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2017 Volume 28 Issue 10
2017, 28(10): 1911-1915
doi: 10.1016/j.cclet.2017.03.034
Abstract:
Protein labeling by using a protein tag and tag-specific fluorescent probes is increasingly becoming a useful technique for the real-time imaging of proteins in living cells. SNAP-tag as one of the most prominent fusion tags has been widely used and already commercially available. Recently, various fluorogenic probes for SNAP-tag based protein labeling were reported. Owing to turn-on fluorescence response, fluorogenic probes for SNAP-tag minimize the fluorescence background caused by unreacted or nonspecifically bound probes and allow for direct imaging in living cells without wash-out steps. Thus, real-time analysis of protein localization, dynamics and interactions has been made possible by SNAP-tag fluorogenic probes. In this review, we describe the design strategies of fluorogenic probes for SNAP-tag and their applications in cellular protein labeling.
Protein labeling by using a protein tag and tag-specific fluorescent probes is increasingly becoming a useful technique for the real-time imaging of proteins in living cells. SNAP-tag as one of the most prominent fusion tags has been widely used and already commercially available. Recently, various fluorogenic probes for SNAP-tag based protein labeling were reported. Owing to turn-on fluorescence response, fluorogenic probes for SNAP-tag minimize the fluorescence background caused by unreacted or nonspecifically bound probes and allow for direct imaging in living cells without wash-out steps. Thus, real-time analysis of protein localization, dynamics and interactions has been made possible by SNAP-tag fluorogenic probes. In this review, we describe the design strategies of fluorogenic probes for SNAP-tag and their applications in cellular protein labeling.
2017, 28(10): 1916-1924
doi: 10.1016/j.cclet.2017.09.032
Abstract:
Adenosine 5'-triphosphate (ATP) not only participates in various physiological activities as the universal energy currency but also implicates in various pathological processes in living cells. Consequently, sensitive and selective detection ATP in live cells, tissues, as well as environmental samples, are urgently demanded. Due to the simple and convenient operation, economy cost, high selectivity for analyte, well biocompatibility and low cytotoxicity, fluorescent sensors for monitoring ATP have aroused great attention of researchers. In recent years, a large number of fluorescent sensors for detecting ATP have developed. This manuscript summarized most of these sensors and the interaction-mechanism between ATP and sensors, mainly including electrostatic interaction, π-π interaction, covalent bonding or hydrogen bond, or combinations of them, and the advantages of each strategy were also generalized. Here, a viewpoint of classification was shown where the sensors were divided into five typed ones according to the structure of probes used.
Adenosine 5'-triphosphate (ATP) not only participates in various physiological activities as the universal energy currency but also implicates in various pathological processes in living cells. Consequently, sensitive and selective detection ATP in live cells, tissues, as well as environmental samples, are urgently demanded. Due to the simple and convenient operation, economy cost, high selectivity for analyte, well biocompatibility and low cytotoxicity, fluorescent sensors for monitoring ATP have aroused great attention of researchers. In recent years, a large number of fluorescent sensors for detecting ATP have developed. This manuscript summarized most of these sensors and the interaction-mechanism between ATP and sensors, mainly including electrostatic interaction, π-π interaction, covalent bonding or hydrogen bond, or combinations of them, and the advantages of each strategy were also generalized. Here, a viewpoint of classification was shown where the sensors were divided into five typed ones according to the structure of probes used.
2017, 28(10): 1925-1928
doi: 10.1016/j.cclet.2017.09.037
Abstract:
A holy grail in neuroscience is to understand how brain functions arise from neural network-level electrical activities. Voltage imaging allows for the direct visualization of electrical signaling at high spatial and temporal resolutions across a large neuronal population. Central to this technique is a palette of genetically-encoded fluorescent probes with fast and sensitive voltage responses. In this review, we chronicle the development and applications of genetically-encoded voltage indicators (GEVIs) over the past two decades, with a primary focus on the structural design that harness the power of fluctuating transmembrane electric fields. We hope this article will inform chemical biologists and protein engineers of the GEVI history and inspire novel design ideas.
A holy grail in neuroscience is to understand how brain functions arise from neural network-level electrical activities. Voltage imaging allows for the direct visualization of electrical signaling at high spatial and temporal resolutions across a large neuronal population. Central to this technique is a palette of genetically-encoded fluorescent probes with fast and sensitive voltage responses. In this review, we chronicle the development and applications of genetically-encoded voltage indicators (GEVIs) over the past two decades, with a primary focus on the structural design that harness the power of fluctuating transmembrane electric fields. We hope this article will inform chemical biologists and protein engineers of the GEVI history and inspire novel design ideas.
