Recent progress in chitosan-based nanoparticles for drug delivery: a review on modifications and therapeutic potential

Chitosan, obtained from chitin by deacetylation, is a versatile biopolymer known for its biocompatibility, biodegradability and environmental friendliness. Combined with its chemical and physical modifiability, these properties have made chitosan an important material in biomedical and pharmaceutical fields, especially in drug delivery systems. Chitosan-based nanomaterials exhibit enhanced functions through various chemical modifications such as thiolation, acetylation, carboxylation and phosphorylation, as well as through physical and enzymatic approaches. These modifications address inherent limitations such as poor solubility, limited acid resistance and insufficient mechanical strength, expanding the applications of chitosan in tissue engineering, gene therapy, vaccine delivery, wound healing and bioimaging. This review provides an in-depth analysis of the chemical structure, physicochemical properties and modification strategies of chitosan. It also explores current methodologies for preparing chitosan nanoparticles, along with drug loading and release techniques. Various targeting strategies employed in chitosan-based delivery systems are examined in detail. To illustrate the clinical relevance of these approaches, representative examples from recent therapeutic studies are included. Moreover, it highlights future research directions and the innovation potential of chitosan-based materials.