Dual-emissive nanoarchitecture of lanthanide-complex-modified silica particles for in vivo ratiometric time-gated luminescence imaging of hypochlorous acid† †Electronic supplementary information (ESI) available: Characterization of the new compounds, Fig. S1–S12 and a video showing the real-time uptake and accumulation of HClO in living Daphnia magna using the RTLNP as a probe. See DOI: 10.1039/c6sc02243j Click here for additional data file. Click here for additional data file.

We have developed a ratiometric time-gated luminescence sensory system for in vivo imaging of hypochlorous acid (HClO) by preparing a dual-emissive nanoarchitecture of europiumand terbiumcomplex-modified silica nanoparticles. The design of this nanoarchitecture is based on our new finding that the strong, long-lived luminescence of the b-diketonate–Eu complex can be rapidly and selectively quenched by HClO. Therefore, the b-diketonate–Eu complex was decorated on the surface of the silica nanoparticles for responding to HClO, while a HClO-insensitive luminescent terbium complex was immobilized in the inner solid core of the nanoparticles to serve as an internal standard. This nanosensing probe combines the advantages of both ratiometric and time-gated detection modes to afford high accuracy and sensitivity. Upon exposure to HClO, the nanoprobe displayed a remarkable luminescence color change from red to green, and the intensity ratio of the green over the red luminescence (I539/I607) showed a rapid, sensitive and selective response to HClO. Additionally, the feasibility of using the nanoprobe for intracellular detection of exogenous and endogenous HClO and for real-time mapping of HClO in small laboratory animals has been demonstrated via ratiometric timegated luminescence imaging microscopy. The results reveal that the constructed nanoarchitecture cloud is a favorable and useful sensing probe for the real-time imaging of HClO in vivo with high specificity and contrast.