2017, 28(10): 1929-1934
doi: 10.1016/j.cclet.2017.08.055
Abstract:
Oxidation and reduction are important chemical and biological processes. The redox state is related with physical functions and health. Thus, it is meaningful to develop tools for study the redox process. Fluorescence is a powerful method to connecting the microcosm and macrocosm. In this review, we discuss the recent progress of reversible fluorescent probes for chemical and biological redox process according to different active centers.
Oxidation and reduction are important chemical and biological processes. The redox state is related with physical functions and health. Thus, it is meaningful to develop tools for study the redox process. Fluorescence is a powerful method to connecting the microcosm and macrocosm. In this review, we discuss the recent progress of reversible fluorescent probes for chemical and biological redox process according to different active centers.
2017, 28(10): 1935-1942
doi: 10.1016/j.cclet.2017.07.018
Abstract:
Formaldehyde, as one of the simplest reactive carbonyl species (RCS), is regarded as a potential carcinogen and a sick house syndrome gas. Recent studies have shown that abnormally high levels of formaldehyde may result in cognitive decline and spatial memory deficits, asthmatic symptoms, Alzheimer's disease, and cancer. Due to the harmfulness of high levels of formaldehyde in nature and humans, it is of great significance to further elucidate the roles and functions of formaldehyde by a non-invasive detection approach. Fluorescence imaging has become a powerful and popular tool in monitoring bio-species owing to their high sensitivity and selectivity, excellent spatiotemporal resolution and non-invasion nature. Therefore, fluorescent probes are widely applied to track and detect formaldehyde in vitro and in vivo which have attracted more and more interest recently. This review focuses on various strategies to design the fluorescent probes for detecting formaldehyde based on different recognition groups.
Formaldehyde, as one of the simplest reactive carbonyl species (RCS), is regarded as a potential carcinogen and a sick house syndrome gas. Recent studies have shown that abnormally high levels of formaldehyde may result in cognitive decline and spatial memory deficits, asthmatic symptoms, Alzheimer's disease, and cancer. Due to the harmfulness of high levels of formaldehyde in nature and humans, it is of great significance to further elucidate the roles and functions of formaldehyde by a non-invasive detection approach. Fluorescence imaging has become a powerful and popular tool in monitoring bio-species owing to their high sensitivity and selectivity, excellent spatiotemporal resolution and non-invasion nature. Therefore, fluorescent probes are widely applied to track and detect formaldehyde in vitro and in vivo which have attracted more and more interest recently. This review focuses on various strategies to design the fluorescent probes for detecting formaldehyde based on different recognition groups.
2017, 28(10): 1943-1951
doi: 10.1016/j.cclet.2017.09.026
Abstract:
Mitochondria and lysosomes are essential cellular organelles in most eukaryotic cells by playing the physiological roles to support the normal functions of cells, as well as the life of the whole body. To date, small-molecule fluorescent probes have been considered as one of the vital tools for monitoring and visualizing multiple biological analytes. This review summarized the recent advances in small-molecule two-photon fluorescent probes for metal ions, reactive oxygen species (ROS) and reactive sulfur species (RSS), and changes inside micro-environment (e.g., pH, viscosity and polarity) in mitochondria and lysosomes, or served as mitotracker and lysotracker with the assistance of two-photon microscopy.
Mitochondria and lysosomes are essential cellular organelles in most eukaryotic cells by playing the physiological roles to support the normal functions of cells, as well as the life of the whole body. To date, small-molecule fluorescent probes have been considered as one of the vital tools for monitoring and visualizing multiple biological analytes. This review summarized the recent advances in small-molecule two-photon fluorescent probes for metal ions, reactive oxygen species (ROS) and reactive sulfur species (RSS), and changes inside micro-environment (e.g., pH, viscosity and polarity) in mitochondria and lysosomes, or served as mitotracker and lysotracker with the assistance of two-photon microscopy.
2017, 28(10): 1952-1956
doi: 10.1016/j.cclet.2017.08.038
Abstract:
Curcuminoid difluoroboron has attractive performance as a promising near-infrared (NIR) fluorescent dye. In this contribution, we designed and synthesized a mitochondria-targeted NIR fluorescent probe DFB1 based on difluoroboron curcuminoid scaffold for the detection of Cys (cysteine). DFB1 employs a curcumin analog as the NIR fluorophore, an acrylate group containing α, β-unsaturated ketone as a functional trigger moiety for Cys, and a triphenylphosphonium (TPP) cation moiety for specifically targeting mitochondria. The remarkable shift of DFB1 with Cys was observed from 470 nm to 590 nm in absorption spectra and from 560 nm to 680 nm in emission spectra. Notably, DFB1 manifests significantly dual-channel and turn-on NIR fluorescent signals simultaneously in response to Cys concentration, which make it favorable for monitoring endogenous Cys activity in vivo. This probe has high sensitivity and selectivity for the detection of Cys over homocysteine (Hcy) and glutathione (GSH). This specific response for Cys was based on differences kinetics of intramolecular adduct/cyclizations. More importantly, biological experiments indicated that this probe could be utilized for the detection of endogenous mitochondrial Cys in living cells.
