Figure 1.

Silk hydrogels used for cell culture studies. (A) Schematic depiction of elastic and viscoelastic silk hydrogel preparation and corresponding macroscopic (scale bar 0.5 cm) and scanning electron microscopic images (scale bar, 200 μm; zoom, 100 μm) of silk hydrogels. (B) Initial elastic modulus (∼1 kPa) and (C) dry mass after 7 and 14 days in the presence and absence of cells, normalized to the value of day 1. (D, E) Stress relaxation under a compressional strain of 15% of the hydrogels in the presence and absence of cells for up to 14 days. Data are presented as mean ± SD, n = 5 independent experiments. Error bars are hidden in the plot symbols when not visible. For *p ≤ 0.05, a comparison of silk hydrogel with and without cell culture at the respective time point.