Figure 3.

Cellular labeling using cross-linked Pdots. (a, b) Flow cytometry measurements made using cross-linked PFBT-NH-PIMA Pdot-streptavidin. Blue curve in (b) shows the positive labeling and red curve shows the negative labeling in the control, where identical experimental conditions were followed but in the absence of primary biotinylated antibody. (c, d) Confocal fluorescence microscopy images of MCF-7 breast-cancer cells labeled with cross-linked PFBT- NH-PIMA Pdot-streptavidin. Panel c shows positive labeling and panel d shows negative labeling performed under the same condition but in the absence of biotinylated primary antibody. Images from left to right: blue fluorescence from the nucleus stain Hoechst 34580; green fluorescence images from Pdot. (e) Confocal fluorescence microscopy image of microtubules in HeLa cells labeled with cross-linked Pdot-streptavidin. The blue channel was from the nucleus stain, while the green channel showed emission from PFBT-NH-PIMA Pdots. The HeLa cells were incubated with both biotinylated anti-α-tubulin and PFBT-NH-PIMA Pdot-streptavidin. All the scale bars represent 20 μm for (c), (d) and (e).