Preparation and characterization of a soluble eggshell membrane/agarose composite scaffold with possible applications in cartilage regeneration

Articular hyaline cartilage is an extremely hydrated, not vascularized tissue with a low-cell density. The damage of this tissue can occur after injuries or gradual stress and tears (osteoarthritis), minor damages can be self-healed in several weeks, but major injuries may eventually require surgery. In fact, in this case, because of nature of the cartilage (the absence of cells and vascularization) it is difficult to expect its natural regeneration in a reasonable amount of time. In recent years, cell therapy, in which cells are directly transplanted, has attracted attention. In this study, a scaffold for implanting chondrocytes was prepared. The scaffold was made as a sponge using the eggshell membrane and agarose. The eggshell membrane is structurally similar to the extracellular matrix and nontoxic due to its many collagen components and has good biocompatibility and biodegradability. However, scaffolds made of collagen only has poor mechanical properties. For this reason, the disulfide bond of collagen extracted from the insoluble eggshell membrane was cut, converted into water-soluble, and then mixed with agarose to prepare a scaffold. Agarose is capable of controlling mechanical properties, has excellent biocompatibility, and is suitable for forming a hydrogel having a three-dimensional porosity. The scaffold was examined for Fourier-transform infrared, mechanical properties, biodegradability, and biocompatibility. In in vitro experiment, cytotoxicity, cell proliferation, and messenger RNA expression were investigated. The study demonstrated that the agarose/eggshell membrane scaffold can be used for chondrocyte transplantation.

Application of double network of gellan gum and pullulan for bone marrow stem cells differentiation towards chondrogenesis by controlling viscous substrates

Hydrogels have a large amount of water that provides a cartilage-like environment and is used in tissue engineering with biocompatibility and adequate degradation rates. In order to differentiate stem cells, it is necessary to adjust the characteristics of the matrix such as stiffness, stress-relaxing time, and microenvironment. Double network (DN) hydrogels provide differences in cellular biological behavior and have interpenetrating networks that combine the advantages of the components. In this study, by varying the viscous substrate of pullulan (PL), the DN hydrogels of gellan gum (GG) and PL were prepared to determine the cartilage differentiation of bone marrow stem cell (BMSC). The characteristics of GG/PL hydrogel were investigated by examining the swelling ratio, weight loss, sol fraction, compressive modulus, and gelation temperature. The viability, proliferation, and toxicity of BMSCs encapsulated in hydrogels were evaluated. Cartilage phenotype and cartilage differentiation were confirmed by morphology, GAG content, and cartilage-specific gene expression. Overall results demonstrate that GG/PL hydrogels can form cartilage differentiation of BMSCs and can be applied for tissue engineering purposes.