Curcuminoid difluoroboron has attractive performance as a promising near-infrared (NIR) fluorescent dye. In this contribution, we designed and synthesized a mitochondria-targeted NIR fluorescent probe DFB1 based on difluoroboron curcuminoid scaffold for the detection of Cys (cysteine). DFB1 employs a curcumin analog as the NIR fluorophore, an acrylate group containing α, β-unsaturated ketone as a functional trigger moiety for Cys, and a triphenylphosphonium (TPP) cation moiety for specifically targeting mitochondria. The remarkable shift of DFB1 with Cys was observed from 470 nm to 590 nm in absorption spectra and from 560 nm to 680 nm in emission spectra. Notably, DFB1 manifests significantly dual-channel and turn-on NIR fluorescent signals simultaneously in response to Cys concentration, which make it favorable for monitoring endogenous Cys activity in vivo. This probe has high sensitivity and selectivity for the detection of Cys over homocysteine (Hcy) and glutathione (GSH). This specific response for Cys was based on differences kinetics of intramolecular adduct/cyclizations. More importantly, biological experiments indicated that this probe could be utilized for the detection of endogenous mitochondrial Cys in living cells.
2017, 28(10): 1957-1960
doi: 10.1016/j.cclet.2017.05.010
Abstract:
Hypochlorous acid (HOCl) plays a vital role in many physiological and pathological processes as one of reactive oxygen species (ROS). Developing highly sensitive and selective methods for HOCl detection is of significant interest. In this work, we developed a benzothiazole based probe 1 for ratiometric fluorescence detection of hypochlorite in living cells. The probe can detect HOCl with high selectivity, fast response (within 30 s) as well as low detection limit (0.18 mmol/L). Fluorescence co-localization studies demonstrated that probe 1 was a mitochondria-targeted fluorescent probe. Furthermore, confocal fluorescence images of HeLa cell indicated that probe 1 could be used for monitoring intracellular HOCl in living cells. Finally, test strips experiment suggests that the probe 1 can detect the hypochlorous acid in tap water accompanied by remarkable color change.
Hypochlorous acid (HOCl) plays a vital role in many physiological and pathological processes as one of reactive oxygen species (ROS). Developing highly sensitive and selective methods for HOCl detection is of significant interest. In this work, we developed a benzothiazole based probe 1 for ratiometric fluorescence detection of hypochlorite in living cells. The probe can detect HOCl with high selectivity, fast response (within 30 s) as well as low detection limit (0.18 mmol/L). Fluorescence co-localization studies demonstrated that probe 1 was a mitochondria-targeted fluorescent probe. Furthermore, confocal fluorescence images of HeLa cell indicated that probe 1 could be used for monitoring intracellular HOCl in living cells. Finally, test strips experiment suggests that the probe 1 can detect the hypochlorous acid in tap water accompanied by remarkable color change.
2017, 28(10): 1961-1964
doi: 10.1016/j.cclet.2017.04.027
Abstract:
Fingerprints are unique and life-long to everyone, so they occupy very important statuses in forensic science. However, due to the limit of current imaging technologies and instruments, recognition and matching of fingerprints are mostly based on their level 2 structures (bifurcation, crossover, and etc.). Moreover, in real-world cases, fingerprints collected in the field are often incomplete or damaged, which adds further difficulty in fingerprint analysis. Quantum dots (QDs) are superior fluorescent imaging agents for latent fingerprints, which can provide both level 2 and level 3 (sweat pores) details. Here, we used red-emitting N-acetylcysteine-capped CdTe QDs as imaging agent for staining of eccrine LFPs. The numbers of level 2 and level 3 features that can be mapped are significantly larger than those obtained by cyanoacrylate fuming, a standard technique being adopted at forensic scene. Therefore, the level 2 and level 3 characteristics from QD-staining were simultaneously extracted for improved fingerprint analysis. A preliminary fingerprint matching based modified Pore Matching algorithm was thus developed based on the integration of both level 2 and level 3 characteristics. Satisfactory results of fingerprint matching were obtained, demonstrating the advantage of the QD-staining for advanced fingerprint analysis.
