Synergistic effects of alginate coating method on cartilage tissue engineering using fibrin/ha composite gel

Abstract

The importance of scaffold biomaterials has greatly been emphasized in in vitro culture of tissue-engineered cartilage and threedimensional (3D) environment. The development of new materials which are able to enhance cellular differentiation is critically important for the future use of biomaterial scaffolds in tissue engineering and regenerative medicine. Here, we demonstrated the feasibility of alginate coating method of fibrin/HA composite gel as a novel trial for cartilage formation. Rabbit chondrocytes were isolated and cultured in DMEM with 10% FBS. Once passaged, the cells were encapsulated with fibrin/HA gel. The experimental groups were divided into 4 groups: fibrin/HA gel culture (F/H), with 1 layer alginate coating (F/H+1AC), with 2 layer alginate coating (F/H+2AC), and with 4 layer alginate coating (F/H+4AC). All groups were cultured in serum free defined media (CDM) for in vitro culture for 4 weeks or were implanted in subcutaneous of nude mice in vivo study. Histological examination with safranin-O and alcian blue showed that the chondrogenic area in all the groups became clear at 1 week and widened homogenously until 4 weeks. However, the chondrogenic differentiation was observed in alginate coated fibrin/HA composite gel without size reduction during the culturing. The results of biochemical and molecular biological evaluation were compatible with those of histological examination. Media analysis and mechanical strength were also carried out. The results showed that the coating method provided proper environment for cartilage formation on fibrin/HA composite gel in CDM with no growth factors. This effect could potentially be useful in the study of in vitro cartilage tissue engineering as well as clinical implications for cartilage regeneration.