Gryczynski I, Hell S W, Lakowicz J R
Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore 21201, USA.
Biophys Chem. 1997 May 21;66(1):13-24. doi: 10.1016/s0301-4622(96)02264-8.
We describe the effects of time-delayed long-wavelength pulses on the intensity and anisotropy decays of pyridine2. The sample was exposed to a continuous train of 360 nm excitation pulses and time-delayed 720 nm pulses. The long-wavelength pulses, which overlapped the emission spectrum of pyridine2, resulted in a spatially localized decrease in intensity at the point of beam overlap. The time-delayed quenching pulses caused a stepwise decrease in the intensity and anisotropy decays, as seen by oscillations in the frequency-domain data. The time-resolved anisotropy was shown to decrease below zero (-0.2) following the vertically polarized quenching pulse. The extent of light quenching depended on the time delay between the excitation and quenching pulses, and can be used to measure the decay time. Light quenching and/or multipulse methods may provide a new class of experiments for fluorescence spectroscopy and imaging.
我们描述了时间延迟的长波长脉冲对吡啶2的强度和各向异性衰减的影响。样品暴露于连续的360nm激发脉冲和时间延迟的720nm脉冲。与吡啶2发射光谱重叠的长波长脉冲导致光束重叠点处强度在空间上局部降低。如频域数据中的振荡所示，时间延迟的猝灭脉冲导致强度和各向异性衰减逐步降低。垂直偏振猝灭脉冲后，时间分辨各向异性显示降至零以下（-0.2）。光猝灭程度取决于激发脉冲和猝灭脉冲之间的时间延迟，可用于测量衰减时间。光猝灭和/或多脉冲方法可能为荧光光谱学和成像提供一类新的实验。
