Chapter 4 - Natural Polymers: Polysaccharides and Their Derivatives for Biomedical Applications

Abstract

Several polymers of both natural and synthetic origin have been used for a variety of biomedical applications including pharmaceutical preparations, drug targeting, imaging, drug delivery, prosthetics, and tissue engineering scaffolds. Due to their reproducible characteristics in terms of their molecular weight, degradation and mechanical properties, synthetic polymers are attractive for a variety of the aforementioned applications. However, synthetic polymers from the biological standpoint, synthetic polymers often lack much-desired bioactivity and biocompatibility, which may translate into adverse side effects. Natural polymers on the other hand are abundant and resemble the components present in biological extracellular matrices. Thus, natural polymers are readily accepted by the body and possess high bioactivity and biocompatibility. Natural polymers can be divided into three major classes according to their chemical structure: (i) polysaccharides, (ii) proteins, and (iii) polyesters. This chapter presents an overview of the polysaccharide-based biomaterials, their structure property, and applications in the area of drug delivery and tissue engineering. Particular emphasis is given to polysaccharides such as (i) hyaluronic acid (HA), (ii) chondroitin sulfate, (iii) chitin and chitosan, (iv) alginates, and (v) cellulose. These polymers and their popular derivatives are also discussed in the context of their chemical and biological properties. Polysaccharides in their native form may not be able to provide all the desired properties for a particular biomedical application. Thus, the chapter also focuses on the polysaccharide derivatives and their blend with other polymers for a variety of biomedical applications.