The present invention provides nanocomposite systems made of metallic nanoparticles stabilized with branched cationic polysaccharides, in particular alditolic or aldonic mono- and oligo-saccharidic derivatives of chitosan, and their preparation obtainable with aqueous solutions of these polysaccharides in the presence or absence of reducing agents. The peculiar chemical and physical-chemical features of these polysaccharides allow to form metallic nanoparticles homogeneously dispersed in the polysaccharidic matrix and an effective stabilization thereof. The properties associated with the nanometric dimensions and the presence of biological signals on polymeric chains may be exploited in applications with antimicrobial activities and of molecular biosensors.
