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[Display omitted] • Based on dicyanoisophorone skeleton a near-infrared fluorescent probe was prepared and used to detect CO with high selectivity. • Two emission channels ratiometric fluorescence changes can be observed through adjusting the ICT effect of probe by CO. • The design of the probe enables it to be used for detecting CO in lysosomal subcellular organelles and further validated through cell co-localization imaging experiments. • The probe can be used to detect the endogenous and exogenous CO in Hela cells and could be used in living mice. • The probe is capable of detecting endogenous and exogenous CO through cell imaging experiments and has been successfully used in living mice. Carbon monoxide (CO) as an endogenous gas signaling molecule possesses important physiological functions and is of great significance in the treatment of various diseases. Real-time tracking of CO in living organisms has become a research hotspot in recent years. This article presents a lysosomal targeted near-infrared ratio fluorescence probe (TBM-CO) for selective detection of CO based on the dicyanoisophorone skeleton and morpholine fragment. The probe TBM-CO with weak ICT effect can be transformed to precursor TBM-NH 2 with strong ICT effect by the traditional Tsuji-Trost reaction procession in the presence of Pd2+ ions. The mechanism was proved by DFT calculation or the MS and HPLC results respectively. In the near-infrared region an obvious ratio fluorescence intensity change (F 686 / F 616) is observed in vitro spectral experiments. The concentration titration experiments indicate that there is a good liner relationship between the ratio fluorescence intensity and the concentration in the range of 0 to 50 μM (R2 = 0.996) and the detection limit is calculated as 0.38 μM. The cell fluorescence imaging and co-localization experiments further demonstrate that TBM-CO is able to detect the exogenous and endogenous CO in lysosomal subcellular organelle. Finally, it was used to detect the changes of CO concentration in living mice successfully. In short, a probe with three advantages of near-infrared emission, ratiometric fluorescence and organelle targeting was reported and used to detect CO successfully in cells and in living mice. [ABSTRACT FROM AUTHOR]

The development of efficient fluorescence-based detection tools with high contrast and accuracy in cancer diagnosis has recently attracted extensive attention. Changes in the microenvironments between cancer and normal cells provide new biomarkers for precise and comprehensive cancer diagnosis. Herein, a dual-organelle-targeted probe with multiple-parameter response is developed to realize cancer detection. We designed a tetraphenylethylene (TPE)-based fluorescent probe TPE-PH-KD connected with quinolinium group for simultaneous detection of viscosity and pH. Due to the restriction on the double bond's rotation, the probe respond to viscosity changes in the green channel with extreme sensitivity. Interestingly, the probe exhibited strong emission of red channel in acidic environment, and the rearrangement of ortho-OH group occurred in the basic form with weak fluorescence when pH increased. Additionally, cell colocalization studies revealed that the probe was located in the mitochondria and lysosome of cancer cells. Following treatment with carbonyl cyanide m -chloro phenylhydrazone (CCCP), chloroquine, and nystatin, the pH or viscosity changes in the dual channels are also monitored in real-time. Furthermore, the probe TPE-PH-KD could effectively discriminate cancer from normal cells and organs with high-contrast fluorescence imaging, which sparked more research on an efficient tool for highly selectively visualizing tumors at the organ level. [Display omitted] • A novel TPE-based fluorescent probe for detection of pH/viscosity in dual channels was developed. • Probe could monitor pH/viscosity fluctuation upon stimulation with CCCP, chloroquine and nystatin. • Probe could distinguish tumor and normal cells and tissues in high contrast by fluorescent imaging. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel resorufin-based fluorescent probe for selective detection of NE was developed. • Probe displayed rapid response time (<10 min) and high selectivity towards NE. • Probe could detect endogenous NE and exocytosis process by fluorescent imaging in living cells and depression-like behavior mice. Norepinephrine (NE), as an important neurotransmitter, is closely associated with the pathogenesis of anxiety and depressive disorders. Effective monitoring of NE fluctuation aids in the diagnosis of depression and the therapeutic assessment of the antidepressant intervention. The construction of novel fluorescent probes with high specificity towards NE for imaging in depression models is still in demand urgently. In this work, a novel resorufin-based red-emitting fluorescent probe for real-time tracking NE was developed. NE can significantly increase the fluorescence of probe LNE by triggering deprotection of carbonothioate ligand via nucleophilic substitution. The probe LNE demonstrated significant NE selectivity and sensitivity over other analytes in vitro. In addition, probe LNE showed a fast response time (<10 min), and the change in fluorescence signal was positively linked with NE concentration, which could be utilized to track the dysregulation of NE in vivo. More importantly, this powerful probe was successfully employed for real-time visual and imaging of NE in living cells and depression-like behavior animals. [ABSTRACT FROM AUTHOR]

Biothiols play an important role in cell protein metabolism and signal transduction, especially Hcy was considered as a new risk factor closely related to many diseases. However, there remain some limitations in selectively detecting Hcy due to its structural similarity to Cys. It is urgent for us to develop a novel indicator to study the pathological process of Hcy. Herein, we constructed a new fluorescent probe TCF-SBD composed of tricyanofuran fluorophore and SBD reaction site for detecting Hcy. The probe TCF-SBD exhibited a strong yellow emission response to Hcy in an "off-on" manner, and showed good selectivity for Hcy over Cys and GSH. The sensing mechanism was confirmed by HPLC, NMR titration and DFT studies. The probe was sensitive to the detection of Hcy with LOD low to 0.23 μM. The powerful probe TCF-SBD succeeded in real-time and selectively visualizing Hcy in living cells. [Display omitted] • Fluorescence probe based on substitution-rearrangement process was synthesized for selective detection of Hcy. • The probe displayed high selective and sensitive for Hcy (detection limit is 0.23 μM). • The probe was applied for fluorescence imaging of exogenous Hcy in living cells. [ABSTRACT FROM AUTHOR]