Ruan Zhipeng, Yang Jun, Li Yonghua, Zhang Kenneth Yin
State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing, 210023, P. R. China.
Chembiochem. 2024 May 2;25(9):e202400094. doi: 10.1002/cbic.202400094. Epub 2024 Apr 9.
Phosphorescent iridium(III) complexes are widely recognized for their unique properties in the excited triplet state, making them crucial for various applications including biological sensing and imaging. Most of these complexes display single phosphorescence emission from the lowest-lying triplet state after undergoing highly efficient intersystem crossing (ISC) and ultrafast internal conversion (IC) processes. However, in cases where these excited-state processes are restricted, the less common phenomenon of dual emission has been observed. This dual emission phenomenon presents an opportunity for developing biological probes and imaging agents with multiple emission bands of different wavelengths. Compared to intensity-based biosensing, where the existence and concentration of an analyte are indicated by the brightness of the probe, the emission profile response involves modifications in emission color. This enables quantification by utilizing the intensity ratio of different wavelengths, which is self-calibrating and unaffected by the probe concentration and excitation laser power. Moreover, dual-emissive probes have the potential to demonstrate distinct responses to multiple analytes at separate wavelengths, providing orthogonal detection capabilities. In this concept, we focus on iridium(III) complexes displaying fluorescence-phosphorescence or phosphorescence-phosphorescence dual emission, along with their applications as biological probes for sensing and imaging.
磷光铱（III）配合物因其在激发三重态下的独特性质而被广泛认可，这使其在包括生物传感和成像在内的各种应用中至关重要。这些配合物中的大多数在经历高效的系间窜越（ISC）和超快内转换（IC）过程后，从最低的三重态发出单一磷光发射。然而，在这些激发态过程受到限制的情况下，已经观察到不太常见的双发射现象。这种双发射现象为开发具有不同波长多个发射带的生物探针和成像剂提供了机会。与基于强度的生物传感不同，在基于强度的生物传感中，分析物的存在和浓度由探针的亮度表示，发射谱响应涉及发射颜色的改变。这使得能够通过利用不同波长的强度比进行定量，该强度比是自校准的，不受探针浓度和激发激光功率的影响。此外，双发射探针有可能在不同波长下对多种分析物表现出不同的响应，提供正交检测能力。在这个概念中，我们专注于显示荧光 - 磷光或磷光 - 磷光双发射的铱（III）配合物，以及它们作为用于传感和成像的生物探针的应用。
