Chitosan is considered as one of the most promising biomaterial of 21st century on accounts of its versatile nature, excellent biodegradability, biocompatibility, antimicrobial activity, non-toxicity, and wide applications. Chitosan is derived from Chitin, a second most abundantly available natural polymer after cellulose.
Chitin is naturally found in the exoskeleton of shellfish such as crabs and shrimps, and in the cell membranes of fungi, yeasts and other microorganisms. It is not soluble in dilute acids, whereas chitosan is soluble in dilute acids.
Chitosan is primarily composed of glucosamine and N-acetyl glucosamine residues with a 1, 4-β-linkage. The presence of primary amines (-NH2) in chitosan gives it a net positive charge and are important for its biological properties.
The production chitosan starts with the selection of suitable source for chitin extraction. Chitin can be extracted from either the animal sources such as shellfish or the non-animal sources such as fungi. The physicochemical properties of chitosan can vary greatly depending on its source.
Chitin is extracted from the natural sources via demineralization and deproteination. The purified Chitin is then treated with concentrated alkalis (e.g. sodium hydroxide) to obtain Chitosan.
The process is known as deacetylation and it affects the final properties of Chitosan such as extent of positive charge (proportion of amine groups in polymer) and molecular weight.
Biological Properties of Chitosan
Chitosan has been extensively studied as a biomaterial for various applications. Some of its key properties are listed in this image. Due to its biodegrdable and biocompatible nature, chitosan has been used in bothe external as well as implantable medical devices.
As a fat binder, it has been used for weight loss agent.
The mucoadhesive and viscosity modifying properties make it useful for drug delivery. The hemostatic, anti-microbial, anti-inflammatory and analgesic properties make it an excellent wound management material.
Chitosan in wound management
- Protects the wound: by acting as a barrier to microbes
- Accelerates hemostasis
- Stimulates natural wound healing
- Relieves pain
- Minimizes scar formation