A novel acidic pH fluorescent probe based on a benzothiazole derivative

Science.gov (United States)

Ma, Qiujuan; Li, Xian; Feng, Suxiang; Liang, Beibei; Zhou, Tiqiang; Xu, Min; Ma, Zhuoyi

2017-04-01

A novel acidic pH fluorescent probe 1 based on a benzothiazole derivative has been designed, synthesized and developed. The linear response range covers the acidic pH range from 3.44 to 6.46, which is valuable for pH researches in acidic environment. The evaluated pKa value of the probe 1 is 4.23. The fluorescence enhancement of the studied probe 1 with an increase in hydrogen ions concentration is based on the hindering of enhanced photo-induced electron transfer (PET) process. Moreover, the pH sensor possesses a highly selective response to H+ in the presence of metal ions, anions and other bioactive small molecules which would be interfere with its fluorescent pH response. Furthermore, the probe 1 responds to acidic pH with short response time that was less than 1 min. The probe 1 has been successfully applied to confocal fluorescence imaging in live HeLa cells and can selectively stain lysosomes. All of such good properties prove it can be used to monitoring pH fluctuations in acidic environment with high sensitivity, pH dependence and short response time.

Ultrasensitive near-infrared fluorescence-enhanced probe for in vivo nitroreductase imaging.

Science.gov (United States)

Li, Yuhao; Sun, Yun; Li, Jiachang; Su, Qianqian; Yuan, Wei; Dai, Yu; Han, Chunmiao; Wang, Qiuhong; Feng, Wei; Li, Fuyou

2015-05-20

Nitroreductase (NTR) can be overexpressed in hypoxic tumors, thus the selective and efficient detection of NTR is of great importance. To date, although a few optical methods have been reported for the detection of NTR in solution, an effective optical probe for NTR monitoring in vivo is still lacking. Therefore, it is necessary to develop a near-infrared (NIR) fluorescent detection probe for NTR. In this study, five NIR cyanine dyes with fluorescence reporting structure decorated with different nitro aromatic groups, Cy7-1-5, have been designed and explored for possible rapid detection of NTR. Our experimental results presented that only a para-nitro benzoate group modified cyanine probe (Cy7-1) could serve as a rapid NIR fluorescence-enhanced probe for monitoring and bioimaging of NTR. The structure-function relationship has been revealed by theoretical study. The linker connecting the detecting and fluorescence reporting groups and the nitro group position is a key factor for the formation of hydrogen bonds and spatial structure match, inducing the NTR catalytic ability enhancement. The in vitro response and mechanism of the enzyme-catalyzed reduction of Cy7-1 have been investigated through kinetic optical studies and other methods. The results have indicated that an electro-withdrawing group induced electron-transfer process becomes blocked when Cy7-1 is catalytically reduced to Cy7-NH2 by NTR, which is manifested in enhanced fluorescence intensity during the detection process. Confocal fluorescence imaging of hypoxic A549 cells has confirmed the NTR detection ability of Cy7-1 at the cellular level. Importantly, Cy7-1 can detect tumor hypoxia in a murine hypoxic tumor model, showing a rapid and significant enhancement of its NIR fluorescence characteristics suitable for fluorescence bioimaging. This method may potentially be used for tumor hypoxia diagnosis.

Behavior of the guanine base in G-quadruplexes probed by the fluorescent guanine analog, 6-methyl isozanthopterin

Energy Technology Data Exchange (ETDEWEB)

Han, Ji Hoon; Chitrapriya, Nataraj; Lee, Hyun Suk; Lee, Young Ae; Kim, Seog K. [Dept. of Chemistry, Yeungnam University, Gyeongsan (Korea, Republic of); Jung, Maeng Joon [Dept. of Chemistry, Kyungpook National University, Daegu (Korea, Republic of)

2017-02-15

In this study, circular dichroism (CD) spectrum and fluorescence techniques were used to examine the dynamic properties and microenvironment of the guanine base (G) at the central loop and at the middle of the G-stem of the G-quadruplex formed from the G{sub 3}T{sub 2}G{sub 3}TGTG{sub 3}T{sub 2}G{sub 3} sequence (G-quadruplex 1), in which the G base at the 10th and 13th position were replaced with a fluorescent G analog, 6-methyl isoxanthopterin (6MI) (G-quadruplex 2 and 3, respectively). For all G-quadruplexes, the CD spectrum revealed a positive band at 263 nm and a shoulder at 298 nm, and the thermal melting profiles were the sum of at least two sigmoidal curves. These observations indicated the presence of two conformers in the G-quadruplex. The fluorescence intensity of G-quadruplex 2 was greater than 3, as expected from the extent of stacking interaction, which is larger in the G(6MI)G sequence than the T(6MI)T sequence. The efficiency of fluorescence quenching by the polar acrylamide quencher and negatively charged I− quencher were larger for G-quadruplex 3, suggesting that 6MI in the G(6MI)G stem is exposed more to the aqueous environment compared to that in the T(6MI)T central loop. In the latter case, 6MI may direct to the center of the top G-quartet layer. The possibility of hydrogen bond formation between the carbonyl group of 6MI and the acrylamide of the G-quadruplex 3 was proposed.

Development of Ultrasonic Modulation Probe for Fluorescence Tomography Based on Acousto-Optic Effect

Directory of Open Access Journals (Sweden)

Trinh Quang Duc

2011-01-01

Full Text Available We have developed an ultrasonic probe for fluorescence modulation to image fluorescence within biological tissues. The probe consists of a focused ultrasonic transducer mounted on actuators for mechanical fan scanning, which can be used in contact with the measuring object aiming for clinical application. The mechanical fan scanning employed in the probe has a beneficial feature of portability. As a result, fluorescent beads, which were localized with the diameter of 2 mm at 20 mm depth in a pork meat tissue, were detected with resolution of 3 mm. The system performance denotes the feasibility of development towards the final goal of ultrasonic fluorescence modulation tomography for clinical applications.

An easily Prepared Fluorescent pH Probe Based on Dansyl.

Science.gov (United States)

Sha, Chunming; Chen, Yuhua; Chen, Yufen; Xu, Dongmei

2016-09-01

A novel fluorescent pH probe from dansyl chloride and thiosemicarbazide was easily prepared and fully characterized by (1)H NMR, (13)C NMR, LC-MS, Infrared spectra and elemental analysis. The probe exhibited high selectivity and sensitivity to H(+) with a pK a value of 4.98. The fluorescence intensity at 510 nm quenched 99.5 % when the pH dropped from 10.88 to 1.98. In addition, the dansyl-based probe could respond quickly and reversibly to the pH variation and various common metal ions showed negligible interference. The recognition could be ascribed to the intramolecular charge transfer caused by the protonation of the nitrogen in the dimethylamino group.

Fluorescence intensity and lifetime-based cyanide sensitive probes for physiological safeguard

International Nuclear Information System (INIS)

Badugu, Ramachandram; Lakowicz, Joseph R.; Geddes, Chris D.

2004-01-01

We characterize six new fluorescent probes that show both intensity and lifetime changes in the presence of free uncomplexed aqueous cyanide, allowing for fluorescence based cyanide sensing up to physiological safeguard levels, i.e. 2 to the anionic R-B - (CN) 3 form, a new cyanide binding mechanism which we have recently reported. The presence of an electron deficient quaternary heterocyclic nitrogen nucleus, and the electron rich cyanide bound form, provides for the intensity changes observed. We have determined the disassociation constants of the probes to be in the range ∼15-84 μM 3 . In addition we have synthesized control compounds which do not contain the boronic acid moiety, allowing for a rationale of the cyanide responses between the probe isomers to be made. The lifetime of the cyanide bound probes are significantly shorter than the free R-B(OH) 2 probe forms, providing for the opportunity of lifetime based cyanide sensing up to physiologically lethal levels. Finally, while fluorescent probes containing the boronic acid moiety have earned a well-deserved reputation for monosaccharide sensing, we show that strong bases such as CN - and OH - preferentially bind as compared to glucose, enabling the potential use of these probes for cyanide safeguard and determination in physiological fluids, especially given that physiologies do not experience any notable changes in pH

Photoswitchable non-fluorescent thermochromic dye-nanoparticle hybrid probes

OpenAIRE

Harrington, Walter N.; Haji, Mwafaq R.; Galanzha, Ekaterina I.; Nedosekin, Dmitry A.; Nima, Zeid A.; Watanabe, Fumiya; Ghosh, Anindya; Biris, Alexandru S.; Zharov, Vladimir P.

2016-01-01

Photoswitchable fluorescent proteins with controllable light?dark states and spectral shifts in emission in response to light have led to breakthroughs in the study of cell biology. Nevertheless, conventional photoswitching is not applicable for weakly fluorescent proteins and requires UV light with low depth penetration in bio-tissue. Here we introduce a novel concept of photoswitchable hybrid probes consisting of thermochromic dye and absorbing nanoparticles, in which temperature-sensitive ...

Detection of Pathogenic Biofilms with Bacterial Amyloid Targeting Fluorescent Probe, CDy11

DEFF Research Database (Denmark)

Kim, Jun Young; Sahu, Srikanta; Yau, Yin Hoe

2016-01-01

Bacterial biofilms are responsible for a wide range of persistent infections. In the clinic, diagnosis of biofilm-associated infections relies heavily on culturing methods, which fail to detect nonculturable bacteria. Identification of novel fluorescent probes for biofilm imaging will greatly...... facilitate diagnosis of pathogenic bacterial infection. Herein, we report a novel fluorescent probe, CDy11 (compound of designation yellow 11), which targets amyloid in the Pseudomonas aeruginosa biofilm matrix through a diversity oriented fluorescent library approach (DOFLA). CDy11 was further demonstrated...

In situ hybridization of phytoplankton using fluorescently labeled rRNA probes

OpenAIRE

Groben, R.; Medlin, Linda

2005-01-01

Fluorescently-labelled molecular probes were used to identify and characterise phytoplankton species using in situ hybridisation coupled with fluorescence microscopy and flow cytometry. The application of this technique is sometimes problematic, because of the many different species with which this method is to be used. Problems that may occur are: probe penetration versus maintanance of cell stability, strong autofluorescence and/or cell lost during the sample processing. Here we present a m...

Chromenoquinoline-based thiol probes: a study on the quencher position for controlling fluorescent Off-On characteristics.

Science.gov (United States)

Kand, Dnyaneshwar; Kalle, Arunasree Marasanapalli; Talukdar, Pinaki

2013-02-13

The design, synthesis and thiol sensing ability of chromenoquinoline-based fluorescent probes 4, 5 and 6 and are reported here. The relative position of the maleimide moiety was varied along the chromenoquinoline fluorophore to decrease the background fluorescence. Lower background fluorescence in probes 4 and 6 was rationalized by the smaller k(r)/k(nr) values compared to that of probe 5. An intramolecular charge transfer (ICT) mechanism was proposed for quenching and the extent was dependent on the position of the maleimide quencher. Fluorescent Off-On characteristics were evaluated by theoretical calculations. All probes were selective only towards thiol containing amino acids. Thiol sensing by probes 4 and 6 were much better compared to 5. Probe 4 displayed a better fluorescence response for less hindered thiol (185-, 223- and 156-fold for Hcy, Cys and GSH, respectively), while for probe 6, a higher enhancement in fluorescence was observed with more hindered thiols (180-, 205- and 245-fold for Hcy, Cys and GSH, respectively). The better response to bulkier thiol, GSH by probe 6 was attributed to the steric crowding at the C-4 position and bulkiness of the GSH group which force the succinimide unit to be in a nearly orthogonal conformation. This spatial arrangement was important in reducing the fluorescence quenching ability of the succinimide moiety. The application of probes 4, 5 and 6 was demonstrated by naked eye detection thiols using a 96-well plate system as well as by live-cell imaging.

Cyanine-based probe\\tag-peptide pair fluorescence protein imaging and fluorescence protein imaging methods

Science.gov (United States)

Mayer-Cumblidge, M. Uljana; Cao, Haishi

2013-01-15

A molecular probe comprises two arsenic atoms and at least one cyanine based moiety. A method of producing a molecular probe includes providing a molecule having a first formula, treating the molecule with HgOAc, and subsequently transmetallizing with AsCl.sub.3. The As is liganded to ethanedithiol to produce a probe having a second formula. A method of labeling a peptide includes providing a peptide comprising a tag sequence and contacting the peptide with a biarsenical molecular probe. A complex is formed comprising the tag sequence and the molecular probe. A method of studying a peptide includes providing a mixture containing a peptide comprising a peptide tag sequence, adding a biarsenical probe to the mixture, and monitoring the fluorescence of the mixture.

Selective imaging of cancer cells with a pH-activatable lysosome-targeting fluorescent probe.

Science.gov (United States)

Shi, Rongguang; Huang, Lu; Duan, Xiaoxue; Sun, Guohao; Yin, Gui; Wang, Ruiyong; Zhu, Jun-Jie

2017-10-02

Fluorescence imaging with tumor-specific fluorescent probe has emerged as a tool to aid surgeons in the identification and removal of tumor tissue. We report here a new lysosome-targeting fluorescent probe (NBOH) with BODIPY fluorephore to distinguish tumor tissue out of normal tissue based on different pH environment. The probe exhibited remarkable pH-dependent fluorescence behavior in a wide pH range from 3.0 to 11.0, especially a sensitive pH-dependent fluorescence change at pH range between 3.5 and 5.5, corresponding well to the acidic microenvironment of tumor cells, in aqueous solution. The response time of NBOH was extremely short and the photostability was proved to be good. Toxicity test and fluorescence cell imaging together with a sub-cellular localization study were carried out revealing its low biotoxicity and good cell membrane permeability. And NBOH was successfully applied to the imaging of tumor tissue in tumor-bearing mice suggesting potential application to surgery as a tumor-specific probe. Copyright © 2017 Elsevier B.V. All rights reserved.

Copper nanoclusters as probes for turn-on fluorescence sensing of L-lysine.

Science.gov (United States)

Zhang, Mingming; Qiao, Juan; Zhang, Shufeng; Qi, Li

2018-05-15

Herein, a unique protocol based on copper nanoclusters (CuNCs) probe for turn-on fluorescence sensing of L-lysine was developed. The fluorescent CuNCs with ovalbumin as the stabilizer was prepared by a simple, one-step and green method. When 370 nm was used as the excitation wavelength, the resultant CuNCs exhibited a pale blue fluorescence with the maximum emission at 440 nm. Interestingly, existence of L-lysine evoked the obvious fluorescence intensity increase of CuNCs. The detection limit of the proposed method for L-lysine was 5.5 μM, with a good linear range from 10.0 μM to 1.0 mM (r 2 = 0.999). Moreover, the possible mechanism for enhanced fluorescence intensity of CuNCs by addition of L-lysine was explored and discussed briefly. Further, the as-prepared fluorescent CuNCs was successfully applied in detection of L-lysine in urine. Our results demonstrated that L-lysine could be monitored by the probe, providing new path for construction of CuNCs as fluorescent probes and showing great potential in quantification of L-lysine in real samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Polarization of fluorescence: a probe of molecular autoionization

International Nuclear Information System (INIS)

Leroi, G.E.; Dehmer, J.L.; Parr, A.C.; Poliakoff, E.D.

1983-01-01

The polarization of fluorescence from excited-state molecular photoions provides a direct probe of the photoionization dynamics and the symmetry signatures of autoionizing resonances. Measurements on CO 2 and CS 2 are presented as examples

Instant live-cell super-resolution imaging of cellular structures by nanoinjection of fluorescent probes.

Science.gov (United States)

Hennig, Simon; van de Linde, Sebastian; Lummer, Martina; Simonis, Matthias; Huser, Thomas; Sauer, Markus

2015-02-11

Labeling internal structures within living cells with standard fluorescent probes is a challenging problem. Here, we introduce a novel intracellular staining method that enables us to carefully control the labeling process and provides instant access to the inner structures of living cells. Using a hollow glass capillary with a diameter of <100 nm, we deliver functionalized fluorescent probes directly into the cells by (di)electrophoretic forces. The label density can be adjusted and traced directly during the staining process by fluorescence microscopy. We demonstrate the potential of this technique by delivering and imaging a range of commercially available cell-permeable and nonpermeable fluorescent probes to cells.

Studies of radiation induced membrane damage in lymphocytes using fluorescent probes

International Nuclear Information System (INIS)

Nikesch, W.

1974-01-01

The fluorescent probes perylene (PER), 1-anilino-8-naphthalene sulfonic acid (ANS), and fluorescein diacetate (FDA) were used to investigate membrane changes caused by ionizing radiation. Probe response to various other perturbations (variation of pH, temperature, and salt concentration, and treatment with phythohemagglutinin (PHA) and saponins) was also investigated to better understand membrane-probe interactions. ANS was used to probe the membrane surface, PER to probe the membrane interior, and FDA to investigate membrane integrity. Polarization of fluorescent light from ANS and PER was used to investigate the microviscosity and order of the membrane surface and interior respectively. Irradiated cells (600 R) were shown to have a decreased rate of hydrolysis of FDA probably due to cytoplasmic changes effecting the enzymatic reaction. Also evident was an increase in loss of intracellular fluorescein and a decrease in PER polarization indicating that the cells have a decreased membrane integrity, possibly the result of an increased disorganization of the phospholipid hydrocarbon chains in the membrane interior. Experiments with PHA link the decreased membrane integrity with the eventual interphase death of the cells. In general it is shown that the fluorescent probes ANS, PER, and FDA provide useful ways to investigate order and microviscosity in the cell membrane surface and interior, membrane surface charges, internal membrane polarity changes, and membrane integrity. (U.S.)

Fluorescent probe based on heteroatom containing styrylcyanine: pH-sensitive properties and bioimaging in vivo

International Nuclear Information System (INIS)

Yang, Xiaodong; Gao, Ya; Huang, Zhibing; Chen, Xiaohui; Ke, Zhiyong; Zhao, Peiliang; Yan, Yichen; Liu, Ruiyuan; Qu, Jinqing

2015-01-01

A novel fluorescent probe based on heteroatom containing styrylcyanine is synthesized. The fluorescence of probe is bright green in basic and neutral media but dark orange in strong acidic environments, which could be reversibly switched. Such behavior enables it to work as a fluorescent pH sensor in the solution state and a chemosensor for detecting acidic and basic volatile organic compounds. Analyses by NMR spectroscopy confirm that the protonation or deprotonation of pyridinyl moiety is responsible for the sensing process. In addition, the fluorescent microscopic images of probe in live cells and zebrafish are achieved successfully, suggesting that the probe has good cell membrane permeability and low cytotoxicity. - Graphical abstract: A novel styrylcyanine-based fluorescent pH probe was designed and synthesized, the fluorescence of which is bright green in basic and neutral media but dark orange in strong acidic environments. Such behavior enables it to work as a fluorescent pH sensor in solution states, and a chemosensor for detecting volatile organic compounds with high acidity and basicity in solid state. In addition, it can be used for fluorescent imaging in living cell and living organism. - Highlights: • Bright green fluorescence was observed in basic and neutral media. • Dark orange fluorescence was found in strong acidic environments. • Volatile organic compounds with high acidity and basicity could be detected. • Bioimaging in living cell and living organism was achieved successfully

Highly selective and rapidly responsive fluorescent probe for hydrogen sulfide detection in wine.

Science.gov (United States)

Wang, Hao; Wang, Jialin; Yang, Shaoxiang; Tian, Hongyu; Liu, Yongguo; Sun, Baoguo

2018-08-15

A new fluorescent probe 6-(2, 4-dinitrophenoxy)-2-naphthonitrile (probe 1) was designed and synthesized for the selective detection of hydrogen sulfide (H 2 S). The addition of H 2 S to a solution of probe 1 resulted in a marked fluorescence turn-on alongside a visual color change from colorless to light yellow. Importantly, this distinct color response indicated that probe 1 could be used as a visual sensor for H 2 S. Moreover, probe 1 was successfully used as a signal tool to determine the H 2 S levels in beer and red wine. Copyright © 2018 Elsevier Ltd. All rights reserved.

Towards Fluorescence In Vivo Hybridization (FIVH) Detection of H. pylori in Gastric Mucosa Using Advanced LNA Probes

DEFF Research Database (Denmark)

Fontenete, Sílvia; Leite, Marina; Guimarães, Nuno

2015-01-01

acid (LNA)/ 2' O-methyl RNA (2'OMe) probe using standard phosphoramidite chemistry and FISH hybridization was then successfully performed both on adhered and suspended bacteria at 37°C. In this work we simplified, shortened and adapted FISH to work at gastric pH values, meaning that the hybridization...... step now takes only 30 minutes and, in addition to the buffer, uses only urea and probe at non-toxic concentrations. Importantly, the sensitivity and specificity of the FISH method was maintained in the range of conditions tested, even at low stringency conditions (e.g., low pH). In conclusion......In recent years, there have been several attempts to improve the diagnosis of infection caused by Helicobacter pylori. Fluorescence in situ hybridization (FISH) is a commonly used technique to detect H. pylori infection but it requires biopsies from the stomach. Thus, the development of an in vivo...

