Activatable red/near-infrared aqueous organic phosphorescence probes for improved time-resolved bioimaging

• Published in: National science review 2024-10
• Main Authors: Li, Yang, Wu, Zhiqin, Huang, Zizhao, Yin, Chenjia, Tian, He, Ma, Xiang
• Format: Article
• Language: English
• ISSN: 2095-5138; 2053-714X
• DOI: 10.1093/nsr/nwae383

Organic red/near-infrared (NIR) room-temperature phosphorescence (RTP) holds significant potential for autofluorescence-free bioimaging and biosensing due to its prolonged persistent luminescence and exceptional penetrability. However, achieving activatable red/NIR organic RTP probes with tunable emission in aqueous solution remains a formidable challenge. Here we report on aqueous organic RTP probes with red/NIR phosphorescence intensity and lifetime amplification. These probes consist of supramolecular assemblies comprising macrocyclic cucurbit[8]uril and amine-containing alkyl-bridged pyridiniums, exhibiting viscosity-activatable phosphorescence with enhanced quantum yield (up to 20%) and lifetime. Notably, by utilizing this activatable organic RTP probe, we successfully achieve two-photon imaging of lysosomal viscosity and millisecond scale time-resolved cell imaging. Moreover, intravital phosphorescence imaging using RTP probe enable the monitoring of viscosity variations in inflammatory mice, demonstrating a significantly improved signal-to-background ratio compared to fluorescence imaging. This activatable red/NIR supramolecular platform facilitates versatile high-resolution phosphorescence imaging for in vivo tracking of specific biomarkers and physiological events.