Fig. 4.

Modulation of VEGF expression of hASCs transfected on silicone hydrogels with different stiffness. A) Fluorescence images of HUVECs stained with calcein and seeded on a regular tissue culture-treated 24 well plate. Scratches were made in the 24 well plate at time zero on HUVEC monolayer. Cells were allowed to migrate into the void area for 24 hours. The conditioned media in the soft and stiff group was supplemented with VEGF secreted by hASCs after 72 hours post-transfection. No VEGF and recombinant human fibroblast growth factor-B (rhFGF-B) were present in the media of the control group (Ctrl-). Scale bar = 200μm. B) Quantification of the surface area covered by HUVECs after proliferation through the original scratches at 12 and 24 hours. The area covered was calculated based on the original area of the scratches at time zero (n=3). C) Quantification of VEGF expression by ELISA after 72 hours post-transfection. Results are normalized based on the VEGF expression of hASCs cultured on the soft substrate (0.5 kPa) (n=3).*= p < 0.05, ** = p < 0.01, *** = p < 0.001.