• Biocompatible
• Cytocompatible
• Antimicrobial
• Anticholesterolemic
• Anti-oxidant
• Anti-inflammatory
• Analgesic
• Hemostatic
• Fungistatic
• Spermicidal
• Antitumorigenic
• Mucoadhesive
• Stimulates angiogenesis
• Activates macrophages
• Promotes granular tissue and scar formation
• Enhances adsorption
• Binds to mammalian and microbial cells aggressively
• Has a regenerative effect on connective gum tissue
• Accelerates the formation of osteoblasts responsible for bone formation
• Central nervous system depressant
• Immunoadjuvant
7 Limitations of Using Chitin
In spite of having abundant availability of chitin in nature, it is extremely insoluble
in dilute aqueous or conventional organic solvents due to its strong intra- and
interhydrogen bonds. Therefore, chitin has yet to find large-scale industrial uses.
No economical and suitable solvent is known for the dissolution of chitin upon
isolation of chitin from the exoskeletons of crustacean shells. The weak solubility
of chitin is the main constraint for its usage in biomedicine and biotechnology, even
though it possesses versatile biological activities.
8 Chemical Modifications of Chitosan
Over decades, much emphasis has been given to chemical modifications of
chitosan, bearing in mind that chitosan is normally insoluble in solutions above
pH 6 and requires acid to be protonated [110]. Chitin has two hydroxyl groups,
whereas chitosan has one reactive amino group as well as two hydroxyl groups in
the repeating N-acetyl glucosamine and glucosamine residues, respectively [111].
Therefore, various chemical modifications have been introduced to increase not
only the water solubility of chitosan but also to chemically modify these groups for
102
J. Dutta
• Cytocompatible
• Antimicrobial
• Anticholesterolemic
• Anti-oxidant
• Anti-inflammatory
• Analgesic
• Hemostatic
• Fungistatic
• Spermicidal
• Antitumorigenic
• Mucoadhesive
• Stimulates angiogenesis
• Activates macrophages
• Promotes granular tissue and scar formation
• Enhances adsorption
• Binds to mammalian and microbial cells aggressively
• Has a regenerative effect on connective gum tissue
• Accelerates the formation of osteoblasts responsible for bone formation
• Central nervous system depressant
• Immunoadjuvant
7 Limitations of Using Chitin
In spite of having abundant availability of chitin in nature, it is extremely insoluble
in dilute aqueous or conventional organic solvents due to its strong intra- and
interhydrogen bonds. Therefore, chitin has yet to find large-scale industrial uses.
No economical and suitable solvent is known for the dissolution of chitin upon
isolation of chitin from the exoskeletons of crustacean shells. The weak solubility
of chitin is the main constraint for its usage in biomedicine and biotechnology, even
though it possesses versatile biological activities.
8 Chemical Modifications of Chitosan
Over decades, much emphasis has been given to chemical modifications of
chitosan, bearing in mind that chitosan is normally insoluble in solutions above
pH 6 and requires acid to be protonated [110]. Chitin has two hydroxyl groups,
whereas chitosan has one reactive amino group as well as two hydroxyl groups in
the repeating N-acetyl glucosamine and glucosamine residues, respectively [111].
Therefore, various chemical modifications have been introduced to increase not
only the water solubility of chitosan but also to chemically modify these groups for
102
J. Dutta