Chapter 3 - Chemically cross-linked polysaccharides for biomedical applications

Abstract

The significance of polysaccharides as the building blocks in the domain of biology and pharmacy has been tremendously increasing. This can be owed to their outstanding attributes such as biodegradability, chemical modification, homogeneity, compatibility with the biological system, low cost, and toxicity. The chemical modification of these biopolymers is promoted by functional moieties on the polysaccharide chains. Nevertheless, their aqueous instability and a lack of required mechanical strength are considered as the major obstacles for the medical applications involving these biopolymers. As a result, the derivatization of the polysaccharides is under investigation for the enhancement of their mechanical properties, which is also important from the formulation point of view. This has led to the use of the cross-linking technique as a stabilization process for designing cross-linked polysaccharides for biomedical applications. Different types of physical, enzymatic, and chemical methods are accessible for establishing the cross-linkages between the polysaccharide chains. An extensive range of methods such as cross-linking with aldehydes, the addition and condensation reactions, free-radical polymerization, and high-energy radiations mediated cross-linking are presented for achieving chemical cross-linking. Hence, these methods are employed for the formation of chemically cross-linked polysaccharides for biomedical usage, including the production of biofilms, polysaccharide-based hydrogels, cross-linked polysaccharide sponges, and regular/ultrafine fibers. In this chapter, different types of cross-linking techniques, along with the significance of chemical cross-linking techniques with relevant biomedical applications have been discussed in detail.