(a) Mass spectra of disulfide-bridged pyrene derivative PnSS before (top) and after (bottom) irradiation; a 10 μM sample was irradiated for 30 minutes at 350nm. (b)(c) Cleavage efficiency for 10μM PS2, PS1 and SS as a function of UV irradiation time. Denatured PAGE gel image was obtained with a digital camera for (b) PS2 (red), PS1 (black) and SS (blue) (c) P1S (green), P3S (red) and P5S (blue) after 5, 15, 25, 40 and 60 min of irradiation. Data were analyzed with Image J software from NIH.