. fat and injection site, confirming the report of Jing et al. (2 06, 207). In addition, our results showed that we could detect labeled cells in vivo up to 6 weeks, thus the SPIO labeling method. particles in the cells were visualized as the blue dots in the cells. ! ! Figure 3-20. Prussian blue staining of iron labeled MSCs in the para- patellar fat. Prussian blue staining was used. staining of the iron labeled MSCs in the surgical scar site. Prussian blue staining was used to detect the presence of the iron labeled MSCs in the surgical scar site. The iron particles in