Figure 4.

(a) Bending behaviors of MFH gradient hydrogel bars with and without embedded cells. Insets show representative photomicrographs of the bent hydrogel bars. (b) Photomicrograph of a NIH3T3-laden MFH-based construct. (c) Representative live/dead image of NIH3T3 fibroblasts in the gradient hydrogel bar. (d) Photomicrograph of a cell-laden “biohelix” structure. (e) Photograph of a cell-laden “bioS” structure. Photographs of (f) a cell-laden “pseudo-four-petal” and (g) a cell-laden “pseudo-six-petal” flower. Inset photographs show the corresponding as-printed structures. Kirigami-based structures and the deformed configurations: hydrogels in bar-grid patterns (h) without and (i) with inner horizontal bars. For cell-laden gradient hydrogel bars (insets in a), only 0.02% HMAP was used as the UV absorber, they were cultured in GM overnight at 37 °C, and then imaged and live/dead stained. For complex cell-laden hydrogel configuration formation, a mixture of 0.02% HMAP and 0.005% RhB UV absorbers was used. These bioconstructs were obtained after culturing in GM at 37 °C overnight, and images were immediately taken after replacing the GM with FBS for clarity. Data are presented as mean ± SD, N = 3.