Figure 1.

Iron oxide magnetic nanoparticles (IO MNPs) increase CXCR4 expression in mesenchymal stem cells (MSCs). (A) Real-time PCR analysis of cell surface receptor expression of IO MNP-treated MSCs. MSCs were incubated with IO MNPs for 2 h. After changing to fresh medium, the cells were continued to culture for 22 h. (B) Western blot analysis of MSC CXCR4 expression after treatment with different concentrations of IO MNPs at the indicated culture time after labeling. The results of Western blotting were quantified by measuring the band density and then normalizing it to GADPH. (C) Effects of IO MNP labeling on MSC migration in the presence and absence of SDF-1α. Representative images of migrated MSCs (arrow) through 12 μm pore sized membrane. (Left) After particle labeling, the same number of MSCs were plated in the upper chambers at a density of 2 × 10⁴ cell/well. Once the cells were in culture for an additional 22 h, the cells in the upper surface of the membrane were removed, while the cells migrated to the lower membrane surface were fixed and stained with crystal violet. (Right) Quantitative analysis of the migration of MSCs untreated and treated with IO MNPs in the presence and absence of SDF-1α. Values represent mean ± SD (*p < 0.05, **p < 0.01).