 Diagrams demonstrating three basic multilamellar phase geometries flat, cylindrical, and spherical. In these images, the sheets indicate the arrangement of the surfactant bilayers in a solvent medium. (Images... 

---