Two-photon two-color excited polarized fluorescence in biologically relevant molecules: investigation of molecular excited state structure and dynamics

在一个联合研究项目的框架内，将研究生物相关分子的排列、取向和旋转相关时间。分子将在不同的偏振方案下使用两种颜色的双光子（2c2p）激光脉冲（这里是约400nm和800nm的可调谐辐射）进行对准和取向。在不同的偏振角下也观察到了荧光。使用两个不同的光子的优点是双重的：可以达到更短的波长（低至265 nm），使得无标记的蛋白质检测成为可能，并且与使用相同光子的双光子激发相比，分子的不同排列成为可能。由于扩散过程，初始排列的分子最终将各向同性地分布。我们打算确定相应的旋转相关时间，其中包含信息的分子与其周围的相互作用。在原理证明中，研究了PTP。研究工作将集中在色氨酸，作为探测蛋白质的特征发色团，和吲哚，一个分子，显示出一些不寻常的光谱特征的研究。此外，其他研究小组也对吲哚进行了一些2c2p实验。这一结果将为O.瓦休京斯基

In the framework of a joint research project the alignment, orientation and rotational correlation time of biological relevant molecules will be studied. The molecules will be aligned and oriented using two color two photon (2c2p) laser pulses under different polarization schemes (here tunable radiation around 400nm and 800nm). The fluorescence is observed for different polarization angle as well. The advantage of using two different photons is twofold: shorter wavelengths (down to 265nm) can be reached making label-free proteine detection possible and different alignments of the molecules become possible compared to two photon excitation using identical photons. Due to diffusion processes, the initial aligned molecules will finally be distributed isotropically. We intend to determine the corresponding rotational correlation time which contains information on the interaction of the molecule with its surrounding. In a proof of principle PTP was investigated. The research work will be focused on the study of tryptophan, as characteristic chromophore for probing proteins, and indole, a molecule which shows some unusual spectroscopic features. In addition, some 2c2p experiments on indole have been performed by other groups. The results will be theoretically and experimentally supported by the research group of O. Vasyutinskii.