Physically crosslinked hydrogels from polysaccharides prepared by freeze-thaw technique

Natural polysaccharides are abundant, inexpensive, renewable, modifiable and have biodegradable and biocompatible characteristics. Polysaccharides offer a very promising source for materials of tomorrow. This review addresses recent progress in polysaccharide-based cryogels, one kind of novel physical hydrogels prepared by freeze-thaw technique under mild conditions and in the absence of organic solvents and toxically crosslinking agents. Polysaccharides used to fabricate physical cryogels here are, hyaluronan, carboxymethylated curdlan, carboxymethylated cellulose, xanthan, β-glucan, locust bean gum, starch (amylose, amylopectin and their mixtures), maltodextrins and agarose. Composite cryogels of based on polysaccharides and polyvinyl alcohol are also introduced. Various physically crosslinked cryogels from polysaccharides with tunable structural, mechanical, biological properties as well as multiple applications are considered and the investigations of the formation mechanism for these cryogels are also addressed.