Advances in Alkylated Chitosan and Its Applications for Hemostasis

Chitosan, a natural polysaccharide, has been widely used as a biomaterial, especially for hemostasis. However, hemostatic materials processed from pure chitosan have limited hemostatic effect and are extremely unstable in some cases; chemical modification is therefore needed to improve the hemostatic properties of chitosan. Through chemical reactions with hydroxyl and amino groups in chitosan macromolecules, such as alkylation, carboxylation, quaternization, etc., different groups can be introduced into the repeating units. Moreover, the introduction of different substituents can endow chitosan with more functions. For example, the introduction of long alkyl chains can improve its hydrophobic property, and greatly improve its hemostatic property. However, there is still no review of alkylated chitosan for hemostasis. Therefore, we introduce in detail several methods (direct alkylation, reductive alkylation and acylation reaction) for preparing alkylated chitosan and its applications for hemostasis.