Flexible poly(methyl methacrylate)-based neural probe: An affordable implementation

Science.gov (United States)

Gasemi, Pejman; Veladi, Hadi; Shahabi, Parviz; Khalilzadeh, Emad

2018-03-01

This research presents a novel technique used to fabricate a deep brain stimulation probe based on a commercial poly(methyl methacrylate) (PMMA) polymer. This technique is developed to overcome the high cost of available probes crucial for chronic stimulation and recording in neural disorders such as Parkinson’s disease and epilepsy. The probe is made of PMMA and its mechanical properties have been customized by controlling the reaction conditions. The polymer is adjusted to be stiff enough to be easily inserted and, on the other hand, soft enough to perform required movements. As cost is one of the issues in the use of neural probes, a simple process is proposed for the production of PMMA neural probes without using expensive equipment and operations, and without compromising performance and quality. An in vivo animal test was conducted to observe the recording capability of a PMMA probe.

Hemoglobin detection using carbon dots as a fluorescence probe.

Science.gov (United States)

Barati, Ali; Shamsipur, Mojtaba; Abdollahi, Hamid

2015-09-15

Herein, we have described the application of high fluorescent carbon dots (CDs) without any surface modification as a simple and fast responding fluorescence probe for sensitive and selective determination of hemoglobin (Hb) in the presence of H2O2. Although Hb itself was able to quench the fluorescence of CDs, based on the inner filter effect (IFE) of the protein that affects both excitation and emission spectra of CDs, the presence of H2O2 resulted in further improvement of the sensitivity of Hb detection. The assay is based on the reaction of Hb with H2O2 that generates reactive oxygen species including hydroxyl (OH•) and superoxide (O2(•-)) radicals under heme degradation and/or iron release from Hb and the subsequent reaction of hydroxyl radicals, as strong oxidizing agents, with CDs resulting in high fluorescence quenching. The proposed probe was used for determination of Hb in concentration range of 1-100 nM with a detection limit of 0.4 nM. The method was successfully applied to the determination of Hb in human blood samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Determination of paraquat in water samples using a sensitive fluorescent probe titration method.

Science.gov (United States)

Yao, Feihu; Liu, Hailong; Wang, Guangquan; Du, Liming; Yin, Xiaofen; Fu, Yunlong

2013-06-01

Paraquat (PQ), a nonselective herbicide, is non-fluorescent in aqueous solutions. Thus, its determination through direct fluorescent methods is not feasible. The supramolecular inclusion interaction of PQ with cucurbit[7]uril was studied by a fluorescent probe titration method. Significant quenching of the fluorescence intensity of the cucurbit[7]uril-coptisine fluorescent probe was observed with the addition of PQ. A new fluorescent probe titration method with high selectivity and sensitivity at the ng/mL level was developed to determine PQ in aqueous solutions with good precision and accuracy based on the significant quenching of the supramolecular complex fluorescence intensity. The proposed method was successfully used in the determination of PQ in lake water, tap water, well water, and ditch water in an agricultural area, with recoveries of 96.73% to 105.77%. The fluorescence quenching values (deltaF) showed a good linear relationship with PQ concentrations from 1.0 x 10(-8) to 1.2 x 10(-5) mol/L with a detection limit of 3.35 x 10(-9) mol/L. In addition, the interaction models of the supramolecular complexes formed between the host and the guest were established using theoretical calculations. The interaction mechanism between the cucurbit[7]uril and PQ was confirmed by 1H NMR spectroscopy.

A rhodamine chromene-based turn-on fluorescence probe for selectively imaging Cu2+ in living cell

Science.gov (United States)

Liu, Wei-Yong; Li, Hai-Ying; Lv, Hong-Shui; Zhao, Bao-Xiang; Miao, Jun-Ying

We describe the development of a rhodamine chromene-based turn-on fluorescence probe to monitor the intracellular Cu2+ level in living cells. The new fluorescent probe with a chlorine group in chromene moiety exhibits good membrane-permeable property than previous reported because the predicted lipophilicity of present probe 4 is stronger than that of methoxyl substituted probe in our previous work (CLogP of 4: 8.313, CLogP of methoxyl substituted probe: 7.706), and a fluorescence response toward Cu2+ under physiological conditions with high sensitivity and selectivity, and facilitates naked-eye detection of Cu2+. The fluorescence intensity was remarkably increased upon the addition of Cu2+ within 1 or 2 min, while the other sixteen metal ions caused no significant effect.

A Pyridazine-Based Fluorescent Probe Targeting Aβ Plaques in Alzheimer’s Disease

Directory of Open Access Journals (Sweden)

Yong Dae Park

2018-01-01

Full Text Available Accumulation of β-amyloid (Aβ plaques comprising Aβ40 and Aβ42 in the brain is the most significant factor in the pathogenesis of Alzheimer’s disease (AD. Thus, the detection of Aβ plaques has increasingly attracted interest in the context of AD diagnosis. In the present study, a fluorescent pyridazine-based dye that can detect and image Aβ plaques was designed and synthesized, and its optical properties in the presence of Aβ aggregates were evaluated. An approximately 34-fold increase in emission intensity was exhibited by the fluorescent probe after binding with Aβ aggregates, for which it showed high affinity (KD = 0.35 µM. Moreover, the reasonable hydrophobic properties of the probe (log P = 2.94 allow it to penetrate the blood brain barrier (BBB. In addition, the pyridazine-based probe was used in the histological costaining of transgenic mouse (APP/PS1 brain sections to validate the selective binding of the probe to Aβ plaques. The results suggest that the pyridazine-based compound has the potential to serve as a fluorescent probe for the diagnosis of AD.

Cyanine-based probe\\tag-peptide pair for fluorescence protein imaging and fluorescence protein imaging methods

Science.gov (United States)

Mayer-Cumblidge, M Uljana [Richland, WA; Cao, Haishi [Richland, WA

2010-08-17

A molecular probe comprises two arsenic atoms and at least one cyanine based moiety. A method of producing a molecular probe includes providing a molecule having a first formula, treating the molecule with HgOAc, and subsequently transmetallizing with AsCl.sub.3. The As is liganded to ethanedithiol to produce a probe having a second formula. A method of labeling a peptide includes providing a peptide comprising a tag sequence and contacting the peptide with a biarsenical molecular probe. A complex is formed comprising the tag sequence and the molecular probe. A method of studying a peptide includes providing a mixture containing a peptide comprising a peptide tag sequence, adding a biarsenical probe to the mixture, and monitoring the fluorescence of the mixture.

A Fluorescent Probe for Sensitive Detection of Hydrazine and Its Application in Red Wine and Water.

Science.gov (United States)

Wang, Jialin; Wang, Hao; Yang, Shaoxiang; Tian, Hongyu; Liu, Yongguo; Hao, Yanfeng; Zhang, Jie; Sun, Baoguo

2018-01-01

A fluorescent probe, 7-(diethylamino)-2-oxo-2H-chromene-4-carbaldehyde (probe 1), was designed and synthesized for the sensitive detection of hydrazine. The addition of N 2 H 4 caused the fluorescence intensity of probe 1 to decrease. The probe's fluorescence was turn-off after adding N 2 H 4 , which could be observed under UV light at 365 nm. Moreover, once treated with different concentrations N 2 H 4 solutions, the solution color change could be distinguished, which indicates that probe 1 could be used as a visual sensor for hydrazine. Moreover, probe 1 can be used as a signal tool to determine hydrazine levels in solutions, such as red wine and water.

Genetically encoded fluorescent probe to visualize phosphatidylinositol

Czech Academy of Sciences Publication Activity Database

Eisenreichová, Andrea; Humpolíčková, Jana; Bouřa, Evžen

2017-01-01

Roč. 284, Suppl 1 (2017), s. 364-365 ISSN 1742-464X. [FEBS Congress /42./ From Molecules to Cells and Back. 10.09.2017-14.09.2017, Jerusalem] R&D Projects: GA ČR GJ15-21030Y; GA MŠk LO1302 Institutional support: RVO:61388963 Keywords : phosphatidylinositol * fluorescent probe Subject RIV: CE - Biochemistry

Fluorescent nanodiamonds as non-photobleachable responsive probes

Czech Academy of Sciences Publication Activity Database

Cígler, Petr

2016-01-01

Roč. 14, č. 5 (2016), s. 232 ISSN 2336-7202. [Sjezd českých a slovenských chemických společností /68./. 04.09.2016-07.09.2016, Praha] R&D Projects: GA ČR(CZ) GA16-16336S Institutional support: RVO:61388963 Keywords : fluorescent nanodiamonds * FNDs * probes Subject RIV: CG - Electrochemistry

Fluorescent Reporters and Biosensors for Probing the Dynamic Behavior of Protein Kinases

Directory of Open Access Journals (Sweden)

Juan A. González-Vera

2015-11-01

Full Text Available Probing the dynamic activities of protein kinases in real-time in living cells constitutes a major challenge that requires specific and sensitive tools tailored to meet the particular demands associated with cellular imaging. The development of genetically-encoded and synthetic fluorescent biosensors has provided means of monitoring protein kinase activities in a non-invasive fashion in their native cellular environment with high spatial and temporal resolution. Here, we review existing technologies to probe different dynamic features of protein kinases and discuss limitations where new developments are required to implement more performant tools, in particular with respect to infrared and near-infrared fluorescent probes and strategies which enable improved signal-to-noise ratio and controlled activation of probes.

A new fluorescent pH probe for imaging lysosomes in living cells.

Science.gov (United States)

Lv, Hong-Shui; Huang, Shu-Ya; Xu, Yu; Dai, Xi; Miao, Jun-Ying; Zhao, Bao-Xiang

2014-01-15

A new rhodamine B-based pH fluorescent probe has been synthesized and characterized. The probe responds to acidic pH with short response time, high selectivity and sensitivity, and exhibits a more than 20-fold increase in fluorescence intensity within the pH range of 7.5-4.1 with the pKa value of 5.72, which is valuable to study acidic organelles in living cells. Also, it has been successfully applied to HeLa cells, for its low cytotoxicity, brilliant photostability, good membrane permeability and no 'alkalizing effect' on lysosomes. The results demonstrate that this probe is a lysosome-specific probe, which can selectively stain lysosomes and monitor lysosomal pH changes in living cells. Copyright © 2013 Elsevier Ltd. All rights reserved.

Visualizing tributyltin (TBT) in bacterial aggregates by specific rhodamine-based fluorescent probes.

Science.gov (United States)

Jin, Xilang; Hao, Likai; She, Mengyao; Obst, Martin; Kappler, Andreas; Yin, Bing; Liu, Ping; Li, Jianli; Wang, Lanying; Shi, Zhen

2015-01-01

Here we present the first examples of fluorescent and colorimetric probes for microscopic TBT imaging. The fluorescent probes are highly selective and sensitive to TBT and have successfully been applied for imaging of TBT in bacterial Rhodobacter ferrooxidans sp. strain SW2 cell-EPS-mineral aggregates and in cell suspensions of the marine cyanobacterium Synechococcus PCC 7002 by using confocal laser scanning microscopy. Copyright © 2014 Elsevier B.V. All rights reserved.

Synergistic Combination of Unquenching and Plasmonic Fluorescence Enhancement in Fluorogenic Nucleic Acid Hybridization Probes.

Science.gov (United States)

Vietz, Carolin; Lalkens, Birka; Acuna, Guillermo P; Tinnefeld, Philip

2017-10-11

Fluorogenic nucleic acid hybridization probes are widely used for detecting and quantifying nucleic acids. The achieved sensitivity strongly depends on the contrast between a quenched closed form and an unquenched opened form with liberated fluorescence. So far, this contrast was improved by improving the quenching efficiency of the closed form. In this study, we modularly combine these probes with optical antennas used for plasmonic fluorescence enhancement and study the effect of the nanophotonic structure on the fluorescence of the quenched and the opened form. As quenched fluorescent dyes are usually enhanced more by fluorescence enhancement, a detrimental reduction of the contrast between closed and opened form was anticipated. In contrast, we could achieve a surprising increase of the contrast with full additivity of quenching of the dark form and fluorescence enhancement of the bright form. Using single-molecule experiments, we demonstrate that the additivity of the two mechanisms depends on the perfect quenching in the quenched form, and we delineate the rules for new nucleic acid probes for enhanced contrast and absolute brightness. Fluorogenic hybridization probes optimized not only for quenching but also for the brightness of the open form might find application in nucleic acid assays with PCR avoiding detection schemes.

A novel polymer probe for Zn(II) detection with ratiometric fluorescence signal

Science.gov (United States)

Diao, Haipeng; Guo, Lixia; Liu, Wen; Feng, Liheng

2018-05-01

A conjugated polymer probe comprised of fluorene, quinolone and benzothiazole units was designed and synthesized by the Suzuki coupling reaction. Through the studies of photophysical and thermal properties, the polymer displays blue-emitting feature and good thermal stability. A ratiometric fluorescence signal of the probe for Zn(II) was observed in ethanol with a new emission peak at 555 nm. The probe possesses a high selectivity and sensitivity for Zn(II) during familiar metal ions in ethanol. The detection limit of the probe for Zn (II) is up to 10-8 mol/L. The electron distributions of the polymer before and after bonding with Zn (II) were investigated by the Gaussian 09 software, which agreed with the experimental results. Noticeably, based on the color property of the probe with Zn(II), a series of color test paper were developed for visual detecting Zn(II) ions. This work helps to provide a platform or pattern for the development of polymer fluorescence probe in the chemosensor field.

An off-on fluorescence probe targeting mitochondria based on oxidation-reduction response for tumor cell and tissue imaging

Science.gov (United States)

Yao, Hanchun; Cao, Li; Zhao, Weiwei; Zhang, Suge; Zeng, Man; Du, Bin

2017-10-01

In this study, a tumor-targeting poly( d, l-lactic-co-glycolic acid) (PLGA) loaded "off-on" fluorescent probe nanoparticle (PFN) delivery system was developed to evaluate the region of tumor by off-on fluorescence. The biodegradability of the nanosize PFN delivery system readily released the probe under tumor acidic conditions. The probe with good biocompatibility was used to monitor the intracellular glutathione (GSH) of cancer cells and selectively localize to mitochondria for tumor imaging. The incorporated tumor-targeting probe was based on the molecular photoinduced electron transfer (PET) mechanism preventing fluorescence ("off" state) and could be easily released under tumor acidic conditions. However, the released tumor-targeting fluorescence probe molecule was selective towards GSH with high selectivity and an ultra-sensitivity for the mitochondria of cancer cells and tissues significantly increasing the probe molecule fluorescence signal ("on" state). The tumor-targeting fluorescence probe showed sensitivity to GSH avoiding interference from cysteine and homocysteine. The PFNs could enable fluorescence-guided cancer imaging during cancer therapy. This work may expand the biological applications of PFNs as a diagnostic reagent, which will be beneficial for fundamental research in tumor imaging. [Figure not available: see fulltext.

A small molecular pH-dependent fluorescent probe for cancer cell imaging in living cell.

Science.gov (United States)

Ma, Junbao; Li, Wenqi; Li, Juanjuan; Shi, Rongguang; Yin, Gui; Wang, Ruiyong

2018-05-15

A novel pH-dependent two-photon fluorescent molecular probe ABMP has been prepared based on the fluorophore of 2, 4, 6-trisubstituted pyridine. The probe has an absorption wavelength at 354 nm and corresponding emission wavelength at 475 nm with the working pH range from 2.20 to 7.00, especially owning a good liner response from pH = 2.40 to pH = 4.00. ABMP also has excellent reversibility, photostability and selectivity which promotes its ability in analytical application. The probe can be excited with a two-photon fluorescence microscopy and the fluorescence cell imaging indicated that the probe can distinguish Hela cancer cells out of normal cells with a two-photon fluorescence microscopy which suggested its potential application in tumor cell detection. Copyright © 2018 Elsevier B.V. All rights reserved.

Characterization of a new series of fluorescent probes for imaging membrane order.

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Joanna M Kwiatek

Full Text Available Visualization and quantification of lipid order is an important tool in membrane biophysics and cell biology, but the availability of environmentally sensitive fluorescent membrane probes is limited. Here, we present the characterization of the novel fluorescent dyes PY3304, PY3174 and PY3184, whose fluorescence properties are sensitive to membrane lipid order. In artificial bilayers, the fluorescence emission spectra are red-shifted between the liquid-ordered and liquid-disordered phases. Using ratiometric imaging we demonstrate that the degree of membrane order can be quantitatively determined in artificial liposomes as well as live cells and intact, live zebrafish embryos. Finally, we show that the fluorescence lifetime of the dyes is also dependent on bilayer order. These probes expand the current palate of lipid order-sensing fluorophores affording greater flexibility in the excitation/emission wavelengths and possibly new opportunities in membrane biology.

In Vivo Fluorescence Lifetime Imaging Monitors Binding of Specific Probes to Cancer Biomarkers

Science.gov (United States)

Ardeshirpour, Yasaman; Chernomordik, Victor; Zielinski, Rafal; Capala, Jacek; Griffiths, Gary; Vasalatiy, Olga; Smirnov, Aleksandr V.; Knutson, Jay R.; Lyakhov, Ilya; Achilefu, Samuel; Gandjbakhche, Amir; Hassan, Moinuddin

2012-01-01

One of the most important factors in choosing a treatment strategy for cancer is characterization of biomarkers in cancer cells. Particularly, recent advances in Monoclonal Antibodies (MAB) as primary-specific drugs targeting tumor receptors show that their efficacy depends strongly on characterization of tumor biomarkers. Assessment of their status in individual patients would facilitate selection of an optimal treatment strategy, and the continuous monitoring of those biomarkers and their binding process to the therapy would provide a means for early evaluation of the efficacy of therapeutic intervention. In this study we have demonstrated for the first time in live animals that the fluorescence lifetime can be used to detect the binding of targeted optical probes to the extracellular receptors on tumor cells in vivo. The rationale was that fluorescence lifetime of a specific probe is sensitive to local environment and/or affinity to other molecules. We attached Near-InfraRed (NIR) fluorescent probes to Human Epidermal Growth Factor 2 (HER2/neu)-specific Affibody molecules and used our time-resolved optical system to compare the fluorescence lifetime of the optical probes that were bound and unbound to tumor cells in live mice. Our results show that the fluorescence lifetime changes in our model system delineate HER2 receptor bound from the unbound probe in vivo. Thus, this method is useful as a specific marker of the receptor binding process, which can open a new paradigm in the “image and treat” concept, especially for early evaluation of the efficacy of the therapy. PMID:22384092

In vivo fluorescence lifetime imaging monitors binding of specific probes to cancer biomarkers.

Directory of Open Access Journals (Sweden)

Yasaman Ardeshirpour

Full Text Available One of the most important factors in choosing a treatment strategy for cancer is characterization of biomarkers in cancer cells. Particularly, recent advances in Monoclonal Antibodies (MAB as primary-specific drugs targeting tumor receptors show that their efficacy depends strongly on characterization of tumor biomarkers. Assessment of their status in individual patients would facilitate selection of an optimal treatment strategy, and the continuous monitoring of those biomarkers and their binding process to the therapy would provide a means for early evaluation of the efficacy of therapeutic intervention. In this study we have demonstrated for the first time in live animals that the fluorescence lifetime can be used to detect the binding of targeted optical probes to the extracellular receptors on tumor cells in vivo. The rationale was that fluorescence lifetime of a specific probe is sensitive to local environment and/or affinity to other molecules. We attached Near-InfraRed (NIR fluorescent probes to Human Epidermal Growth Factor 2 (HER2/neu-specific Affibody molecules and used our time-resolved optical system to compare the fluorescence lifetime of the optical probes that were bound and unbound to tumor cells in live mice. Our results show that the fluorescence lifetime changes in our model system delineate HER2 receptor bound from the unbound probe in vivo. Thus, this method is useful as a specific marker of the receptor binding process, which can open a new paradigm in the "image and treat" concept, especially for early evaluation of the efficacy of the therapy.

A flavone-based turn-on fluorescent probe for intracellular cysteine/homocysteine sensing with high selectivity.

Science.gov (United States)

Zhang, Jian; Lv, Yanlin; Zhang, Wei; Ding, Hui; Liu, Rongji; Zhao, Yongsheng; Zhang, Guangjin; Tian, Zhiyuan

2016-01-01

A new type of flavone-based fluorescent probe (DMAF) capable of cysteine (Cys)/homocysteine (Hcy) sensing with high selectivity over other amino acids was developed. Such type of probe undergoes Cys/Hcy-mediated cyclization reaction with the involvement of its aldehyde group, which suppresses of the photoinduced electron transfer (PET) process of the probe molecule and consequently leads to the enhancement of fluorescence emission upon excitation using visible light. The formation of product of the Cys/Hcy-mediated cyclization reaction was confirmed and the preliminary fluorescence imaging experiments revealed the biocompatibility of the as-prepared probe and validated its practicability for intracellular Cys/Hcy sensing. Copyright © 2015 Elsevier B.V. All rights reserved.

