FIG. 2.

Trypan blue staining of hESC colonies treated with smoke solution for 24 h exhibited cell death at 1 PE but not at 0.1 PE. (A) Typical control colony with little trypan blue staining, whereas the insert shows a less frequently observed control with slightly more staining. Other colonies were treated with 0.1 PE of MS smoke (B–E), 1 PE of MS smoke (F–I), 0.1 PE of SS smoke (J–M), or 1 PE of SS smoke (N–Q). Images were taken using brightfield microscopy. Scale bars for 1 PE SS smoke treatments = 10 μm, and all other scale bars = 20 μm. (R) and (S) are Hoffman and fluorescent images of control colonies stained with Magic Red Caspase 3 & 7 Detection Kit. (T) and (U) are Hoffman and fluorescent images of colonies treated with 1 PE of Quest SS smoke solutions and then stained with Magic Red. For Magic Red groups, scale bars = 50 μm. For both trypan blue and caspase detection, images are representatives from two separate experiments. PE = amount of smoke in one puff that dissolves in 1 ml of medium.