Fibro/chondrogenic differentiation of dental stem cells into chitosan/alginate scaffolds towards temporomandibular joint disc regeneration

Once damaged, articular cartilage has very little capacity for spontaneous healing because of the avascular nature of the tissue. Although many repair techniques have been proposed over the past four decades, none has sucessfully regenerated long-lasting hyaline cartilage tissue to replace damaged cartilage. Tissue engineering approaches, such as transplantation of isolated chondrocytes, have recently demonstrated tremendous clinical potential for regeneration of hyaline-like cartilage tissue and treatment of chondral lesions. As such a new approach emerges, new important questions arise. One of such questions is: what kinds of biomaterials can be used with chondrocytes to tissue-engineer articular cartilage? The success of chondrocyte transplantation and/or the quality of neocartilage formation strongly depend on the specific cell-carrier material. The present article reviews some of those biomaterials, which have been suggested to promote chondrogenesis and to have potentials for tissue engineering of articular cartilage. A new biomaterial, a chitosan-based polysaccharide hydrogel, is also introduced and discussed in terms of the biocompatibility with chondrocytes.

A biodegradable scaffold in tissue engineering serves as a temporary skeleton to accommodate and stimulate new tissue growth. Here we report on the development of a biodegradable porous scaffold made from naturally derived chitosan and alginate polymers with significantly improved mechanical and biological properties as compared to its chitosan counterpart. Enhanced mechanical properties were attributable to the formation of a complex structure of chitosan and alginate. Bone-forming osteoblasts readily attached to the chitosan-alginate scaffold, proliferated well, and deposited calcified matrix. The in vivo study showed that the hybrid scaffold had a high degree of tissue compatibility. Calcium deposition occurred as early as the fourth week after implantation. The chitosan-alginate scaffold can be prepared from solutions of physiological pH, which may provide a favorable environment for incorporating proteins with less risk of denaturation. Coacervation of chitosan and alginate combined with liquid-solid separation provides a scaffold with high porosity, and mechanical and biological properties suitable for rapid advancement into clinical trials.