Preparation methods of chitosan nanoparticles: a review

Chitosan is a natural polysaccharide which has been frequently used for the development of diverse materials due to its outstanding physicochemical and biological properties. Chitosan nanoparticles are generally produced by "bottom-up" strategies, where polymeric assembling is promoted by various molecular interactions. However, a group of strategies called "top-down", based on the deconstruction of macroscopic structures, has recently generated great interest as an alternative for obtaining nanomaterials. This paper reviews relevant research findings on the production of chitosan-based nanoparticle systems over the last decades. Evidences showed that chitosan nanoparticles play a relevant role in the research of polymeric nanomaterials with biomedical and pharmaceutical applications. This, due to the diversity of production methods which influence the properties of the obtained materials, such as particle size, capacity of incorporation and release of bioactive compounds, surface charge, mucoadhesivity, among others.