Fingerprints are unique and life-long to everyone, so they occupy very important statuses in forensic science. However, due to the limit of current imaging technologies and instruments, recognition and matching of fingerprints are mostly based on their level 2 structures (bifurcation, crossover, and etc.). Moreover, in real-world cases, fingerprints collected in the field are often incomplete or damaged, which adds further difficulty in fingerprint analysis. Quantum dots (QDs) are superior fluorescent imaging agents for latent fingerprints, which can provide both level 2 and level 3 (sweat pores) details. Here, we used red-emitting N-acetylcysteine-capped CdTe QDs as imaging agent for staining of eccrine LFPs. The numbers of level 2 and level 3 features that can be mapped are significantly larger than those obtained by cyanoacrylate fuming, a standard technique being adopted at forensic scene. Therefore, the level 2 and level 3 characteristics from QD-staining were simultaneously extracted for improved fingerprint analysis. A preliminary fingerprint matching based modified Pore Matching algorithm was thus developed based on the integration of both level 2 and level 3 characteristics. Satisfactory results of fingerprint matching were obtained, demonstrating the advantage of the QD-staining for advanced fingerprint analysis.
2017, 28(10): 1965-1968
doi: 10.1016/j.cclet.2017.07.016
Abstract:
Monitoring mitochondrial derived copper(Ⅱ) in live cells is highly demanded, but accurately detecting is unmet due to the interference with cytoplasmic copper(Ⅱ). Herein, we have reported the design, synthesis and characterization of photocontrollable fluorogenic probe, MCu-3, which is equipped with a photo-labile group (nitrobenzyl group) and mitochondria targeting unit (triphenylphosphonium salt). This novel probe showed an intense fluorescence enhancement in response to copper(Ⅱ) without interference from other metal cations in the biological condition (pH 6-9). The detection limit is 1.7×10-7 mol/L in HEPES buffer. The confocal fluorescence imaging results demonstrated MCu-3 can visualize mitochondrial copper(Ⅱ) in live mammalian cells. The clear advantage of our photocontrollable method is successful to avoid the influence of cytoplasmic copper(Ⅱ) during mitochondria specific detection.
Monitoring mitochondrial derived copper(Ⅱ) in live cells is highly demanded, but accurately detecting is unmet due to the interference with cytoplasmic copper(Ⅱ). Herein, we have reported the design, synthesis and characterization of photocontrollable fluorogenic probe, MCu-3, which is equipped with a photo-labile group (nitrobenzyl group) and mitochondria targeting unit (triphenylphosphonium salt). This novel probe showed an intense fluorescence enhancement in response to copper(Ⅱ) without interference from other metal cations in the biological condition (pH 6-9). The detection limit is 1.7×10-7 mol/L in HEPES buffer. The confocal fluorescence imaging results demonstrated MCu-3 can visualize mitochondrial copper(Ⅱ) in live mammalian cells. The clear advantage of our photocontrollable method is successful to avoid the influence of cytoplasmic copper(Ⅱ) during mitochondria specific detection.
2017, 28(10): 1969-1974
doi: 10.1016/j.cclet.2017.07.027
Abstract:
It is significant for cell physiology to keep the homeostasis of pH, and it is highly demanded to develop ratiometric fluorescent sensors toward pH. In this work, under mild condition, through the electrostatic interaction between carbon nanodots (CDs) and organic molecules, two novel ratiometric fluorescence hybrid nanosensors were fabricated for sensing acidic pH. These nanohybrid systems possess dual emission peaks at 455 and 527 nm under a single excitation wavelength of 380 nm in acidic pH condition. With the increasing of pH, the fluorescence of the 1, 8-naphthalimide derivative completely quenches, while the blue fluorescence of CDs keeps constant. Furthermore, the CDs organic molecular nanohybrids exhibit excellent anti-disturbance ability, reversible pH sensing ability, and a linear response range in wide pH range respectively. Besides the ability to target lysosome, with one of the nanosensor, stimulated pH change has been successfully tracked in a ratiometric manner via fluorescence imaging.
It is significant for cell physiology to keep the homeostasis of pH, and it is highly demanded to develop ratiometric fluorescent sensors toward pH. In this work, under mild condition, through the electrostatic interaction between carbon nanodots (CDs) and organic molecules, two novel ratiometric fluorescence hybrid nanosensors were fabricated for sensing acidic pH. These nanohybrid systems possess dual emission peaks at 455 and 527 nm under a single excitation wavelength of 380 nm in acidic pH condition. With the increasing of pH, the fluorescence of the 1, 8-naphthalimide derivative completely quenches, while the blue fluorescence of CDs keeps constant. Furthermore, the CDs organic molecular nanohybrids exhibit excellent anti-disturbance ability, reversible pH sensing ability, and a linear response range in wide pH range respectively. Besides the ability to target lysosome, with one of the nanosensor, stimulated pH change has been successfully tracked in a ratiometric manner via fluorescence imaging.
