Investigation of Excited-State Photophysical Properties of Water Soluble Gallium Corrole

The photophysical properties of the excited states of the water-soluble gallium corrole (Ga(tpfc) (SO3Na)(2)) and fluorescence lifetime imaging in three kinds of living cell lines have been investigated using the steady-state and time-resolved spectroscopic techniques. In comparison with gallium corrole (Ga(tpfc) (py)) in six selected solvents, Ga(tpfc) (SO3Na)(2) shows the much weaker emission and B-band absorption, and the Q-band absorption exhibits red-shift of about 15 nm, the fluorescence lifetime decreases, while the triplet lifetime increases. The internal transition time from the B-band to the Q-band of Ga(tpfc) (SO3Na)(2) is similar to that of Ga(tpfc) (py) in toluene. The high polarity of the water has an important impact on the dynamics of the singlet and triplet states, which may result in efficient electron transfer to the oxygen. This observation has been confirmed by the EPR experiment. Without the aid of carrier proteins, Ga(tpfc) (SO3Na)(2) can penetrate into three kinds of living cell lines: mouse fibroblast (L-929), human breast cancer (MCF-7), and human prostate carcinoma (PC-3M). Efficient energy transfer and intracellular high accumulation has been observed in the PC-3M cell line, which results in the fluorescence quench and shorter lifetime.