Fig. 1

PEG modification to the surface of MSCs. A Fluorescence intensity of FITC-PEG-C3H10T1/2 cells. Streptavidin-modified C3H10T1/2 cells or unmodified C3H10T1/2 cells were incubated with FITC-PEG-biotin. The fluorescence intensity was measured using a microplate reader. The results are expressed as percentages of the value at 1 h. The error bars represent ± SD, n = 4, *p < 0.05 versus FITC-PEG-biotin + C3H10T1/2 group. B Confocal imaging of FITC-PEG-C3H10T1/2 cells. Streptavidin-modified C3H10T1/2 cells or unmodified C3H10T1/2 cells were incubated with FITC-PEG-biotin. The cells were cultured for 3 h and observed using a confocal laser scanning microscope (scale bars: 20 μm). C Retention time of PEG modification. Streptavidin-modified C3H10T1/2 cells were incubated with Alexa488-PEG-biotin, and the fluorescence intensity was measured using a microplate reader. The error bars represent ± SD, n = 4