Figure 4.

Seeded scaffolds with post-printing void fraction modifications support highly viable 2.5D cell culture. Void fractions in 4x1 mm disc-shaped scaffolds were tuned by degrading thioester-linked microgels mixed with amide microgels at ratios of 0:100, 20:80, and 40:60. A) Without altering porosity of jammed microgels, multi-millimeter granular constructs were not fully colonized by seeded cells within 3 days. B–C) Scaffolds retaining 80% and 60% initial microgels were rapidly colonized across the depth of the printed construct. Bin widths for all histograms are ~0.01. Labeled black lines in viability histograms represent population-wide average. x-z projection was generated from a confocal z-stack with a slice thickness of 20 μm. Live and dead cells were respectively stained with calcein AM (green) and ethidium homodimer (red). Scale bars in the top panels = 500 μm.