(A) Percentage of cells undergoing apoptosis analyzed at zero, one and two days post treatments for cells left as untreated control (C group), treated with dispase and suspended as cell sheets (D group), or trypsinized and suspended as single cells (T group). Trypsinized cells, lacking both cell-substrate and cell-cell contact, exhibited significantly increased apoptosis after one day post treatment. (B) The general caspase inhibitor Z-VAD-FMK (ZVAD) significantly reduced apoptosis in trypsinized single cells. Keratinocytes were grouped into three broad groups: untreated controls (C group, lane 1–3), dispase-lifted and suspended as sheets for one day (D group, lane 4–6), and trypsinized and suspended as single cells for one day (T group, lane 7–9). DMSO was used as a vehicle control. ** p<0.01.