Polysaccharide hydrogels are becoming increasingly important for biomedical applications. One of the most exploited saccharide-based biopolymer is hyaluronic acid (HYA), a natural glycosaminoglycan able to form viscous solution or physical gels. Recently a new physical hydrogel (HYADD¿ 4) has been obtained with the introduction of2¿3 % of the carboxylate groups grafted with a hexadecylic amine moiety. These alkyl side-chains are responsible for the gel formation even in very dilute aqueous solutions. Applications of this molecule as viscoelastic regulator in osteo-arthritic pathologies have been recently outlined. We propose now to carry on a detailed QENS study on the dynamics of the random polysaccharide network of these gels to clarify the effect of junction topology on the polymer dynamics by comparing HYA and HYADD¿4 gels at different concentrations and temperatures.