Figure 4.

3D printed bone-mimicking radial-gradient scaffolds. (a)-(i) Photos of the 3D printed fractal-like β-TCP/PCL and dye/Alg sample with 3 iterations, which are axonometric drawings (a), axial drawings ((b) and (c)), longitudinal drawings ((d) and (e)), enlarged drawings of the inner scaffolds ((f) and (g)), and enlarged drawings of the outer scaffolds ((h) and (i)). The red and blue boxes represent the inner and outer structures of the 3-iteration fractal-like scaffolds, respectively. (j) and (k) Top and axial side views of live (green)/dead (red) CLSM images of the white box part (b) of the bio-printed fractal-like scaffolds. (l) and (m) Pictures of the 3D printed fractal-like PLGA sample. (a), (b), (d), (f), and (h) are optical images; (c), (e), (g), and (i) are CT images. Scale bars, 500 μm ((f) and (h)); 1 mm ((g) and (i)); 5 mm ((b)-(e), and (m)).