Fluorescent Probes for Analysis and Imaging of Monoamine Oxidase Activity

Energy Technology Data Exchange (ETDEWEB)

Kim, Dokyoung; Jun, Yong Woong; Ahn, Kyo Han [POSTECH, Pohang (Korea, Republic of)

2014-05-15

Monoamine oxidases catalyze the oxidative deamination of dietary amines and amine neurotransmitters, and assist in maintaining the homeostasis of the amine neurotransmitters in the brain. Dysfunctions of these enzymes can cause neurological and behavioral disorders including Parkinson's and Alzheimer's diseases. To understand their physiological roles, efficient assay methods for monoamine oxidases are essential. Reviewed in this Perspective are the recent progress in the development of fluorescent probes for monoamine oxidases and their applications to enzyme assays in cells and tissues. It is evident that still there is strong need for a fluorescent probe with desirable substrate selectivity and photophysical properties to challenge the much unsolved issues associated with the enzymes and the diseases.

pH-dependent fluorescence property of methyl red isomers in silver colloids

International Nuclear Information System (INIS)

Wong, Jian-How; Lee, Szetsen

2012-01-01

We report the use of silver (Ag) colloids in the spectroscopic differentiation of methyl red (MR) isomers (o-MR, m-MR, p-MR) by fluorescence techniques. Under different pH conditions, the formation of MR-Ag complex has an impact on the fluorescence band shapes and peak position shift, which are distinctive between MR isomers. The fluorescence quenching between 400 and 414 nm accompanied by simultaneous enhancement between 510 and 541 nm changes with pH are closely related to energy transfer efficiency and the interaction between the MR isomers and the Ag surface.

A benzothiazole-based fluorescent probe for hypochlorous acid detection and imaging in living cells

Science.gov (United States)

Nguyen, Khac Hong; Hao, Yuanqiang; Zeng, Ke; Fan, Shengnan; Li, Fen; Yuan, Suke; Ding, Xuejing; Xu, Maotian; Liu, You-Nian

2018-06-01

A benzothiazole-based turn-on fluorescent probe with a large Stokes shift (190 nm) has been developed for hypochlorous acid detection. The probe displays prompt fluorescence response for HClO with excellent selectivity over other reactive oxygen species as well as a low detection limit of 0.08 μM. The sensing mechanism involves the HClO-induced specific oxidation of oxime moiety of the probe to nitrile oxide, which was confirmed by HPLC-MS technique. Furthermore, imaging studies demonstrated that the probe is cell permeable and can be applied to detect HClO in living cells.

Design and Evaluation of Novel Polymyxin Fluorescent Probes

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Bo Yun

2017-11-01

Full Text Available Polymyxins (polymyxin B and colistin are cyclic lipopeptide antibiotics that serve as a last-line defence against Gram-negative “superbugs”. In the present study, two novel fluorescent polymyxin probes were designed through regio-selective modifications of the polymyxin B core structure at the N-terminus and the hydrophobic motif at positions 6 and 7. The resulting probes, FADDI-285 and FADDI-286 demonstrated comparable antibacterial activity (MICs 2–8 mg/L to polymyxin B and colistin (MICs 0.5–8 mg/L against a panel of gram-negative clinical isolates of Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa. These probes should prove to be of considerable utility for imaging cellular uptake and mechanistic investigations of these important last-line antibiotics.

Cu2+-labeled dansyl compounds as fluorescent and PET probes for imaging apoptosis.

Science.gov (United States)

Han, Junyan; Wang, Xukui; Yu, MeiXiang

2016-11-15

Compound DNSTT-Cu 2+ , a novel chelate of Cu 2+ with DOTA conjugated to a fluorescent dansyl fragment, is developed for imaging cell apoptosis. Apoptotic U-87MG cells could be selectively visualized by the fluorescence of DNSTT-Cu 2+ from cytoplasm of cells, confirmed by the fluorescence of apoptosis cells co-labeled with Alexa Fluor 568-labeled annexin V, a conventional probe for selectively labeling membranes of apoptosis cells. A radioactive 64 Cu 2 + analog, DNSTT- 64 Cu 2+ , was easily synthesized, providing a potential PET probe for imaging apoptosis in vivo. Copyright © 2016 Elsevier Ltd. All rights reserved.

Spectrally-resolved response properties of the three most advanced FRET based fluorescent protein voltage probes.

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Hiroki Mutoh

Full Text Available Genetically-encoded optical probes for membrane potential hold the promise of monitoring electrical signaling of electrically active cells such as specific neuronal populations in intact brain tissue. The most advanced class of these probes was generated by molecular fusion of the voltage sensing domain (VSD of Ci-VSP with a fluorescent protein (FP pair. We quantitatively compared the three most advanced versions of these probes (two previously reported and one new variant, each involving a spectrally distinct tandem of FPs. Despite these different FP tandems and dissimilarities within the amino acid sequence linking the VSD to the FPs, the amplitude and kinetics of voltage dependent fluorescence changes were surprisingly similar. However, each of these fluorescent probes has specific merits when considering different potential applications.

Detection of Dysplastic Intestinal Adenomas Using a Fluorescent Folate Imaging Probe

Directory of Open Access Journals (Sweden)

Wei-Tsung Chen

2005-01-01

Full Text Available Macrophages have long been recognized as a prominent component of tumors. Activated macrophages overexpress folate receptors and we used this phenomenon to image inflammatory reactions in colon dysplasia using a fluorescent folate probe (FFP. APCΔ468 mice injected with FFP showed fluorescent adenomas (target-to-background ratio, adenoma vs. adjacent normal mucosa, of 2.46 ± 0.41, significantly higher (p < .001 than adenomas in animals injected with a non-folate-containing control probe. Fluorescence-activated cell-sorting analysis revealed a 3-fold higher content of Mac1-positive cells in colonic adenomas compared with normal adjacent mucosa (6.8% vs. 2.2%, and confirmed the source of FFP-positive cells to be primarily an F4/80-positive macrophage subpopulation. Taken together, these results indicate that FFP potentially can be used to image dysplastic intestinal adenomas in vivo.

Folate receptor targeting silica nanoparticle probe for two-photon fluorescence bioimaging

Science.gov (United States)

Wang, Xuhua; Yao, Sheng; Ahn, Hyo-Yang; Zhang, Yuanwei; Bondar, Mykhailo V.; Torres, Joseph A.; Belfield, Kevin D.

2010-01-01

Narrow dispersity organically modified silica nanoparticles (SiNPs), diameter ~30 nm, entrapping a hydrophobic two-photon absorbing fluorenyl dye, were synthesized by hydrolysis of triethoxyvinylsilane and (3-aminopropyl)triethoxysilane in the nonpolar core of Aerosol-OT micelles. The surface of the SiNPs were functionalized with folic acid, to specifically deliver the probe to folate receptor (FR) over-expressing Hela cells, making these folate two-photon dye-doped SiNPs potential candidates as probes for two-photon fluorescence microscopy (2PFM) bioimaging. In vitro studies using FR over-expressing Hela cells and low FR expressing MG63 cells demonstrated specific cellular uptake of the functionalized nanoparticles. One-photon fluorescence microscopy (1PFM) imaging, 2PFM imaging, and two-photon fluorescence lifetime microscopy (2P-FLIM) imaging of Hela cells incubated with folate-modified two-photon dye-doped SiNPs were demonstrated. PMID:21258480

Synchronous fluorescence based biosensor for albumin determination by cooperative binding of fluorescence probe in a supra-biomolecular host-protein assembly.

Science.gov (United States)

Patra, Digambara

2010-01-15

A synchronous fluorescence probe based biosensor for estimation of albumin with high sensitivity and selectivity was developed. Unlike conventional fluorescence emission or excitation spectral measurements, synchronous fluorescence measurement offered exclusively a new synchronous fluorescence peak in the shorter wavelength range upon binding of chrysene with protein making it an easy identification tool for albumin determination. The cooperative binding of a fluorescence probe, chrysene, in a supramolecular host-protein assembly during various albumin assessments was investigated. The presence of supramolecular host molecules such as beta-cyclodextrin, curucurbit[6]uril or curucurbit[7]uril have little influence on sensitivity or limit of detection during albumin determination but reduced dramatically interference from various coexisting metal ion quenchers/enhancers. Using the present method the limit of detection for BSA and gamma-Globulin was found to be 0.005 microM which is more sensitive than reported values. Copyright 2009 Elsevier B.V. All rights reserved.

An intramolecular charge transfer process based fluorescent probe for monitoring subtle pH fluctuation in living cells.

Science.gov (United States)

Sun, Mingtai; Du, Libo; Yu, Huan; Zhang, Kui; Liu, Yang; Wang, Suhua

2017-01-01

It is crucial to monitor intracellular pH values and their fluctuation since the organelles of cells have different pH distribution. Herein we construct a new small molecule fluorescent probe HBT-O for monitoring the subtle pH values within the scope of neutral to acid in living cells. The probe exhibited good water solubility, a marked turquoise to olivine emission color change in response to pH, and tremendous fluorescence hypochromatic shift of ∼50nm (1718cm -1 ) as well as the increased fluorescence intensity when the pH value changed from neutral to acid. Thus, the probe HBT-O can distinguish the subtle changes in the range of normal pH values from neutral to acid with significant fluorescence changes. These properties can be attributed to the intramolecular charge transfer (ICT) process of the probe upon protonation in buffer solutions at varied pH values. Moreover, the probe was reversible and nearly non-toxic for living cells. Then the probe was successfully used to detect pH fluctuation in living cells by exhibiting different fluorescence colors and intensity. These findings demonstrate that the probe will find useful applications in biology and biomedical research. Copyright © 2016 Elsevier B.V. All rights reserved.

The application of anti-ESAT-6 monoclonal antibody fluorescent probe in ex vivo near-infrared fluorescence imaging in mice with pulmonary tuberculosis.

Science.gov (United States)

Feng, Feng; Zhang, Haoling; Zhu, Zhaoqin; Li, Cong; Shi, Yuxin; Zhang, Zhiyong

2014-09-01

Here, we aimed to assess the feasibility of anti-ESAT-6 monoclonal antibody (mAb) coupling with IR783 and rhodamine fluorescent probe in the detection of ESAT-6 expression in tuberculosis tissue of mice using near-infrared fluorescence imaging. IR783 and rhodamine were conjugated to the anti-ESAT-6 mAb or IgG. Mice in the experimental group were injected with fluorescence-labeled mAb probe, and mice in the control group were injected with fluorescence-labeled non-specific IgG antibody. Twenty-four hours later, the lung tissue of mice was examined using ex vivo near-infrared fluorescence imaging. In addition, the contrast-to-noise ratio (CNR) was calculated by measuring the signal intensities of the pulmonary lesions, normal lung tissue and background noise. The frozen lung tissue section was examined under fluorescence microscopy and compared with hemoxylin and eosin (HE) staining. The ex vivo near-infrared fluorescence imaging showed that the fluorescence signal in the lung tuberculosis lesions in the experimental group was significantly enhanced, whereas there was only a weak fluorescence signal or even no fluorescence signal in the control group. CNR values were 64.40 ± 7.02 (n = 6) and 8.75 ± 3.87 (n = 6), respectively (t = 17.01, p fluorescence accumulation distribution detected under fluorescence microscopy was consistent with HE staining of the tuberculosis region. In conclusion, anti-ESAT-6 mAb fluorescent probe could target and be applied in specific ex vivo imaging of mice tuberculosis, and may be of further use in tuberculosis in living mice. Copyright © 2013 John Wiley & Sons, Ltd.

A dansyl-rhodamine ratiometric fluorescent probe for Hg2+ based on FRET mechanism.

Science.gov (United States)

Xie, Puhui; Guo, Fengqi; Wang, Lingyu; Yang, Sen; Yao, Denghui; Yang, Guoyu

2015-03-01

Based on resonance energy transfer (FRET) from dansyl to rhodamine 101, a new fluorescent probe (compound 1) containing rhodamine 101 and a dansyl unit was synthesized for detecting Hg(2+) through ratiometric sensing in DMSO aqueous solutions. This probe shows a fast, reversible and selective response toward Hg(2+) in a wide pH range. Hg(2+) induced ring-opening reactions of the spirolactam rhodamine moiety of 1, leading to the formation of fluorescent derivatives that can serve as the FRET acceptors. Very large stokes shift (220 nm) was observed in this case. About 97-fold increase in fluorescence intensity ratio was observed upon its binding with Hg(2+).

Probing phosphate ion via the europium(III)-modulated fluorescence of gold nanoclusters

International Nuclear Information System (INIS)

Ding, Shou-Nian; Li, Chun-Mei; Gao, Bu-Hong; Kargbo, Osman; Zhou, Chan; Chen, Xi; Wan, Neng

2014-01-01

Fluorescent gold nanoclusters (Au-NCs) were synthesized by a one-pot method using 11-mercaptoundecanoic acid as a reducing and capping reagent. It is found that the red fluorescence of the Au-NCs is quenched by the introduction of Eu(III) at pH 7.0, but that fluorescence is restored on addition of phosphate. The Au-NCs were investigated by transmission electron microscopy and fluorescence photographs. The effect of pH on fluorescence was studied in the range from pH 6 to 10 and is found to be strong. Based on these findings, we have developed an assay for phosphate. Ions such as citrate, Fe(CN) 6 3− , SO 4 2− , S 2 O 8 2− , Cl − , HS − , Br − , AcO − , NO 2 − , SCN − , ClO 4 − , HCO 3 − , NO 3 − , Cd 2+ , Ba 2+ , Zn 2+ , Mg 2+ , and glutamate do not interfere, but ascorbate and Fe 3+ can quench Au-NCs fluorescence. The fluorescent nanocluster probe responds to phosphate in the range from 0.18 to 250 μM, and the detection limit is 180 nM. The probe also responds to pyrophosphate and ATP. (author)

Hoechst tagging: a modular strategy to design synthetic fluorescent probes for live-cell nucleus imaging.

Science.gov (United States)

Nakamura, Akinobu; Takigawa, Kazumasa; Kurishita, Yasutaka; Kuwata, Keiko; Ishida, Manabu; Shimoda, Yasushi; Hamachi, Itaru; Tsukiji, Shinya

2014-06-11

We report a general strategy to create small-molecule fluorescent probes for the nucleus in living cells. Our strategy is based on the attachment of the DNA-binding Hoechst compound to a fluorophore of interest. Using this approach, simple fluorescein, BODIPY, and rhodamine dyes were readily converted to novel turn-on fluorescent nucleus-imaging probes.

A benzothiazole-based fluorescent probe for distinguishing and bioimaging of Hg{sup 2+} and Cu{sup 2+}

Energy Technology Data Exchange (ETDEWEB)

Gu, Biao; Huang, Liyan; Su, Wei; Duan, Xiaoli; Li, Haitao, E-mail: haitao-li@hunnu.edu.cn; Yao, Shouzhuo

2017-02-15

A new benzothiazole-based fluorescent probe 2-(benzo[d]thiazol-2-yl)-4-(1,3- dithian-2-yl)phenol (BT) with two different reaction sites, a thioacetal group (site 1 for Hg{sup 2+}), and O and N atoms of the benzothiazole dye (site 2 for Cu{sup 2+}), was designed and synthesized. The probe BT showed ratiometric fluorescent response to Hg{sup 2+} and fluorescence quenching behavior to Cu{sup 2+}, which induces naked-eye fluorescent color changes from green to blue and colorless, respectively. Moreover, it displayed highly sensitivity and selectivity toward Hg{sup 2+} and Cu{sup 2+} without interference from other metal ions. The sensing mechanisms were also confirmed by {sup 1}H NMR titration, mass spectrum and Job's plot analyses. Finally, probe BT was successfully used for fluorescent imaging of Hg{sup 2+} and Cu{sup 2+} in living cells, demonstrating its potential applications in biological science. - Highlights: • A benzothiazole-based probe for multiple metal ions has been firstly developed. • The differential sensing mechanisms of Hg{sup 2+} and Cu{sup 2+} relied on different reaction. • The probe could be used to monitor Hg{sup 2+} and Cu{sup 2+}in vitro and in vivo with distinct fluorescence changes.

Glucose oxidase-functionalized fluorescent gold nanoclusters as probes for glucose

International Nuclear Information System (INIS)

Xia, Xiaodong; Long, Yunfei; Wang, Jianxiu

2013-01-01

Highlights: ► A glucose oxidase/gold nanocluster conjugates formed by etching chemistry. ► Integration of the bioactivities and fluorescence properties within a single unit. ► These conjugates serve as novel fluorescent probe for glucose. -- Abstract: Creation and application of noble metal nanoclusters have received continuous attention. By integrating enzyme activity and fluorescence for potential applications, enzyme-capped metal clusters are more desirable. This work demonstrated a glucose oxidase (an enzyme for glucose)-functionalized gold cluster as probe for glucose. Under physiological conditions, such bioconjugate was successfully prepared by an etching reaction, where tetrakis (hydroxylmethyl) phosphonium-protected gold nanoparticle and thioctic acid-modified glucose oxidase were used as precursor and etchant, respectively. These bioconjugates showed unique fluorescence spectra (λ em max = 650 nm, λ ex max = 507 nm) with an acceptable quantum yield (ca. 7%). Moreover, the conjugated glucose oxidase remained active and catalyzed reaction of glucose and dissolved O 2 to produce H 2 O 2 , which quenched quantitatively the fluorescence of gold clusters and laid a foundation of glucose detection. A linear range of 2.0 × 10 −6 –140 × 10 −6 M and a detection limit of 0.7 × 10 −6 M (S/N = 3) were obtained. Also, another horseradish peroxidase/gold cluster bioconjugate was produced by such general synthesis method. Such enzyme/metal cluster bioconjugates represented a promising class of biosensors for biologically important targets in organelles or cells

Gd(iii)-doped carbon dots as a dual fluorescent-MRI probe

KAUST Repository

Bourlinos, Athanasios B.; Bakandritsos, Aristides; Kouloumpis, Antonios; Gournis, Dimitrios; Krysmann, Marta; Giannelis, Emmanuel P.; Polakova, Katerina; Safarova, Klara; Hola, Katerina; Zboril, Radek

2012-01-01

We describe the synthesis of Gd(iii)-doped carbon dots as dual fluorescence-MRI probes for biomedical applications. The derived Gd(iii)-doped carbon dots show uniform particle size (3-4 nm) and gadolinium distribution and form stable dispersions in water. More importantly, they exhibit bright fluorescence, strong T1-weighted MRI contrast and low cytotoxicity. © The Royal Society of Chemistry 2012.

Colorimetric and Fluorescent Bimodal Ratiometric Probes for pH Sensing of Living Cells.

Science.gov (United States)

Liu, Yuan-Yuan; Wu, Ming; Zhu, Li-Na; Feng, Xi-Zeng; Kong, De-Ming

2015-06-01

pH measurement is widely used in many fields. Ratiometric pH sensing is an important way to improve the detection accuracy. Herein, five water-soluble cationic porphyrin derivatives were synthesized and their optical property changes with pH value were investigated. Their pH-dependent assembly/disassembly behaviors caused significant changes in both absorption and fluorescence spectra, thus making them promising bimodal ratiometric probes for both colorimetric and fluorescent pH sensing. Different substituent identity and position confer these probes with different sensitive pH-sensing ranges, and the substituent position gives a larger effect. By selecting different porphyrins, different signal intensity ratios and different fluorescence excitation wavelengths, sensitive pH sensing can be achieved in the range of 2.1-8.0. Having demonstrated the excellent reversibility, good accuracy and low cytotoxicity of the probes, they were successfully applied in pH sensing inside living cells. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Two colorimetric and ratiometric fluorescence probes for hydrogen sulfide based on AIE strategy of α-cyanostilbenes

Science.gov (United States)

Zhao, Baoying; Yang, Binsheng; Hu, Xiangquan; Liu, Bin

2018-06-01

Aggregation-induced emission (AIE) active fluorescent probes have attracted great potential in biological sensors. In this paper two cyanostilbene based fluorescence chemoprobe Cya-NO2 (1) and Cya-N3 (2) were developed and evaluated for the selective and sensitive detection of hydrogen sulfide (H2S). Both of these probes behave aggression-induced emission (AIE) activity which fluoresces in the red region with a large Stokes shift. They exhibit rapid response to H2S with enormous colorimetric and ratiometric fluorescent changes. They are readily employed for assessing intracellular H2S levels.

Fluorescent and Colorimetric Molecular Recognition Probe for Hydrogen Bond Acceptors

OpenAIRE

Pike, Sarah Jane; Hunter, Christopher Alexander

2018-01-01

The association constants for formation of 1 : 1 complexes between a H-bond donor, 1-naphthol, and a diverse range of charged and neutral H-bond acceptors have been measured using UV/vis absorption and fluorescence emission titrations. The performance of 1-naphthol as a dual colorimetric and fluorescent molecular recognition probe for determining the H-bond acceptor (HBA) parameters of charged and neutral solutes has been investigated in three solvents. The data were employed to establish sel...

Far-red fluorescent probes for canonical and non-canonical nucleic acid structures: current progress and future implications.

