Bioreactor mimicking knee-joint movement for the regeneration of tissue-engineered cartilage

Efforts to minimize the sacrifice of laboratory animals have become a recent worldwide trend. This trend has triggered a number of studies toward developing effective methods to replace the animal experiments. In this study, we developed a biomimetic bioreactor system that simulates the movements of the human knee joint. The system consists of a knee-joint drive and a unit capable of culturing cells at the joint surface. The knee-joint drive is designed to apply dynamic stimulation similar to the real bending motion of the knee joint. We employed a commercial incubator for comparative evaluation and validation of our laboratory-made cell-culture unit mounted in a bioreactor. The results revealed that the ability of the proposed system in culturing cells was similar to that of the commercial incubator. The cell culture was evaluated by dividing the knee joint into zones according to the size of the stimulus. The results confirmed that the cell assessment stimulated by the knee-joint movement was two times higher than that having no stimulation. Overall, the study helped establish that the cell characteristics is more effective when an appropriate external stimulus is applied according to the target tissue. The study is also expected to form the basis for implementing an ex-vivo environment that can potentially replace animal and cadaver experiments in the future. In the future, follow-up studies will be conducted on the in-vivo environment and the characteristics of each organ and tissue for effective tissue regeneration.