Bilipid layer membrane 155

Fig. 4.8. (Below) A diagram of the bilipid layer membrane of a vesicle or a cell with (above) a typical lipid, phosphatidylcholine. Large molecules and ions cannot penetrate the membrane as illustrated by the ions surrounding and inside a cell, but the distribution is reversed in vesicles (see Chapter 7). The ions create chemical and electrical field gradients across the membrane.

Free nano continua or discontinua can be defined, also, as surface, line, and point elements, and as their combinations. Free surface elements are ideally composed of two nanolayers placed symmetrically each other (Figure 1.6). Such structures are ideal membranes and can be composed of solid materials, liquids, and even gasses. Ideal membranes exist in nature, e.g., bilipide cell membranes and black surfactant bubbles (Figure 1.7a and b). It is visible that both membranes are composed of only two molecular layers of asymmetric surface-active molecules, with hydrophilic ends placed outward (cell membranes) or inward (surfactant bubbles). Ideal membranes, composed... 

The lipid bilayer is a thin polar membrane made of two layers of lipid molecules. These membranes are flat sheets that form a continuous barrier around the cell and thus acts as a good antibacterial agent. Derivatives of neomycin B are examples of bilipids [73, 74]. 

The electron involved in the donor-acceptor interaction need not originate from the actual surface layer but may well come from the interior of the bilipid membrane, for example, from intramembrane proteins. The electron escape depth in organic materials is comparable to intermolecular distances. 

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