Optical Coherence Elastography of Engineered and Developing Tissue

Abstract

Biomechanical elastic properties are among the many variables used to characterize in vivo and in vitro tissues. Since these properties depend largely on the micro- and macroscopic structural organizationtissue, it is crucial to understand the mechanical properties and the alterations that occurtissues respond to external forces or to disease processes. Using a novel technique calledcoherence elastography (OCE), we mapped the spatially distributed mechanical displacementsstrains in a representative model of a developing, engineered tissue as cells began to proliferateattach within a three-dimensional collagen matrix. OCE was also performed in the complextissue of the Xenopus laevis (African frog) tadpole. Displacements were quantifieda cross-correlation algorithm on pre- and postcompression images, which were acquired usingcoherence tomography (OCT). The images of the engineered tissue were acquired over a 10-development period to observe the relative strain differences in various regions. OCE was abledifferentiate changes in strain over time, which corresponded with cell proliferation and matrixas confirmed with histological observations. By anatomically mapping the regional variationstiffness with micron resolution, it may be possible to provide new insight into the complexby which engineered and natural tissues develop complex structures.