The effects of photobleaching on electrochemiluminescence (ECL) was investigated for the first time. The plasma membrane of Chinese Hamster Ovary (CHO) cells was labeled with a [Ru(bpy)3 ]2+ derivative. Selected regions of the fixed cells were photobleached using the confocal mode with sequential stepwise illumination or cumulatively and they were imaged by both ECL and photoluminescence (PL). ECL was generated with a model sacrificial coreactant, tri-n-propylamine. ECL microscopy of the photobleached regions shows lower ECL emission. We demonstrate a linear correlation between the ECL decrease and the PL loss due to the photobleaching of the labels immobilized on the CHO membranes. The presented strategy provides valuable information on the fundamentals of the ECL excited state and opens new opportunities for exploring cellular membranes by combining ECL microscopy with photobleaching techniques such as fluorescence recovery after photobleaching (FRAP) or fluorescence loss in photobleaching (FLIP) methods.
Keywords: cell membranes; electrochemiluminescence; microscopy; photobleaching; single cell studies.
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