Biomechanical Characterization of Single Chondrocytes

Normal cartilage functions to cushion and distribute loads throughout the joint. The tissue’s constitutive cells, chondrocytes, experience a variety of stresses as a result of these functional aspects, but the effects of these stresses on the individual cells are largely unknown. To understand the mechanical integrity of chondrocytes and how these properties change in response to various stimuli, mechanical testing systems for single cells have been developed. These systems are able to apply a wide variety of load types to characterize cellular biomechanics, and must rely on complex mathematical models to calculate these properties. This chapter reviews the five major mechanical testing systems that are used to test single chondrocytes, their distinct advantages, and discusses the salient results they have produced relating to chondrocyte mechanics and mechanosensitivity. Using these testing systems, it is clear that mechanical signals play a major role in chondrocyte gene expression, and these changes are essential to understand when developing functional cartilage replacements.