Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, UK.
Chem Soc Rev. 2021 Jul 21;50(14):8193-8213. doi: 10.1039/d1cs00310k. Epub 2021 Jun 1.
The principles of the design of responsive luminescent probes and sensors based on lanthanide emission are summarised, based on a mechanistic understanding of their mode of action. Competing kinetic pathways for deactivation of the excited states that occur are described, highlighting the need to consider each of the salient quenching processes. Such an analysis dictates the choice of both the ligand and its integral sensitising moiety for the particular application. The key aspects of quenching involving electron transfer and vibrational and electronic energy transfer are highlighted and exemplified. Responsive systems for pH, pM, pX and pO and selected biochemical analytes are distinguished, according to the nature of the optical signal observed. Signal changes include both simple and ratiometric intensity measurements, emission lifetime variations and the unique features associated with the observation of circularly polarised luminescence (CPL) for chiral systems. A classification of responsive lanthanide probes is introduced. Examples of the operation of probes for reactive oxygen species, citrate, bicarbonate, α-AGP and pH are used to illustrate reversible and irreversible transformations of the ligand constitution, as well as the reversible changes to the metal primary and secondary coordination sphere that sensitively perturb the ligand field. Finally, systems that function by modulation of dynamic quenching of the ligand or metal excited states are described, including real time observation of endosomal acidification in living cells, rapid urate analysis in serum, accurate temperature assessment in confined compartments and high throughput screening of drug binding to G-protein coupled receptors.
基于对镧系元素发光探针和传感器作用机制的理解，总结了基于镧系元素发射设计响应性发光探针和传感器的原则。描述了使激发态失活的竞争动力学途径，突出了需要考虑每种显著的猝灭过程。这种分析决定了特定应用中配体及其整体敏化部分的选择。强调并举例说明了涉及电子转移以及振动和电子能量转移的猝灭的关键方面。根据观察到的光学信号的性质，区分了用于 pH、pM、pX 和 pO 以及选定生化分析物的响应系统。信号变化包括简单和比率强度测量、发射寿命变化以及与手性系统中圆偏振发光 (CPL) 的观察相关的独特特征。介绍了响应性镧系探针的分类。以用于活性氧、柠檬酸盐、重碳酸盐、α-AGP 和 pH 的探针的操作为例，说明了配体结构的可逆和不可逆转化，以及对敏化配体场的金属初级和次级配位球的可逆变化。最后，描述了通过调制配体或金属激发态的动态猝灭来起作用的系统，包括在活细胞中实时观察内体酸化、在血清中快速分析尿酸盐、在封闭隔室中准确评估温度以及高通量筛选药物与 G 蛋白偶联受体的结合。
