Figure 5. In vivo evaluation of non-labeled and USPIO-labeled and collagen scaffolds.
A) T1-and T2-weighted MRI of subcutaneously implanted scaffolds over a time period of 22 days. The images clearly show that the labeled scaffolds could be sensitively detected and accurately localized. B) Quantitative analysis by R2 and R2* relaxometry. C) Light and fluorescence microscopy analysis of non-labeled and USPIO-labeled collagen scaffolds ex vivo. Cells were stained with hematoxylin and eosin (H&E), with Hoechst (blue; nuclei) and with antibodies against the macrophage marker F4/80 (red). Collagen autofluorescence is depicted in green. Scale bars indicate 200 μm. D) Quantitative evaluation of the macrophage staining by area fraction analysis. No qualitative and quantitative differences in scaffold acceptance and macrophage infiltration were observed for labeled vs. non-labeled scaffolds.