Figure 1.
Optical and SEM micrographs of the PHBV and PHBV/BG scaffolds.
The PHBV and PHBV/BG scaffolds prepared using the compression molding, thermal processing and salt particulate leaching method had a regular shape, and some pores on the surface of the scaffolds can be observed. The SEM images show that the PHBV and PHBV/BG scaffolds exhibited a macroporous structure with interconnected open pores, and the pore size varied from 30 µm to 300 µm. Scale bar = 100 µm.
Figure 2.
Characterization of the scaffolds.
As shown in Fig. 2, both the PHBV and PHBV/BG scaffolds were fabricated in the shape of rectangular prisms with the same volume and the same porosity (p>0.05). However, there were significant differences between PHBV and PHBV/BG in terms of the compressive strength, water absorptivity, water contact angle and cell adhesion.
Figure 3.
Fluorescence analysis of cell migration.
GFP labeling showed that the cells could easily migrate toward the inner region of the scaffolds in in vitro culture in the PHBV/BG group. In the PHBV group, the cells primarily assembled on the surface of the scaffolds, even after 12 h of culture. Scale bar = 100 µm.
Figure 4.
Gross view of tissue engineered cartilage and cell proliferation for each group.
The DNA content of the cells retrieved from the different scaffolds at different time points during in vitro culture was determined. The DNA content of the PHBV/BG group was significantly higher than that of the PHBV group. The results of the MTT assay showed that the incorporation of BG enhanced chondrocyte proliferation. The chondrocyte-scaffold constructs were harvested after 3 weeks of culture in vitro, and it was observed that the chondrocyte-scaffold constructs formed cartilage-like tissue.
Figure 5.
Gross evaluation of in vivo engineered constructs.
There were significant differences between the two groups in terms of the thickness, side length, volume and wet weight from 4 to 12 weeks in vivo (p<0.05). These results indicate that the incorporation of BG into PHBV can promote the adhesion and proliferation of chondrocytes on scaffolds.
Figure 6.
The collagen content, GAG content and comp. modulus.
The collagen and GAG contents and the comp. modulus were significantly higher in the PHBV/BG group than in the PHBV group at different time points (p<0.05).
Figure 7.
Full-thickness histological images of in vivo engineered cartilage.
The constructs in the PHBV/BG group were much thicker, with thicker cartilage-like tissue layers, than those in the PHBV group. Scale bar = 100 µm.