High-resolution elasticity imaging for tissue engineering

An elasticity microscope provides high resolution images of tissue elastici ty. With this instrument, it may be possible to monitor cell growth and tis sue development in tissue engineering. To test this hypothesis, elasticity micrographs were obtained in two model systems commonly used for tissue eng ineering. In the first, strain images of a tissue-engineered smooth muscle sample clearly identified a several hundred micron thick cell layer from it s supporting matrix. Because a one-dimensional mechanical model was appropr iate for this system, strain images alone were sufficient to image the elas tic properties. In contrast, a second system was investigated in which a si mple one-dimensional mechanical model was inadequate. Uncultured collagen m icrospheres embedded in an otherwise homogeneous gel were imaged with the e lasticity microscope. Strain images alone did not clearly depict the elasti c properties of the hard spherical cell carriers, However, reconstructed el asticity images could differentiate the hard inclusion from the background gel. These results strongly suggest that the elasticity microscope may be a valuable tool for tissue engineering and other applications requiring the elastic properties of soft tissue at high spatial resolution (75 mu m or le ss).