Amino-functionalized polysaccharide derivatives: Synthesis, properties and application

Abstract

Polysaccharides, cellulose and chitin are fundamental structural biopolymers of our biome, they therefore demonstrate relatively high tensile strength compared to other biopolymers and great diversity. Aqueous insolubility is a natural requirement for these polymers to be fit for purpose. However, non-natural aminated polysaccharides, such as 6-deoxy-6-amino derivatives, display improved solubility profiles, thus allowing further modification in a wider range of protic and aprotic polar solvents. Improved aqueous solubility and additional charge density aids, among others, modest antimicrobial, antioxidant, anticancer and gene transfection properties. Cellulosic and chitinous feedstock is naturally abundant and ideal for further valorisation. However, limitations in environmentally desirable solvents and inconsistency in chemical processing are a key hurdle in the path to commercial exploitation of 6-deoxy-6-aminocellulose and 6-deoxy-6-aminochitosan. This review intents to highlight the successes and challenges in the chemical process methodology that influence optimal valorisation of cellulosic and chitinous waste in the context of exploiting waste derived biopolymers. Note that this review is focused on the synthesis of 6-deoxy-6-amino derivatives and not 6-O-linked aminated derivatives.