Science.gov (United States)

Suseela, Y V; Narayanaswamy, Nagarjun; Pratihar, Sumon; Govindaraju, Thimmaiah

2018-02-05

The structural diversity and functional relevance of nucleic acids (NAs), mainly deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), are indispensable for almost all living organisms, with minute aberrations in their structure and function becoming causative factors in numerous human diseases. The standard structures of NAs, termed canonical structures, are supported by Watson-Crick hydrogen bonding. Under special physiological conditions, NAs adopt distinct spatial organisations, giving rise to non-canonical conformations supported by hydrogen bonding other than the Watson-Crick type; such non-canonical structures have a definite function in controlling gene expression and are considered as novel diagnostic and therapeutic targets. Development of molecular probes for these canonical and non-canonical DNA/RNA structures has been an active field of research. Among the numerous probes studied, probes with turn-on fluorescence in the far-red (600-750 nm) region are highly sought-after due to minimal autofluorescence and cellular damage. Far-red fluorescent probes are vital for real-time imaging of NAs in live cells as they provide good resolution and minimal perturbation of the cell under investigation. In this review, we present recent advances in the area of far-red fluorescent probes of DNA/RNA and non-canonical G-quadruplex structures. For the sake of continuity and completeness, we provide a brief overview of visible fluorescent probes. Utmost importance is given to design criteria, characteristic properties and biological applications, including in cellulo imaging, apart from critical discussion on limitations of the far-red fluorescent probes. Finally, we offer current and future prospects in targeting canonical and non-canonical NAs specific to cellular organelles, through sequence- and conformation-specific far-red fluorescent probes. We also cover their implications in chemical and molecular biology, with particular focus on decoding various disease

A new rhodamine-based fluorescent probe for the discrimination of Fe"3"+ from Fe"2"+

International Nuclear Information System (INIS)

You, Qi Hua; Huang, Hua Bin; Zhuang, Zhi Xia; Wang, Xiao Ru; Chan, Wing Hong

2016-01-01

A new rhodamine-based fluorescent probe for the discrimination of Fe"3"+ from Fe"2"+ has been designed and investigated. The probe shows an immediate visual color change in response to Fe"3"+ and Cu"2"+, while only Fe"3"+ triggers the fluorescent change of the probe. The existence of large amount of other metal ions shows negligible interference in the detection of Fe"3"+. The association constant K_a_s_s of 4.64 × 10"8 M"-"2 (R"2 = 0.994) and 5.38 × 10"8 M"-"2 (R"2 = 0.991) of the complex was derived from UV/Vis and fluorescence titration assuming 1:2 stoichiometry of probe–Fe"3"+ complex, respectively

[A cell-based detection of ciguatoxin using sodium fluorescence probe].

Science.gov (United States)

Yuan, Jian-hui; Yang, Hui; Tang, Huan-wen; Huang, Wei; Xu, Xin-yun; Liu, Jian-jun; Ke, Yue-bin; Cheng, Jin-quan; Zhuang, Zhi-xiong

2011-04-01

To establish a cell-based detection method of ciguatoxin using fluorescence assay. Mouse neuroblastoma N-2A cells were exposed to ouabain and veratridine and different concentrations of standard ciguatoxin samples (P-CTX-1) to establish the curvilinear relationship between the toxin dosage and fluorescence intensity using the sodium fluorescence probe CoroNaTM Green. The toxicity curvilinear relationship was also generated between the toxin dosage and cell survival using CCK-8 method. Based on these standard curves, the presence of ciguatoxin was detected in 33 samples of deep-sea coral fish. A correlation was found between the detection results of cell-based fluorescence assay and cytotoxicity assay, whose detection limit reached 103 g/ml and 1012 g/ml, respectively. The cell-based fluorescent assay sensitivity showed a higher sensitivity than cytotoxicity assay with a 2-4 h reduction of the detection time. The cell-based fluorescent assay can quickly and sensitively detect ciguatoxin and may serve as a good option for preliminary screening of the toxin.

In vivo near-infrared fluorescence imaging of amyloid-β plaques with a dicyanoisophorone-based probe

Energy Technology Data Exchange (ETDEWEB)

Zhu, Jia-ying; Zhou, Lin-fu; Li, Yu-kun [School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, 510006 (China); Chen, Shuo-bin [School of Pharmaceutical Science, Sun Yat-sen University, Guangzhou, 510006 (China); Yan, Jin-wu, E-mail: yjw@scut.edu.cn [School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, 510006 (China); Zhang, Lei, E-mail: lzhangce@scut.edu.cn [School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, 510006 (China)

2017-04-08

A dicyanoisophorone-based probe with two-photon absorption and NIR emission was developed for the in vivo fluorescence imaging of amyloid-β plaques, which exhibited high selectivity toward Aβ aggregates over other intracellular proteins. The detection limit was calculated to be as low as 109 nM. In vivo imaging studies indicated that the probe could penetrate the blood–brain barrier and label Aβ plaques in the living transgenic mice, and its specific binding to cerebral Aβ plaques was further confirmed by one- and two-photon ex vivo fluorescence imaging. All these results featured its promising application prospects for amyloid-β sensing in basic research and biomedical research. - Highlights: • A two-photon probe (DCIP-1) with NIR emission based on dicyanoisophorone group, for the in vivo fluorescence imaging of amyloid-β plaques, was reported. • The probe showed turn-on fluorescence (13-fold) with a large Stokes shift upon inserting into the hydrophobic pockets of Aβ aggregates. • The in vivo imaging studies indicated that the probe can penetrate the blood–brain barrier efficiently and discriminate APP/PS1 transgenic mice from WT controls.

In vivo near-infrared fluorescence imaging of amyloid-β plaques with a dicyanoisophorone-based probe

International Nuclear Information System (INIS)

Zhu, Jia-ying; Zhou, Lin-fu; Li, Yu-kun; Chen, Shuo-bin; Yan, Jin-wu; Zhang, Lei

2017-01-01

A dicyanoisophorone-based probe with two-photon absorption and NIR emission was developed for the in vivo fluorescence imaging of amyloid-β plaques, which exhibited high selectivity toward Aβ aggregates over other intracellular proteins. The detection limit was calculated to be as low as 109 nM. In vivo imaging studies indicated that the probe could penetrate the blood–brain barrier and label Aβ plaques in the living transgenic mice, and its specific binding to cerebral Aβ plaques was further confirmed by one- and two-photon ex vivo fluorescence imaging. All these results featured its promising application prospects for amyloid-β sensing in basic research and biomedical research. - Highlights: • A two-photon probe (DCIP-1) with NIR emission based on dicyanoisophorone group, for the in vivo fluorescence imaging of amyloid-β plaques, was reported. • The probe showed turn-on fluorescence (13-fold) with a large Stokes shift upon inserting into the hydrophobic pockets of Aβ aggregates. • The in vivo imaging studies indicated that the probe can penetrate the blood–brain barrier efficiently and discriminate APP/PS1 transgenic mice from WT controls.

Two sugar-rhodamine "turn-on" fluorescent probes for the selective detection of Fe3 +

Science.gov (United States)

Chen, Qing; Fang, Zhijie

2018-03-01

Two new sugar-rhodamine fluorescent probes (RDG1 and RDG2) have been synthesized and characterized by 1H NMR, 13C NMR and HRMS. Their UV-Vis, fluorescence spectra and fluorescence-response to Fe3 + are investigated and discussed. RDG1 had a very nice linear relationship between UV absorbance and Fe3 + concentration with the correlation coefficient as high as 0.997 and the detection limit is 3.46 × 10- 6 M. Upon the addition of Fe3 +, the spirolactam ring of RDG1 was opened and a 1:1 metal ligand complex was formed from Job's plot. The results showed that RDG1 can be used as an effective fluorescent probe for selective detection of Fe3 + in water. RDG2 was incorporated the well-known rhodamine group and a water-soluble D-glucose group within one molecule and can be used for detecting Fe3 + in natural water as a selective fluorescent sensor. The addition of Fe3 + into RDG2 resulted in a strongly enhanced fluorescence as well as color change of solution from colorless to pink. Job's plot of RDG2 indicated 1:1 stoichiometry of RDG2-Fe3 +. RDG2 can serve as a probe for Fe3 + between pH = 4.0 to 7.0 and it's detection limit is 2.09 × 10- 6 M. The OFF-ON fluorescent mechanisms of RDG1-Fe3 + and RDG2-Fe3 + are proposed.

Determination of the ratio between mercaptalbumin and nonmercaptalbumin by HPLC with fluorescence probe specifically binding to albumin.

Science.gov (United States)

Ohyama, Kaname; Kishikawa, Naoya; Matsuo, Aya; Imazato, Takahiro; Ueki, Yukitaka; Wada, Mitsuhiro; Nakashima, Kenichiro; Kuroda, Naotaka

2014-01-01

A simple and selective HPLC-fluorescence (FL) method with FL probe, 4-[4-(4-dimethylaminophenyl)-5-phenyl-1H-imidazol-2-yl]benzoic acid methyl ester (DAPIM), for simultaneous determination of mercaptalbumin (HMA) and nonmercaptalbumin (HNA1) was developed. After HMA and HNA1 were separated on an ion-exchange column, they were on-line and post-column mixed with DAPIM. The DAPIM-albumin complex produces FL (λex 370nm and λem 510nm); however, DAPIM solution never gives the FL. Based on this mechanism, selective determination of HMA and HNA1 were achieved without any pretreatment and interfering peak. The proposed method was applied to the measurement of HMA and HNA1 in human serum of healthy volunteers and diabetes mellitus patients. Copyright © 2013 Elsevier B.V. All rights reserved.

Selective and sensitive fluorescence-shift probes based on two dansyl groups for mercury(ii) ion detection.

Science.gov (United States)

Ma, Li-Jun; Liu, Jialun; Deng, Lefang; Zhao, Meili; Deng, Zhifu; Li, Xutian; Tang, Jian; Yang, Liting

2014-11-01

Two probes ( and ) bearing two dansyl fluorophores were synthesized and applied to the detection of mercury(ii) ions in aqueous solution. These probes exhibited a selective response to Hg(2+) in a buffered solution, with high sensitivity and a unique fluorescence response signal which displayed a blue-shift effect in the fluorescence emission peak. The Hg(2+) recognition mechanisms of the probes were determined by NMR spectroscopy, ESI-MS and UV-vis spectroscopy. The results showed that probe and mercury(ii) ions formed an unusual 2:2 stoichiometric ratio complex, while probe and Hg(2+) formed a multidentate complex with a stoichiometric ratio of 2:1.

Sensitive and Selective Ratiometric Fluorescence Probes for Detection of Intracellular Endogenous Monoamine Oxidase A.

Science.gov (United States)

Wu, Xiaofeng; Li, Lihong; Shi, Wen; Gong, Qiuyu; Li, Xiaohua; Ma, Huimin

2016-01-19

Monoamine oxidase A (MAO-A) is known to widely exist in most cell lines in the body, and its dysfunction (unusually high or low levels of MAO-A) is thought to be responsible for several psychiatric and neurological disorders. Thus, a sensitive and selective method for evaluating the relative MAO-A levels in different live cells is urgently needed to better understand the function of MAO-A, but to our knowledge such a method is still lacking. Herein, we rationally design two new ratiometric fluorescence probes (1 and 2) that can sensitively and selectively detect MAO-A. The probes are constructed by incorporating a recognition group of propylamine into the fluorescent skeleton of 1,8-naphthalimide, and the detection mechanism is based on amine oxidation and β-elimination to release the fluorophore (4-hydroxy-N-butyl-1,8-naphthalimide), which is verified by HPLC analysis. Reaction of the probes with MAO-A produces a remarkable fluorescence change from blue to green, and the ratio of fluorescence intensity at 550 and 454 nm is directly proportional to the concentration of MAO-A in the ranges of 0.5-1.5 and 0.5-2.5 μg/mL with detection limits of 1.1 and 10 ng/mL (k = 3) for probes 1 and 2, respectively. Surprisingly, these probes show strong fluorescence responses to MAO-A but almost none to MAO-B (one of two isoforms of MAO), indicating superior ability to distinguish MAO-A from MAO-B. The high specificity of the probes for MAO-A over MAO-B is further supported by different inhibitor experiments. Moreover, probe 1 displays higher sensitivity than probe 2 and is thus investigated to image the relative MAO-A levels in different live cells, such as HeLa and NIH-3T3 cells. It is found that the concentration of endogenous MAO-A in HeLa cells is approximately 1.8 times higher than that in NIH-3T3 cells, which is validated by the result from an ELISA kit. Additionally, the proposed probes may find more uses in the specific detection of MAO-A between the two isoforms of MAO

Synthesis and application of a highly selective copper ions fluorescent probe based on the coumarin group

Science.gov (United States)

He, Guangjie; Liu, Xiangli; Xu, Jinhe; Ji, Liguo; Yang, Linlin; Fan, Aiying; Wang, Songjun; Wang, Qingzhi

2018-02-01

A highly selective copper ions fluorescent probe based on the coumarin-type Schiff base derivative 1 (probe) was produced by condensation reaction between coumarin carbohydrazide and 1H-indazole-3-carbaldehyde. The UV-vis spectroscopy showed that the maximum absorption peak of compound 1 appeared at 439 nm. In the presence of Cu2 + ions, the maximum peak decreased remarkably compared with other physiological important metal ions and a new absorption peak at 500 nm appeared. The job's plot experiments showed that complexes of 1:2 binding mode were formed in CH3CN:HEPES (3:2, v/v) solution. Compound 1 exhibited a strong blue fluorescence. Upon addition of copper ions, the fluorescence gradually decreased and reached a plateau with the fluorescence quenching rate up to 98.73%. The detection limit for Cu2 + ions was estimated to 0.384 ppm. Fluorescent microscopy experiments demonstrated that probe 1 had potential to be used to investigate biological processes involving Cu2 + ions within living cells.

Glucose oxidase-functionalized fluorescent gold nanoclusters as probes for glucose

Energy Technology Data Exchange (ETDEWEB)

Xia, Xiaodong [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201 (China); Long, Yunfei, E-mail: l_yunfei927@163.com [School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201 (China); Wang, Jianxiu, E-mail: jxiuwang@csu.edu.cn [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China)

2013-04-15

Highlights: ► A glucose oxidase/gold nanocluster conjugates formed by etching chemistry. ► Integration of the bioactivities and fluorescence properties within a single unit. ► These conjugates serve as novel fluorescent probe for glucose. -- Abstract: Creation and application of noble metal nanoclusters have received continuous attention. By integrating enzyme activity and fluorescence for potential applications, enzyme-capped metal clusters are more desirable. This work demonstrated a glucose oxidase (an enzyme for glucose)-functionalized gold cluster as probe for glucose. Under physiological conditions, such bioconjugate was successfully prepared by an etching reaction, where tetrakis (hydroxylmethyl) phosphonium-protected gold nanoparticle and thioctic acid-modified glucose oxidase were used as precursor and etchant, respectively. These bioconjugates showed unique fluorescence spectra (λ{sub em} {sub max} = 650 nm, λ{sub ex} {sub max} = 507 nm) with an acceptable quantum yield (ca. 7%). Moreover, the conjugated glucose oxidase remained active and catalyzed reaction of glucose and dissolved O{sub 2} to produce H{sub 2}O{sub 2}, which quenched quantitatively the fluorescence of gold clusters and laid a foundation of glucose detection. A linear range of 2.0 × 10{sup −6}–140 × 10{sup −6} M and a detection limit of 0.7 × 10{sup −6} M (S/N = 3) were obtained. Also, another horseradish peroxidase/gold cluster bioconjugate was produced by such general synthesis method. Such enzyme/metal cluster bioconjugates represented a promising class of biosensors for biologically important targets in organelles or cells.

A novel pH sensitive water soluble fluorescent nanomicellar sensor for potential biomedical applications.

Science.gov (United States)

Georgiev, Nikolai I; Bryaskova, Rayna; Tzoneva, Rumiana; Ugrinova, Iva; Detrembleur, Christophe; Miloshev, Stoyan; Asiri, Abdullah M; Qusti, Abdullah H; Bojinov, Vladimir B

2013-11-01

Herein we report on the synthesis and sensor activity of a novel pH sensitive probe designed as highly water-soluble fluorescent micelles by grafting of 1,8-naphthalimide-rhodamine bichromophoric FRET system (RNI) to the PMMA block of a well-defined amphiphilic diblock copolymer-poly(methyl methacrylate)-b-poly(methacrylic acid) (PMMA48-b-PMAA27). The RNI-PMMA48-b-PMAA27 adduct is capable of self-assembling into micelles with a hydrophobic PMMA core, containing the anchored fluorescent probe, and a hydrophilic shell composed of PMAA block. Novel fluorescent micelles are able to serve as a highly sensitive pH probe in water and to internalize successfully HeLa and HEK cells. Furthermore, they showed cell specificity and significantly higher photostability than that of a pure organic dye label such as BODIPY. The valuable properties of the newly prepared fluorescent micelles indicate the high potential of the probe for future biological and biomedical applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

Fluorescent porous silicon biological probes with high quantum efficiency and stability.

Science.gov (United States)

Tu, Chang-Ching; Chou, Ying-Nien; Hung, Hsiang-Chieh; Wu, Jingda; Jiang, Shaoyi; Lin, Lih Y

2014-12-01

We demonstrate porous silicon biological probes as a stable and non-toxic alternative to organic dyes or cadmium-containing quantum dots for imaging and sensing applications. The fluorescent silicon quantum dots which are embedded on the porous silicon surface are passivated with carboxyl-terminated ligands through stable Si-C covalent bonds. The porous silicon bio-probes have shown photoluminescence quantum yield around 50% under near-UV excitation, with high photochemical and thermal stability. The bio-probes can be efficiently conjugated with antibodies, which is confirmed by a standard enzyme-linked immunosorbent assay (ELISA) method.

Hairpin-like fluorescent probe for imaging of NF-κB transcription factor activity.

Science.gov (United States)

Metelev, Valeri; Zhang, Surong; Tabatadze, David; Bogdanov, Alexei

2011-04-20

Three oligodeoxyribonucleotides (ODN) covalently labeled with near-infrared (NIR) fluorochromes were synthesized and characterized with a goal of comparing in vitro a hairpin-based and a duplex-based FRET probe designed for the detection of human recombinant NF-κB p50/p65 heterodimer binding to DNA. Using deoxyguanosine phosphoramidite with a phosphorus-linked aminoethylene (diethylene glycol) hydrophilic linker, we synthesized ODNs with internucleoside reactive sites. The hairpin loop amino linker was modified with IRDye 800CW (FRET acceptor), and the 3'-end was modified with Cy5.5 (FRET donor) using a dithio-linker. To obtain a duplex probe, we conjugated Cy5.5 and 800CW to complementary strands at the distance of ten base pairs in the resultant duplex. No quenching of dyes was observed in either probe. The FRET efficiency was higher in the duplex (71%) than in the hairpin (56%) due to a more favorable distance between the donor and the acceptor. However, the hairpin design allowed more precise ratiometric measurement of fluorescence intensity changes as a result of NF-κB p50/p65 binding to the probe. We determined that as a result of binding there was a statistically significant increase of fluorescence intensity of Cy5.5 (donor) due to a decrease of FRET if normalized by 800CW intensity measured independently of FRET. We conclude that the hairpin based probe design allows for the synthesis of a dual fluorescence imaging probe that renders signal changes that are simple to interpret and stoichiometrically correct for detecting transcription factor-DNA interactions.

Visualization of mcr mRNA in a methanogen by fluorescence in situ hybridization with an oligonucleotide probe and two-pass tyramide signal amplification (two-pass TSA-FISH).

Science.gov (United States)

Kubota, Kengo; Ohashi, Akiyoshi; Imachi, Hiroyuki; Harada, Hideki

2006-09-01

Two-pass tyramide signal amplification-fluorescence in situ hybridization (two-pass TSA-FISH) with a horseradish peroxidase (HRP)-labeled oligonucleotide probe was applied to detect prokaryotic mRNA. In this study, mRNA of a key enzyme for methanogenesis, methyl coenzyme M reductase (mcr), in Methanococcus vannielii was targeted. Applicability of mRNA-targeted probes to in situ hybridization was verified by Clone-FISH. It was observed that sensitivity of two-pass TSA-FISH was significantly higher than that of TSA-FISH, which was further increased by the addition of dextran sulphate in TSA working solution. Signals from two-pass TSA-FISH were more reliable compared to the weak, spotty signals yielded by TSA-FISH.

A new simple phthalimide-based fluorescent probe for highly selective cysteine and bioimaging for living cells

Science.gov (United States)

Shen, Youming; Zhang, Xiangyang; Zhang, Youyu; Zhang, Chunxiang; Jin, Junling; Li, Haitao

2017-10-01

A new turn-on phthalimide fluorescent probe has designed and synthesized for sensing cysteine (Cys) based on excited state intramolecular proton transfer (ESIPT) process. It is consisted of a 3-hydroxyphthalimide derivative moiety as the fluorophore and an acrylic ester group as a recognition receptor. The acrylic ester acts as an ESIPT blocking agent. Upon addition of cystein, intermolecular nucleophilic attack of cysteine on acrylic ester releases the fluorescent 3-hydroxyphthalimide derivative, thereby enabling the ESIPT process and leading to enhancement of fluorescence. The probe displays high sensitivity, excellent selectivity and with large Stokes shift toward cysteine. The linear interval range of the fluorescence titration ranged from 0 to 1.0 × 10- 5 M and detection limit is low (6 × 10- 8 M). In addition, the probe could be used for bio-imaging in living cells.

