Cartilage engineering: Current status and future trends

Abstract

Articular cartilage provides the surface of articulating joints with frictionless movement while absorbing loading forces. The tissue's extracellular matrix (ECM) is comprised mainly of type II collagen and proteoglycans which are maintained by chondrocytes, the resident cell population. Cartilage is a structurally complex tissue, with zones that exhibit different cell morphologies and extracellular matrix structure depending on distance from the articulating surface. The tissue is both alymphatic and avascular. All nutrient, oxygen, and waste exchange occurs through diffusion. This, along with low cell density and proliferation, contributes to the tissue's limited ability to repair ECM damage. The high number of people suffering from arthritis has led to a plethora of cartilage engineering research. Recent efforts have focused on aiding the body in cartilage restoration through both cell-based and acellular biomaterials. A variety of synthetic and natural polymers have been created for this purpose, each with their benefits and drawbacks. To date, an ideal biomaterial has yet to be created that can optimally repair or regenerate damaged cartilage. Here we highlight current biomaterial trends in cartilage engineering and examine future directions within the field. © 2011 Springer-Verlag/Wien.