(a) Representative 3D track reconstructions for cell migration in island architectures. (b) Mean squared displacements, mean speeds, sphericity, and migration track length for migrating cells. N = 3, n > 200 cells. (c) Representative images of alkaline phosphatase staining (blue), indicating early osteogenic differentiation, for MSC cultured in island gels for 7 days. Scale bar is 200 μm. (d) Corresponding ALP (+) fraction of cells. n ≥ 3 images from 3 independent replicates. (e) Representative images of RUNX2 (green), DAPI (cyan), and F-actin (magenta) of MSCs cultured in island gels for 7 days. (f) Corresponding RUNX2 nuclear to cytoplasmic ratio of cells cultured in each island gel. N=3, n > 53 cells. Scale bar is 30 microns. mean ± sd * p < 0.05; **, p < 0.01; ***p < 0.0001 by one-way ANOVA.