Establishment of a novel immunoassay system for rapid detection of 2,4-dichlorophenoxyacetic acid residues based on magnetic-fluorescent probes

Directory of Open Access Journals (Sweden)

WANG Yuanfeng

2014-12-01

Full Text Available A novel immunoassay system based on magnetic-fluorescent probes was established to detect 2.4-dichlorophenoxyacetic acid (2,4-D residue in liquid system in food and agricultural products.The composites of anti-2,4-D antibody bound to Fe3O4@SiO2-NH2 was employed as the solid phase as well as magnetic probe.The composites composed of 2,4-D-OVA labeled with CdTe@SiO2-NH2 as the fluorescent probe was used to produce fluorescent signal.2,4-D and its fluorescent probe competed binding the antibody on the surface of the magnetic probe.The optimization of 2,4-D-OVA dosage,coupling PH and reaction time in preparing the fluorescent probe were investigated.It showed that in the synthesis of fluorescent probe 8.2 was the optimal pH,70 min was the optimal coupling time,500 μL amount of 2,4-D-OVA.The standard curve was obtained with the concentration of 2,4-D and the maximum fluorescence intensity.The detection limit of the assay was gotten and it was 3.55×10-8.One reaction step and one washing step were needed.The assay significantly shortened the testing time and amplified the detection signal compared with classic ELISA.

Synovitis in mice with inflammatory arthritis monitored with quantitative analysis of dynamic contrast-enhanced NIR fluorescence imaging using iRGD-targeted liposomes as fluorescence probes

Directory of Open Access Journals (Sweden)

Wu H

2018-03-01

Full Text Available Hao Wu,1,2,* Haohan Wu,1,2,* Yanni He,1 Zhen Gan,2 Zhili Xu,1,2 Meijun Zhou,1,2 Sai Liu,1,2 Hongmei Liu1 1Department of Ultrasonography, Guangdong Second Provincial General Hospital Affiliated to Southern Medical University, Guangzhou, China; 2Department of Ultrasonography, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China *These authors contributed equally to this work Background: Rheumatoid arthritis (RA is a common inflammatory disorder characterized primarily by synovitis and pannus formation in multiple joints, causing joints destruction and irreversible disability in most cases. Early diagnosis and effective therapy monitoring of RA are of importance for achieving the favorable prognosis. Methods: We first prepared the targeted fluorescence probes, and then explored the feasibility of near-infrared (NIR fluorescence molecular imaging to detect and evaluate the RA via the targeted fluorescence probes by quantitative analysis in this study. Results: The targeted fluorescence probes (indocyanine green-liposomes decorated with iRGD peptide [iLPs] was successfully prepared. The quantitative analysis found that strong fluorescence signal was detected in inflamed paws and the fluorescence signal in iLPs group was 3.03-fold higher than that in non-targeted (indocyanine green-liposomes decorated without iRGD peptide [LPs] group (P<0.01 at 15 min after injection, whereas the fluorescence signal from iLPs signal can almost not be observed in the non-inflamed paws, showing the high sensitivity and accuracy for arthritis by the NIR fluorescence imaging based on iLPs. Conclusion: The NIR fluorescence imaging by iLPs may facilitate improved arthritis diagnosis and early assessment of the disease progression by providing an in vivo characterization of angiogenesis in inflammatory joint diseases. Keywords: rheumatoid arthritis, synovitis, diagnosis, near-infrared fluorescence imaging, iRGD-targeted probes

Design and Investigation of Optical Properties of N-(Rhodamine-B)-Lactam-Ethylenediamine (RhB-EDA) Fluorescent Probe.

Science.gov (United States)

Soršak, Eva; Volmajer Valh, Julija; Korent Urek, Špela; Lobnik, Aleksandra

2018-04-14

This study presents chemical modification of a Rhodamine B (RhB) sensor probe by ethylenediamine (EDA), and investigation of its spectral as well as sensor properties to the various metals. The synthesised N -(Rhodamine-B)-lactam-ethylenediamine (RhB-EDA) fluorescent probe shows interesting optical sensor properties, and high sensitivity and selectivity to Ag⁺ ions among all the tested metal ions (K⁺, Mg 2+ , Cu 2+ , Ni 2+ , Fe 2+ , Pb 2+ , Na⁺, Mn 2+ , Li⁺, Al 3+ , Co 2+ , Hg 2+ , Sr 2+ , Ca 2+ , Ag⁺, Cd 2+ and Zn 2+ ), while the well-known Rhodamine B (RhB) fluorescent probe shows much less sensitivity to Ag⁺ ions, but high sensitivity to Fe 2+ ions. The novel fluorescent sensor probe RhB-EDA has the capabilities to sense Ag⁺ ions up to µM ranges by using the fluorescence quenching approach. The probe displayed a dynamic response to Ag⁺ in the range of 0.43 × 10 -3 -10 -6 M with a detection limit of 0.1 μM. The sensing system of an RhB-EDA novel fluorescent probe was optimised according to the spectral properties, effect of pH and buffer, photostability, incubation time, sensitivity, and selectivity. Since all the spectral and sensing properties were tested in green aqueous media, although many other similar sensor systems rely on organic solvent solutions, the RhB-EDA sensing probe may be a good candidate for measuring Ag⁺ ions in real-life applications.

An excited-state intramolecular photon transfer fluorescence probe for localizable live cell imaging of cysteine

Science.gov (United States)

Liu, Wei; Chen, Wen; Liu, Si-Jia; Jiang, Jian-Hui

2017-03-01

Small molecule probes suitable for selective and specific fluorescence imaging of some important but low-concentration intracellular reactive sulfur species such as cysteine (Cys) pose a challenge in chemical biology. We present a readily available, fast-response fluorescence probe CHCQ-Ac, with 2-(5‧-chloro-2-hydroxyl-phenyl)-6-chloro-4(3 H)-quinazolinone (CHCQ) as the fluorophore and acrylate group as the functional moiety, that enables high-selectivity and high-sensitivity for detecting Cys in both solution and biological system. After specifically reacted with Cys, the probe undergoes a seven-membered intramolecular cyclization and released the fluorophore CHCQ with excited-state intramolecular photon transfer effect. A highly fluorescent, insoluble aggregate was then formed to facilitate high-sensitivity and high-resolution imaging. The results showed that probe CHCQ-Ac affords a remarkably large Stokes shift and can detect Cys under physiological pH condition with no interference from other analytes. Moreover, this probe was proved to have excellent chemical stability, low cytotoxicity and good cell permeability. Our design of this probe provides a novel potential tool to visualize and localize cysteine in bioimaging of live cells that would greatly help to explore various Cys-related physiological and pathological cellular processes in cell biology and diagnostics.

Smart lanthanide coordination polymer fluorescence probe for mercury(II) determination

Energy Technology Data Exchange (ETDEWEB)

Liu, Baoxia [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); Huang, Yankai [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China); Zhu, Xu; Hao, Yuanqiang [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); Ding, Yujie [College of Biochemical Engineering, Anhui Polytechnic University, Wuhu 241000 (China); Wei, Wei; Wang, Qi [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); Qu, Peng, E-mail: qupeng0212@163.com [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China); Xu, Maotian, E-mail: xumaotian@sqnc.edu.cn [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China)

2016-03-17

Lanthanide coordination polymers (LCPs) have recently emerged as attractive biosensor materials due to their flexible components, high tailorable properties and unique luminescence features. In this work, we designed a smart LCP probe of Tb-CIP/AMP {(CIP, ciprofloxacin) (AMP, adenosine monophosphate)} for Hg{sup 2+} detection by using lanthanide ions as metal nodes, CIP as ligand molecule, and AMP as bridging linker and recognition unit. Tb-CIP/AMP emits strong green luminescence due to the inclusion of AMP, which withdraws the coordinated water molecules and shields Tb{sup 3+} from the quenching effect of O–H vibration in water molecules. The subsequent addition of Hg{sup 2+} into Tb-CIP/AMP can strongly quench the fluorescence because of the specific coordination interaction between AMP and Hg{sup 2+}. As a kind of Hg{sup 2+} nanosensor, the probe exhibited excellent selectivity for Hg{sup 2+} and high sensitivity with detection limit of 0.16 nM. In addition, the probe has long fluorescence lifetime up to millisecond and has been applied to detect Hg{sup 2+} in drinking water and human urine samples with satisfactory results. We envision that our strategy, in the future, could be extended to the designation of other LCP-based hypersensitive time-gated luminescence assays in biological media and biomedical imaging. - Highlights: • Lanthanide coordination polymer of Tb-CIP/AMP was synthesized via a simple self-assembly process. • AMP was employed as a bifunctional molecule for both fluorescence sensitization and target recognition. • Hypersensitive detection of Hg{sup 2+} was achieved based on time-resolved spectroscopy.

Smart lanthanide coordination polymer fluorescence probe for mercury(II) determination

International Nuclear Information System (INIS)

Liu, Baoxia; Huang, Yankai; Zhu, Xu; Hao, Yuanqiang; Ding, Yujie; Wei, Wei; Wang, Qi; Qu, Peng; Xu, Maotian

2016-01-01

Lanthanide coordination polymers (LCPs) have recently emerged as attractive biosensor materials due to their flexible components, high tailorable properties and unique luminescence features. In this work, we designed a smart LCP probe of Tb-CIP/AMP {(CIP, ciprofloxacin) (AMP, adenosine monophosphate)} for Hg"2"+ detection by using lanthanide ions as metal nodes, CIP as ligand molecule, and AMP as bridging linker and recognition unit. Tb-CIP/AMP emits strong green luminescence due to the inclusion of AMP, which withdraws the coordinated water molecules and shields Tb"3"+ from the quenching effect of O–H vibration in water molecules. The subsequent addition of Hg"2"+ into Tb-CIP/AMP can strongly quench the fluorescence because of the specific coordination interaction between AMP and Hg"2"+. As a kind of Hg"2"+ nanosensor, the probe exhibited excellent selectivity for Hg"2"+ and high sensitivity with detection limit of 0.16 nM. In addition, the probe has long fluorescence lifetime up to millisecond and has been applied to detect Hg"2"+ in drinking water and human urine samples with satisfactory results. We envision that our strategy, in the future, could be extended to the designation of other LCP-based hypersensitive time-gated luminescence assays in biological media and biomedical imaging. - Highlights: • Lanthanide coordination polymer of Tb-CIP/AMP was synthesized via a simple self-assembly process. • AMP was employed as a bifunctional molecule for both fluorescence sensitization and target recognition. • Hypersensitive detection of Hg"2"+ was achieved based on time-resolved spectroscopy.

Organic liquids-responsive β-cyclodextrin-functionalized graphene-based fluorescence probe: label-free selective detection of tetrahydrofuran.

Science.gov (United States)

Hu, Huawen; Xin, John H; Hu, Hong; Wang, Xiaowen; Lu, Xinkun

2014-06-06

In this study, a label-free graphene-based fluorescence probe used for detection of volatile organic liquids was fabricated by a simple, efficient and low-cost method. To fabricate the probe, a bio-based β-cyclodextrin (β-CD) was firstly grafted on reduced graphene surfaces effectively and uniformly, as evidenced by various characterization techniques such as Ultraviolet/Visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy and transmission electron microscopy. The subsequent inclusion of Rhodamine B (RhB) into the inner cavities of the β-CD grafted on the graphene surfaces was achieved easily by a solution mixing method, which yielded the graphene-based fluorescent switch-on probe. In addition, the gradual and controllable quenching of RhB by Fluorescence Resonance Energy Transfer from RhB to graphene during the process of stepwise accommodation of the RhB molecules into the β-CD-functionalized graphene was investigated in depth. A wide range of organic solvents was examined using the as-fabricated fluorescence probe, which revealed the highest sensitivity to tetrahydrofuran with the detection limit of about 1.7 μg/mL. Some insight into the mechanism of the different responsive behaviors of the fluorescence sensor to the examined targets was also described.

Organic Liquids-Responsive β-Cyclodextrin-Functionalized Graphene-Based Fluorescence Probe: Label-Free Selective Detection of Tetrahydrofuran

Directory of Open Access Journals (Sweden)

Huawen Hu

2014-06-01

Full Text Available In this study, a label-free graphene-based fluorescence probe used for detection of volatile organic liquids was fabricated by a simple, efficient and low-cost method. To fabricate the probe, a bio-based β-cyclodextrin (β-CD was firstly grafted on reduced graphene surfaces effectively and uniformly, as evidenced by various characterization techniques such as Ultraviolet/Visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy and transmission electron microscopy. The subsequent inclusion of Rhodamine B (RhB into the inner cavities of the β-CD grafted on the graphene surfaces was achieved easily by a solution mixing method, which yielded the graphene-based fluorescent switch-on probe. In addition, the gradual and controllable quenching of RhB by Fluorescence Resonance Energy Transfer from RhB to graphene during the process of stepwise accommodation of the RhB molecules into the β-CD-functionalized graphene was investigated in depth. A wide range of organic solvents was examined using the as-fabricated fluorescence probe, which revealed the highest sensitivity to tetrahydrofuran with the detection limit of about 1.7 μg/mL. Some insight into the mechanism of the different responsive behaviors of the fluorescence sensor to the examined targets was also described.

Fluorescent probe encapsulated hydrogel microsphere for selective and reversible detection of Hg{sup 2+}

Energy Technology Data Exchange (ETDEWEB)

Song, Zhenhu; Wang, Fang; Qiang, Jian; Zhang, Zhijie; Chen, Yahui; Wang, Yong; Zhang, Wei; Chen, Xiaoqiang

2017-03-15

We developed a simple and sensitive hydrogel sensor in the form of microspheres by using fluorescence probe encapsulated within a hydrogel matrix for the detection of Hg{sup 2+}. The traditional fluorescence probes suspended in solution are not transportable and recoverable. To overcome these disadvantages, we devised poly(ethylene glycol) diacrylate-based hydrogel microspheres in which fluorescence probe (R19S) was embedded at high density. The functionalized hydrogel microspheres were prepared by combining a microfluidic device with UV light. The hydrogel microspheres-based sensor exhibited good selectivity to Hg{sup 2+} among various metal ions and high sensitivity with a detection limit of 90 nM. Furthermore, after binding with Hg{sup 2+}, the R19S encapsulated hydrogel microspheres can be separated from testing samples easily and treated with the solution containing KI to remove Hg{sup 2+} and realize reusable detection. The current work may offer a new method for Hg{sup 2+} recognition with a more efficient manner.

Terbium fluorescence as a sensitive, inexpensive probe for UV-induced damage in nucleic acids

International Nuclear Information System (INIS)

El-Yazbi, Amira F.; Loppnow, Glen R.

2013-01-01

Graphical abstract: -- Highlights: •Simple, inexpensive, mix-and-read assay for positive detection of DNA damage. •Recognition of undamaged DNA via hybridization to a hairpin probe. •Terbium(III) fluorescence reports the amount of damage by binding to ssDNA. •Tb/hairpin is a highly selective and sensitive fluorescent probe for DNA damage. -- Abstract: Much effort has been focused on developing methods for detecting damaged nucleic acids. However, almost all of the proposed methods consist of multi-step procedures, are limited, require expensive instruments, or suffer from a high level of interferences. In this paper, we present a novel simple, inexpensive, mix-and-read assay that is generally applicable to nucleic acid damage and uses the enhanced luminescence due to energy transfer from nucleic acids to terbium(III) (Tb 3+ ). Single-stranded oligonucleotides greatly enhance the Tb 3+ emission, but duplex DNA does not. With the use of a DNA hairpin probe complementary to the oligonucleotide of interest, the Tb 3+ /hairpin probe is applied to detect ultraviolet (UV)-induced DNA damage. The hairpin probe hybridizes only with the undamaged DNA. However, the damaged DNA remains single-stranded and enhances the intrinsic fluorescence of Tb 3+ , producing a detectable signal directly proportional to the amount of DNA damage. This allows the Tb 3+ /hairpin probe to be used for sensitive quantification of UV-induced DNA damage. The Tb 3+ /hairpin probe showed superior selectivity to DNA damage compared to conventional molecular beacons probes (MBs) and its sensitivity is more than 2.5 times higher than MBs with a limit of detection of 4.36 ± 1.2 nM. In addition, this probe is easier to synthesize and more than eight times cheaper than MBs, which makes its use recommended for high-throughput, quantitative analysis of DNA damage

SYTO probes: markers of apoptotic cell demise.

Science.gov (United States)

Wlodkowic, Donald; Skommer, Joanna

2007-10-01

As mechanistic studies on tumor cell death advance towards their ultimate translational goal, there is a need for specific, rapid, and high-throughput analytical tools to detect diverse cell demise modes. Patented DNA-binding SYTO probes, for example, are gaining increasing interest as easy-to-use markers of caspase-dependent apoptotic cell death. They are proving convenient for tracking apoptosis in diverse hematopoietic cell lines and primary tumor samples, and, due to their spectral characteristics, appear to be useful for the development of multiparameter flow cytometry assays. Herein, several protocols for multiparametric assessment of apoptotic events using SYTO probes are provided. There are protocols describing the use of green fluorescent SYTO 16 and red fluorescent SYTO 17 dyes in combination with plasma membrane permeability markers. Another protocol highlights the multiparametric use of SYTO 16 dye in conjunction with the mitochondrial membrane potential sensitive probe, tetramethylrhodamine methyl ester (TMRM), and the plasma membrane permeability marker, 7-aminoactinomycin D (7-AAD).

Nitroolefin-based BODIPY as a novel water-soluble ratiometric fluorescent probe for detection of endogenous thiols

Science.gov (United States)

Kang, Jin; Huo, Fangjun; Chao, Jianbin; Yin, Caixia

2018-04-01

Small molecule biothiols, including cysteine (Cys), homocysteine (Hcy), and glutathione (GSH), play many crucial roles in physiological processes. In this work, we have prepared a nitroolefin-based BODIPY fluorescent probe with excellent water solubility for detection thiols, which displayed ratiometric fluorescent signal for thiols. Incorporation of a nitroolefin unit to the BODIPY dye would transform it into a strong Michael acceptor, which would be highly susceptible to sulfhydryl nucleophiles. This probe shows an obvious ratio change upon response with thiols, an increase of the emission at 517 nm along with a concomitant decrease of fluorescence peak at 573 nm. Moreover, these successes of intracellular imaging experiments in A549 cells indicated that this probe is suitable for imaging of ex-/endogenous thiols in living cells.

A highly selective turn-on fluorescent probe for hypochlorous acid based on hypochlorous acid-induced oxidative intramolecular cyclization of boron dipyrromethene-hydrazone

International Nuclear Information System (INIS)

Chen, Wei-Chieh; Venkatesan, Parthiban; Wu, Shu-Pao

2015-01-01

Highlights: • A BODIPY-based fluorescent probe for sensing HOCl was developed. • The probe utilizes the HOCl-promoted cyclization in response to the amount of HOCl. • The probe might have application in the investigation of HOCl in biological systems. - Abstract: A BODIPY-based fluorescent probe, HBP, was developed for the detection of hypochlorous acid based on the specific hypochlorous acid-promoted oxidative intramolecular cyclization of heterocyclic hydrazone in response to the amount of HOCl. The reaction is accompanied by a 41-fold increase in the fluorescent quantum yield (from 0.004 to 0.164). The fluorescence intensity of the reaction between HOCl and HBP is linear in the HOCl concentration range of 1–8 μM with a detection limit of 2.4 nM (S/N = 3). Confocal fluorescence microscopy imaging using RAW264.7 cells showed that the new probe HBP could be used as an effective fluorescent probe for detecting HOCl in living cells

A highly selective turn-on fluorescent probe for hypochlorous acid based on hypochlorous acid-induced oxidative intramolecular cyclization of boron dipyrromethene-hydrazone

Energy Technology Data Exchange (ETDEWEB)

Chen, Wei-Chieh; Venkatesan, Parthiban; Wu, Shu-Pao, E-mail: spwu@mail.nctu.edu.tw

2015-07-02

Highlights: • A BODIPY-based fluorescent probe for sensing HOCl was developed. • The probe utilizes the HOCl-promoted cyclization in response to the amount of HOCl. • The probe might have application in the investigation of HOCl in biological systems. - Abstract: A BODIPY-based fluorescent probe, HBP, was developed for the detection of hypochlorous acid based on the specific hypochlorous acid-promoted oxidative intramolecular cyclization of heterocyclic hydrazone in response to the amount of HOCl. The reaction is accompanied by a 41-fold increase in the fluorescent quantum yield (from 0.004 to 0.164). The fluorescence intensity of the reaction between HOCl and HBP is linear in the HOCl concentration range of 1–8 μM with a detection limit of 2.4 nM (S/N = 3). Confocal fluorescence microscopy imaging using RAW264.7 cells showed that the new probe HBP could be used as an effective fluorescent probe for detecting HOCl in living cells.

