Fluorescence of hematoporphyrin in living cells and in solution.

The fluorescence properties of hematoporphyrin (Hp) and its derivative (HpD) were investigated in leukemia cells and in normal lymphocytes under a microscope, and the results were compared with those in solution. The spectra and the time behaviour of Hp (or HpD) fluorescence in living cells were found to be almost the same as those in Hp solution of very high concentration. This implies that Hp is much more concentrated in the cells than in the medium. It was also found that irradiation with intense light easily gives rise to a photoproduct which gives an additional peak in the fluorescence spectrum. Possible methods to increase the sensitivity of cancer detection and localization are discussed.