Biological hydrogel synthesized from hyaluronic acid, gelatin and chondroitin sulfate by click chemistry.

Abstract: In order to mimic the natural cartilage extracellular matrix, which is composed of core proteins and glycosaminoglycans, a biological hydrogel was synthesized from the biopolymers hyaluronic acid (HA), chondroitin sulfate (CS) and gelatin via click chemistry. HA and CS were modified with 11-azido-3,6,9-trioxaundecan-1-amine (AA) and gelatin was modified with propiolic acid (PA). The molecular structures were verified by ¹H nuclear magnetic resonance, infrared spectroscopy and elemental analysis, giving substitution degrees of 29%, 89% and 44% for HA–AA, CS–AA and gelatin–PA (G–PA), respectively. The –N₃ groups of HA–AA and CS–AA were reacted with the acetylene groups of G–PA, catalyzed by Cu(I), to form triazole rings, thereby forming a cross-linked hydrogel. The gelation time was decreased monotonically with increasing Cu(I) concentration up to 0.95mgml⁻¹. The hydrogel obtained was in a highly swollen state and showed the characteristics of an elastomer. Incubation in phosphate-buffered saline for 4weeks resulted in a weight loss of up to 45%. Moreover, about 20% gelatin and 10% CS were released from the hydrogel in 2weeks. In vitro cell culture showed that the hydrogel could support the adhesion and proliferation of chondrocytes. [Copyright &y& Elsevier]