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Hydrogen sulfide and cysteine are momentous endogenous regulators of many physiological processes and maintain a dynamic balance of redox in living organisms. To investigate the inter-relationship of them in vivo, there is a pressing need to develop analytical molecular tools to identify related biomolecules. We construct a mitochondria-targeted single fluorescence probe (Mit-CM) for separately and continuously visualizing H 2 S, Cys and H 2 S/Cys with multi-response fluorescence signals. Mit-CM has the following advantages: (Ⅰ) colorimetric and ratiometric: two well-separated emission bands can ensure accurate detection of the analyte and significant color changes contribute to rapid identification of the analyte by the naked eye; (Ⅱ) mitochondrial localization: study the physiological functions of H 2 S and Cys in mitochondria; (Ⅲ) separate and continuous detection of H 2 S and Cys: reveal the inter-relationship and interconversion of them in biological system. Moreover, the desirable attributes of low cytotoxicity, better biocompatibility and excellent mitochondria enrichment ability indicate that Mit-CM can be employed to achieve detection and observe distribution of H 2 S, Cys and H 2 S/Cys in living organism. Image 1 • Ratiometric and colorimetric: contribute to accurate detection and rapid discrimination of the analyte. • Mitochondrial localization: study the physiological function of H 2 S and Cys in the mitochondria. • Separate and continuous detection of H 2 S and Cys: reveal the inter-relationship and interconversion of them in biological systems. [ABSTRACT FROM AUTHOR]

Aggregation-induced emission photosensitizers (AIE-PSs) targeting different subcellular organelles with time-dependent manner are highly promising for clinical applications but rarely reported. Herein, we designed and synthesized the near-infrared (NIR) emission AIE-PS (CTQ-S) with broad absorption and excellent type I reactive oxygen species (ROS) generation efficiency that was superior to the widely used PS (Rose Bengal and Chlorine 6). With short-term incubation, CTQ-S anchored on the cell membrane (Rr: 0.843, Rr is for Pearson correlation coefficient) and gradually entered the mitochondria (Rr: 0.937) of cancer cells, showing excellent time-dependent fluorescence fluorescent imaging effect. Furthermore, CTQ-S realized the selective photodynamic therapy (PDT) effect in a time-dependent manner under white light irradiation. This work provided a new way for cancer cells fluorescence imaging and PDT. [Display omitted] • A NIR emission AIE-PS with wide absorption bands and large Stokes shifts. • CTQ-S displayed remarkable type I ROS generation efficiency. • Time-dependent targeting of the cell membrane or mitochondria of cancer cells. • Superior colocalization effect on cell membrane (0.843) and mitochondrial (0.937). • It exhibited a potent selective PDT effect by inducing mitochondrial damage. [ABSTRACT FROM AUTHOR]

Abstract Cysteine(Cys) is tightly related to physiological and pathological of human, and the imbalance of concentration of cysteine in the intracellular are associated with many diseases. Here, a novel NIR fluorescent probe TCF-Cys was designed and synthesized, and both the optimal excitation and emission wavelength of them were between 650 and 900 nm, that within the "optical window" of biological tissues. In aqueous solution, TCF-Cys , which with an acrylate extremity as a recognizing unit, exhibited excellent "turn-on" fluorescence response for Cys superior to other amino acids and thiols with a limit of detection of 0.1323 μM. Moreover, as an excellent naked-eye colorimetric indicator, TCF-Cys could effectively distinguishing the Cys, Hcy and GSH in aqueous solution through color change. Then, the response mechanism of TCF-Cys for Cys was revealed by TLC, 1H NMR, HPLC, HRMS and DFT calculation. Finally, TCF-Cys was successfully employed to fluorescence specifically map of exogenous and endogenous Cys in living cells and zebrafish with low toxicity. Graphical abstract A novel probe TCF-Cys for colorimetric and NIR fluorescent detection of Cys in aqueous solution and fluorescence imaging endogenous and exogenous Cys in living HeLa cells and zebrafish. Unlabelled Image Highlights • Novel NIR fluorescent probes TCF-Cys was designed and synthesized. • TCF-Cys showed selective "turn-on" fluorescence response to Cys in solution. • Cys, Hcy and GSH were distinguished by TCF-Cys through the solution color change. • The mechanism was studied by TLC, 1H NMR, HPLC, HRMS and DFT calculation. • TCF-Cys has been successfully utilized to image living cells and zebrafish. [ABSTRACT FROM AUTHOR]

[Display omitted] • Extreme quantum yields (51.57 % at solid state). • Significant lysosome-targeted specificity (Rr = 0.912). • Tracking of lysosomes' dynamic movement in living cells. High-fidelity imaging and long-term visualization of lysosomes are pivotal factors in the functional assessment of lysosomes, which perform an instrumental role in the physiological activity of cells. However, commercial probes have great limitations in lysosome exploration resulting from the aggregation-caused quenching effect as well as photobleaching instability and small Stokes shift. Therefore, we constructed a novel probe named TTAM with triphenylamine as the matrix and morpholine ring as the targeting group. In contrast with commonly accessible Lyso-tracker Red, TTAM has the merits of aggregation-induced emission effect, extremely high quantum yields (51.57 % solid-state) as well as fluorescence intensity, significant photostability, and high resolution. These properties make it ideal for imaging and activity monitoring lysosomes, which provides a powerful condition for bio-imaging. [ABSTRACT FROM AUTHOR]

