New “Tribo-bioreactor” for In-situ Monitoring of the Mechanical Stress Transmission at the Cellular Level: Application to Cartilage Tissue Engineering

The mechanotransduction is an important aspect to provide suitable conditions for the cartilage engineering process. Therefore, a new bioreactor was developed to apply different mechanical stresses to cell/organ culture. It allows performing cell culture in situ with appropriate mechanical constraints according to the real-time evolution of the physical parameters with the possibility of microscopic observation. In addition to the two-dimensional mechanical stimulation of a scaffold, the originality of this device is in situ monitoring of the cells and rheological measurements. This study presents the design of the new prototype with the validation of its different functions. First, the mechanical characterization of different non-biological samples is performed to calibrate the rheological measurement. Then, the monitoring of fluorescent beads in different scaffolds is carried out to estimate the mechanical stress transmitted to the cells. Finally, the ability of the device to handle a cell culture of human chondrocytes seeded in a scaffold is evaluated. The combined functions of the new bioreactor open the possibility to develop new scaffolds with optimal mechanical stress transmission, which is the basis of tissue engineering of cartilage.