Hydrogels Based on Natural Polysaccharides and Their Applications

Abstract

Hydrogels were discovered in 1960 where they were first applied as soft contact lenses. They are composed of polymers organized in a three dimensional network that are able to absorb high quantities of water. Polymers can be synthetic or from natural sources. Examples of natural polymers include proteins and polysaccharides. This article focuses on hydrogels prepared from natural polysaccharides followed by their applications. Natural polysaccharides provide attractive properties to fabricate hydrogels, for example, they are of low cost, biocompatible, and biodegradable. However, they have poor mechanical strength, which is required for some applications. Like mechanical strength, other desired properties of the natural polysaccharides can be improved by modifying their chemical structure, changing hydrogel fabrication procedure, and/or combining the natural polysaccharides with other materials. Most of commercial hydrogel products are based on synthetic polymers. Even though some commercial natural polysaccharide-based hydrogels may be found for some biomedical applications, most of these materials are limited to research investigations. This is because a specific natural polysaccharide will present different physical and chemical properties depending on the source it is prevenient of or on the isolation method. Therefore, this article presents the most common natural polysaccharides studied for hydrogel production and their properties. The use of such hydrogels in biomedical, food, oil, agriculture, water treatment, and energy is also presented, where the most natural polysaccharides used for each specific application are discussed.