Chitosan-based nanoparticles against bacterial infections.

Chitosan nanomaterials have become a hot topic in biomedicine due to exerting antimicrobial effects with interestingly high levels of biodegradability and biocompatibility without causing toxicity. Regarded as a potential means of wound dressing with antimicrobial activity, chitosan exhibits higher efficiency when it is functionally modified with other natural compounds, metallic antimicrobial particles and antibiotics. Mechanistically, the antibacterial effect of chitosan is mostly, associated with the death-proceeding leakage of intracellular content, induced by malfunction and altered permeability of the negatively charged cell membrane, on which chitosan is adsorbed. Moreover, chitosan nanoparticles (NPs) are endowed with favorable features of NPs (i.e., large surface-to-volume ratio, high functionalization possibilities and a greater capacity for drug loading), as well as that of their chitosan base, thereby possessing strengthened antibacterial potential. In addition, polycations target negatively charged bacterial membranes, so bacteria cells are more strongly affected by polycationic chitosan NPs than pure chitosan.