Chitosan-based nano-objects for drug delivery: a review of their chemical modifications, supramolecular organization and biological fate

Abstract

Chitosan is a widely applied polysaccharide in different fields due to its versatility, biocompatibility and low toxicity. Its structure possesses reactive functional groups that can be modified without involving the chain backbone, which improves its physicochemical and biochemical properties. Several chemical modifications such as alkylation, acylation, thiolation, and grafting with polymers and active molecules can be combined with various supramolecular chemistry approaches such as crosslinking, self-assembly, polyelectrolyte-complex formation, ionic gelation, and polymerization to formulate chitosan-based nano-objects that can encapsulate many active pharmaceutical ingredients, eventually enabling new applications of chitosan in the pharmaceutical, biomedical and biotechnological fields. This review summarizes the critical findings of some recent works published in the last years on the chemical modification of chitosan; the design of chitosan-based nano-objects for the encapsulation and controlled delivery of active pharmaceutical ingredients; and the biodistribution, biodegradation and toxicology of the nano-objects.