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Abstract Time-gated luminescence (TGL) bioassay technique using luminescent lanthanide complexes as probes has exhibited excellent practicability in detection of various analytes in autofluorescence-rich biosamples. Herein, a novel copper(II)-coupled lanthanide complex-based luminescence probe has been developed for the ratiometric TGL detection of hydrogen sulfide (H 2 S) in vitro and in vivo. The probe is constructed based on a dual-functional ligand that was synthesized by conjugating di(2-picolyl)amine with terpyridine polyacid (DATP) using the "click chemistry" method. The as-prepared ligand can coordinate to Eu3+ and Tb3+ ions with its terpyridine polyacid moiety to display long-lived emissions of Eu3+ and Tb3+ ions, while the further coordination of its di(2-picolyl)amino moiety to Cu2+ induces to the luminescence quenching of the Eu3+ complexes, which allows the probe consisting of the heterometallic Cu2+-DATP-Eu3+/Tb3+ complexes to be constructed. After the probe was reacted with H 2 S to lead to the release of Cu2+ from the complexes, the emission of Eu3+ at 610 nm was remarkably enhanced, while that of Tb3+ at 540 nm was changed slightly. This luminescence response feature allowed the probe to be conveniently applied for the ratiometric TGL determination of H 2 S with I 610 /I 540 as the signal. The applicability of the probe for quantitative detection of H 2 S in human sera as well as for imaging of H 2 S in living cells and zebrafish were evaluated. All of the results proved the potential of the probe for in vitro and in vivo applications. Graphical abstract A novel copper (II)-coupled lanthanide complexes-based luminescence probe for the ratiometric time-gated luminescence detection of H 2 S in vitro and in vivo. Image 1 Highlights • A novel ratiometric time-gated luminescence probe for hydrogen sulfide was developed. • The probe combines both advantages of ratiometric and time-gated detection modes to afford high accuracy and sensitivity. • The probe was successfully used for imaging of exogenous and endogenous H 2 S in living cells and laboratory animals. • The convenient synthesis strategy of "click chemistry" was used for constructing lanthanide complex-based probes. [ABSTRACT FROM AUTHOR]

Bimodal photoluminescence-magnetic resonance (MR) imaging technique has attracted tremendous attention due to its great potential in biomedical researches and clinical practices. Herein a novel multifunctional magnetoluminescent nanocomposite, FA-Gd-Tb@SiO 2 , was found to serve as an effective probe for bimodal time-gated luminescence/MR imaging of cancer cells in vitro and in vivo. The nanoprobe was designed by integrating a luminescent Tb3+ complex, a Gd(III)-based contrast agent and a tumor-targeting molecule, folic acid (FA), into a silica nanoparticle. The integration of these functional moieties allows the nanoprobe to be employed for specific imaging of cancer cells with background-free TGL and non-invasive MR imaging modes. In addition, the optical and magnetic properties were dramatically improved after implicating the newly synthesized nanoarchitecture. In vitro cellular TGL imaging demonstrated that the FA-Gd-Tb@SiO 2 nanoprobe could recognize and accumulate in cancer cells overexpressing FA receptor. Furthermore, in vivo study revealed that the as-prepared nanoprobe was able to effectively enhance T 1 -weighted MR contrast and TGL intensity in tumor tissue, which might contribute to the precise detection and tracing of cancer cells, as well as diagnosis and therapy of tumor in clinical. Multifunctional magnetoluminescent silica nanoparticles for tumor-targeted time-gated luminescence/magnetic resonance imaging in vitro and in vivo. Image 1 • Multifunctional tumor-targetable silica nanoparticles for bimodal TGL/MR imaging of cancer cells were developed. • The nanoprobe can be employed for imaging of cancer cells with both background-free TGL and non-invasive MR imaging modes. • The nanoprobe can visualize tumors with various resolutions (from single cell to whole living body) and no depth limit. • The bimodal TGL/MR imaging method can improve the accuracy of cancer diagnosis and minimize potential artifacts. [ABSTRACT FROM AUTHOR]

Development of fluorescent/luminescent probes for rapid, selective and sensitive detection of reactive oxygen species (ROS) is of great significance for understanding the roles of ROS in pathophysiological processes. In the present research, a visible-light-excitable Eu3+ complex-based probe, Eu(L) 3 (DPBT), is designed and synthesized for the time-gated luminescence (TGL) determination of hypochlorous acid (HClO) in vitro and in vivo. The proposed probe exhibits a rapid, selective and sensitive TGL response to HClO, and excellent localization of mitochondria in living cells with low cytotoxicity. These features allow the probe to be used for the TGL sensing and imaging of HClO formation in mimic inflammatory cells at a subcellular level, as well as in endotoxin-induced liver injury and rheumatoid arthritis in live mice. In addition, by immobilizing the probe in the PEG hydrogel, the smart sensor films with rapid response to HClO were prepared, and successfully used for the real-time monitoring of HClO generation in mouse wounds, in order to distinguish the infected wounds from acute ones. Overall, this study provides a useful tool for the clinical monitoring and treatment of wound diseases. • A novel mitochondria-targetable time-gated luminescence probe for HClO was developed. • The as-prepared Eu3+ complex-based luminescence probe possesses a broad excitation window including visible light. • The probe can be used for imaging HClO in mitochondria of living cells, as well as in liver injury and RA mouse models. • The probe-doped smart sensor films were successfully used for the real-time monitoring of HClO generation in mouse wounds. [ABSTRACT FROM AUTHOR]