The development of circularly polarised luminescence microscopy and responsive CPL probes

偏振光是由右旋和左旋圆偏振分量相加而成的。当某些金属离子被提升到高能态时，它们可以发光。如果该金属离子周围的环境是手性的，即左手或右手，那么发射的光可以在左手或右手成分中得到丰富。这种现象被称为圆偏振发光。它在手性Eu和Tb配合物的红光或绿光发射中得到了很好的定义，并在这些金属离子的几种配合物中观察到了它。当手性金属络合物位于其他右旋或左旋物种存在的情况下，发射的光可能会改变其圆偏振，并且可以使用记录这些变化的光谱仪随时间跟踪这种变化。因此，“探针”金属络合物的局部手性环境是通过其发射的圆偏振的变化来报告的。在这个项目中，我们试图在使用显微镜观察发光金属络合物的空间局域化的同时跟踪这种变化。我们将首次建立一种显微镜，能够监测从发射的Eu和Tb金属离子的络合物发射的光的圆偏振的变化。同时，我们将制造一系列左手和右手金属络合物，这些络合物不仅具有发射性和抗降解性，而且还可以与重要的生物活性物种结合，这些生物活性物种本身是手性的，如蛋白质、血清白蛋白或常见的手性分子维生素C。我们已经证明，相关的发射性金属络合物可以被设计为细胞渗透性，并可以被设计为优先驻留在活细胞的某些隔间中。因此，我们将率先在活细胞内跟踪或绘制这些生物活性手性探针，使用新的显微镜来监控它们独特的光学信号，报告它们局部环境的情况。

Polarised light is made up by adding together right handed and left handed circularly polarised components. Certain metal ions can emit light when they are raised into a high energy state. If the environment around that metal ion is chiral, i.e. left or right handed, then the emitted light can be enriched in the left or right handed component. This phenomenon is called circularly polarised luminescence. It is most well-defined in the emission of red or green light from chiral europium and terbium complexes, and has been observed for several complexes of these metal ions. When a chiral metal complex is located in the presence of other species that are right or left-handed, the emitted light may change its circular polarisation and this change can be tracked with time using a spectrometer that records these changes. Thus, the local chiral environement of the 'probe' metal complex is reported by changes to the circular polarisation of its emission.In this project, we seek to track such changes while observing the spatial localisation of the light-emitting metal complex using a microscope. We will build for the first time, a microscope that is able to monitor changes in the circular polarisation of emitted light from complexes of the emissive europium and terbium metal ions. In parallel, we shall make a series of left and right handed metal complexes that are not only emissive and resist degradation, but also can bind to important bioactive species that are themselves chiral, such as the protein, serum albumin, or the common chiral molecule, vitamin C. We have already shown that related emissive metal complexes can be engineered to be cell-permeable and can be designed to reside preferentially in certain compartments within a living cell. Thus, we shall pioneer the tracking or mapping of these bioactive chiral probes inside a living cell, using the new microscope to monitor their unique optical signal that reports on their local surroundings.