罗丹明B的光猝灭和荧光去极化及其在生物物理学中的应用

Lakowicz Joseph R, Gryczyński Ignacy, Bogdanov Valery, Kuśba Jόzef

Center for Fluorescence Spectroscopy, Department of Biological Chemistry, School of Medicine, University of Maryland at Baltimore, 108 North Greene Street, Baltimore, Maryland 21201.

J Phys Chem. 1994 Jan;98(1):334-342. doi: 10.1021/j100052a055.

The fluorescence intensity of rhodamine B (RhB) was found to display a sublinear dependence on incident power when excited with the focused output of a cavity-dumped dye laser. This effect was found to be proportional to the amplitude of the emission spectrum at the incident wavelength and to be associated with a decrease in the time-zero anisotropy of RhB. The absence of changes in the intensity decay law or rotational correlation time indicates the absence of photochemical processes. These results are consistent with "light quenching" of RhB due to stimulated emission. In viscous solution the extent of depolarization of the emission was found to be in agreement with theoretical expressions which account for photoselective light quenching and for spatial inhomogeneities in the incident laser beam. The phenomenon of light quenching has numerous potential applications in biophysics, such as studies of the orientation and dynamics of fluorescent macromolecules.

当用腔倒空染料激光器的聚焦输出进行激发时，发现罗丹明B（RhB）的荧光强度对入射功率呈现亚线性依赖关系。发现这种效应与入射波长处发射光谱的幅度成正比，并且与RhB的初始各向异性降低有关。强度衰减规律或旋转相关时间没有变化，这表明不存在光化学过程。这些结果与受激发射导致的RhB“光猝灭”一致。在粘性溶液中，发现发射的去极化程度与考虑光选择性光猝灭和入射激光束空间不均匀性的理论表达式一致。光猝灭现象在生物物理学中有许多潜在应用，例如对荧光大分子的取向和动力学的研究。