A Hyperelastic Contact Model for the Indentation of Chondrocytes and Cartilage Extracellular Matrix

The use of micro and nanoindentation to map the elasticity of cartilage chondrocytes and extracellular matrix has been driven by the desire to understand the changes in microstructure and micromechanical properties of the tissue associated with development and with diseases such as osteoarthritis. Advances in atomic force microscopy (AFM) have facilitated application of the technique to soft tissues, allowing the concurrent imaging and mechanical probing of minute sample regions at high resolution. Examples of the capabilities of the AFM in studying cartilage biomechanics include its use in investigating changes in the elastic properties of the articular surface during development [1], comparing the dynamic elastic response at the microscale and the nanoscale [2], and measuring the elastic moduli of different zones [3].