image: Constructing activatable organic phosphorescent probes through host guest strategies can be applied for time-resolved imaging at the cellular level, as well as afterglow imaging and viscosity detection at the in vivo level.
Credit: ©Science China Press
This research was conducted under the leadership of Professor Xiang Ma and Dr. Yang Li from East China University of Science and Technology. Yang Li successfully synthesized an activatable red/near-infrared organic room temperature phosphorescence (RTP) probe via supramolecular assembly between macrocyclic CB[8] and guest molecules LnC (n = 1–3). It was discovered that the secondary amino groups within the LnC molecular framework function as water-based RTP regulatory sites, whereas the introduction of Boc and nitrogen heterocyclic butyl groups enhances phosphorescence emission. The initial investigation focused on the impact of molecular modifications and structural parameters on the phosphorescence properties of these supramolecular assemblies, and a potential mechanism for viscosity-induced RTP activation was proposed. As the solution viscosity increases, the red/near-infrared phosphorescence intensity and lifetime of the LnC components are markedly enhanced.
Li and Ma confirmed that probe L1C exhibits outstanding stability, biocompatibility, and specificity in viscosity response. They assessed the optical performance of activatable organic RTP probes across a range of biological imaging and biosensing applications, including lysosome-targeted two-photon imaging, monitoring lysosome viscosity in cells, time-resolved cellular imaging, and in vivo phosphorescence imaging of viscosity changes in an inflammation mouse model.
The research team discovered that probe L1C demonstrated lysosome-specific targeting, millisecond-level time-resolved cellular phosphorescence imaging, and two-photon imaging of intracellular viscosity. Notably, in vivo phosphorescence imaging revealed that probe L1C could monitor viscosity changes in inflammatory mice with a high signal-to-background ratio (SBR > 80) in real-time. Consequently, the findings from this study are anticipated to significantly advance the field of high-contrast phosphorescence imaging, facilitating real-time visualization of critical physiological processes in cells and in vivo biosensing.
Li stated, "This type of activatable organic phosphorescent probe will offer novel developmental pathways for the biomedical applications of organic room-temperature phosphorescent materials. We are confident that, as imaging technologies, including time-resolved techniques, continue to advance, these probes will assume an even more significant role."
The activatable red/near-infrared supramolecular platform developed in this study is capable of accurately reflecting complex and dynamic biological microenvironments, enhancing phosphorescence imaging resolution, and offering novel strategies for the in vivo exploration of specific biomarkers and pathological processes.
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See the article:
Activatable red/near-infrared aqueous organic phosphorescence probes for improved time-resolved bioimaging
https://doi.org/10.1093/nsr/nwae383
Journal
National Science Review