Figure 4.

A zonal microstructured scaffold mimics the structure of AC and subchondral bone to repairing osteochondral defects: (a) cross-section of the complete scaffold showing each unique zone, (b) partially fused poly-ε-caprolactone (PCL) fibers used to adhere the electrospun mat to the underlying foam using residual solvent (top-down image), (c) a cross-sectional view of the porogen-electrospun interface, (d) vertical channels through the directionally frozen foam (top-down image), (e) a cross-sectional view of the directionally frozen-electrospun interface, and (f) melt-electrowritten osteo component (top-down image). The osteo component consisted of 20 μm diameter fibers stacked at 200 μm intervals in a 90-degree lay-down pattern. Figure at right is a conceptual schematic of the zonal microstructured osteochondral scaffold, features are not proportionally represented. Scale bars for images a, b, c, d, e, and f are 250, 10, 50, 100, 25, and 100 μm, respectively. Reproduced from Steele et al.⁷⁰