Disclosed herein are methods, systems, and compositions for enhancing the effectiveness of β-
cell (Beta-
cell)-based therapies. Also disclosed herein are methods, systems, and compositions related to identifying, sorting and separating heterogeneous populations of
stem cell-derived pancreatic β-cells (sBCs) into more useful and functionally homogeneous
cell populations. In many embodiments, the most mature and functional of the sBCs are identified and live-sorted using the cell
surface protein Ectonucleoside Triphosphate Diphosphohydrolase-3 (ENTP3), which is also referred to as CD39L3. The presently disclosed methods, systems, and compositions are useful for cell therapies, for example replacement therapy. In many embodiments the disclosed systems, methods, and compositions are useful in treatments for diabetes. In some embodiments, the disclosed methods, systems, and compositions may be useful in treating, preventing, and / or curing diabetes, for example type-1 diabetes.