2017, 28(10): 1975-1978
doi: 10.1016/j.cclet.2017.07.002
Abstract:
Optical imaging, as an important molecular imaging modality, has emerged many attractions in studying the biological or molecular events both in cell level and living subject because of its high resolution and sensitivity, noninvasive manner and low cost. Herein, we bring novel insights into a water-soluble conjugated polyelectlyte by deeply studying its properties in cells. Poly(9, 9-bis (6'-N, N, N-trimethy-lammonium hexyl)fluorene phenylene) (PFP), a good biosensing material, was studied in this paper. The biocompatibility of PFP was investigated in different cells, and cell cycle analysis was carried out to explore the reasons of different biocompatibility of PFP to cells. After irradiation, fluorescence enhancement of blue emission and turn-on of long-wavelength emission of PFP in HepG2 cells was observed, which was first reported as far as we know. The differentiated biocompatibility of PFP and its particular imaging properties in cancer cells can help to guide the application of conjugated polymers in cells and provide a new dimension in designing sensitive and responsive imaging materials.
Optical imaging, as an important molecular imaging modality, has emerged many attractions in studying the biological or molecular events both in cell level and living subject because of its high resolution and sensitivity, noninvasive manner and low cost. Herein, we bring novel insights into a water-soluble conjugated polyelectlyte by deeply studying its properties in cells. Poly(9, 9-bis (6'-N, N, N-trimethy-lammonium hexyl)fluorene phenylene) (PFP), a good biosensing material, was studied in this paper. The biocompatibility of PFP was investigated in different cells, and cell cycle analysis was carried out to explore the reasons of different biocompatibility of PFP to cells. After irradiation, fluorescence enhancement of blue emission and turn-on of long-wavelength emission of PFP in HepG2 cells was observed, which was first reported as far as we know. The differentiated biocompatibility of PFP and its particular imaging properties in cancer cells can help to guide the application of conjugated polymers in cells and provide a new dimension in designing sensitive and responsive imaging materials.
2017, 28(10): 1979-1982
doi: 10.1016/j.cclet.2017.07.004
Abstract:
Developing the novel fluorescent dyes with a larger Stokes shift is still a challenge in the research of fluorescence probes. In this work, a naphthalimide-modified near-infrared cyanine dye with an emission at 785 nm has been synthesized for lysosome-targeting imaging. This fluorescent dye showed a large Stokes shift (up to 165 nm) and favorable lysosome-targeting property, which facilitated it to be a potential candidate for studying of lysosomal functions. The result also indicated that the probe is a promising contrast agent for in vivo imaging in mouse models.
Developing the novel fluorescent dyes with a larger Stokes shift is still a challenge in the research of fluorescence probes. In this work, a naphthalimide-modified near-infrared cyanine dye with an emission at 785 nm has been synthesized for lysosome-targeting imaging. This fluorescent dye showed a large Stokes shift (up to 165 nm) and favorable lysosome-targeting property, which facilitated it to be a potential candidate for studying of lysosomal functions. The result also indicated that the probe is a promising contrast agent for in vivo imaging in mouse models.
2017, 28(10): 1983-1986
doi: 10.1016/j.cclet.2017.08.024
Abstract:
Ascorbic acid (AA) serves as a key coenzyme in many metabolic pathways. Enough daily AA supplements from different dietary sources are the only way for human to maintain their AA levels in body. Determination of AA content in different foods guides to build healthy diet, which is of great biomedical significance. Hence, developing a highly selective and instantaneous fluorescent nanoprobe for the detection of AA in biological samples is highly needed. Here we present a novel turn-on fluorescent nanoprobe using lanthanide-doped upconversion nanoparticles (UCNPs) and cobalt oxyhydroxide (CoOOH) nanoflakes for monitoring AA in fruit samples. In this nanosystem, the UCNPs can be adsorbed onto the CoOOH nanoflakes, leading to a remarkable fluorescence decrease through Förster resonance energy transfer. Furthermore, the AA could trigger the disassembly of the CoOOH to liberate the upconverted fluorescence. The UCNPs-based nanoprobe can provide an effective platform for highly selective and rapid detection of AA in biological samples.
Ascorbic acid (AA) serves as a key coenzyme in many metabolic pathways. Enough daily AA supplements from different dietary sources are the only way for human to maintain their AA levels in body. Determination of AA content in different foods guides to build healthy diet, which is of great biomedical significance. Hence, developing a highly selective and instantaneous fluorescent nanoprobe for the detection of AA in biological samples is highly needed. Here we present a novel turn-on fluorescent nanoprobe using lanthanide-doped upconversion nanoparticles (UCNPs) and cobalt oxyhydroxide (CoOOH) nanoflakes for monitoring AA in fruit samples. In this nanosystem, the UCNPs can be adsorbed onto the CoOOH nanoflakes, leading to a remarkable fluorescence decrease through Förster resonance energy transfer. Furthermore, the AA could trigger the disassembly of the CoOOH to liberate the upconverted fluorescence. The UCNPs-based nanoprobe can provide an effective platform for highly selective and rapid detection of AA in biological samples.
