Design and development of cyclic hydrostatic stress generating machine for articular cartilage chondrocytes

Abstract

Mechanical stimulation of articular cartilage at certain range of loading plays important role in the maintenance of tissue under normal physiological conditions, whereas abnormal forces might lead to its degeneration and pathological condition like osteoarthritis. With an objective to elucidate the role of mechanical stresses and their molecular/cellular correlations on cartilage metabolism, we have designed and developed a custom-made machine for generating hydrostatic load (cyclic and static) on articular cartilage chondrocytes cultured in alginate matrix. The main machine frame consists of three functional units: sample holding unit (to keep the cell sample), loading unit (to generate the load) and control-cum-driving unit (to operate and control the load patterns). The working mechanism of cyclic hydrostatic stress-generating machine is based on cam/follower arrangement and controlled by a two-phase stepper motor. The machine has been developed and used for generating physiological cyclic as well as static pressure ranging from 1-3 MPa under wide frequencies (0.33-3 Hz) at chondrocytes laden alginate beads. Efficacy and accuracy of machine has been evaluated by studying load-related alterations in morphological
properties of goat chondrocytes encapsulated in alginate beads.