Chitosan: Structural and Chemical Modification, Properties, and Application

Abstract

Chitosan is a polymer of natural origins that possesses many favourable properties [...]

Strategies to Prepare Chitin and Chitosan-Based Bioactive Structures Aided by Deep Eutectic Solvents: A Review

“…As already pointed out in the Introduction, and because of its unique structure, chitosan exhibits plenty of intrinsic therapeutical properties [60,62,63,77,91,207,208], summarized in Table 2 (containing some updated references).…”

“…However, it should be noted that it is difficult to work with chitin, as it is insoluble in aqueous acidic media due to its acetylated residues [45,56,57]. Thus, efforts have been made to use chitin to produce more soluble compounds, such as chitosan [58][59][60][61][62][63], a biopolymer generally obtained via the chemical [64] or biotechnological [65,66] deacetylation of chitin, which exhibits a unique, versatile, and variable structure [67][68][69][70][71][72][73]. Structurally, chitosan (Figure 2b) is a copolymer formed D-glucosamine units (GlcN, major component, Figure 2) and GlcNAc units [74] connected by linear β-(1,4)-links (Figure 2b).…”

“…This limitation restricts their processability and hinders their potential applications in industries where solvent-based processing methods are prevalent. Attempts to enhance the solubility of chitin/chitosan and other biopolymers often involve chemical modifications, such as derivatization or grafting of functional groups [101], to disrupt these structural arrangements and introduce solubilizing moieties; specifically for chitin/chitosan modification, many examples can be found in the literature [63,95,[102][103][104][105]. However, such modifications can alter the biopolymers' properties and biodegradability, posing challenges in maintaining their eco-friendly characteristics.…”