The absorption spectra were recorded on a Cary 300 UV-Vis double beam spectrophotometer (Agilent Technologies, Santa Clara, USA). Steady-state spectral and Time- 0.2% Triton X-100. Thereafter cells were stained with either Nuc-DAOTA + (75 µM) and Propidium Iodide (75 µM) for 15 minutes. After a brief wash the cells were mounted with glycerol on a slide and imaged with a Zeiss LSM 980 using a 63X/1.4 oil objective with a 488 nm laser set to 10% output (16.3 μW excitation lens). The staining and imaging experiment was repeated 3 times, each with 3 cells. A time series was setup scanning a single cell for 200 seconds, corresponding to 157 scans. After that, regions of interest were setup for measuring bleaching over time. Nuc-DAOTA + seemed to stain the nucleus more uniformly whereas Propidium Iodide primarily bound to the nucleoli in the 3T3 cells (Figure ) and (b), ESI). For that reason, Propidium Iodide bleaching was measured as an average of multiple stained regions in the cells.