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Abstract: 1,4‐Dithiothreitol (DTT) has wide applications in cell biology and biochemistry. Development of effective methods for monitoring DTT in biological systems is important for the safe handling and study of toxicity to humans. Herein, we describe a two‐photon fluorescence probe (Rh‐DTT) to detect DTT in living systems for the first time. Rh‐DTT showed high selectivity and sensitivity to DTT. Rh‐DTT can be successfully used for the two‐photon imaging of DTT in living cells, and also can detect DTT in living tissues and mice. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H2O2) plays important roles in the regulation of many biological processes, and the abnormal level of H2O2 has close relation with the initiation and progression of many diseases. Herein, we describe a novel red-emissive fluorescence probe (RhoB) for the visualization of H2O2 in living cells, tissues and animals. RhoB was constructed on the basis of a xanthene-based red-emissive dye, and displayed nearly no fluorescence. After the treatment with H2O2, RhoB can exhibit red fluorescence with the emission wavelength at 638 nm. RhoB exhibited highly sensitive and selective response to H2O2. Density functional theory (DFT) calculations were conducted to shed light on the optical properties of RhoB, and natural bond orbital (NBO) calculations demonstrate that the boron atom shows the highest positive electricity and further support the response mechanism. RhoB was successfully applied for imaging of exogenous and endogenous H2O2 in living cells, and also can be utilized for visualizing H2O2 in living tissues and animals. [ABSTRACT FROM AUTHOR]

Herein, we report a unique D–π–A–π–D type fluorescent probe. The probe, with a large π system and two ICT processes, was sensitive to intracellular viscosity. Furthermore, the probe was successfully applied for the two-photon imaging of intracellular viscosity. [ABSTRACT FROM AUTHOR]

Very recently, aggregation-induced emission (AIE) and two-photon (TP) emission materials have attracted great attention owing to their widespread applications. Herein, interestingly, we described a unique single fluorophore core with different substituents that can show either outstanding AIE or TP fluorescence properties. The introduction of an electron donating unit such as a tertiary amine group on the phenanthrenequinone imidazole core afforded a novel AIE-based fluorescent material PIN. The optical studies of PIN revealed that appropriate structural modifications on the phenanthrenequinone imidazole core could result in AIE character. On the other hand, modification of an electron-withdrawing moiety such as an indolium moiety on the same phenanthrenequinone imidazole-core provided a new material PID, which exhibited favorable TP emission, indicating that phenanthrenequinone imidazole derivatives could be exploited as TP materials. Furthermore, we have demonstrated that the novel AIE or TP materials constructed herein can be successfully applied for sensing targets of interest in aqueous and biological settings owing to their highly desirable emission profiles. The intriguing finding that careful modification of the phenanthrenequinone imidazole scaffold could afford excellent AIE or TP materials may open a new avenue to engineer robust materials with diverse properties based on a versatile core for various applications. [ABSTRACT FROM AUTHOR]

Nitroxyl (HNO) plays important roles in the regulation of many physiological and pathological processes, and can serve as a potential therapeutic agent for cardiovascular disease. The development of HNO detection in living systems is greatly important for in-depth studies of its biosynthesis and activities. Herein, we describe a novel two-photon red-emissive fluorescence probe (RP) for imaging HNO in living cells and tissues. RP was based on a red-emissive dye, Rho, and showed no fluorescence. When responding to HNO, RP can emit red fluorescence with the emission wavelength at 638 nm. RP exhibited a sensitive and selective response to HNO. Theoretical calculations demonstrated that the overlaps between the HOMO and LUMO were large for Rho and tiny for RP, consistent with the absorption and fluorescence properties of Rho and RP. Assisted by three-dimensional (3D) imaging, the two-photon imaging of HNO with red emission color in living tissues was successfully performed. [ABSTRACT FROM AUTHOR]

Lysosomal pH is closely related to the metastasis and apoptosis of cancer cells. Detecting lysosomal pH changes in cancer cells could be helpful for analyzing tumor progressions and in-depth study of the roles of lysosomes in tumor invasion and metastasis. Herein, we describe a novel tumor-targeting and lysosome-specific two-photon fluorescent probe (BN-lys) for imaging pH changes for the first time. Biotin was employed as the tumor-targeting module, and morpholine was selected as the lysosome-specific group and the pH site to control the fluorescence by photoinduced electron transfer (PET) mechanism. With a pKa value of 5.36, BN-lys showed a fast and reversible fluorescence response to pH. Under the guidance of the biotin group, BN-lys displayed strong one-photon and two-photon fluorescence responses to lysosomal pH in cancer cells, while it displayed weak fluorescence in normal cells. Furthermore, BN-lys could be applied for the imaging of chloroquine-stimulated lysosomal pH changes in living cells. These features demonstrate that this probe could have practical applications in biological research. [ABSTRACT FROM AUTHOR]

