Abstract:

BACKGROUND: Hynamic mechanical loading devices or bioreactors contain perfusion bioreactor, hydraulic system, and dynamic compression device, shear system, stretching device or the combination of some devices. However, all these devices can not characterize the mechanical state of cartilage, and the function of constructed cartilage is far from natural cartilage.
OBJECTIVE: A novel loading device for articular engineering construction was firstly proposed, and to analyze the mechanical behavior of chondrocytes under this loading device.
METHODS: The rolling depression loading device comprised roll controlling system and compression-adjusting system. In roll controlling system, the roller could roll over tissue engineered constructs with uniform velocity via controlling stepper motor and gear. The compressive subsystem could produce uniform, controlled compressions by relatively sliding of two wedge blocks.
RESULTS AND CONCLUSION: Under the device, constructs would endure the dynamical compressive deformation and stress deformation. Finite element analysis showed that the rolling depression load provided constructs with complex mechanical conditions, namely, pressure-tensile stress presented alternately on the superficial zone of tissue engineered constructs, -45° to   + 45° periodic changed angles could be found between rolling-direction plane and surface in the mesopelagic zone, and compressive stress presented in the deep layer, which closely to the X,Y, Z-directions. The loading mode of this device is consistent with articular mode, thus, it may benefit the functional construction of engineered cartilage.