Chitosan

Chitosan is a cationic polysaccharide made by removing acetyl groups from chitin. Its amino groups give it pH-dependent solubility and strong interactions with negatively charged substances.

Chitin: Chitin is a structural polysaccharide made of N-acetylglucosamine units, found in arthropod exoskeletons and fungal cell walls. Removing acetyl groups from chitin produces chitosan.
Flocculation: The aggregation of suspended particles into larger clusters that can settle or be filtered. Chitosan can bind charged particles and promote their removal from water.
Polysaccharide: A carbohydrate polymer composed of many monosaccharide units linked by glycosidic bonds. Chitosan’s long chains consist of modified sugar units.
Cellulose: Cellulose is a plant cell-wall polysaccharide made of glucose units linked in linear chains. Unlike chitosan, cellulose lacks amino groups and is not typically cationic.
Degree of deacetylation: The fraction of chitin’s acetyl groups removed during conversion to chitosan. It determines how many amino groups chitosan can carry charge on.
Chitosan dressing: A wound covering made wholly or partly from chitosan-based material. Chitosan’s absorbency and interactions with blood components motivate wound-dressing designs.
Glucosamine: An amino sugar that forms the principal deacetylated unit in chitosan. Its amino group supplies chitosan’s characteristic basic sites.
Alginate: Alginate is an anionic polysaccharide obtained mainly from brown algae and some bacteria. Its negative charge makes it a frequent counterpart in chitosan complexes.
Polyelectrolyte: A polymer whose repeating units bear ionizable groups that acquire electrical charge in solution. Protonated amino groups make chitosan a cationic polyelectrolyte.
Chitosan nanoparticles: Nanoscale particles made from chitosan, often formed by ionic crosslinking or related methods. They are studied as carriers for drugs and other bioactive compounds.

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CephalopodCompared with: Cephalopod beaks contain chitin, a source material studied for biomaterials.