The use of dynamic culture devices in articular cartilage tissue engineering
Tissue engineered repair of articular cartilage has now become a clinical reality with techniques for cell culture having advanced from laboratory experimentation to clinical application. Despite the advances in the use of this technology in clinical applications, the basic cell culture techniques for autologous chondrocytes are still based on primitive in-vitro monolayer culture methods. Articular chondrocytes are known to undergo fibroblastic change in monolayer culture as this is not their normal state in-vivo. They are more likely to maintain their phenotype when cultured in three dimensional environments. In this state they become spherical in shape and synthesise normal cartilage matrix products. Various substances are being presently investigated with the aim of designing a suitable material that is biocompatible, biodegradable and suitable for implantation. The major problem of culturing cells in three dimensional scaffolds is the limitation posed by the biomaterial on nutrient diffusion to cells deep within the scaffold. In order for this technology to succeed in clinical practice there is a important need to develop solutions to overcome these diffusional restraints. The use of dynamic culture devices which can, not only stimulate chondrocytes, but also maintain their original characteristics are investigated in this project. This thesis tests the hypothesis that culture within a dynamic culture device ie a rotating wall vessel bioreactor or roller bottles, enhances proliferation and cartilage-specific matrix synthesis by chondrocytes seeded in a three dimensional construct. The long term survival of chondrocytes in hydrogel matrices is also examined and cell cultures in dynamic devices are compared with traditional static culture systems. Biochemical, histological and immunostain data is presented an the possibility of using human cells is also explored.