A synthetic nucleus pulposus is provided that is useful in treatment of degenerative disc disease, augmentation of a degenerate disc, and alleviation of back pain. In an embodiment the synthetic nucleus pulposus comprises hyaluronan macromolecules that have been cross-linked via dihydroxyphenyl linkages. The synthetic nucleus pulposus restores or improves the water-retention capability of the disc. A method of treating an intervertebral disc with the cross-linked hyaluronan macromolecules is also provided. A method of regenerative therapy to address loss of cells of nucleus pulposus of an intervertebral disc based on treatment with the cross-linked hyaluronan macromolecules and mesenchymal stem cells is also provided.