Transplantation of mBax_499 mRNA treated hESC-CMs and testing for teratoma formation. Cardiac differentiated hESCs were treated with mBax_499 mRNA at day 15 for 24 h. (a) FACS analysis of cells stained with OCT3/4 for pluripotency (n = 3). p value was generated using one-way ANOVA with Tukey’s post-hoc test for multiple comparisons. *p < 0.05. (b–d) Teratoma formation was evaluated by injecting 106 cells in matrigel subcutaneously into SCID/NOD mice. (b) selected images of MRI body scan of subject without teratoma (left) and subject with teratoma (right - red arrow). (c) Bar graph representing the summarized results. (d) Selected images of Hematoxylin & Eosin staining of embedded tissues, dissected from mice that developed teratomas, presenting structures from all three germ layers. MES – mesoderm, ECT – ectoderm, END – endoderm. Scale bar: 100 µm.