The present invention provides an injectable hydrogel composition comprising an aqueous dispersion of inorganic nanoparticles linked to a block copolymer by means of a functional group that is present in the copolymer, wherein said block copolymer has a lower critical solution temperature (LCST) in an aqueous medium, wherein the block copolymer comprises a thermoresponsive polymer block and an osmotically active polymer block and wherein the number average molecular weight of the block copolymer is at least 2 kDa. The hydrogel composition according to the invention has a low viscosity below the LCST and forms a gel by heating to a temperature above the LCST of the block copolymer.The described hydrogels can be used in the sustained release of medicaments, tissue engineering, release agent of osmotic polymers and other medical and non-medical applications.
