Study of Carbon Nanotubes Effects on the Chondrogenesis of Human Adipose Derived Stem Cells in Alginate Scaffold

Osteoarthritis is one of the most common diseases in middle‑aged populations in the World and could become the fourth principal cause of disability by the year 2020. One of the critical properties for cartilage tissue engineering (TE) is the ability of scaffolds to closely mimic the extracellular matrix and bond to the host tissue. Therefore, TE has been presented as a technique to introduce the best combination of cells and biomaterial scaffold and to stimulate growth factors to produce a cartilage tissue resembling natural articular cartilage. The aim of study is to improve differentiation of adipose derived stem cells (ADSCs) into chondrocytes in order to provide a safe and modern treatment for patients suffering from cartilage damages. After functionalization, dispersions and sterilizing carbon nano‑tubes (CNTs), a new type of nanocomposite gel was prepared from water‑soluble CNTs and alginate. ADSCs seeded in 1.5% alginate scaffold and cultured in chondrogenic media with and without transforming growth factor‑β1 (TGF‑β1) for 7 and 14 days. The genes expression of sex determining region Y‑box 9 (SOX9), types II and X collagens was assessed by real‑time polymerase chain reaction and the amount of aggrecan (AGC) and type I collagen was measured by ELISA. Our findings showed that the expression of essential cartilage markers, SOX9, type II collagen and AGC, in differentiated ADSCs at the concentration of 1 μg/ml CNTs in the presence of TGF‑β1 were significantly increased in comparison with the control group (P < 0.001). Meanwhile, type X collagen expression and also type I collagen production were significantly decreased (P < 0.001). The results showed that utilized three‑dimensional scaffold had a brilliant effect in promoting gene expression of chondrogenesis.