Figure 4

Cell images at different stages of growth. Control cells at (a) Day 2, (b) Day 4, and (c) Day 6 of growth. Notice the extensive fiber concentration but depleted cell content as early as Day 2. Treated cells (d) Day 2 and (e) Day 4 are significantly more populated with differentiated cardiomyocytes when compared with controls (p < 0.05 by t-test, n = 5). (f) Day 6 cells show even more extensive cardiomyocyte growth aided by the thick scaffold underlay (p < .01 by t-test, n = 5). (g) Transmission electron microscope images of treated cells were taken at Day 4. Notice cell infiltration, adhesion, and active division. Scale bar 30 μm. Nanoscaffolds are labeled with blue arrowheads; cell bundles with red arrowheads.