Direct fluorescence in situ hybridization on human metaphase chromosomes using quantum dot-platinum labeled DNA probes

Energy Technology Data Exchange (ETDEWEB)

Hwang, Gyoyeon [Chemical Kinomics Research Center, Future Convergence Research Division, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Biological Chemistry, Korea University of Science and Technology, 217, Gajeong-ro, Yuseong-gu, Deajeon (Korea, Republic of); Lee, Hansol [Chemical Kinomics Research Center, Future Convergence Research Division, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Lee, Jiyeon, E-mail: jylee@kist.re.kr [Chemical Kinomics Research Center, Future Convergence Research Division, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Biological Chemistry, Korea University of Science and Technology, 217, Gajeong-ro, Yuseong-gu, Deajeon (Korea, Republic of)

2015-11-13

The telomere shortening in chromosomes implies the senescence, apoptosis, or oncogenic transformation of cells. Since detecting telomeres in aging and diseases like cancer, is important, the direct detection of telomeres has been a very useful biomarker. We propose a telomere detection method using a newly synthesized quantum dot (QD) based probe with oligonucleotide conjugation and direct fluorescence in situ hybridization (FISH). QD-oligonucleotides were prepared with metal coordination bonding based on platinum-guanine binding reported in our previous work. The QD-oligonucleotide conjugation method has an advantage where any sequence containing guanine at the end can be easily bound to the starting QD-Pt conjugate. A synthesized telomeric oligonucleotide was bound to the QD-Pt conjugate successfully and this probe hybridized specifically on the telomere of fabricated MV-4-11 and MOLT-4 chromosomes. Additionally, the QD-telomeric oligonucleotide probe successfully detected the telomeres on the CGH metaphase slide. Due to the excellent photostability and high quantum yield of QDs, the QD-oligonucleotide probe has high fluorescence intensity when compared to the organic dye-oligonucleotide probe. Our QD-oligonucleotide probe, conjugation method of this QD probe, and hybridization protocol with the chromosomes can be a useful tool for chromosome painting and FISH. - Highlights: • We prepared a probe linked between QD and telomeric oligonucleotide with platinum-guanine bonding. • Telomeres were detected by our new telomere probes successfully in three different human metaphase chromosomes. • QDPt-DNA probe has high fluorescence intensity in comparison with organic dye-DNA probe.

Non-Covalent Fluorescent Labeling of Hairpin DNA Probe Coupled with Hybridization Chain Reaction for Sensitive DNA Detection.

Science.gov (United States)

Song, Luna; Zhang, Yonghua; Li, Junling; Gao, Qiang; Qi, Honglan; Zhang, Chengxiao

2016-04-01

An enzyme-free signal amplification-based assay for DNA detection was developed using fluorescent hairpin DNA probes coupled with hybridization chain reaction (HCR). The hairpin DNAs were designed to contain abasic sites in the stem moiety. Non-covalent labeling of the hairpin DNAs was achieved when a fluorescent ligand was bound to the abasic sites through hydrogen bonding with the orphan cytosine present on the complementary strand, accompanied by quench of ligand fluorescence. As a result, the resultant probes, the complex formed between the hairpin DNA and ligand, showed almost no fluorescence. Upon hybridization with target DNA, the probe underwent a dehybridization of the stem moiety containing an abasic site. The release of ligand from the abasic site to the solution resulted in an effective fluorescent enhancement, which can be used as a signal. Compared with a sensing system without HCR, a 20-fold increase in the sensitivity was achieved using the sensing system with HCR. The fluorescent intensity of the sensing system increased with the increase in target DNA concentration from 0.5 nM to 100 nM. A single mismatched target ss-DNA could be effectively discriminated from complementary target DNA. Genotyping of a G/C single-nucleotide polymorphism of polymerase chain reaction (PCR) products was successfully demonstrated with the sensing system. Therefore, integrating HCR strategy with non-covalent labeling of fluorescent hairpin DNA probes provides a sensitive and cost-effective DNA assay. © The Author(s) 2016.

A cell-surface-anchored ratiometric fluorescent probe for extracellular pH sensing.

Science.gov (United States)

Ke, Guoliang; Zhu, Zhi; Wang, Wei; Zou, Yuan; Guan, Zhichao; Jia, Shasha; Zhang, Huimin; Wu, Xuemeng; Yang, Chaoyong James

2014-09-10

Accurate sensing of the extracellular pH is a very important yet challenging task in biological and clinical applications. This paper describes the development of an amphiphilic lipid-DNA molecule as a simple yet useful cell-surface-anchored ratiometric fluorescent probe for extracellular pH sensing. The lipid-DNA probe, which consists of a hydrophobic diacyllipid tail and a hydrophilic DNA strand, is modified with two fluorescent dyes; one is pH-sensitive as pH indicator and the other is pH-insensitive as an internal reference. The lipid-DNA probe showed sensitive and reversible response to pH change in the range of 6.0-8.0, which is suitable for most extracellular studies. In addition, based on simple hydrophobic interactions with the cell membrane, the lipid-DNA probe can be easily anchored on the cell surface with negligible cytotoxicity, excellent stability, and unique ratiometric readout, thus ensuring its accurate sensing of extracellular pH. Finally, this lipid-DNA-based ratiometric pH indicator was successfully used for extracellular pH sensing of cells in 3D culture environment, demonstrating the potential applications of the sensor in biological and medical studies.

Poly(o-phenylenediamine) colloid-quenched fluorescent oligonucleotide as a probe for fluorescence-enhanced nucleic acid detection.

Science.gov (United States)

Tian, Jingqi; Li, Hailong; Luo, Yonglan; Wang, Lei; Zhang, Yingwei; Sun, Xuping

2011-02-01

In this Letter, we demonstrate that chemical oxidation polymerization of o-phenylenediamine (OPD) by potassium bichromate at room temperature results in the formation of submicrometer-scale poly(o-phenylenediamine) (POPD) colloids. Such colloids can absorb and quench dye-labeled single-stranded DNA (ssDNA) very effectively. In the presence of a target, a hybridization event occurs, which produces a double-stranded DNA (dsDNA) that detaches from the POPD surface, leading to recovery of dye fluorescence. With the use of an oligonucleotide (OND) sequence associated with human immunodeficiency virus (HIV) as a model system, we demonstrate the proof of concept that POPD colloid-quenched fluorescent OND can be used as a probe for fluorescence-enhanced nucleic acid detection with selectivity down to single-base mismatch.

A new Schiff base based on vanillin and naphthalimide as a fluorescent probe for Ag+ in aqueous solution

Science.gov (United States)

Zhou, Yanmei; Zhou, Hua; Ma, Tongsen; Zhang, Junli; Niu, Jingyang

2012-03-01

A new Schiff base based on vanillin and naphthalimide was designed and synthesized as fluorescent probe. The probe showed high selectivity for Ag+ over other metal ions such as Pb2+, Na+, K+, Cd2+, Ba2+, Cr3+, Zn2+, Cu2+, Ni2+, Ca2+, Al3+ and Mg2+ in aqueous solution. A new fluorescence emission was observed at 682 nm in the presence of Ag+ ion. The fluorescence intensity quenched with increasing the concentration of Ag+ at 682 nm. The method of job's plot confirmed the 1:2 complex between Ag+ and probe, and the mechanism was proposed.

Bodipy-FL-Verapamil: A Fluorescent Probe for the Study of Multidrug Resistance Proteins

Directory of Open Access Journals (Sweden)

Anna Rosati

2004-01-01

Full Text Available Most of the substances used as fluorescent probes to study drug transport and the effect of efflux blockers in multidrug resistant cells have many drawbacks, such as toxicity, unspecific background, accumulation in mitochondria. New fluorescent compounds, among which Bodipy‐FL‐verapamil (BV, have been therefore proposed as more useful tools. The uptake of BV has been evaluated by cytofluorimetry and fluorescence microscopy using cell lines that overexpress P‐glycoprotein (P388/ADR and LLC‐PK1/ADR or MRP (multidrug resistance‐related protein (PANC‐1 and clinical specimens from patients. The effect of specific inhibitors for P‐glycoprotein (verapamil and vinblastine or MRP (MK571 and probenecid has been also studied. BV intracellular concentrations were significantly lower in the two P‐glycoprotein overexpressing cell lines in comparison with the parental lines. In addition, verapamil and vinblastine increased the intracellular concentrations of the dye; MK571 and probenecid, two MRP inhibitors, increased BV levels in PANC‐1 cells, that express this protein. These findings were confirmed in clinical specimens from patients. Fluorescence microscopy revealed a faint fluorescence emission in P‐glycoprotein or MRP expressing cell lines; however, treatment with specific inhibitors significantly increased the fluorescence. BV is a useful tool for studying multidrug resistance proteins with different techniques such as cytofluorimetry and fluorescence microscopy, but does not discriminate between P‐glycoprotein and MRP. In comparison with other classic fluorescent probes, the assay with this dye is extremely rapid, simple, not toxic for cells, devoid of fluorescent background, and can be useful in the clinical settings.

A Thiazole Coumarin (TC) Turn-On Fluorescence Probe for AT-Base Pair Detection and Multipurpose Applications in Different Biological Systems

Science.gov (United States)

Narayanaswamy, Nagarjun; Kumar, Manoj; Das, Sadhan; Sharma, Rahul; Samanta, Pralok K.; Pati, Swapan K.; Dhar, Suman K.; Kundu, Tapas K.; Govindaraju, T.

2014-01-01

Sequence-specific recognition of DNA by small turn-on fluorescence probes is a promising tool for bioimaging, bioanalytical and biomedical applications. Here, the authors report a novel cell-permeable and red fluorescent hemicyanine-based thiazole coumarin (TC) probe for DNA recognition, nuclear staining and cell cycle analysis. TC exhibited strong fluorescence enhancement in the presence of DNA containing AT-base pairs, but did not fluoresce with GC sequences, single-stranded DNA, RNA and proteins. The fluorescence staining of HeLa S3 and HEK 293 cells by TC followed by DNase and RNase digestion studies depicted the selective staining of DNA in the nucleus over the cytoplasmic region. Fluorescence-activated cell sorting (FACS) analysis by flow cytometry demonstrated the potential application of TC in cell cycle analysis in HEK 293 cells. Metaphase chromosome and malaria parasite DNA imaging studies further confirmed the in vivo diagnostic and therapeutic applications of probe TC. Probe TC may find multiple applications in fluorescence spectroscopy, diagnostics, bioimaging and molecular and cell biology. PMID:25252596

Selective turn-on fluorescent probes for imaging hydrogen sulfide in living cells.

Science.gov (United States)

Montoya, Leticia A; Pluth, Michael D

2012-05-16

Hydrogen sulfide (H(2)S) is an important biological messenger but few biologically-compatible methods are available for its detection. Here we report two bright fluorescent probes that are selective for H(2)S over cysteine, glutathione and other reactive sulfur, nitrogen, and oxygen species. Both probes are demonstrated to detect H(2)S in live cells. This journal is © The Royal Society of Chemistry 2012

A lysosome-locating and acidic pH-activatable fluorescent probe for visualizing endogenous H2O2 in lysosomes.

Science.gov (United States)

Liu, Jun; Zhou, Shunqing; Ren, Jing; Wu, Chuanliu; Zhao, Yibing

2017-11-20

There is increasing evidence indicating that lysosomal H 2 O 2 is closely related to autophagy and apoptotic pathways under both physiological and pathological conditions. Therefore, fluorescent probes that can be exploited to visualize H 2 O 2 in lysosomes are potential tools for exploring diverse roles of H 2 O 2 in cells. However, functional exploration of lysosomal H 2 O 2 is limited by the lack of fluorescent probes capable of compatibly sensing H 2 O 2 under weak acidic conditions (pH = 4.5) of lysosomes. Lower spatial resolution of the fluorescent visualization of lysosomal H 2 O 2 might be caused by the interference of signals from cytosolic and mitochondrial H 2 O 2 , as well as the non-specific distribution of the probes in cells. In this work, we developed a lysosome-locating and acidic-pH-activatable fluorescent probe for the detection and visualization of H 2 O 2 in lysosomes, which consists of a H 2 O 2 -responsive boronate unit, a lysosome-locating morpholine group, and a pH-activatable benzorhodol fluorophore. The response of the fluorescent probe to H 2 O 2 is significantly more pronounced under acidic pH conditions than that under neutral pH conditions. Notably, the present probe enables the fluorescence sensing of endogenous lysosomal H 2 O 2 in living cells without external stimulations, with signal interference from the cytoplasm and other intracellular organelles being negligible.

A unique dual recognition hairpin probe mediated fluorescence amplification method for sensitive detection of uracil-DNA glycosylase and endonuclease IV activities.

Science.gov (United States)

Wu, Yushu; Yan, Ping; Xu, Xiaowen; Jiang, Wei

2016-03-07

Uracil-DNA glycosylase (UDG) and endonuclease IV (Endo IV) play cooperative roles in uracil base-excision repair (UBER) and inactivity of either will interrupt the UBER to cause disease. Detection of UDG and Endo IV activities is crucial to evaluate the UBER process in fundamental research and diagnostic application. Here, a unique dual recognition hairpin probe mediated fluorescence amplification method was developed for sensitively and selectively detecting UDG and Endo IV activities. For detecting UDG activity, the uracil base in the probe was excised by the target enzyme to generate an apurinic/apyrimidinic (AP) site, achieving the UDG recognition. Then, the AP site was cleaved by a tool enzyme Endo IV, releasing a primer to trigger rolling circle amplification (RCA) reaction. Finally, the RCA reaction produced numerous repeated G-quadruplex sequences, which interacted with N-methyl-mesoporphyrin IX to generate an enhanced fluorescence signal. Alternatively, for detecting Endo IV activity, the uracil base in the probe was first converted into an AP site by a tool enzyme UDG. Next, the AP site was cleaved by the target enzyme, achieving the Endo IV recognition. The signal was then generated and amplified in the same way as those in the UDG activity assay. The detection limits were as low as 0.00017 U mL(-1) for UDG and 0.11 U mL(-1) for Endo IV, respectively. Moreover, UDG and Endo IV can be well distinguished from their analogs. This method is beneficial for properly evaluating the UBER process in function studies and disease prognoses.

Selective and Sensitive Detection of Cyanide Based on the Displacement Strategy Using a Water-Soluble Fluorescent Probe

Science.gov (United States)

La, Ming; Hao, Yuanqiang; Wang, Zhaoyang; Han, Guo-Cheng; Qu, Lingbo

2016-01-01

A water-soluble fluorescent probe (C-GGH) was used for the highly sensitive and selective detection of cyanide (CN−) in aqueous media based on the displacement strategy. Due to the presence of the recognition unit GGH (Gly-Gly-His), the probe C-GGH can coordinate with Cu2+ and consequently display ON-OFF type fluorescence response. Furthermore, the in situ formed nonfluorescent C-GGH-Cu2+ complex can act as an effective OFF-ON type fluorescent probe for sensing CN− anion. Due to the strong binding affinity of CN− to Cu2+, CN− can extract Cu2+ from C-GGH-Cu2+ complex, leading to the release of C-GGH and the recovery of fluorescent emission of the system. The probe C-GGH-Cu2+ allowed detection of CN− in aqueous solution with a LOD (limit of detection) of 0.017 μmol/L which is much lower than the maximum contaminant level (1.9 μmol/L) for CN− in drinking water set by the WHO (World Health Organization). The probe also displayed excellent specificity for CN− towards other anions, including F−, Cl−, Br−, I−, SCN−, PO4 3−, N3 −, NO3 −, AcO−, SO4 2−, and CO3 2−. PMID:26881185

Selective and Sensitive Detection of Cyanide Based on the Displacement Strategy Using a Water-Soluble Fluorescent Probe

Directory of Open Access Journals (Sweden)

Ming La

2016-01-01

Full Text Available A water-soluble fluorescent probe (C-GGH was used for the highly sensitive and selective detection of cyanide (CN− in aqueous media based on the displacement strategy. Due to the presence of the recognition unit GGH (Gly-Gly-His, the probe C-GGH can coordinate with Cu2+ and consequently display ON-OFF type fluorescence response. Furthermore, the in situ formed nonfluorescent C-GGH-Cu2+ complex can act as an effective OFF-ON type fluorescent probe for sensing CN− anion. Due to the strong binding affinity of CN− to Cu2+, CN− can extract Cu2+ from C-GGH-Cu2+ complex, leading to the release of C-GGH and the recovery of fluorescent emission of the system. The probe C-GGH-Cu2+ allowed detection of CN− in aqueous solution with a LOD (limit of detection of 0.017 μmol/L which is much lower than the maximum contaminant level (1.9 μmol/L for CN− in drinking water set by the WHO (World Health Organization. The probe also displayed excellent specificity for CN− towards other anions, including F−, Cl−, Br−, I−, SCN−, PO43-, N3-, NO3-, AcO−, SO42-, and CO32-.

Intrinsically Labeled Fluorescent Oligonucleotide Probes on Quantum Dots for Transduction of Nucleic Acid Hybridization.

Science.gov (United States)

Shahmuradyan, Anna; Krull, Ulrich J

2016-03-15

Quantum dots (QDs) have been widely used in chemical and biosensing due to their unique photoelectrical properties and are well suited as donors in fluorescence resonance energy transfer (FRET). Selective hybridization interactions of oligonucleotides on QDs have been determined by FRET. Typically, the QD-FRET constructs have made use of labeled targets or have implemented labeled sandwich format assays to introduce dyes in proximity to the QDs for the FRET process. The intention of this new work is to explore a method to incorporate the acceptor dye into the probe molecule. Thiazole orange (TO) derivatives are fluorescent intercalating dyes that have been used for detection of double-stranded nucleic acids. One such dye system has been reported in which single-stranded oligonucleotide probes were doubly labeled with adjacent thiazole orange derivatives. In the absence of the fully complementary (FC) oligonucleotide target, the dyes form an H-aggregate, which results in quenching of fluorescence emission due to excitonic interactions between the dyes. The hybridization of the FC target to the probe provides for dissociation of the aggregate as the dyes intercalate into the double stranded duplex, resulting in increased fluorescence. This work reports investigation of the dependence of the ratiometric signal on the type of linkage used to conjugate the dyes to the probe, the location of the dye along the length of the probe, and the distance between adjacent dye molecules. The limit of detection for 34mer and 90mer targets was found to be identical and was 10 nM (2 pmol), similar to analogous QD-FRET using labeled oligonucleotide target. The detection system could discriminate a one base pair mismatch (1BPM) target and was functional without substantial compromise of the signal in 75% serum. The 1BPM was found to reduce background signal, indicating that the structure of the mismatch affected the environment of the intercalating dyes.

ESIPT-Based Photoactivatable Fluorescent Probe for Ratiometric Spatiotemporal Bioimaging

Directory of Open Access Journals (Sweden)

Xiaohong Zhou

2016-10-01

Full Text Available Photoactivatable fluorophores have become an important technique for the high spatiotemporal resolution of biological imaging. Here, we developed a novel photoactivatable probe (PHBT, which is based on 2-(2-hydroxyphenylbenzothiazole (HBT, a small organic fluorophore known for its classic luminescence mechanism through excited-state intramolecular proton transfer (ESIPT with the keto form and the enol form. After photocleavage, PHBT released a ratiometric fluorophore HBT, which showed dual emission bands with more than 73-fold fluorescence enhancement at 512 nm in buffer and more than 69-fold enhancement at 452 nm in bovine serum. The probe displayed a high ratiometric imaging resolution and is believed to have a wide application in biological imaging.

RELIC: a novel dye-bias correction method for Illumina Methylation BeadChip.

Science.gov (United States)

Xu, Zongli; Langie, Sabine A S; De Boever, Patrick; Taylor, Jack A; Niu, Liang

2017-01-03

The Illumina Infinium HumanMethylation450 BeadChip and its successor, Infinium MethylationEPIC BeadChip, have been extensively utilized in epigenome-wide association studies. Both arrays use two fluorescent dyes (Cy3-green/Cy5-red) to measure methylation level at CpG sites. However, performance difference between dyes can result in biased estimates of methylation levels. Here we describe a novel method, called REgression on Logarithm of Internal Control probes (RELIC) to correct for dye bias on whole array by utilizing the intensity values of paired internal control probes that monitor the two color channels. We evaluate the method in several datasets against other widely used dye-bias correction methods. Results on data quality improvement showed that RELIC correction statistically significantly outperforms alternative dye-bias correction methods. We incorporated the method into the R package ENmix, which is freely available from the Bioconductor website ( https://www.bioconductor.org/packages/release/bioc/html/ENmix.html ). RELIC is an efficient and robust method to correct for dye-bias in Illumina Methylation BeadChip data. It outperforms other alternative methods and conveniently implemented in R package ENmix to facilitate DNA methylation studies.

