Cellular entry and nuclear targeting by a highly anionic molecular umbrella

A fluorescently labeled, persulfated molecular umbrella (1) has been synthesized from cholic acid, lysine, spermine, and Coumarin 343 and found capable of entering live HeLa cells. The distributions of 1 throughout the cytoplasm and the nucleus were diffuse and punctate, respectively. This finding, together with its ability to cross liposomal membranes by passive diffusion, suggests that passive diffusion plays a significant role in the ability of I to enter cells. The fact that I is concentrated at the nucleus raises the possibility that molecular umbrellas of this type could be used for the nuclear targeting of drugs.