Differential behaviour of cationic triphenylamine derivatives in fixed and living cells: triggering and imaging cell deathElectronic supplementary information (ESI) available: Experimental details, sub-cellular localization, biochemical analysis, photocytotoxicity. See DOI: 10.1039/c5cc05970d

Triphenylamines are on/off fluorescent DNA minor groove binders, allowing nuclear staining of fixed cells. By contrast, they accumulate in the cytoplasm of living cells and efficiently trigger cell apoptosis upon prolonged visible light irradiation. This process occurs concomitantly with their subcellular re-localization to the nucleus, enabling fluorescence imaging of apoptosis. Nuclear staining by cationic triphenylamines is spontaneous in fixed cells while a cytoplasm-nucleus translocation is strictly dependent on light illumination in living cells and concomitant to a fast cell death process.