Optical Fluorescence Imaging-based Monitoring of Myocardial Tissue Regeneration after Transplanting Prevascularized Tissue Construct Fabricated by 3D Bioprinting Technology

Stem cell therapy has been actively studied as a treatment for ischemic heart disease. Particularly, a patch-type carrier can improve the therapeutic effect by enhancing homing and engraftment of stem cells into damaged myocardial tissues. From a therapeutic point of view, longitudinal monitoring of living cells is essential to understand the mechanisms of neovascularization induced by stem cells. Optical fluorescence imaging can provide long-term live tracking of multiple target cells due to its high sensitivity and multimodal capability. Also, the recent development of molecular probes, which are target-specific and nontoxic with optical and physicochemical stability in the near-infrared (NIR) window, contributes to in vivo live cell tracking. Therefore, this study aims to monitor the efficacy of cardiac stem cell-laden patch in ischemic myocardial tissue by using optical fluorescence imaging based on the NIR probes. First, we used three sets of spectral filter and CCD sensor. Second, contrast agents were selected to observe ischemic tissue, mitochondria, and lipoprotein. Using 3D bioprinting technology, we fabricated a pre-vascularized tissue construct with bioink composed of decellularized extracellular matrix and stem cells. Finally, we observed the interaction between the delivered construct and the ischemic myocardial tissue after transplanting it into the heart of the rats.2