Abstract
The uptake and selective accumulation of fluorescent labels and drugs into organelles of cultured cells currently are widely investigated in biomedical research. In such studies, co-localization procedures are frequently used to identify the accumulation sites of compounds with biological activity. A drawback with fluorescent labeling is the autofluorescence of some cell organelles, which can hinder the precise assessment of co-localization. We report here labeling of the Golgi apparatus of A-549 cells using the photosensitizer zinc(II)-phthalocyanine (ZnPc) and co-localization with the Golgi probe NBD C6-ceramide. The blue autofluorescence signal of mitochondria can be subtracted easily from the original picture by image processing, after which the co-localization of the isolated red ZnPc signal with the green signal from the Golgi probe is considerably improved.