血卟啉及其衍生物在水溶液和细胞内的时间分辨荧光的研究

本文报道了血叶啉衍生物(Hpd)及其由高压液相色谱法分离制备的4种主要成分以及血叶啉,血叶啉二盐酸盐和原叶啉(Ⅸ)二钠盐等8种叶啉衍生物分别在水溶液和CHO细胞内的荧光衰变动力学的研究,实验表明,除Hpd分离组分d的荧光寿命略短外,其余7种在水落液里的荧光寺命均在15ns左右,并发现它们的荧光态在细胞内衰变加快,然而,分离组分d在细胞内的荧光寿命却明显加长.根据实验结果,本文对叶啉衍生物的最低激发单线态在细胞内的驰豫过程提出了一种可能的模式,它反映了叶啉衍生物在细胞内与某种细胞组分的结合以及它们之间的能量传递.分析表明,荧光寿命的缩短意味着光敏效率的降低.

THE TIME-RESOLVED FLUORSCENCE STUDIES OF HAEMATOPORPHYRIN AND RELATED DERIVA TIVES IN AQUEOUS SOIUTION AND IN CELLS

The life-time of fluorescent state of haematoporphyrin derivatives(Hpd), its 4 major components(a,b,c,d) separated by HPLC, haematoporphyrin in forms of both free base and dihydrochloride and protoporphyrin IX disodium salt were measured in aqueous solution and in CHO cells respectively. Except for the Hpd-component d (a possible dimer of haematoporphyrin) which has a slightly low value, the fluorescence life-times are around a value of 15 ns for the rest of all tested compounds in aqueous solution. It was found that the fluorescencedecayed obviously fast when the porphyrin derivatives were taken in cells with an exception of the Hpd-component d for which the fluorescence life-time was significantly lengthened.A possible relaxation pathway of the lowest excited singlet state of the porphyrin derivatives in cells is proposed to explain the changs in the fluorescence decay rate in which the interaction between porphyrins and cell constituents is taken into account.The shortening of the fluorescence life-time may imply that the quantum yield of the excited triplet state of the porphyrin derivatives in cells is less than that in aqueous solution, vice versa. Thus, it may be concluded that most of the porphyrin derivatives become less effetive in photosensitization when they are taken in cells, but the Hpd-component d is an exception. This supfi-sing finding may have some important biological implications.