ABSTRACT
Nature chose polysaccharides as one of the main materials for
forming various structures including trees, plants, algae, and
crustaceans. Polysaccharides, with about 40 different monosaccha-
ride structures, different O-glycosidic linkage types, and various
molecular weights, present extremely diverse physical, chemical,
and biological properties [1, 2]. The monosaccharides (or sugar
moieties) in homopolysaccharides and heteropolysaccharides can
contain various substituents such as acyl groups, amino acids,
or inorganic residues. It is the physicochemical properties of
these monosaccharide repeating units and their sequences that
determine their material properties in biological systems [3].
Polysaccharides have been used widely in pharmaceutical and
biomedical applications, particularly in drug delivery and tissue
engineering, for their recognized biocompatibility (or nontoxicity),
biodegradability, and hydrophilicity. Polysaccharides are known
to have biochemical similarities with human extracellular matrix
(ECM) components and, thus, may be readily accepted by the
body [4]. Commonly used polysaccharides include agarose, alginate,
carrageenan, cellulose, chitin, chitosan, chondroitin sulfate, dextran,
gellan, guar gum, hyaluronic acid, pectin, pullulan, scleroglu-
can, starch, xanthan gum, xyloglucan, and other polysaccharides
[4-8]. Polysaccharides form hydrogels when they are exposed to low
amounts of water that are not sufficient to dissolve the polymer.
Polysaccharides can also form hydrogels through crosslinking either
by chemical or physical means [9].