2017, 28(10): 1987-1990
doi: 10.1016/j.cclet.2017.08.021
Abstract:
A new fluorescent probe (Rhod-Sec) for selenol detection with ultralow background fluorescence have been developed in this paper, which showed a 380-fold off-on fluorescence response, and the nontoxic Rhod-Sec is well suitable for detecting and imaging both exogenous and endogenous selenol in living cells. It also can be applied to visualize the fluctuation of selenol in HepG2 cells through LPS-induced cells oxidation resistance.
A new fluorescent probe (Rhod-Sec) for selenol detection with ultralow background fluorescence have been developed in this paper, which showed a 380-fold off-on fluorescence response, and the nontoxic Rhod-Sec is well suitable for detecting and imaging both exogenous and endogenous selenol in living cells. It also can be applied to visualize the fluctuation of selenol in HepG2 cells through LPS-induced cells oxidation resistance.
2017, 28(10): 1991-1993
doi: 10.1016/j.cclet.2017.08.054
Abstract:
α-Ketoglutaric acid (α-KA) is an important metabolic intermediate in tricarboxylic acid circle in our body. The mutations of isocitrate dehydrogenase-1 (IDH1) and isocitrate dehydrogenase-2 (IDH2), however, will lead to the transformation of α-KA into 2-hydroxyglutarate (2-HG), which is confirmed to closely related to actue myeloid leukemia (AML). Therefore it is of great significance to detect α-KA level changes in serum. In this paper, a fluorescent "off-on" probe CH for α-KA was designed based on naphthalimide fluorophore by introducing a hydrazine group for α-KA recognition and a long alkyl amino chain to enhance PET efficiency and water solubility. Cetyltrimethyl ammonium bromide (CTAB) was added toform self-assembly micelles for accelerating the recognition process. CH shows a 28-fold fluorescence enhancement ((I-I0)/I0 at 550 nm) over other biological species by optimizing the chemical recognition process of CH with α-KA. Significantly, CH was successfully applied for thefluorescence discrimination of all kinds of blood cancer serum samples. This work would provide a potential method that is quick and convenient for sensing α-KA and may promote fluorescence detection in clinical diagnosis.
α-Ketoglutaric acid (α-KA) is an important metabolic intermediate in tricarboxylic acid circle in our body. The mutations of isocitrate dehydrogenase-1 (IDH1) and isocitrate dehydrogenase-2 (IDH2), however, will lead to the transformation of α-KA into 2-hydroxyglutarate (2-HG), which is confirmed to closely related to actue myeloid leukemia (AML). Therefore it is of great significance to detect α-KA level changes in serum. In this paper, a fluorescent "off-on" probe CH for α-KA was designed based on naphthalimide fluorophore by introducing a hydrazine group for α-KA recognition and a long alkyl amino chain to enhance PET efficiency and water solubility. Cetyltrimethyl ammonium bromide (CTAB) was added toform self-assembly micelles for accelerating the recognition process. CH shows a 28-fold fluorescence enhancement ((I-I0)/I0 at 550 nm) over other biological species by optimizing the chemical recognition process of CH with α-KA. Significantly, CH was successfully applied for thefluorescence discrimination of all kinds of blood cancer serum samples. This work would provide a potential method that is quick and convenient for sensing α-KA and may promote fluorescence detection in clinical diagnosis.
2017, 28(10): 1994-1996
doi: 10.1016/j.cclet.2017.07.019
Abstract:
A fluorescence-enhanced probe PY, which is based on integration of pyrene moiety and amino acid group, was developed for the orthogonal recognition of In3+ and Al3+ by the quick formation of 1:1 complex. PY shows high selectivity and sensitivity for In3+ in NaOAc/HOAc (pH 4.8) buffer solution but rather for Al3+ in methanol. Moreover, this probe shows good cell permeability, and the recognition of In3+ by PY was successfully applied in bioimaging, which was the first example for detection of this metal ion in living cells.
A fluorescence-enhanced probe PY, which is based on integration of pyrene moiety and amino acid group, was developed for the orthogonal recognition of In3+ and Al3+ by the quick formation of 1:1 complex. PY shows high selectivity and sensitivity for In3+ in NaOAc/HOAc (pH 4.8) buffer solution but rather for Al3+ in methanol. Moreover, this probe shows good cell permeability, and the recognition of In3+ by PY was successfully applied in bioimaging, which was the first example for detection of this metal ion in living cells.
2017, 28(10): 1997-2000
doi: 10.1016/j.cclet.2017.08.023
Abstract:
Imaging hypoxia using fluorescence probes for nitroreductase (NTR) have attracted much attention in last decade. At least three different linkers have been commonly used to connect the recognition unit and reporting unit in reported probes for NTR. Meanwhile, the linker is known to be a key factor for achieving best sensing performance. In this work, three near-infrared fluorescence probes CyNP-1, CyNP-2 and CyNP-3 were designed and synthesized from an aminocyanine dye CyNP. The three probes have the same recognition unit and same fluorescence reporting unit, but different linkers. CyNP-1 was found to have the best sensing performance for NTR with 40-fold of fluorescence enhancement. It is well investigated how the difference of the linkers brings out the different sensing performance by HPLC, MS and docking calculations. In the end, CyNP-1 was found to have good selectivity for NTR and used to imaging hypoxia in Hela cells.
