Confocal imaging reveals some dead or membrane-permeable cells in mouse islets 4 h after coating that disappear by day 2 in culture. Islets were stained with CellTracker Green CMFDA (live cell, green), propidium iodide (PI; permeable membrane, red), and Hoechst 33342 (nucleic acid, blue) stains. Images are overlaid Z stacks of 19–24 images. Scale bar, is 200 μm for all 3 images.