血卟啉单甲醚在生理盐水溶液中光漂白的研究

目的观察在光动力学反应过程中血卟啉单甲醚(HMME)的光漂白现象,探讨其影响因素。方法通过本研究建立的光敏剂荧光分析系统,应用光学多通道分析仪对生理盐水溶液中HMME介导的光动力反应过程中光漂白的情况进行监测。HMME的浓度分别为1、10μg/ml。Nd∶YAG倍频532nm激光作为光动力的照射光源,同时利用其作为荧光激发光源。在光动力反应过程中采集溶液的荧光光谱,并进行分析处理。结果光敏剂HMME在一定的浓度范围内,初始浓度越高,光漂白的速率越快。在HMME的光漂白过程中于639nm处出现新的荧光峰。根据漂白造成的自体背景的变化,HMME的光漂白可以分为两个阶段:(1)在0～45min阶段,随着照光过程的持续,HMME在613nm与674nm处的荧光特征峰强度下降,同时在639nm处出现新的荧光峰,且其强度持续增强,自体背景强度起伏很小,稳定在HMME初始荧光强度的0.16倍左右;(2)而45～90min阶段,随着照光时间延长,在613、674和639nm处荧光峰的强度均下降,自体背景强度呈接近于线性持续增强,到照光结束时增至HMME初始荧光强度的约0.45倍。结论HMME的光漂白是一个较复杂的过程,初始浓度影响其漂白的速度,并伴有光漂白产物的生成及其再漂白的现象。

Photobleaching of Hematoporphyrin Monomethyl Ether in Normal Saline Solution

Objective To establish a fluorescence spectroscopy system and to investigate the phenomena of photobleaching during photodynamic reaction induced by hematoporphyrin monomethyl ether （HMME）.Methods The photobleching process of HMME was monitored by optical multichannel analyzer. The concentration of HMME was 1 μg/ml and 10 μg/ml. 532 nm Laser was used both as light source for PDT and as excitation light source for HMME fluorescence. During the procedure of PDT, the fluorescence spectrum of the sample was collected, stored in the computer and processed for results.Results The photobleaching process at high concentration was more rapidly than that at low concentration. A new fluorescence peak emerged at 639 nm during the photobleaching process of HMME. According to the variation of the background fluorescence, the photobleaching process could be divided into two stages： （1）in the early stage of laser irradiation,the fluorescence intensity at 613 nm and 674 nm decreased with the prolonging of time, and the fluorescence intensity at 639 nm increased.（2）In the later stage, all the three fluorescence peaks decreased, but the self-background fluorescence increased very quickly, and the intensity at the end of irradiation was 1.45 times of the initial intensity.Conclusions The photobleaching of HMME is a very complicated process, and can be affected by the initial concentration of HMME with generation of photoproduct during this process, and with rebleaching phenomena.