Sensing for intracellular thiols by water-insoluble two-photon fluorescent probe incorporating nanogel

Energy Technology Data Exchange (ETDEWEB)

Guo, Xudong; Zhang, Xin; Wang, Shuangqing; Li, Shayu [Beijing National Laboratory for Molecular Sciences, Key laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Hu, Rui, E-mail: hurui@iccas.ac.cn [Beijing National Laboratory for Molecular Sciences, Key laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Li, Yi, E-mail: yili@mail.ipc.ac.cn [Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Yang, Guoqiang, E-mail: gqyang@iccas.ac.cn [Beijing National Laboratory for Molecular Sciences, Key laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

2015-04-15

Highlights: • A novel “turn-on” two-photon fluorescent probe based on a π-conjugated triarylboron luminogen was designed and synthesized. • Fast, selective and sensitive detection of biothiols in 100% aqueous solution by simply loaded on a nanogel. • Single-photon and two-photon fluorescent bioimaging of biothiols in NIH/3T3 fibroblasts. - Abstract: A novel “turn-on” two-photon fluorescent probe containing a π-conjugated triarylboron luminogen and a maleimide moiety DMDP-M based on the photo-induced electron transfer (PET) mechanism for biothiol detection was designed and synthesized. By simply loading the hydrophobic DMDP-M on a cross-linked Pluronic{sup ®} F127 nanogel (CL-F127), a probing system DMDP-M/CL-F127 was established, which shows quick response, high selectivity and sensitivity to cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) in aqueous phase. The DMDP-M/CL-F127 system presented the fastest response to Cys with a rate constant of 0.56 min{sup −1}, and the detection limit to Cys was calculated to be as low as 0.18 μM. The DMDP-M/CL-F127 system has been successfully applied to the fluorescence imaging of biothiols in NIH/3T3 fibroblasts either with single-photon or two-photon excitation because of its high biocompatibility and cell-membrane permeability. The present work provides a general, simple and efficient strategy for the application of hydrophobic molecules to sensing biothiols in aqueous phase, and a novel sensing system for intracellular biothiols fitted for both single-photon and two-photon fluorescence imaging.

In vivo imaging of membrane type-1 matrix metalloproteinase with a novel activatable near-infrared fluorescence probe.

Science.gov (United States)

Shimizu, Yoichi; Temma, Takashi; Hara, Isao; Makino, Akira; Kondo, Naoya; Ozeki, Ei-Ichi; Ono, Masahiro; Saji, Hideo

2014-08-01

Membrane type-1 matrix metalloproteinase (MT1-MMP) is a protease activating MMP-2 that mediates cleavage of extracellular matrix components and plays pivotal roles in tumor migration, invasion and metastasis. Because in vivo noninvasive imaging of MT1-MMP would be useful for tumor diagnosis, we developed a novel near-infrared (NIR) fluorescence probe that can be activated following interaction with MT1-MMP in vivo. MT1-hIC7L is an activatable fluorescence probe comprised of anti-MT1-MMP monoclonal antibodies conjugated to self-assembling polymer micelles that encapsulate NIR dyes (IC7-1, λem : 858 nm) at concentrations sufficient to cause fluorescence self-quenching. In aqueous buffer, MT1-hIC7L fluorescence was suppressed to background levels and increased approximately 35.5-fold in the presence of detergent. Cellular uptake experiments revealed that in MT1-MMP positive C6 glioma cells, MT1-hIC7L showed significantly higher fluorescence that increased with time as compared to hIC7L, a negative control probe lacking the anti-MT1-MMP monoclonal antibody. In MT1-MMP negative MCF-7 breast adenocarcinoma cells, both MT1-hIC7L and hIC7L showed no obvious fluorescence. In addition, the fluorescence intensity of C6 cells treated with MT1-hIC7L was suppressed by pre-treatment with an MT1-MMP endocytosis inhibitor (P imaging using probes intravenously administered to tumor-bearing mice showed that MT1-hIC7L specifically visualized C6 tumors (tumor-to-background ratios: 3.8 ± 0.3 [MT1-hIC7L] vs 3.1 ± 0.2 [hIC7L] 48 h after administration, P fluorescence in MCF-7 tumors. Together, these results show that MT1-hIC7L would be a potential activatable NIR probe for specifically detecting MT1-MMP-expressing tumors. © 2014 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.

A Novel Water-soluble Ratiometric Fluorescent Probe Based on FRET for Sensing Lysosomal pH.

Science.gov (United States)

Song, Guang-Jie; Bai, Su-Yun; Luo, Jing; Cao, Xiao-Qun; Zhao, Bao-Xiang

2016-11-01

A new ratiometric fluorescent probe based on Förster resonance energy transfer (FRET) for sensing lysosomal pH has been developed. The probe (RMPM) was composed of imidazo[1,5-α]pyridine quaternary ammonium salt fluorophore as the FRET donor and the rhodamine moiety as the FRET acceptor. It's the first time to report that imidazo[1,5-α]pyridine quaternary ammonium salt acts as the FRET donor. The ratio of fluorescence intensity of the probe at two wavelengths (I 424 /I 581 ) changed significantly and responded linearly toward minor pH changes in the range of 5.4-6.6. It should be noted that it's rare to report that a ratiometric pH probe could detect so weak acidic pH with pKa = 6.31. In addition, probe RMPM exhibited excellent water-solubility, fast-response, all-right selectivity and brilliant reversibility. Moreover, RMPM has been successfully applied to sensing lysosomal pH in HeLa cells and has low cytotoxicity.

A NBD-based simple but effective fluorescent pH probe for imaging of lysosomes in living cells

Energy Technology Data Exchange (ETDEWEB)

Cao, Xiang-Jian [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Taishan College, Shandong University, Jinan 250100 (China); Chen, Li-Na [Institute of Developmental Biology, School of Life Science, Shandong University, Jinan 250100 (China); Zhang, Xuan [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Taishan College, Shandong University, Jinan 250100 (China); Liu, Jin-Ting [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Chen, Ming-Yu [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Taishan College, Shandong University, Jinan 250100 (China); Wu, Qiu-Rong [Institute of Developmental Biology, School of Life Science, Shandong University, Jinan 250100 (China); Taishan College, Shandong University, Jinan 250100 (China); Miao, Jun-Ying, E-mail: miaojy@sdu.edu.cn [Institute of Developmental Biology, School of Life Science, Shandong University, Jinan 250100 (China); Zhao, Bao-Xiang, E-mail: bxzhao@sdu.edu.cn [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)

2016-05-12

NBDlyso with lysosome-locating morpholine moiety has been developed as a high selective and sensitive fluorescent pH probe. This probe can respond to acidic pH (2.0–7.0) in a short time (less than 1 min) and not almost change after continuously illuminated for an extended period by ultraviolet light. The fluorescence intensity of NBDlyso enhanced 100-fold in acidic solution, with very good linear relationship (R{sup 2} = 0.996). The pK{sub a} of probe NBDlyso is 4.10. Therefore, NBDlyso was used to detect lysosomal pH changes successfully. Besides, X-ray crystallography was used to verify the structure of NBDlyso, and the recognition mechanism involving photo-induced electron transfer was interpreted theoretically by means of DFT and TDDFT calculations skillfully when NBDlyso comes into play under the acidic condition. This probe showed good ability to sense pH change in living cell image. - Highlights: • An effective NBD-based fluorescent pH probe was developed. • The sensing mechanism was interpreted by theoretical calculation. • This probe was successfully used to monitor lysosoml pH changes in Hela cells.

A NBD-based simple but effective fluorescent pH probe for imaging of lysosomes in living cells

International Nuclear Information System (INIS)

Cao, Xiang-Jian; Chen, Li-Na; Zhang, Xuan; Liu, Jin-Ting; Chen, Ming-Yu; Wu, Qiu-Rong; Miao, Jun-Ying; Zhao, Bao-Xiang

2016-01-01

NBDlyso with lysosome-locating morpholine moiety has been developed as a high selective and sensitive fluorescent pH probe. This probe can respond to acidic pH (2.0–7.0) in a short time (less than 1 min) and not almost change after continuously illuminated for an extended period by ultraviolet light. The fluorescence intensity of NBDlyso enhanced 100-fold in acidic solution, with very good linear relationship (R"2 = 0.996). The pK_a of probe NBDlyso is 4.10. Therefore, NBDlyso was used to detect lysosomal pH changes successfully. Besides, X-ray crystallography was used to verify the structure of NBDlyso, and the recognition mechanism involving photo-induced electron transfer was interpreted theoretically by means of DFT and TDDFT calculations skillfully when NBDlyso comes into play under the acidic condition. This probe showed good ability to sense pH change in living cell image. - Highlights: • An effective NBD-based fluorescent pH probe was developed. • The sensing mechanism was interpreted by theoretical calculation. • This probe was successfully used to monitor lysosoml pH changes in Hela cells.

FLOW CYTOMETRIC APPLICABILITY OF FLUORESCENT VITALITY PROBES ON PHYTOPLANKTON1.

Science.gov (United States)

Peperzak, Louis; Brussaard, Corina P D

2011-06-01

The applicability of six fluorescent probes (four esterase probes: acetoxymethyl ester of Calcein [Calcein-AM], 5-chloromethylfluorescein diacetate [CMFDA], fluorescein diacetate [FDA], and 2',7'-dichlorofluorescein diacetate [H 2 DCFDA]; and two membrane probes: bis-(1,3-dibutylbarbituric acid) trimethine oxonol [DiBAC 4 (3)] and SYTOX-Green) as vitality stains was tested on live and killed cells of 40 phytoplankton strains in exponential and stationary growth phases, belonging to 12 classes and consisting of four cold-water, 26 temperate, and four warm-water species. The combined live/dead ratios of all six probes indicated significant differences between the 12 plankton classes (P live/dead ratios of FDA and CMFDA were not significantly different from each other, and both performed better than Calcein-AM and H 2 DCFDA (P live/dead ratios) among all six probes belonged to nine genera from six classes of phytoplankton. In conclusion, FDA, CMFDA, DIBAC 4 (3), and SYTOX-Green represent a wide choice of vitality probes in the study of phytoplankton ecology, applicable in many species from different algal classes, originating from different regions and at different stages of growth. © 2011 Phycological Society of America.

Fluorescent molecular probes based on excited state prototropism in lipid bilayer membrane

Science.gov (United States)

Mohapatra, Monalisa; Mishra, Ashok K.

2012-03-01

Excited state prototropism (ESPT) is observed in molecules having one or more ionizable protons, whose proton transfer efficiency is different in ground and excited states. The interaction of various ESPT molecules like naphthols and intramolecular ESPT (ESIPT) molecules like hydroxyflavones etc. with different microheterogeneous media have been studied in detail and excited state prototropism as a probe concept has been gaining ground. The fluorescence of different prototropic forms of such molecules, on partitioning to an organized medium like lipid bilayer membrane, often show sensitive response to the local environment with respect to the local structure, physical properties and dynamics. Our recent work using 1-naphthol as an ESPT fluorescent molecular probe has shown that the incorporation of monomeric bile salt molecules into lipid bilayer membranes composed from dipalmitoylphosphatidylcholine (DPPC, a lung surfactant) and dimyristoylphosphatidylcholine (DMPC), in solid gel and liquid crystalline phases, induce appreciable wetting of the bilayer up to the hydrocarbon core region, even at very low (fisetin, an ESIPT molecule having antioxidant properties, in lipid bilayer membrane has been sensitively monitored from its intrinsic fluorescence behaviour.

Turn-on fluorescence probes based on pyranine/viologen charge-transfer complexes for the determination of nucleotides

Energy Technology Data Exchange (ETDEWEB)

Schäferling, Michael, E-mail: Michael.schaeferling@utu.fi; Lang, Thomas; Schnettelker, Annette

2014-10-15

The formation of ground state charge-transfer complexes between pyranine (8-hydroxypyrene-1,3,6-trisulfonic acid) and viologen (paraquat) derivatives is utilized for the design of novel fluoroionophores for the determination of phosphate species, particularly of nucleotides. The strong quenching of the pyranine fluorescence by viologen-type charge transfer acceptors can be countermanded if these are functionalized with triethylammonium groups that serve as recognition elements for phosphate anions. We report on the fluorogenic responses of these water-soluble molecular probes in presence of different phosphates. Absorbance measurements give additional information on the charge transfer complex formation and the interaction with nucleotides. The experimental data show that these aggregates form attractive, simple and versatile fluorescence turn-on probes for nucleoside triphosphates. The reversibility of the fluorescence response is demonstrated by means of an enzymatic model assay using ATPase for the decomposition of adenosine triphosphate. - Highlights: • Pyranine/viologen charge-transfer complexes as molecular probe for ATP recognition. • Fluorescence turn on mechanism. • Selective compared to other nucleotides and phosphate anions. • Fast and reversible response applicable to monitor enzymatic reactions.

A simple rhodamine hydrazide-based turn-on fluorescent probe for HOCl detection.

Science.gov (United States)

Zhang, Zhen; Zou, Yuan; Deng, Chengquan; Meng, Liesu

2016-06-01

Hypochlorous acid (HOCl) plays a crucial role in daily life and mediates a variety of physiological processes, however, abnormal levels of HOCl have been associated with numerous human diseases. It is therefore of significant interest to establish a simple, selective, rapid and sensitive fluorogenic method for the detection of HOCl in environmental and biological samples. A hydrazide-containing fluorescent probe based on a rhodamine scaffold was facilely developed that could selectively detect HOCl over other biologically relevant reactive oxygen species, reactive nitrogen species and most common metal ions in vitro. Via an irreversible oxidation-hydrolysis mechanism, and upon HOCl-triggered opening of the intramolecular spirocyclic ring during detection, the rhodamine hydrazide-based probe exhibited large fluorescence enhancement in the emission spectra with a fast response, low detection limit and comparatively wide pH detection range in aqueous media. The probe was further successfully applied to monitoring trace HOCl in tap water and imaging both exogenous and endogenous HOCl within living cells. It is anticipated that this simple and useful probe might be an efficient tool with which to facilitate more HOCl-related chemical and biological research. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Synthesis and spectral properties of Methyl-Phenyl pyrazoloquinoxaline fluorescence emitters: Experiment and DFT/TDDFT calculations

Science.gov (United States)

Gąsiorski, P.; Matusiewicz, M.; Gondek, E.; Uchacz, T.; Wojtasik, K.; Danel, A.; Shchur, Ya.; Kityk, A. V.

2018-01-01

Paper reports the synthesis and spectroscopic studies of two novel 1-Methyl-3-phenyl-1H-pyrazolo[3,4-b]quinoxaline (PQX) derivatives with 6-substituted methyl (MeMPPQX) or methoxy (MeOMPPQX) side groups. The optical absorption and fluorescence emission spectra are recorded in solvents of different polarity. Steady state and time-resolved spectroscopy provide photophysical characterization of MeMPPQX and MeOMPPQX dyes as materials for potential luminescence or electroluminescence applications. Measured optical absorption and fluorescence emission spectra are compared with quantum-chemical DFT/TDDFT calculations using long-range corrected xc-functionals, LRC-BLYP and CAM-B3LYP in combination with self-consistent reaction field model based on linear response (LR), state specific (SS) or corrected linear response (CLR) solvations. Performances of relevant theoretical models and approaches are compared. The reparameterized LRC-BLYP functional (ω = 0.231 Bohr-1) in combination with CLR solvation provides most accurate prediction of both excitation and emission energies. The MeMPPQX and MeOMPPQX dyes represent efficient fluorescence emitters in blue-green region of the visible spectra.

Probe for intracellular concentrations of drugs: delayed fluorescence from acridine orange

International Nuclear Information System (INIS)

Wardman, P.; Dennis, M.F.; White, J.

1989-01-01

The aim of this work is to develop fluorescent probes that will indicate effective concentrations of therapeutic agents, or endogenous protectors, at important cellular sites. Acridine orange associates with nucleic acids and emits a 'delayed' fluorescence signal. This signal is quenched by oxidants such as oxygen, nitroaryl radiosensitizers, adriamycin and mitomycin-c, and reductants such as thiols, ascorbate and other radioprotectors. The quenching of the acridine orange delayed fluorescence reflects the effective concentration of these therapeutically-important oxidants and reductants near DNA. The relative concentration of basic radiosensitizers such as pimonidazole (Ro 03-8799) near the DNA is greater than that of misonidazole. Thiols quench the delayed fluorescence signal according to the degree of ionization of the thiol function; this may model the reactivity of thiols with guanine radical sites in DNA. Ascorbate and aminopyrine do not quench the delayed fluorescence from cells stained with acridine orange as these compounds are taken up by cells very inefficiently

A quick response fluorescent probe based on coumarin and quinone for glutathione and its application in living cells

Energy Technology Data Exchange (ETDEWEB)

Dai, Xi [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Du, Zhi-Fang [Taishan College, Shandong University, Jinan 250100 (China); Wang, Li-Hong; Miao, Jun-Ying [Institute of Developmental Biology, School of Life Science, Shandong University, Jinan 250100 (China); Zhao, Bao-Xiang, E-mail: bxzhao@sdu.edu.cn [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)

2016-05-30

We have designed and synthesized a simple but effective fluorescent probe for sensing glutathione (GSH) by PET process based on coumarin and quinone, which worked as fluorophore and reaction site, respectively. The probe could discriminate GSH from cysteine and homocysteine within 1 min in PBS-buffered solution. The sensing mechanism was confirmed by density functional theory (DFT), viscosity test, fluorescence spectrum analysis and HRMS, respectively. The probe has a low limit of detection (0.1 μM) and finally been used in cell imaging successfully. - Highlights: • This probe can discriminate glutathione from sulfhydryl compound by PET process. • This probe can be used to determine glutathione in aqueous solution within 1 min. • This probe has been successfully applied in living cell image.

A quick response fluorescent probe based on coumarin and quinone for glutathione and its application in living cells

International Nuclear Information System (INIS)

Dai, Xi; Du, Zhi-Fang; Wang, Li-Hong; Miao, Jun-Ying; Zhao, Bao-Xiang

2016-01-01

We have designed and synthesized a simple but effective fluorescent probe for sensing glutathione (GSH) by PET process based on coumarin and quinone, which worked as fluorophore and reaction site, respectively. The probe could discriminate GSH from cysteine and homocysteine within 1 min in PBS-buffered solution. The sensing mechanism was confirmed by density functional theory (DFT), viscosity test, fluorescence spectrum analysis and HRMS, respectively. The probe has a low limit of detection (0.1 μM) and finally been used in cell imaging successfully. - Highlights: • This probe can discriminate glutathione from sulfhydryl compound by PET process. • This probe can be used to determine glutathione in aqueous solution within 1 min. • This probe has been successfully applied in living cell image.

Intravascular atherosclerotic imaging with combined fluorescence and optical coherence tomography probe based on a double-clad fiber combiner

Science.gov (United States)

Liang, Shanshan; Saidi, Arya; Jing, Joe; Liu, Gangjun; Li, Jiawen; Zhang, Jun; Sun, Changsen; Narula, Jagat; Chen, Zhongping

2012-07-01

We developed a multimodality fluorescence and optical coherence tomography probe based on a double-clad fiber (DCF) combiner. The probe is composed of a DCF combiner, grin lens, and micromotor in the distal end. An integrated swept-source optical coherence tomography and fluorescence intensity imaging system was developed based on the combined probe for the early diagnoses of atherosclerosis. This system is capable of real-time data acquisition and processing as well as image display. For fluorescence imaging, the inflammation of atherosclerosis and necrotic core formed with the annexin V-conjugated Cy5.5 were imaged. Ex vivo imaging of New Zealand white rabbit arteries demonstrated the capability of the combined system.

A single pH fluorescent probe for biosensing and imaging of extreme acidity and extreme alkalinity.

Science.gov (United States)

Chao, Jian-Bin; Wang, Hui-Juan; Zhang, Yong-Bin; Li, Zhi-Qing; Liu, Yu-Hong; Huo, Fang-Jun; Yin, Cai-Xia; Shi, Ya-Wei; Wang, Juan-Juan

2017-07-04

A simple tailor-made pH fluorescent probe 2-benzothiazole (N-ethylcarbazole-3-yl) hydrazone (Probe) is facilely synthesized by the condensation reaction of 2-hydrazinobenzothiazole with N-ethylcarbazole-3-formaldehyde, which is a useful fluorescent probe for monitoring extremely acidic and alkaline pH, quantitatively. The pH titrations indicate that Probe displays a remarkable emission enhancement with a pK a of 2.73 and responds linearly to minor pH fluctuations within the extremely acidic range of 2.21-3.30. Interestingly, Probe also exhibits strong pH-dependent characteristics with pK a 11.28 and linear response to extreme-alkalinity range of 10.41-12.43. In addition, Probe shows a large Stokes shift of 84 nm under extremely acidic and alkaline conditions, high selectivity, excellent sensitivity, good water-solubility and fine stability, all of which are favorable for intracellular pH imaging. The probe is further successfully applied to image extremely acidic and alkaline pH values fluctuations in E. coli cells. Copyright © 2017 Elsevier B.V. All rights reserved.