Although Alzheimer's disease (AD) was first described over 100 years ago, there is still no suitable biomarker for diagnosing AD in easily collectable samples (e.g., blood plasma, saliva, and urine). Here, we investigated the relationship between morning urine formaldehyde concentration and cognitive impairment in patients with post-stroke dementia (PSD) or AD in this cross-sectional survey for 7 years. Cognitive abilities of the study participants (n = 577, four groups: 231 controls, 61 stroke, 65 PSD, and 220 AD) were assessed by Mini-Mental State Examination (MMSE). Morning urine formaldehyde concentrations were measured by high performance liquid chromatography (HPLC). Gender- and age-matched participants were selected from the four groups (n = 42 in each group). Both semicarbazide-sensitive amine oxidase (SSAO, a formaldehyde-generating enzyme) and formaldehyde levels in the blood and urine were analyzed by using an enzyme-linked immunosorbent assay (ELISA) and HPLC, respectively. We found that morning urine formaldehyde levels were inversely correlated with MMSE scores. The threshold value (the best Cut-Off value) of formaldehyde concentration for predicting cognitive impairment was 0.0418mM in patients with PSD (Sensitivity: 92.3%; Specificity: 77.1%), and 0.0449mM in patients with AD (Sensitivity: 94.1%; Specificity: 81.8%), respectively. The results of biochemical analysis revealed that the observed increase in urine formaldehyde resulted from an overexpression of SSAO in the blood. The findings suggest that measuring the concentration of formaldehyde in overnight fasting urine could be used as a potentially noninvasive method for evaluating the likelihood of ensuing cognitive impairment or dementia. [ABSTRACT FROM AUTHOR]

A correction to the article "Construction of a Near-Infrared Fluorescent Turn-On Probe for Selenol and Its Bioimaging Application in Living Animals," by H. Chen and colleagues is presented.

Fluorescence imaging is a powerful approach for noninvasive and real-time visualization and tracking of biomolecules and biological processes in living systems. The fluorescent chemosensors with dual/triple interplaying sensing mechanisms tend to provide diverse fluorescence signals or amplify the response signals, which are propitious to simultaneously track multiple analytes or to improve the selectivity and sensitivity of the chemosensors. Thus, the development of dual/triple sensing mechanism-based chemosensors has attracted great interest recently. This review highlights the representative cases of the fluorescent chemosensors with dual/triple interplaying sensing mechanisms published since 2010, and these chemosensors are classified according to the types of the interplaying sensing mechanisms, including ICT–FRET, PET–FRET, PET–ICT–ESIPT, etc. [ABSTRACT FROM AUTHOR]

Investigation of the physiological and pathological functions of formaldehyde (FA) are largely restricted by a lack of useful FA imaging agents, in particular, those that allow detection of FA in the context of living tissues. Herein, we present the rational design, synthesis, and photophysical property studies of the first two-photon fluorescent FA probe, Na-FA. Importantly, the highly desirable attributes of the probe Na-FA (such as a very large turn-on signal (up to 900-fold), a low detection limit, and a very fast onset imparted by the unique design aspects of the probe), make it possible to monitor endogenous FA in living tissues for the first time. Furthermore, sodium bisulfite was identified as a simple and convenient inhibitor of FA within biological environments. [ABSTRACT FROM AUTHOR]

The article presents information on the journal's editors and editorial board for the issue as well as mentions the issue's contents which include topics such as nanoparticles, biosensors, and drug delivery systems.

Nitroxyl (HNO) is one of the important reactive nitrogen species (RNS) and show significant biological activities with significant therapeutic potential. Herein, three novel turn-on probes (NP-1–3) based on structurally related dyes with different emission colors as fluorescent scaffolds have been developed for detecting HNO in biological systems. The probes exhibit high sensitivity, excellent selectivity, desirable performance at physiological pH and low cytotoxicity. By incubating living cells with these probes simultaneously, we demonstrate the multicolor imaging of HNO with emission colors in the range of green to near-infrared (NIR) in living systems for the first time. Furthermore, probe NP-3 responds to HNO with a significant turn-on NIR fluorescence signal upon excitation in the NIR region, and it is successfully applied for sensing HNO in living mice. [ABSTRACT FROM AUTHOR]

As selenocysteine (Sec) carries out the majority of the functions of the various Se-containing species in vivo, it is of high importance to develop reliable and rapid assays with biocompatibility to detect Sec. Herein, an NIR fluorescent turn-on probe for highly selective detection of selenol was designed and synthesized. The probe exhibits large turn-on signal upon treatment with selenocysteine (R-SeH), and it was further demonstrated that the new NIR fluorescent probe can be employed to image selenol in living animals. [ABSTRACT FROM AUTHOR]

A new class of locked-flavylium fluorophores with tunable emission wavelengths based on intramolecular charge transfer were designed, synthesized, and evaluated. The optical studies indicate that sensor LF3 can display an intriguing character, fluorescence ratiometric response in three channels by tuning the ICT efficiencies. [ABSTRACT FROM AUTHOR]

ABSTRACT 1,3-Diphenyl-5-(9-anthryl)-2-pyrazoline and 1,3-diphenyl-5-(9-anthryl)-1 H-pyrazole with an anthryl chromophore were synthesized and characterized using 1H NMR, 13C NMR, FT-IR, mass spectrometry and elemental analysis. Their optical properties were characterized by UV-vis absorption and fluorescence spectroscopy. It was observed that the absorption and fluorescence spectra of the two compounds showed a red shift with respect to that of anthracene. Pyrazole exhibited high fluorescent quantum yields (Φf = 0.90 in toluene) while pyrazoline showed nearly no fluorescence in solution. The significant fluorescence divergence of the two similar compounds was investigated theoretically through density functional theory (DFT) calculations. The energetically lowest-lying state S1 in the pyrazoline exhibited both characteristics of locally excited and electron-transfer states that resulted in the fluorescence quenching of anthryl chromophore whereas the S1 state in the pyrazole corresponded to an optically allowed state that led to high fluorescence quantum yields in solutions. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]