Lipid-derived polymeric material

Plants are unique in that the structural component of their outer envelope (cuticle) consists of a hydroxy fatty acid polymer, cutin, whereas other organisms use polymers of amino acids or carbohydrates for this purpose. Underground parts and healed wound surfaces of plants are protected by another type of lipid-derived polymeric material, suberin, which is laid down outside the plasma membrane and in close contact with the inside of the cell... 

Stems and leaves of plants are covered with a layer of fatty material. The structural component is an hydroxy fatty acid polymer-cutin. Underground parts and wound surfaces are covered in another type of lipid-derived polymeric material - suberin. Both these polymers are associated with or embedded in a complex mixture of lipids imprecisely called waxes. (Strictly speaking a wax is an ester between a long chain fatty acid and a fatty alcohol section 4.7.)... 

The THM reaction linked to GC, GC/mass spectrometry (MS), and MS has been successfully applied to the chemical characterization of a number of synthetic and natural products, including resins, lipids, waxes, wood products, soil sediments, and microorganisms. This technique is also very effective for the detailed characterization of the synthetic polymeric materials, especially the condensation polymers, such as polyesters and polycarbonates, because many simplified pyrograms are usually obtained that consist of peaks of methyl derivatives from the constituents of the polymer samples almost quantitatively. In this chapter, the instrumental and methodological aspects of Py-GC in the presence of the organic alkali are briefly described, and then some typical applications to the precise compositional analyses and microstructural elucidation inclusive of the intractable cross-linking structures for various condensation type polymeric materials are discussed. 

The surface layers of plants are covered in cutin or suberin (Section 2.11). Both of these polymeric structures are lipid-derived. Furthermore, the lipid nature of the surface covering is enriched by the presence of wax (Section 2.10), especially in the cuticle. There are two problems which should be borne in mind when considering the structural determination of these compounds. Firstly, cutin and suberin are polymers whose extraction from tissues and analysis thereafter pose all the problems usually associated with such materials. Secondly, wax, cutin and suberin have variable compositions depending on environmental and developmental conditions and, especially, on the nature of the tissue being analysed. 

Several comprehensive reviews on polymerizable lipids and supramolecular structures derived from them appeared between 1985 and 2002 [3,25-31], Consequently, this review focuses on developments in this field during 2000-2008. These include synthesis of new types of polymerizable lipids, creation and characterization of novel poly(lipid) membrane systems, and applications of polymerized vesicles and membranes in chemical sensing, separations science, drug delivery, materials biocompatibility, and other fields. 

It is by no means necessary to use natural lipids in order to form membranes. Modem bioorganic chemistry rather tends to develop new molecules, which allow production of membrane materials with properties unknown in nature (e.g., ultrathin asymmetrical membranes with different headgroups on the in- and outsides, polymeric membranes, and membranes that can be isolated and stored without water see Sec. 2.5). Table 2.2.5 reproduces a few useful artificial amphiphiles derived from simple fatty acids and fatty alcohols. 

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