Tissue Deformation Stage

Harrick’s new Tissue Deformation Imaging Stage (TDIS™) is a microscope micro-rheometer accessory designed for use with confocal and fluorescence upward-looking (inverted) microscopes manufactured by Leica, Nikon, Olympus and Zeiss. Combined with other components in a complete TDIS™ System, the stage is capable of measuring the shear and compression properties of soft biological samples such as cartilage, sclera and corneal tissue.

Many biological tissues are highly complex and inhomogeneous in their structure and composition. As a result, their mechanical properties exhibit clear spatial variations. Determining these location-dependent mechanical properties and understanding their biological functions are critical for tissue engineers attempting to create replacement tissues that mimic the properties of native tissue. In addition, the ability to compare the spatial dependence of mechanical properties in healthy and damaged tissue may provide insight into the effects of wear or disease.

As a particular example, articular cartilage, the soft connective tissue that coats bones in joints, has a structure that is highly dependent on depth from the articular surface. In vivo, this tissue is constantly subject to both shear and axial forces. However, the frequency and depth dependence of its shear and compression properties are poorly understood. Given the fact that cartilage damage due to osteoarthritis exhibits clear spatial variations, measuring the spatially dependent shear and compression properties in healthy and diseased articular cartilage can aid the understanding of the origin of osteoarthritis and assist in the development of a sensitive diagnostic tool for this disease.

The new TDIS™ introduces a device that combines the ability to image cells within a sample of biological tissue with simultaneous force transduction and control of shear or compression, thereby allowing researchers to measure fine spatial variations in the mechanical properties of these materials. Samples up to 10 mm on a side can be accommodated.

Acknowledgments:

The TDIS™ was developed with the help of Dr. Itai Cohen and Dr. Mark Buckley of the Cornell University Physics Department. The project was supported in part by the Cornell Center for Materials Research (CCMR) JumpStart Program.

Publications:

Buckley, M. R.; Gleghorn, J. P.; Bonassar, L. J.; Cohen, I. J. Biomech. 2008, 41 (11), 2430.

Michalek, A. J.; Buckley, M. R.; Bonassar, L. J.; Cohen, I.; Iatridis, J. C. J. Biomech. 2009, 42 (14), 2279.

Buckley, M. R.; Bergou, A. J.; Fouchard, J.; Bonassar, J.; Cohen, I. J. Biomech. 2010, 43 (4), 796.