Fig. 4: Ex vivo human skin equivalent (HSE) model of the film hydrogels.

a Representative images of MTT staining for wound healing. b Quantitative measurement of the MTT assay at the day 4 and day 7 time points (triplicated; n = 9 biologically independent samples, two-tailed Student’s t test, data are presented as mean values ± SEM). c Representative immunostaining images of H&E, p63, Keratin 10 (K10), and Keratin 14 (K14) after treatment with the PPN(C4)−1 hydrogel and its variants (PP-N is without PIM(C4)−1, and PPN- is without NAC). Scale bar = 100 μm.