Fig. 3. Fluorescence images of 605QD and Cy5 obtained by TIRF-based single-molecule detection in the absence (A–C) and presence (D–F) of methylated DNA. The fluorescence signal of 605QD is shown in green (A and D), and the fluorescence signal of Cy5 is shown in red (B and E), and the colocalization of the 605QD and Cy5 fluorescence signals is shown in yellow (C and F). The concentration of methylated DNA is 1.0 × 10–11 M. The concentration of each DNA probes X, Y, X′ and Y′ is 1.0 × 10–6 M. The concentration of 605QD is 8.3 nM. The scale bar is 2 μm.
