We have developed an incubator housed, biaxial-tissue-loading device capable of applying axial deformations as small as 1 μm and sinusoidal rotations as small as 0.01°. Axial resolution is 50 nm for applying sinewaves as low as 10 μm (or 1% based on a 1 mm thickness) or as large as 100 μm. Rotational resolution is 0.0005°. The machine is small enough (30 cm high × 25 cm × 20 cm) to be placed in a standard incubator for long-term tissue culture loading studies. In metabolic studies described here, application of sinusoidal macroscopic shear deformation to articular cartilage explants resulted in a significant increase in the synthesis of proteoglycan and proteins (uptake of ³⁵S-sulfate and ³H-proline) over controls held at the same static offset compression.
Mechanotransduction; Shear; Tissue loading; Chondrocyte metabolism; Cartilage biomechanics