Imaging hypoxia using fluorescence probes for nitroreductase (NTR) have attracted much attention in last decade. At least three different linkers have been commonly used to connect the recognition unit and reporting unit in reported probes for NTR. Meanwhile, the linker is known to be a key factor for achieving best sensing performance. In this work, three near-infrared fluorescence probes CyNP-1, CyNP-2 and CyNP-3 were designed and synthesized from an aminocyanine dye CyNP. The three probes have the same recognition unit and same fluorescence reporting unit, but different linkers. CyNP-1 was found to have the best sensing performance for NTR with 40-fold of fluorescence enhancement. It is well investigated how the difference of the linkers brings out the different sensing performance by HPLC, MS and docking calculations. In the end, CyNP-1 was found to have good selectivity for NTR and used to imaging hypoxia in Hela cells.
2017, 28(10): 2001-2004
doi: 10.1016/j.cclet.2017.09.023
Abstract:
Radical detection has attracted significant attention recently. Here we have developed a scaffold through covalent assembly principle (OR570), which could facile applications in detection of oxidative radicals. The primary advantage of the assembly type probe lies at the turn-on fluorescence signal from a zero background and hence high fluorescence turn-on ratio for sensitive detection of weak signal.
Radical detection has attracted significant attention recently. Here we have developed a scaffold through covalent assembly principle (OR570), which could facile applications in detection of oxidative radicals. The primary advantage of the assembly type probe lies at the turn-on fluorescence signal from a zero background and hence high fluorescence turn-on ratio for sensitive detection of weak signal.
2017, 28(10): 2005-2008
doi: 10.1016/j.cclet.2017.09.014
Abstract:
The pH values of lysosomes in cancer cells is slightly lower than that in normal cells, which can be used to distinguish cancer cells from normal cells. According to this, a naphthalimide-rhodamine based fluorescent probe (hereafter referred to as RBN) with a pKa of 4.20 was designed and synthesized for ratiometric sensing of cellular pH via fluorescence resonance energy transfer (FRET), which can respond to different pH precisely through ratiometric fluorescence intensity (I577/I540). RBN can be employed to distinguish cancer cells from normal cells on the basis of different fluorescent response, in particular, RBN showed excellent water solubility and low cell toxicity, all these are quite significant for potential application in cancer diagnose and therapy.
The pH values of lysosomes in cancer cells is slightly lower than that in normal cells, which can be used to distinguish cancer cells from normal cells. According to this, a naphthalimide-rhodamine based fluorescent probe (hereafter referred to as RBN) with a pKa of 4.20 was designed and synthesized for ratiometric sensing of cellular pH via fluorescence resonance energy transfer (FRET), which can respond to different pH precisely through ratiometric fluorescence intensity (I577/I540). RBN can be employed to distinguish cancer cells from normal cells on the basis of different fluorescent response, in particular, RBN showed excellent water solubility and low cell toxicity, all these are quite significant for potential application in cancer diagnose and therapy.
2017, 28(10): 2009-2013
doi: 10.1016/j.cclet.2017.08.037
Abstract:
By modifying the salicylic-acid moiety with electron-withdrawing or -donating groups, three new terbium complexes (LⅠ·Tb, LⅡ·Tb, LⅢ·Tb) based on tripodal carboxylate ligands were synthesized. Due to different pull-push electronic effects of ligands, the fluorescence intensities of these terbium complexes significantly varied, that is:LⅡ·Tb > LⅢ·Tb > LⅠ·Tb. Meanwhile, the characteristic peaks at 492 nm (5D4 → 7F6) and 547 nm (5D4 → 7F5) showed "Off-On-Off" fluorescence response to various pH conditions, which indicated that all of them can be used as the highly sensitive pH fluorescent probes. Notably, using LⅡ Tb with the best fluorescence performance as a probe, some patients' urine samples can be easily monitored through the response triggered by pH value. Therefore, LⅡ Tb has the potential to auxiliarily diagnose some diseases in clinical practice through pH detection of routine urine test.