Three new coumarin–based derivatives with similar molecular structure were synthesized through a simple Schiff base reaction and their fluorescent properties were investigated in detail. Among of the compounds showed aggregation–induced emission (AIE) characteristics and high quantum efficiency ( Φ F ), of which compound 1 powder showed the strongest emission peak 570 nm ( Φ F = 25.3%), compound 2 solid exhibited 610 nm fluorescence emission peak ( Φ F = 3.3%), while the maximum emission wavelength of compound 3 powder red–shift to 640 nm ( Φ F = 16.8%). Meanwhile, compounds 1–3 showed long fluorescence lifetimes with respective 8.86 μs, 8.97 μs and 8.51 μs. The appearance of fluorescence properties can be attributed to efficient the excited state intramolecular proton transfer (ESIPT) and the twisted intramolecular charge transfer (TICT). Furthermore, due to the good luminescent properties, high stabilities and the large Stokes–shifts, the three compounds were ideal candidates for promising applications in organic lightemitting diodes (OLEDs). [ABSTRACT FROM AUTHOR]

A novel label-free fluorescent chemodosimeter (C1) was synthesized, based on coumarin and N-(4-aminobenzoyl)-β-alanine, for the selective detection of cysteine (Cys) over glutathione (GSH), which involved a click reaction of Cys to C N of a Schiff base. The probe C1 featured a fast response (about 3 min), emission in the visible region, and high selectivity. Addition of Cys in HEPES-NaOH solution (pH 7.4) to C1 in water resulted in the appearance of a new emission peak at 445 nm, in company with remarkable enhancement of fluorescence intensity, while other amino acids did not induce any significant fluorescence change. Meanwhile, the addition reaction of Cys to C1 elicited 90.8-fold fluorescence intensity enhancement, which resulted in a change of emission color from orange to blue. [ABSTRACT FROM AUTHOR]

A series of novel fluorene derivatives containing –PO(OH) 2 ( 1 , 2 ), –HS ( 3 ), and –N + (CH 3 ) 3 ( 4 ) were synthesized and only phosphonic-functionalized fluorene derivatives can detect Fe 3+ with high selectivity over other metal ions. The fluorescence quenching of 1 and 2 with titration Fe 3+ in water–DMF solution fits the Perrin model of static quenching. Spectral analysis showed that Fe 3+ bound with fluorene-based chemosensor through the O-atoms at the phosphonic group to form nonfluorescent complexes. The binding ratio was estimated by the Job plot and the trace levels of iron in samples were successfully monitored. [ABSTRACT FROM AUTHOR]

Abstract: Novel phosphonic acid-functionalized fluorene derivatives 9, 9-bis (3′-phosphonic acid propyl)-2,7-diphenylfluorene and 2,7-diphenylfluorene-9-ylphosphonic acid, synthesized by Suzuki–Miyaura coupling reaction, were evaluated as a chemoselective Fe3+ ion sensor. Through the disappearance of the characteristic sorption peak of PO, POH and the form of new broad band (POFe stretching bands) in FT-IR spectra, it was verified that the Fe3+ ion cause the quenching of their fluorescence emission, due to the Fe3+ ion binding to them via the O-atoms of the phosphonic group. UV–vis analyses also gave evidences by the change of absorption peak of them. A linear relationship that flowed with the Perrin model of static quenching was observed between the relative fluorescence intensity (ln F 0/F) of BPPDPF and the concentration of iron(III) in the range of 1–8μM with a detection limit of 0.02μM, so was with DPFPA in the range of 1–5μM with a detection limit of 0.01μM. Selectivity of them for Fe3+ was demonstrated over other metal ions by photoluminescence analysis in DMF–H2O solution. It showed that the other studied metal ions do not affect the determination of iron. We successfully monitored trace levels of iron (III) in tap water samples. [Copyright &y& Elsevier]

Reactive sulfur species (RSS), primarily containing glutathione (GSH), cysteine (Cys), hydrogen sulfide (H 2 S) and hydrogen polysulfides (H 2 S n , n > 1), were crucial endogenous biological signal molecules. Among them, H 2 S and H 2 S n played extremely momentous roles in many physiological and pathological processes. Limited by the vivo environmental diversity and complexity, it was highly desirable to rely on the single fluorescence probe platform to visualize H 2 S n and H 2 S according different fluorescence signals. Herein, we reported a two-photon excited fluorescent probe MC-S n that had the following merits: (Ⅰ) ratiometric and colorimetric: reducing detection errors and conducting visual analysis; (Ⅱ) two-photon microscope: better performance in vivo and vitro imaging; (Ⅲ) two specific sulfide reaction sites: studying on the mutual transformation of H 2 S n and H 2 S in biological systems. Furthermore, take advantages of low cytotoxicity (cell viability ≥ 85.99%), low limit of detection (21 nM), significant photostability, excellent pH stability, quick response behavior (175 s) and high penetration depth (110 μm), MC-S n can be employed to visualize endogenous and exogenous H 2 S n and H 2 S in cells, liver tissues and zebrafish. • Ratiometric and colorimetric: reducing detection errors and conducting visual analysis. • Two-photon microscope: better performance in vivo and vitro imaging. • Two specific sulfide reaction sites: studying on the mutual transformation of H2Sn and H2S in biological systems. • Low limit of detection (21 nM) and high penetration depth (110 μm). [ABSTRACT FROM AUTHOR]