Here, we report a reversible photoacoustic (PA) probe, BDP-DOH, to image the localized redox state in vivo via monitoring the dynamic changes of the redox couple, superoxide anion (O 2•−

Photoclickable fluorogenic probes will enable visualization of specific biomolecules with precise spatiotemporal control in their native environment. However, the fluorogenic tagging of DNA with current photocontrolled clickable probes is still challenging. Herein, we demonstrated the fast (19.5 ± 2.5 M −1 s −1 ) fluorogenic labeling and imaging of DNA in vitro and in vivo with rationally designed coumarin-fused tetrazoles under UV LED photoirradiation. With a water-soluble, nuclear-specific coumarin-fused tetrazole (CTz-SO 3 ), the metabolically synthesized DNA in cultured cells was effectively labeled and visualized, without fixation, via "photoclick" reaction. Moreover, the photoclickable CTz-SO 3 enabled real-time, spatially controlled imaging of DNA in live zebrafish.

No abstract

Detection and visualization of hydrogen sulphide (H2S) is crucial for understanding its physiological and pathological roles towards human health and diseases, but precisely tracking of H2S in vivo remains challenging due to the limitations of available analytical methods. In this study, we developed a novel ratiometric photoacoustic (PA) nanoprobe for selective detection and imaging of H2S in biological fluids, live cells, brain tissues and animals. The nanoprobe AzHD-LP was fabricated by encapsulation of a newly synthesized H2S-responsive near-infrared (NIR) dye (AzHD) within a liposome (LP). The as-prepared AzHD-LP exhibits a dramatically red-shift response of its absorption peak after reduction reaction of AzHD with H2S: the absorbance of AzHD-LP centered at 600 and 700 nm is decreased and increased, respectively, producing a turn-on ratiometric PA signal in the presence of H2S. Typically, under the excitation of a 532 nm and 700 nm pulsed laser, the selective detection and imaging of H2S was achieved in aqueous solution, living cells and brain tissues of Alzheimer's diseased mice. Moreover, after AzHD-LP conjugated with a tumor-targeting peptide - c(RGDyK) as RGD-AzHD-LP - ratiometric PA mapping of the intratumoral generated H2S in the HCT116 colon tumor-bearing live mice was demonstrated.

Injudicious or inappropriate use of antibiotics has led to the prevalence of drug-resistant bacteria, posing a huge menace to global health. Here, a selfassembled aggregation-induced emission (AIE) nanosphere (AIE-PEG 1000 NPs) that simultaneously possesses near-infrared region II (NIR-II) fluorescence emissive, photothermal, and photodynamic properties is prepared using a multifunctional AIE luminogen (AIE-4COOH). The AIE-PEG 1000 NPs were encapsulated with teicoplanin (Tei) and ammonium bicarbonate (AB) into lipid nanovesicles to form a laseractivated "nanobomb" (AIE-Tei@AB NVs) for the multimodal theranostics of drugresistant bacterial infections. In vivo experiments validate that the "nanobomb" enables high-performance NIR-II fluorescence, infrared thermal, and ultrasound (AB decomposition during the photothermal process to produce numerous CO 2 /NH 3 bubbles, which is an efficient ultrasound contrast agent) imaging of multidrug-resistant bacteria-infected foci after intravenous administration of AIE-Tei@AB NVs followed by 660 nm laser stimulation. The highly efficient photothermal and photodynamic features of AIE-Tei@AB NVs, combined with the excellent pharmacological property of rapidly released Tei during bubble generation and NV disintegration, collectively promote broad-spectrum eradication of three clinically isolated multidrugresistant bacteria strains and rapid healing of infected wounds. This multimodal imaging-guided synergistic therapeutic strategy can be extended for the theranostics of superbugs.