CM-pyranine is resistant to photobleaching.

<p>Microdroplets of CM-pyranine and fluorescein were photobleached at 405 and 489 nm, respectively (see Experimental section for details). Progress of photobleaching was monitored by confocal imaging of the microdroplets. The fluorescence at any time is normalized to the intensity at <i>t</i> = 0. Two representative time courses are shown. For all measurements performed, mean half-lives were 1510 ± 230 sec (or 25.1 ± 3.8 min; n = 3) and 11.2 ± 3.1 sec (n = 8) for CM-pyranine and fluorescein, respectively.