荧光光谱用于光动力疗法中光敏剂光漂白特性研究

应用荧光光谱技术研究溶液中血卟啉单甲醚(HMME)的光漂白与光产物生成.以532 nm倍频Nd:YAG激光器照射样品,功率密度为100 mW·cm-2,以光学多通道分析仪(OMA)采集荧光光谱.照光过程与荧光光谱采集同步进行.通过构建基本光谱与最小二乘拟合,由单条实测光谱中分解求得HMME荧光(613 nm)、光产物荧光(639 nm)及自体荧光的强度.HMME初始浓度不超过10μg·mL-1时符合荧光-浓度线性函数关系.对照光过程的荧光光谱监测同时观察到HMME漂白、光产物生成与漂白,以及样品光学特性变化引起的自体荧光强度起伏.光产物漂白后的二次产物引起样品光学特性显著改变.所建立的荧光光谱探测系统与光谱分析方法可满足光敏剂漂白特性体外研究的需要,并为光动力治疗的剂量学在体监测提供有效研究方法.

Fluorescence Spectroscopy Study on Photobleaching Properties of Photosensitizers in Photodynamic Therapy

The photobleaching and formation of photoproduct of hematoporphyrin monomethyl ether (HMME) was investigated in solution by fluorescence spectroscopy. Irradiation was performed by 532 nm double-frequency Nd : YAG laser at a fluence rate of 100 mW x cm(-2), meanwhile the collection of fluorescence spectra was implemented an by optical multi-channel analyzer (OMA). Utilizing the basis spectra constructed and least-square fitting, the intensity of HMME fluorescence (613 nm), photoproduct fluorescence (639 nm) and autofluorescence can be resolved respectively from the single measured spectrum. The correlation between fluorescence intensity and the concentration of HMME is consistent with linear function at concentrations not exceeding 10 microg x mL(-1). Monitoring the fluorescence spectroscopy during irradiation, three kinds of information were obtained, including photobleaching of HMME, formation and bleaching of photoproduct, as well as variation to fluorescence intensity due to the change of sample optical properties. Product generated by bleaching of photoproduct causes significant in sample optical properties. The implementation of fluorescence spectroscopy measurement and spectral analysis method presented here can be utilized effectively for both ex vivo investigation of photobleaching characteristics of photosensitizer and in vivo monitoring for dosimetry in photodynamic therapy.