Uptake and cell-killing activities of a series of Victoria blue derivatives in a mouse mammary tumour cell line.

The triarylmethane dye Victoria blue BO (VBBO) is a known photosensitizer which has been shown to induce a cytotoxic response in vitro. Several novel Victoria blue derivatives, with varying physicochemical properties, have been compared to VBBO, with respect both to dark toxicity and phototoxicity, on a mouse mammary tumour cell line, EMT6. Photosensitizer uptake was observed using confocal fluorescence microscopy. The chemical differences, particularly in the naphthyl substitution of the derivatives were shown to alter the light:dark toxicity differential and the uptake of the photosensitizers.