A digital image correlation based technique to control the development of a skeletal muscle engineered tissue by measuring its surface strain field

X-MET (Ex-vivo Muscle Engineered Tissue) is a promising 3-dimensional model of skeletal muscle for in vitro tests and in vivo transplant. X-MET is an in vitro cultured tissue and has several properties in common with adult skeletal muscle, from biological and morphological to functional ones. To monitor the X-MET's growing improvements, we developed an experimental system based on Digital Image Correlation (DIC) to precisely measure the tissue's contractile capability, thus trying to prevent the formation of any anisotropic or inhomogeneous parts. We employed a high speed camera mounted on a stereomicroscope, and synchronized the image acquisition with the electrical stimulation and the force response measurement. The capability of measuring the 2-dimensional surface strain field in any desired Region Of Interest (ROI) allowed to obtain a comprehensive monitoring of the tissue's formation, both at a global and a local level. Preliminary results confirmed the adequacy of the system to measure tissue's strain field in complete accordance with the force measurement. Moreover, an in-depth analysis allowed to precisely pinpoint the sub-zones where discontinuities arise during tissue formation, returning essential information to improve X-MET generation process.