Effect of Hydroxyapatite on the Preparation and Properties of Alginate Hydrogel

A novel crosslingking system, hydroxyapatite-D-glucono-δ-lactone (HA-GDL) was developed to prepare alginate hydrogel, in which calcium ions can be released to initiate gelation. A series of hydrogels were prepared by adjusting the sodium alginate (SA) concentration and the molar ratio of calcium ion in HA to carboxyl of SA. Gelation time, surface morphology, mechanical property and swelling capacity of hydrogels crosslinked by HA-GDL system were characterized and compared with that crosslinked by the calcium carbonate- D-glucono-δ-lactone (CaCO3-GDL) system. The results show that under the same conditions, the hydrogels obtained from the HA-GDL system have faster gelation rate, more uniform structure, stronger mechanical strength and lower swelling ratio compared with that obtained from CaCO3-GDL system. Chondrocytes of newborn rabbit are embedded in alginate hydrogels to construct tissue engineered cartilage in vitro. Primary results show that the alginate hydrogels prepared with HA-GDL system have good cell compatibility and are with potential to be used as a scaffold for cartilage repair.