Chitosan, derived from chitin deacetylation found in crustacean exoskeletons and fungal cell walls, has multiple biomedical applications. It serves as a drug delivery agent and an adjuvant by stimulating the immune system. Chitosan activates the NLRP3 inflammasome, leading to increased IL-1β production. In vaccine studies, it induces a balanced Th1/Th2 immune response.