Figure 3.

Single-molecule characterization of rhodamines 4 and 5. (A) Representative single-molecule fluorescence time traces showing the number of detected photons from single molecules of 4. (B) Histogram showing the distribution of photons. The mean number of photons for 4 was calculated using a single-exponential fit (blue line). (C) The on/off duty cycle was calculated for 4 and plotted as a function of time (orange squares). The average duty cycle was calculated for the last 100 s of acquisition where the switching events reach a quasi-equilibrium state (gray box). This duty cycle was used to determine the survival fraction during image acquisition and is plotted against time (blue dots). (D) Image showing single molecules of 4 in 1% w/v PVA on glass. (E) Representative single-molecule fluorescence time traces showing the number of detected photons from single molecules of 5. (F) The mean number of photons for 5 was calculated using a single-exponential fit (blue line). (G) The on/off duty cycle was calculated for 5 and plotted as a function of time (orange squares). The average duty cycle was calculated for the last 100 s of acquisition where the switching events reach a quasi-equilibrium state (gray box). This duty cycle was used to determine the survival fraction of 5 during image acquisition and is plotted against time (blue dots). (H) Image showing single molecules of 5 in 1% w/v PVA on a glass surface.