Abstract
It is demonstrated that a highly sensitive synchroscan streak camera technique for picosecond time-resolved fluorescence spectroscopy is very useful for the investigation of fast dynamic behaviours of biomolecular systems. The technique is applied for studies of 1)incorporation and excretion processes of hematoporphyrin derivative (HpD) into and from malignant tumor cells in vitro and 2)relaxation processes from the electronic excited-state of nucleic acidic bases (9-methyladenine: 9Me-A), as follows.
1)HpD study: The results show that the aggregate component of HpD which has a fast fluorescence lifetime of 100 ps and a red-shifted band of -660 nm in comparison with a monomer band accumulates more and more in the cells with the increase of the incubation time. The aggregate excretes from the cells in the very different manner from the monomer. The mechanisms are discussed.
2)9Me-A study: The result shows diffusion-free intermolecular excimer formation in liquid aqueous solution of 9Me-A. The excimer fluorescence (330 ps lifetime) appars at 380 nm, at longer wavelength than the monomer fluorescence (5 ps lifetime). The excimer is formed via a weakly coupled stacking dimer composed of ground-state monomers.
