Although research and clinical applications for stem cells have increased dramatically in the last decade, development of new assay formats and reagents has not kept pace. The current Colony Forming Cell (CFC) assay, which relies on colony evaluation and enumeration by microscopy after culture on plates, is slow with a cell culture period of about 14-16 days. The microscopic scoring method used in this assay format also limits the number of cells that can be screened. Using single cell gel microdrop (GMD) encapsulation technology and flow cytometry, this SBIR aims to develop a rapid, quantitative assay to simultaneously detect colony formation and identify cell lineage. Using this assay format, sub-populations of cells of interest can be isolated, and propagated for further studies and use in therapeutic applications. The proposed assay will provide a rapid method for identifying and isolating sub-populations of stem cells of interest for use in research and clinical applications, including cellular therapies for diseases such as chronic heart disease, end-stage kidney disease, liver failure and cancer. ? ? ?