FIG. 2.

Effects of gel stiffness on the cellular morphology. (A) Fluorescence immunostaining images of human dermal fibroblasts (HDFs) in the hydrogels with varied elastic moduli (E) of 0.7 (A-1), 1.6 (A-2), and 2.2 kPa (A-3). Cell nucleus and intracellular actin were stained with DAPI (blue color) and phalloidin (green), respectively. (B) Fluorescence immunostaining images of cellular β1 integrin expression (green) and cell nucleus (blue) in the hydrogels with varied E of 0.7 (A-1), 1.6 (A-2), and 2.2 kPa (A-3).(C) Effects of E on the extent of cellular stretching, quantified with the cell area using ImageJ software. The differences between the three conditions were statistically significant (*p<0.05). (D) Effects of E on the cellular nucleus aspect ratio, calculated as the ratio of cellular minor axis (width) to major axis (height). The differences between cells encapsulated in the hydrogel with E of 0.7 and 1.6 kPa and those in the hydrogel with E of 2.2 kPa were statistically significant (*p<0.05). All characterizations presented in (A–D) were made 3 days after cell encapsulation in the hydrogels. (E) Effects of E on the intracellular β1 integrin expression. Integrin expression was examined on days 3 and 11 after cell encapsulation into the hydrogels. On day 11, the differences between cells encapsulated in the hydrogel with E of 1.6 kPa and those in the hydrogel with E of 0.7 and 2.2 kPa were statistically significant (*p<0.05). In all analysis, 150 cells were analyzed for each condition. Color images available online at www.liebertpub.com/tea