Baker A, Kanofsky J R
Research Service, Edward Hines, Jr., Department of Veterans Affairs Hospital, Hines, Illinois 60141.
Arch Biochem Biophys. 1991 Apr;286(1):70-5. doi: 10.1016/0003-9861(91)90009-8.
Near-infrared emission (1170-1475 nm) was studied from L1210 leukemia cells incubated with polyporphyrin (fractionated hematoporphyrin derivative), suspended in deuterium oxide buffer, and then exposed to light. Following pulsed laser excitation, the near-infrared emission decayed in two phases. The first phase of the emission (0-2 microseconds) was principally due to polyporphyrin fluorescence. The second phase of the emission (20-90 microseconds) was due mainly to singlet oxygen. Evidence supporting the assignment of the second phase emission to singlet oxygen included a spectral analysis showing a peak near 1270 nm and reductions in the second phase emission caused by the singlet oxygen quenchers, histidine, carnosine, and water. The second phase emission decayed in a biexponential manner with lifetimes of 4.5 +/- 0.5 and 49 +/- 4 microseconds. Most of the singlet oxygen in the second phase emission was likely due to singlet oxygen that was generated near the surface of the L1210 leukemia cells and then diffused into the deuterium oxide buffer. Direct measurements of singlet oxygen phosphorescence at 1270 nm may prove to be a useful analytical technique for studying photochemical generation of singlet oxygen in cultured cells.
研究了用多卟啉（分级血卟啉衍生物）孵育、悬浮于氧化氘缓冲液中然后曝光的L1210白血病细胞的近红外发射（1170 - 1475纳米）。在脉冲激光激发后，近红外发射呈两相衰减。发射的第一相（0 - 2微秒）主要归因于多卟啉荧光。发射的第二相（20 - 90微秒）主要归因于单线态氧。支持将第二相发射归因于单线态氧的证据包括光谱分析显示在1270纳米附近有一个峰值，以及由单线态氧猝灭剂组氨酸、肌肽和水导致的第二相发射减少。第二相发射以双指数方式衰减，寿命分别为4.5±0.5微秒和49±4微秒。第二相发射中的大多数单线态氧可能是由于在L1210白血病细胞表面附近产生然后扩散到氧化氘缓冲液中的单线态氧。直接测量1270纳米处的单线态氧磷光可能被证明是一种用于研究培养细胞中单线态氧光化学产生的有用分析技术。
