Ionic liquids in the processing and chemical modification of chitin and chitosan for biomedical applications

Ionic liquids (ILs) have huge potential to provide advances in many areas such as energy, pharmaceutical
formulations, biomedical sciences, and technology. In the biomedical field, ILs have been intensively
investigated for use as potential solvents for some polysaccharides to overcome their lack of solubility
and processability. This review focuses on the application of ILs as solvents and reaction media to develop
chitin- and chitosan-based materials. Dissolution of chitin and chitosan in ILs such as 1-butyl-imidazolium acetate (BMIMAc) and 1-ethyl-3-methylimidazolium chloride (BMIMCl) has been used to create
materials including sponges, films, microspheres, and aerogels. Moreover, ILs have a key role in chemical
reactions, hydrolysis, acetylation, deacetylation and graft copolymerization of chitin/chitosan, promoting
homogeneous media and thus enhancing the efficiency of the reactions. The resulting materials can be
applied in wound healing, tissue regeneration, gene delivery, and drug delivery systems. In particular, they
have been designed to support tissue regeneration and to act as hemostatic and antibacterial agents and/
or delivery vehicles for drugs. Although IL platforms offer new ways for the sustainable processing of
chitin and chitosan to a variety of matrices, studies involving their in vivo biocompatibility are scarce, and
this has prevented these advances being turned into clinical solutions.