15502-m-pleumeekers

Figure 2. Scanning electron microscopy and microtomography of bilayer BNC scaffold. (A) Photograph of bilayer BNC scaffold (side view). Comparison between (B,C) scanning electron microscopy images of bilayer BNC scaffolds and (D) 3D reconstructed model of the porous layer using microtomography. Similar honeycomb arrangement of sheet-like structures is visible in both images. (E) Higher magnification of the area marked red in (D) . Morphometric analysis of segmented porous layer: (F) Morphometric parameters (Sc.Po = Scaffold Porosity ; Pore.Th = Volume-weighted mean pore size ; Wall.Th = Scaffold Wall Thickness ; and Wall.N = Scaffold Wall Number) and (G) histogram of pore size distribution. Purification of bilayer BNC scaffolds The bilayer BNC scaffolds were successfully purified from endotoxins, as shown by the low endotoxin level (0.15 ± 0.09 EU/ml) found after 14 days of washing with endotoxin-free water. (Table 2) This value is three times lower than the endotoxin limit (0.5 EU/ml) set by the FDA for medical devices [352]. The result from endotoxin analysis verified the effectiveness of the purification process to remove endotoxins from the bilayer BNC scaffolds. 160 CHAPTER 8