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。某些金属离子在被提升到高能态时可以发光。如果金属离子周围的环境是手性的，即左手或右手的，则发射的光可以富含左手或右手分量。这种现象被称为圆偏振发光。它在手性铕和铽络合物的红光或绿色光发射中是最明确的，并且已经在这些金属离子的几种络合物中观察到。当手性金属络合物位于存在其他右旋或左旋物质的情况下时，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增强是通过其发射的圆偏振的变化来报告的。在这个项目中，我们试图跟踪这种变化，同时使用显微镜观察发光金属络合物的空间定位。我们将建立第一次，一个显微镜，能够监测发射铕和铽金属离子的复合物发射光的圆偏振的变化。与此同时，我们将制备一系列左手和右手金属络合物，它们不仅具有发射性和抗降解性，而且还可以与本身具有手性的重要生物活性物质结合，例如蛋白质、血清白蛋白或常见的手性分子维生素C。我们已经表明，相关的发射金属络合物可以被设计成细胞可渗透的，并且可以被设计成优先驻留在活细胞内的某些隔室中。因此，我们将率先在活细胞内跟踪或映射这些生物活性手性探针，使用新的显微镜来监测它们独特的光学信号，报告它们的局部环境。

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.