The present invention regards a biological material comprising: a) a liquid carrier comprising a viscous solution containing at least one natural and/or semisynthetic polysaccharide, and having a Dynamic viscosity measured at 20° C. and at shear rate of D=350 s−1, comprised between 100 and 250 c Poise and/or a Kinematic viscosity comprised between 99 and 248 cSt (measured at the same conditions); b) a culture of mesenchymal stem cells, and/or c) a platelet-rich hemo-derivative. This type of material in form of viscous liquid is particularly suitable for the therapy of osteoarthrosis, ligament damage, in particular tendon and cartilage damage) and may be administered intra-articularly, intradermally or directly applied in situ without altering the properties of the mesenchymal stem cells and/or platelets contained therein.