Recent studies on alginate blends, composites, and nanocomposites

Abstract

Alginate is the generic name given to the salts of alginic acids. Alginic acids are polysaccharides molecules which are built up of uronic acid residues, molecules with a carboxyl group on the carbon that is not part of the ring, Commercial alginates are currently obtained by extraction from brown seaweeds such as Laminaria digitata, Laminaria hyperborea, and Macrocystis pyrifera. However, several bacteria such as the nitrogen-fixing aerobe Azotobacter vinelandii and the opportunistic pathogen Pseudomonas aeruginosa also produce alginate. Alginates are unique in terms of their properties such as emulsifiers, thickeners, stabilizers, gelling and film forming, resultingin several applications for the food and pharmaceutical industries. Alginate has been regarded as an excellent polysachaccharide for gel systems because of its unique features such as biocompatibility, biodegradability, immnogenecity, and non-toxicity. In the biomedical area, alginates have been used as devices in several human health applications, such as excipients in drug delivery (DDS), wound dressings, as dental impression materials and in some formulations preventing gastric reflux, among others. Main characteristics and chemical modification, along with some interesting properties and applications are reviewed in this chapter.