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 has reactive functional groups that can be modified without involving the chain backbone, which improves its physicochemical and biochemical properties. Several chemical modifications as alkylation, acylation, thiolation, grafting with polymers and active molecules, can be combined with various supramolecular chemistry approaches as crosslink, self-assembly, polyelectrolyte complexes, ionic gelation, polymerization to formulate chitosan-based nano-objects able to encapsulate many active pharmaceutical ingredients, eventually providing to chitosan new possibilities in the pharmaceutical, biomedical and biotechnological fields. This review summarizes the knowledge developed in some recent works published in the last years regarding chemical modifications of chitosan, the design of chitosan-based nano-objects for the encapsulation and controlled delivery of active pharmaceutical ingredients, their biodistribution, biodegradation and toxicology.