Cross-linking Chemistry of Type I and Type III Collagen with Anionic Polysaccharides - Natural Polymers, Biopolymers, Biomaterials, and Their Composites, Blends, and IPNs - page 169

Figure 6. (a) and (b).
Chemistry BehiNd the Cross-liNKiNG meChaNism oF CollaGeN
With aa
From the above schematic representation, we found collagen and AA cross-linked
through covalent linkage (chemical cross-linking). When the required concentration of
collagen and AA (I) was mixed, the reaction starts from the ester formation in AA (II)
due to loss of water according to Anson et al. (2009). Since the resultant lactones are
biologically active, ready to interact with free -NH 2 group of lysine in collagen chain
(III) and (IV) as shown above.
With regard to the thermal analyses of cross-linked biopolymer material (AACC
1 and AACC 3) and the plain (native) material, we observed an increase in thermal
stability upon cross-linking with AA. Salome Machado et al. (2002) observed similar
results for the cross-linking of collagen with chitosan. Derivative information's shown
in Figure 4(a) and 4(b) emphasizes, sharp peak at 252ºC corresponds to AA alone and
a broad peak at 327ºC corresponds to collagen alone. When collagen was mixed with
AA at optimized concentration, the peak shifted towards right side for the cross-linked
polymer material. This implies the cross-linking between Type I, Type III collagen, and
AA. Nevertheless, when the concentration of AA increased to more than 1.5%, there