Injectable hydrogels with high fixed charge density and swelling pressure for nucleus pulposus repair: Biomimetic glycosaminoglycan analogues - Sivan, S; Roberts, S; Urban, J; Menage, J; Bramhill, J; Campbell, D; Franklin, V; Lydon, F; Merkher, Y; Maroudas, A; Tighe, B (Acta Biomaterialia, 2014)