['We demonstrate a method that includes colocalization studies to analyze cell suspensions after isolation and to characterize 3-dimensional grafts consisting of cells and matrix in vitro and in vivo.', 'Neonatal rat cardiomyocytes were labelled by CFDA-SE after harvest. Cells in the isolated cell suspension, the embodied cells in the seeded scaffolds were characterized measuring features such as viability and distribution of the cell types.', 'Selective cell count revealed high yields of viable cardiomyocytes. After seeding cells in collagen matrix, viability of the cells decreased gradually in the time process in vitro. Histology of implanted bioartificial myocardial tissue detected viable cardiomyocytes within the graft.'] Does carboxyfluorescein diacetate succinimidyl ester facilitate cell tracing and colocalization studies in bioartificial organ engineering?