Figure 4.

Cell binding of the sTN29 aptamer. Binding curves of the 5′-biotinylated sTN29a (A) or sTN29b (B) on MDA-MB-231 cells for calculation of the apparent Kd of aptamer-cell interaction. Binding was analyzed using the streptavidin-biotin-based assay. Data shown are mean ± SD of three independent experiments. (C,D) Representative confocal images of MDA-MB-231 (C) and BT-474 (D) cells were incubated for 10 min at RT with the indicated Alexa 647-labeled aptamers. Alexa 647-labeled aptamer, WGA-488, and nuclei are visualized in red, green, and blue, respectively. All digital images were captured at the same setting to allow direct comparison of staining patterns. Magnification 63×, 1.0× digital zoom, scale bar = 10 μm. At least three independent experiments were performed. In (C), co-localization results appear yellow in the merged images. Inset: 4× digital zoom.