Biomedical Engineering Reference
In-Depth Information
FIGURE 6.1
Chemical structure of alginate.
6.4.1.5 Chitosan and Chitin
Chitin is a copolymer of
N
-acetyl-glucosamine and
N
-glucosamine units randomly or block distributed
throughout the biopolymer chain, depending on the processing method used to derive the biopolymer
(
Khor and Lim, 2003
). The biopolymer is termed chitin if the number of
N
-acetyl-glucosamine units is
higher than 50%. Otherwise, the biopolymer is termed chitosan. Chitin and chitosan are commercially
obtained from shellfish sources such as shrimps and crabs.
Chitosan is a variant of chitin, a partially deacetylated counterpart.
Figure 6.2
depicts the
difference in molecular structure of chitin and chitosan. Chitosan is degradable by enzymes in
humans and is structurally similar to naturally occurring glycosaminolglycans. Chitosan is soluble
in dilute acids and once dissolved, it can be gelled by extruding the solution into a nonsolvent
or increasing the pH value. Chitosan is degraded by lysozyme and the degradation kinetics is
FIGURE 6.2
Difference between the chemical structure of chitin and chitosan.
Search WWH ::
Custom Search