Chitosan (Nano)formulations as Therapeutic Tools for Neurodegenerative Diseases: A Comprehensive Review

According to the World Health Organization, Alzheimer's disease and other forms of dementia were the seventh leading cause of death in 2021. The prevalence of these disorders is predictable to increase with life expectancy, and their control is hampered by several factors, including late diagnosis due to the lack of specific biomarkers and the absence of disease-modifying treatments, as currently available therapies can only lighten some of the symptoms. Nanotechnology could be the key to overcoming some of the limitations associated with neurodegenerative diseases, as nanomaterials have excellent properties compared to their bulk counterparts and can be used as drug delivery systems, diagnostic tools and platforms for tissue regeneration. Chitosan is a biopolymer with numerous properties that impart it with great potential for biomedical applications, in particular its ability to cross the blood-brain barrier and its versatility in nanoscale design. In this context, the aim of this review is to provide an in-depth analysis of the latest developments and future opportunities for chitosan (nano)formulations for the treatment and management of neurodegenerative diseases.