Mechanical Performance of Engineered Heart Tissue Can Be Measured with POC-Based Video Analysis

Recently, research aiming at elucidation of causes and therapies of diseases using artificial tissues derived from disease-specific induced pluripotent stem cells (iPSCs) has been active. An important part of this approach is to quantitatively measure the functional health or performance of the artificial tissue of interest. Specifically, in the engineered heart tissue (EHT), it is very important to measure its contraction and relaxation forces. To this end, we develop a method based on the Phase-only Correlation (POC) for measuring contractile and diastolic forces by culturing cardiomyocytes on a pair of pillars with known mechanical properties and capturing video of tissue movement in response to a cyclic stimulus using a fluorescence microscope. The method tracks the tissue movement over the frames and then determines its maximum deflection and frequency by fitting the detected deflection to a sine function. We show that our method enables the measurement of the mechanical performance of the EHT. Accuracy analysis reveals that our method exhibits better accuracy compared to the known HOG-based method.