λ-type carrageenan (λ-CAR) polysaccharides remain overlooked in the preparation of medical nanoparticles (NP) due to their unsuitable rheological properties and undesired biological effects, although they can also offer advantageous properties. To overcome these obstacles, oligosaccharide derivatives (λ-COS) have been successfully applied to the synthesis of stable NP incorporating both, ferrite cores and divalent manganese (Mn