Figure 2.

Oxygen-controllable hydrogel matrices. (a) A schematic illustration of hydrogel formation with oxygen consumption in the laccase-mediated crosslinking reaction; (b) a computer simulation of oxygen gradients throughout the hydrogel matrices, suggesting our hydrogel matrices provide an oxygen-controllable microenvironment; (c) confocal microscopic images of ECFCs cultured within the different oxygen levels (hypoxic vs. non-hypoxic); confocal z-stacks and orthogonal sections show lumen formation (indicated by arrows) within the vascular networks (phalloidin in green; nuclei in blue). Scale bars, 50 mm. From Park et al. [22]. Copyright 2014 with permission from Nature Publishing Group.