Chitosan-derived antibacterial and antifungal agents: a review of recent strategies for activity enhancement

Abstract

Chitosan (CS), a naturally occurring biopolymer derived from chitin, has garnered significant attention for its intrinsic antimicrobial properties, biocompatibility, and biodegradability. However, its limited solubility and relatively moderate activity under physiological conditions have prompted the development of various strategies to enhance its antimicrobial performance. This review provides an up-to-date overview (2024–2025) of recent advances in the design and modification of CS-based materials to improve their antimicrobial efficacy against a broad spectrum of pathogens. Emphasis is placed on chemical modifications, such as quaternization, carboxymethylation, and the grafting of functional groups, as well as on physical strategies, including nanoparticle formulation, hybridization with metal ions or oxides, and incorporation into composite materials. The review also discusses the mechanisms by which these modifications enhance antimicrobial action, along with their potential applications in biomedical devices, wound dressings, food packaging, and water treatment.