Figure 1.
Surface characteristics and and biomechanical properties of disc shaped PLA, BG20 and BG40.
Surface characteristics were analysed by SEM (A). The upper row provides an overview, the lower row presents a detailed view on distinct surface characteristics. Biomaterials with bioglass demonstrated a much more jagged surface with greater pores (arrows) than pure PLA. Red scale bar: 100 µm (upper row), 30 µm (Lower row). A sagittal cross section of PLA, BG20 and BG40 is shown in (B). PLA (left) appeared relatively homogenous with great cavities and pores, whereas BG20 (middle) and BG40 (right) demonstrated a biphasic structure. The upper part of BG20 and BG40 is characterized by an amorphic structure with pores and channels whereas the lower part has a higher density with few small pores. Red scale bar: 200 µm (PLA, BG20), 300 µm (BG40). The ultimate load of the disc shaped biomaterial specimen is depicted in (C). The median ultimate load as measured by a three point bending test increases slightly with the bioglass content of the biomaterials (n = 8, not significant).
Table 1.
Group setup and number of animals per group.
Figure 2.
Characteristics of cells in vitro and evidence of cells seeded on the scaffold placed in the skull critical size defect.
Shape and appearance of EPCs and MSCs obtained from rats in (A) and (B), respectively. Dil-uptake as a marker of endothelial differentiation is exemplarily shown for EPCs seeded on BG20 (C), the calcium deposition as measured by von Kossa staining revealed osteogenic differentiation of MSCs (black areas, D). Adherence of MSCs and EPCs one hour after seeding to the BG20 scaffold (E). MSCs and EPCs can be differentiated by size. Position of scaffold loaded with cells (arrow) in the skull critical size defect of the rat (F). Scale bars: 100 µm (A, B), 200 µm (D), 10 µm (E).
Figure 3.
Gross histology of skull defect 3 months after scaffold implantation.
Area location (A). Normal rat skull (B). No signs of inflammation are visible. Membrane surrounding the defect (arrows). Staining indicates membrane ossification. Marked increase in new bone formation when implants are populated with progenitor cells and contain a bioglass fraction (G, H, I, J, K, L). PLA = polylactic acid. BG20 = PLA + 20% bioglass, BG40 = PLA + 40% bioglass. MSC = mesenchymal stem cells, dMSC = differentiated mesenchymal stem cells, EPC = endothelial progenitor cells. nb = new bone, b = bone.
Figure 4.
Gross histology of the liver and kidney 3 months after scaffold implantation.
No relevant alterations were seen in the treatment groups, compared to control animals and animals with an empty defect. PLA = polylactic acid. BG20 = PLA + 20% bioglass, BG40 = PLA + 40% bioglass. MSC = mesenchymal stem cells, dMSC = differentiated mesenchymal stem cells, EPC = endothelial progenitor cells.
Table 2.
Free radical markers after 3 months.
Table 3.
Body weight (bw) and relative organ weight after 3 months.
Table 4.
Hematologic and inflammatory parameters after 3 months.
Table 5.
Serum biochemistry (part 1) after 3 months.
Table 6.
Serum glucose, total protein content and urea after 3 months.