Polysaccharides alginic acid

Akhland MS, Schuchmann HP, von Sonntag C. Degradation of the polysaccharide alginic acid a comparison of the effects of UV light and ozone. Environ Sci Technol 1990 24 379-383. 

In the present study, the polysaccharide alginic acid (AlA) with molecular weight (Mw) of 250 000 was chosen as a polyanion. The strong basic protein protamine sulfate (PtS) with Mw about 5000 was used as a polycation. The calcium carbonate matrices were successively employed as a core material because they dissolve in mild conditions and are non toxic. Our motivation to study this combination was to reach the more biocompatible shell composition. 

The stable hollow microcapsules on the basis of natural polysaccharide alginic acid and protein protamine sulfate are formed via LbL method. The (PtS/AlA)4 microcapsules fabricated are promising for biomedical applications. 

Figure 22.11. Cellulose is a structural and rather chemically inert component of terrestrial plants. Alginic acid is synthesized by marine algae and has medicinal properties. Some polysaccharides contain nitrogen in the form of amino sugars. The primary example of this is chitin, which composes the exoskeletons of Crustacea. An amino sugar contains an amine in place of a hydroxyl group. In other polysaccharides, sugars combine with lipids and proteins. These form glycoUpids and glycoproteins, respectively.

The same group investigated the separation of fluorescently labled sugars by different CDs as well as linear polysaccharides (dextrin 10, dextran, laminarin, and alginic acid) and oligosaccharides in the presence of borate... 

The natural polymers frequently used for the preparation of pharmaceutical gels include tragacanth, pectin, carrageenan, agar, and alginic acid, as well as semisynthetic polysaccharides such as methylcellulose, hydroxymethylcellulose, and carb-oxymethylcellulose. 

Formation of L-guluronic acid, a component of the alginic acid-like polysaccharide produced by P. aeruginosa and Azotobacter vinelandii, requires special comment. In this case, a polymer built from /3-(l- 4)-linked D-mannosyluronic acid residues serves as an intermediate in the biosynthesis.204,205 Part of the D-mannosyluronic acid residues in the polymer is subjected to an epimerization at C-5 catalyzed by an exocellular enzyme of the micro-organism,205-207 producing a polysaccharide composed of structural blocks that contain only D-mannosyluronic acid or only l-gulosyluronic acid residues, as well %s some having both. The mechanism of the epimerization remains unclear. 

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