Mechanical Properties of Tissue Engineered
 Materials and Products

For some tissue engineered materials, it is essential to characterize their mechanical properties. Cartilage for instance whether natural or tissue-engineered is designed to be a structural material. As such, its mechanical properties can be a critical determination of how well it will perform. Cartilage that differs in aggregate modulus from its interfacing cartilage may promote osteoarthritis.

Alberts Biomechanics does creep indentation tests based on the biphasic theory of cartilage. With these tests, we can determine virtually all of the viscoelastic properties of cartilage and of similar tissue-engineered materials. A porous indentor made from sintered steel is used for the indentation. The indentor is designed to be more permeable than the tissue, so that only the mechanical properties of the solid phase of the material are measured.

From the creep indentation curve and a measurement of the thickness of the tissue, we can determine:

  • The aggregate modulus: The linear stress/strain relationship in a confined compression test.
  • The Poisson's ratio: The negative of the ratio of the lateral strain to axial strain due to an applied axial load.

Once the above two constants are known, one can also determine the material's Young's modulus and shear modulus.

The biphasic theory also gives us the permeability of the tissue which provides information on the tissue's viscoelastic or timed-dependent properties.

We have a data base of the viscoelastic properties of healthy and diseased human and various species of animal cartilage at various sites in the body. The measurements we obtained from your tissue can be compared with those values.

If you work with tissue engineered materials and need to characterize their mechanical properties, please contact us.

Home  |  Past Projects  |  Pub References  |  Circulim Vitae  |  Contact Us