4.4.4 Apoptosis analysis
The number of apoptotic and necrotic cells was analyzed by AM&PI staining apoptosis detection kit. In brief, 2 × 105HaCaT cells were cultured overnight in 6-well plates. After removing the culture medium, the cells were incubated in the extraction solution obtained by soaking the hydrogels in culture medium for 24 h. The cells were stained with AM (5 μl) and PI (5 μl), left in dark for 15 min then observed by fluorescence microscopy.