By modifying the salicylic-acid moiety with electron-withdrawing or -donating groups, three new terbium complexes (LⅠ·Tb, LⅡ·Tb, LⅢ·Tb) based on tripodal carboxylate ligands were synthesized. Due to different pull-push electronic effects of ligands, the fluorescence intensities of these terbium complexes significantly varied, that is:LⅡ·Tb > LⅢ·Tb > LⅠ·Tb. Meanwhile, the characteristic peaks at 492 nm (5D4 → 7F6) and 547 nm (5D4 → 7F5) showed "Off-On-Off" fluorescence response to various pH conditions, which indicated that all of them can be used as the highly sensitive pH fluorescent probes. Notably, using LⅡ Tb with the best fluorescence performance as a probe, some patients' urine samples can be easily monitored through the response triggered by pH value. Therefore, LⅡ Tb has the potential to auxiliarily diagnose some diseases in clinical practice through pH detection of routine urine test.
2017, 28(10): 2014-2018
doi: 10.1016/j.cclet.2017.09.027
Abstract:
Rhodamine-based fluorescent probe is widely used in chemical analysis, environmental analysis and life sciences area due to their excellent optical properties. Based on the thiophilic property of Hg2+, using C=S structural motif as the core segment, our group have designed and synthesized three novel probes containing cinnamyl aldehyde with different substituents, exhibiting high selectivity and excellent sensitivity. The structure-property relationships of these probes have been investigated that the optical change caused by electron withdrawing effect and heavy atom effect. Furthermore, these Hg2+ probes could be applied in living mice imaging, which provide a promising tool for quantitative mercury (Ⅱ) ion imaging in living organism.
Rhodamine-based fluorescent probe is widely used in chemical analysis, environmental analysis and life sciences area due to their excellent optical properties. Based on the thiophilic property of Hg2+, using C=S structural motif as the core segment, our group have designed and synthesized three novel probes containing cinnamyl aldehyde with different substituents, exhibiting high selectivity and excellent sensitivity. The structure-property relationships of these probes have been investigated that the optical change caused by electron withdrawing effect and heavy atom effect. Furthermore, these Hg2+ probes could be applied in living mice imaging, which provide a promising tool for quantitative mercury (Ⅱ) ion imaging in living organism.
2017, 28(10): 2019-2022
doi: 10.1016/j.cclet.2017.07.030
Abstract:
A ratiometric fluorescent sensor (Hoe-NI) was developed by connecting a nucleus targeted Hoechst unit to a naphthalimide dye via "click chemistry". The sensor achieves high specific nucleus labeling with wash-free staining method in various kinds of living cells. The fluorescence ratio of the two emission bands (450 nm for Hoechst and 505 nm for naphthalimide) is changed sensitively to the variation of DNA concentrations, which provides the quantitative information in the processes of DNA damage induced by hydroxyl radicals and antitumor drug. Therefore, Hoe-NI is a recommendable sensor for the monitoring of nuclear DNA damage that reveals the health status of cells.
A ratiometric fluorescent sensor (Hoe-NI) was developed by connecting a nucleus targeted Hoechst unit to a naphthalimide dye via "click chemistry". The sensor achieves high specific nucleus labeling with wash-free staining method in various kinds of living cells. The fluorescence ratio of the two emission bands (450 nm for Hoechst and 505 nm for naphthalimide) is changed sensitively to the variation of DNA concentrations, which provides the quantitative information in the processes of DNA damage induced by hydroxyl radicals and antitumor drug. Therefore, Hoe-NI is a recommendable sensor for the monitoring of nuclear DNA damage that reveals the health status of cells.
2017, 28(10): 2023-2026
doi: 10.1016/j.cclet.2017.08.051
Abstract:
A coumarin-based compound (1) was designed and synthesized as a new turn-on fluorescent probe for the detection of cysteine. The probe exhibited higher selectivity towards the target molecule over other thiol and amino acids at pH 7.2 in aqueous media CH3CN-HEPES (0.02 mol/L, pH 7.2, 1: 9, v/v). The reaction mechanism is attributed to the cysteine-induced SNAr substitution-rearrangement reaction. Remarkable enhancement of up to 20-fold in fluorescence intensity was achieved in the detection of cysteine. When applied for the fluorescence imaging of cysteine, the compound 1 emitted a green fluorescence in Hi5 cell cytoplasm. The in vivo imaging of Caenorhabditis elegans had further confirmed the cysteine detection by compound 1.
A coumarin-based compound (1) was designed and synthesized as a new turn-on fluorescent probe for the detection of cysteine. The probe exhibited higher selectivity towards the target molecule over other thiol and amino acids at pH 7.2 in aqueous media CH3CN-HEPES (0.02 mol/L, pH 7.2, 1: 9, v/v). The reaction mechanism is attributed to the cysteine-induced SNAr substitution-rearrangement reaction. Remarkable enhancement of up to 20-fold in fluorescence intensity was achieved in the detection of cysteine. When applied for the fluorescence imaging of cysteine, the compound 1 emitted a green fluorescence in Hi5 cell cytoplasm. The in vivo imaging of Caenorhabditis elegans had further confirmed the cysteine detection by compound 1.
