Fig. 7

MG-63 osteoblasts transfected with PEI-SPIO-NPs/pDNA or PEI-NPs/pDNA under the condition of no magnetic field, non-uniform magnetic field, or uniform magnetic field. GFP-pDNA was used for reporter gene in combination with PEI-NPs or PEI-SPIO-NPs (N/P = 10), and the cells were exposed to the non-uniform or uniform magnetic fields for 20 min. At 24-h post-transfection, cell images were captured under an inverted fluorescent microscope. PolyMag-200 comprise commercial magnetic transfection reagents that were used as positive control, naked pDNA was used as the negative control. a At × 40 magnification in an inverted fluorescent microscope. b Transfection efficiency was calculated by flow cytometer and c statistical analysis of the transfection efficiency of PEI-SPIO-NPs/pDNA group, PolyMag-200/pDNA group and PEI-NPs/pDNA group. The results are expressed as the mean ± SD (n = 5, one-way ANOVA, *P < 0.05, **P < 0.01)