Cartilage is an avascular, aneural, and alymphatic tissue with a small number of chondrocytes surrounded by a rich extracellular matrix (ECM). The ECM of cartilage is made up of tissue fluid and structural macromolecules: collagens, type II, proteoglycans, other collagens (III, VI, IX, X, XI, XII, and XIV), and noncollagenous proteins and glycoproteins [12,13]. The amount of these ECM components and cells vary according to tissue location, age, and load/nonload-bearing settings, as well as on the type of species. In hyaline articular cartilage, these macromolecules and cells are arranged in a layered three-level zonal structure throughout the tissue depth, as shown in Fig. 9.1 [11,14]. This ordered macromolecular arrangement and the high water content retained using proteoglycans is important for articular cartilage as a load-bearing tissue .
Cartilage tissue engineering
As stated above, cartilage tissue engineering utilizes a combination of cells, biocompatible scaffold material, growth factors, and suitable growth conditions to achieve the goal of producing a neocartilage tissue with a high amount of chondrogenic matrix proteins, proteoglycans, and collagen, type II.