A new rhodamine-based fluorescent probe for the discrimination of Fe{sup 3+} from Fe{sup 2+}

Energy Technology Data Exchange (ETDEWEB)

You, Qi Hua; Huang, Hua Bin; Zhuang, Zhi Xia; Wang, Xiao Ru [Dept. of Science and Technology for Inspection, Xiamen Huaxia University, Xiamen (China); Chan, Wing Hong [Dept. of of Chemistry, Hong Kong Bap tist University, Hong Kong (China)

2016-11-15

A new rhodamine-based fluorescent probe for the discrimination of Fe{sup 3+} from Fe{sup 2+} has been designed and investigated. The probe shows an immediate visual color change in response to Fe{sup 3+} and Cu{sup 2+}, while only Fe{sup 3+} triggers the fluorescent change of the probe. The existence of large amount of other metal ions shows negligible interference in the detection of Fe{sup 3+}. The association constant K{sub ass} of 4.64 × 10{sup 8} M{sup -2} (R{sup 2} = 0.994) and 5.38 × 10{sup 8} M{sup -2} (R{sup 2} = 0.991) of the complex was derived from UV/Vis and fluorescence titration assuming 1:2 stoichiometry of probe–Fe{sup 3+} complex, respectively.

A novel fluorescence probe based on triphenylamine Schiff base for bioimaging and responding to pH and Fe3+

International Nuclear Information System (INIS)

Wang, Lei; Yang, Xiaodong; Chen, Xiuli; Zhou, Yuping; Lu, Xiaodan; Yan, Chenggong; Xu, Yikai; Liu, Ruiyuan; Qu, Jinqing

2017-01-01

A novel fluorescence probe 1 based on triphenylamine was synthesized and characterized by NMR, IR, high resolution mass spectrometry and elemental analysis. Its fluorescence was quenched when pH below 2. There was a linear relationship between the fluorescence intensity and pH value ranged from 2 to 7. And its fluorescence emission was reversibility in acidic and alkaline solution. Furthermore, it exhibited remarkable selectivity and high sensitivity to Fe 3+ and was able to detect Fe 3+ in aqueous solution with low detection limit of 0.511 μM. Job plot showed that the binding stoichiometry of 1 with Fe 3+ was 1:1. Further observations of 1 H NMR titration suggested that coordination interaction between Fe 3+ and nitrogen atom on C =N bond promoted the intramolecular charge transfer (ICT) or energy transfer process causing fluorescence quenching. Additionally, 1 was also able to be applied for detecting Fe 3+ in living cell and bioimaging. - Graphical abstract: Triphenylamine based fluorescence probe can detect pH and Fe 3+ simultaneously in aqueous solution and be applied for detecting Fe 3+ in living cell and bioimaging. - Highlights: • The fluorescence probe is sensitive to pH in strong acid conditions. • The fluorescence chemosensor can detect pH and Fe 3+ simultaneously. • The recognition is able to carry out in aqueous solution. • The probe can also be applied for detecting Fe 3+ in living cell and bioimaging. • The sensor is synthesized easily with one step.

New fluorescent probes for detection and characterization of amyloid fibrils

Science.gov (United States)

Gorbenko, Galyna; Trusova, Valeriya; Kirilova, Elena; Kirilov, Georgiy; Kalnina, Inta; Vasilev, Aleksey; Kaloyanova, Stefka; Deligeorgiev, Todor

2010-08-01

The applicability of the novel fluorescent probes, aminoderivative of benzanthrone ABM, squaraine dye SQ-1 and polymethine dye V2 to identification and structural analysis of amyloid fibrils has been evaluated using the lysozyme model system in which fibrillar aggregates have been formed in concentrated ethanol solution. The association constant, binding stoichiometry and molar fluorescence of the bound dye have been determined. ABM was found to surpass classical amyloid marker ThT in the sensitivity to the presence of fibrillar aggregates. Resonance energy transfer measurements involving ABM-SQ-1 and SQ-1-V2 donor-acceptor pairs yielded the limits for fractal-like dimension of lysozyme fibrils.

Benzothiadiazole Derivatives as Fluorescence Imaging Probes: Beyond Classical Scaffolds.

Science.gov (United States)

Neto, Brenno A D; Carvalho, Pedro H P R; Correa, Jose R

2015-06-16

This Account describes the origins, features, importance, and trends of the use of fluorescent small-molecule 2,1,3-benzothiadiazole (BTD) derivatives as a new class of bioprobes applied to bioimaging analyses of several (live and fixed) cell types. BTDs have been successfully used as probes for a plethora of biological analyses for only a few years, and the impressive responses obtained by using this important class of heterocycle are fostering the development of new fluorescent BTDs and expanding the biological applications of such derivatives. The first use of a fluorescent small-molecule BTD derivative as a selective cellular probe dates back to 2010, and since then impressive advances have been described by us and others. The well-known limitations of classical scaffolds urged the development of new classes of bioprobes. Although great developments have been achieved by using classical scaffolds such as coumarins, BODIPYs, fluoresceins, rhodamines, cyanines, and phenoxazines, there is still much to be done, and BTDs aim to succeed where these dyes have shown their limitations. Important organelles and cell components such as nuclear DNA, mitochondria, lipid droplets, and others have already been successfully labeled by fluorescent small-molecule BTD derivatives. New technological systems that use BTDs as the fluorophores for bioimaging experiments have been described in recent scientific literature. The successful application of BTDs as selective bioprobes has led some groups to explore their potential for use in studying membrane pores or tumor cells under hypoxic conditions. Finally, BTDs have also been used as fluorescent tags to investigate the action mechanism of some antitumor compounds. The attractive photophysical data typically observed for π-extended BTD derivatives is fostering interest in the use of this new class of bioprobes. Large Stokes shifts, large molar extinction coefficients, high quantum yields, high stability when stored in solution or

Fluorescence-Based Comparative Binding Studies of the Supramolecular Host Properties of PAMAM Dendrimers Using Anilinonaphthalene Sulfonates: Unusual Host-Dependent Fluorescence Titration Behavior

Directory of Open Access Journals (Sweden)

Natasa Stojanovic

2010-04-01

Full Text Available This work describes the fluorescence enhancement of the anilinonaphthalene sulfonate probes 1,8-ANS, 2,6-ANS, and 2,6-TNS via complexation with PAMAM dendrimer hosts of Generation 4, 5 and 6. The use of this set of three very closely related probes allows for comparative binding studies, with specific pairs of probes differing only in shape (1,8-ANS and 2,6-ANS, or in the presence of a methyl substituent (2,6-TNS vs. 2,6-ANS. The fluorescence of all three probes was significantly enhanced upon binding with PAMAM dendrimers, however in all cases except one, a very unusual spike was consistently observed in the host fluorescence titration plots (fluorescence enhancement vs. host concentration at low dendrimer concentration. This unprecedented fluorescence titration curve shape makes fitting the data to a simple model such as 1:1 or 2:1 host: guest complexation very difficult; thus only qualitative comparisons of the relative binding of the three guests could be made based on host titrations. In the case of G4 and G5 dendrimers, the order of binding strength was qualitatively determined to be 1,8-ANS < 2,6-ANS indicating that the more streamlined 2,6-substituted probes are a better match for the dendrimer cavity shape than the bulkier 1,8-substituted probe. This order of binding strength was also indicated by double fluorometric titration experiments, involving both host and guest titrations. Further double fluorometric titration experiments on 2,6-ANS in G4 dendrimer revealed a host concentration-dependent change in the nature of the host: guest complexation, with multiple guests complexed per host molecule at very low host concentrations, but less than one guest per host at higher concentrations.

A fast-response two-photon fluorescent probe for imaging endogenous H2O2 in living cells and tissues

Science.gov (United States)

Lu, Yanan; Shi, Xiaomin; Fan, Wenlong; Black, Cory A.; Lu, Zhengliang; Fan, Chunhua

2018-02-01

As a second messenger, hydrogen peroxide plays significant roles in numerous physiological and pathological processes and is related to various diseases including inflammatory disease, diabetes, neurodegenerative disorders, cardiovascular disease and Alzheimer's disease. Two-photon (TP) fluorescent probes reported for the detection of endogenous H2O2 are rare and most have drawbacks such as slow response and low sensitivity. In this report, we demonstrate a simple H2O2-specific TP fluorescent probe (TX-HP) containing a two-photon dye 6-hydroxy-2,3,4,4a-tetrahydro-1H-xanthen-1-one (TX) on the modulation of the ICT process. The probe exhibits a rapid fluorescent response to H2O2 in 9 min with both high sensitivity and selectivity. The probe can detect exogenous H2O2 in living cells. Furthermore, the probe is successfully utilized for imaging H2O2 in liver tissues.

DNA methylation levels analysis in four tissues of sea cucumber Apostichopus japonicus based on fluorescence-labeled methylation-sensitive amplified polymorphism (F-MSAP) during aestivation.

Science.gov (United States)

Zhao, Ye; Chen, Muyan; Storey, Kenneth B; Sun, Lina; Yang, Hongsheng

2015-03-01

DNA methylation plays an important role in regulating transcriptional change in response to environmental stimuli. In the present study, DNA methylation levels of tissues of the sea cucumber Apostichopus japonicus were analyzed by the fluorescence-labeled methylation-sensitive amplified polymorphism (F-MSAP) technique over three stages of the aestivation cycle. Overall, a total of 26,963 fragments were amplified including 9112 methylated fragments among four sea cucumber tissues using 18 pairs of selective primers. Results indicated an average DNA methylation level of 33.79% for A. japonicus. The incidence of DNA methylation was different across tissue types in the non-aestivation stage: intestine (30.16%), respiratory tree (27.61%), muscle (27.94%) and body wall (56.25%). Our results show that hypermethylation accompanied deep-aestivation in A. japonicus, which suggests that DNA methylation may have an important role in regulating global transcriptional suppression during aestivation. Further analysis indicated that the main DNA modification sites were focused on intestine and respiratory tree tissues and that full-methylation but not hemi-methylation levels exhibited significant increases in the deep-aestivation stage. Copyright © 2014 Elsevier Inc. All rights reserved.

A fusion-spliced near-field optical fiber probe using photonic crystal fiber for nanoscale thermometry based on fluorescence-lifetime measurement of quantum dots.

Science.gov (United States)

Fujii, Takuro; Taguchi, Yoshihiro; Saiki, Toshiharu; Nagasaka, Yuji

2011-01-01

We have developed a novel nanoscale temperature-measurement method using fluorescence in the near-field called fluorescence near-field optics thermal nanoscopy (Fluor-NOTN). Fluor-NOTN enables the temperature distributions of nanoscale materials to be measured in vivo/in situ. The proposed method measures temperature by detecting the temperature dependent fluorescence lifetimes of Cd/Se quantum dots (QDs). For a high-sensitivity temperature measurement, the auto-fluorescence generated from a fiber probe should be reduced. In order to decrease the noise, we have fabricated a novel near-field optical-fiber probe by fusion-splicing a photonic crystal fiber (PCF) and a conventional single-mode fiber (SMF). The validity of the novel fiber probe was assessed experimentally by evaluating the auto-fluorescence spectra of the PCF. Due to the decrease of auto-fluorescence, a six- to ten-fold increase of S/N in the near-field fluorescence lifetime detection was achieved with the newly fabricated fusion-spliced near-field optical fiber probe. Additionally, the near-field fluorescence lifetime of the quantum dots was successfully measured by the fabricated fusion-spliced near-field optical fiber probe at room temperature, and was estimated to be 10.0 ns.

Rapid probing of photocatalytic activity on titania-based self-cleaning materials using 7-hydroxycoumarin fluorescent probe

International Nuclear Information System (INIS)

Guan Huimin; Zhu Lihua; Zhou Hehui; Tang Heqing

2008-01-01

Self-cleaning materials are widely applied, but the available methods for determining their photocatalytic activity are time consuming. A simple analysis method was proposed to evaluate rapidly the photocatalytic activity of self-cleaning materials. This method is based on monitoring of a highly fluorescent product generated by the self-cleaning materials after illumination. Under UV irradiation, holes photo-induced on the surface of self-cleaning materials can oxidize water molecules (or hydroxide ions) adsorbed on the surface to produce hydroxyl radicals, which then quantitatively oxidize coumarin to highly fluorescent 7-hydroxycoumarin. It was observed that the fluorescence intensity of photo-generated 7-hydroxycoumarin at 456 nm (excited at 346 nm) linearly increased with irradiation time, and the fluorescence intensity at a given irradiation time was linearly proportional to the photocatalytic activity of self-cleaning materials. Consequently, the photocatalytic activity of self-cleaning materials was able to be probed simply by using this new method, which requires an analysis time of 40 min, being much less than 250 min required for a dye method

Probing the graphite band structure with resonant soft-x-ray fluorescence

Energy Technology Data Exchange (ETDEWEB)

Carlisle, J.A.; Shirley, E.L.; Hudson, E.A. [Lawrence Berkeley National Lab., CA (United States)] [and others

1997-04-01

Soft x-ray fluorescence (SXF) spectroscopy using synchrotron radiation offers several advantages over surface sensitive spectroscopies for probing the electronic structure of complex multi-elemental materials. Due to the long mean free path of photons in solids ({approximately}1000 {angstrom}), SXF is a bulk-sensitive probe. Also, since core levels are involved in absorption and emission, SXF is both element- and angular-momentum-selective. SXF measures the local partial density of states (DOS) projected onto each constituent element of the material. The chief limitation of SXF has been the low fluorescence yield for photon emission, particularly for light elements. However, third generation light sources, such as the Advanced Light Source (ALS), offer the high brightness that makes high-resolution SXF experiments practical. In the following the authors utilize this high brightness to demonstrate the capability of SXF to probe the band structure of a polycrystalline sample. In SXF, a valence emission spectrum results from transitions from valence band states to the core hole produced by the incident photons. In the non-resonant energy regime, the excitation energy is far above the core binding energy, and the absorption and emission events are uncoupled. The fluorescence spectrum resembles emission spectra acquired using energetic electrons, and is insensitive to the incident photon`s energy. In the resonant excitation energy regime, core electrons are excited by photons to unoccupied states just above the Fermi level (EF). The absorption and emission events are coupled, and this coupling manifests itself in several ways, depending in part on the localization of the empty electronic states in the material. Here the authors report spectral measurements from highly oriented pyrolytic graphite.

Quantitative generalized ratiometric fluorescence spectroscopy for turbid media based on probe encapsulated by biologically localized embedding

International Nuclear Information System (INIS)

Yan, Xiu-Fang; Chen, Zeng-Ping; Cui, Yin-Yin; Hu, Yuan-Liang; Yu, Ru-Qin

2016-01-01

PEBBLE (probe encapsulated by biologically localized embedding) nanosensor encapsulating an intensity-based fluorescence indicator and an inert reference fluorescence dye inside the pores of stable matrix can be used as a generalized wavelength-ratiometric probe. However, the lack of an efficient quantitative model render the choices of inert reference dyes and intensity-based fluorescence indicators used in PEBBLEs based generalized wavelength-ratiometric probes rather limited. In this contribution, an extended quantitative fluorescence model was derived specifically for generalized wavelength-ratiometric probes based on PEBBLE technique (QFM GRP ) with a view to simplify the design of PEBBLEs and hence further extend their application potentials. The effectiveness of QFM GRP has been tested on the quantitative determination of free Ca 2+ in both simulated and real turbid media using a Ca 2+ sensitive PEBBLE nanosensor encapsulating Rhod-2 and eosin B inside the micropores of stable polyacrylamide matrix. Experimental results demonstrated that QFM GRP could realize precise and accurate quantification of free Ca 2+ in turbid samples, even though there is serious overlapping between the fluorescence excitation peaks of eosin B and Ca 2+ bound Rhod-2. The average relative predictive error value of QFM GRP for the test simulated turbid samples was 5.9%, about 2–4 times lower than the corresponding values of partial least squares calibration model and the empirical ratiometric model based on the ratio of fluorescence intensities at the excitation peaks of Ca 2+ bound Rhod-2 and eosin B. The recovery rates of QFM GRP for the real and spiked turbid samples varied from 93.1% to 101%, comparable to the corresponding results of atomic absorption spectrometry. - Highlights: • An advanced model was derived for generalized wavelength-ratiometric PEBBLEs. • The model can simplify the design of generalized wavelength-ratiometric PEBBLEs. • The model realized accurate

Comparison of N-alkyl acridine orange dyes as fluorescence probes for the determination of cardiolipin

Energy Technology Data Exchange (ETDEWEB)

Kaewsuya, P.; Miller, J.D. [Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056 (United States); Danielson, N.D. [Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056 (United States)], E-mail: danielnd@muohio.edu; Sanjeevi, J.; James, P.F. [Department of Zoology, Miami University, Oxford, OH 45056 (United States)

2008-09-26

The phospholipid (PL), cardiolipin (CL), is found almost exclusively in the inner membrane of mitochondria and loss of CL is considered as an important indication of cell apoptosis. Previously, 10-N-nonyl acridine orange (NAO) has been used as a fluorescent probe for the visualization of CL in mitochondrial cell membranes and in solution. In this work for the determination of CL, we have synthesized two new fluorescent probes, n-tetradecyl acridine orange (C14-AO), and n-octadecyl acridine orange (C18-AO) by reacting acridine orange with the corresponding n-alkyl bromide. Using excitation and emission wavelengths at about 500 and 525 nm and varying the percentage of methanol in water as the solvent, no interaction between CL and the fluorescent probes at 75% is noted but a proportional quenching of the fluorescence signal by CL is observed at 50% or less for C14-AO and 60% or less for C18-AO. Binding efficiency of these fluorescent probes to CL is compared using dye concentrations of 5, 10, and 20 {mu}M. C18-AO shows a better sensitivity than C14-AO and NAO, respectively, but is less selective. For C14-AO, the detection limit and limit of quantitation are 0.07 and 0.21 {mu}M, respectively, which are better than those previously reported for NAO. One anionic PL, phosphatidic acid, shows some quenching interference to both the C14 and C18 dyes but only at concentrations above the working range for sample analysis. The CL in mitochondrial membrane samples is determined by standard addition using C14-AO. The level of CL in the outer mitochondrial membrane compared to the inner membrane is significantly increased due to the addition of cadmium chloride into the cells causing cell apoptosis.

Amino acid detection using fluoroquinolone–Cu2+ complex as a switch-on fluorescent probe by competitive complexation without derivatization

International Nuclear Information System (INIS)

Farokhcheh, Alireza; Alizadeh, Naader

2014-01-01

In this work, we describe the use of fluoroquinolone–Cu 2+ complex as a competitive switch-on fluorescence probe for amino acid determination without derivatization. The fluorescence intensity of this probe, which has been reduced due to effective quenching by Cu 2+ ion, increases drastically by an addition of amino acid (glycine, phenylalanine, sarcosine, aspargine, alanine, proline, arginine, aspartic acid, glutamic acid, lysine, leucine and isoleucine). The overall stability constants of Cu 2+ ion complexes with amino acids were determined by fluorometric titration of fluoroquinolone-Cu 2+ complex with the amino acid solution. Furthermore, the probe shows high calibration sensitivity toward aspartic acid. The fluorescence signal depends linearly on the amino acid concentration within the range of concentration from 1.2×10 −7 to 1.1×10 −5 mol L −1 for aspartic acid. The detection limit was found 2.7×10 −8 mol L −1 with the relative standard deviation (RSD%) about 2.1% (five replicate). -- Highlights: • Amino acids are detected by using fluoroquinolone–Cu 2+ complex as fluorescent probe. • Amino acids were detected based on a competitive complexation reaction. • Probe has been able to recognize amino acids through switch-on fluorescence behavior. • Ultra-trace level of aspartic and glutamic acid is determined without derivatization

Spectroscopic quantification of 5-hydroxymethylcytosine in genomic DNA using boric acid-functionalized nano-microsphere fluorescent probes.

Science.gov (United States)

Chen, Hua-Yan; Wei, Jing-Ru; Pan, Jiong-Xiu; Zhang, Wei; Dang, Fu-Quan; Zhang, Zhi-Qi; Zhang, Jing

2017-05-15

5-hydroxymethylcytosine (5hmC) is the sixth base of DNA. It is involved in active DNA demethylation and can be a marker of diseases such as cancer. In this study, we developed a simple and sensitive 2-(4-boronophenyl)quinoline-4-carboxylic acid modified poly (glycidyl methacrylate (PBAQA-PGMA) fluorescent probe to detect the 5hmC content of genomic DNA based on T4 β-glucosyltransferase-catalyzed glucosylation of 5hmC. The fluorescence-enhanced intensity recorded from the DNA sample was proportional to its 5-hydroxymethylcytosine content and could be quantified by fluorescence spectrophotometry. The developed probe showed good detection sensitivity and selectivity and a good linear relationship between the fluorescence intensity and the concentration of 5 hmC within a 0-100nM range. Compared with other fluorescence detection methods, this method not only could determine trace amounts of 5 hmC from genomic DNA but also could eliminate the interference of fluorescent dyes and the need for purification. It also could avoid multiple labeling. Because the PBAQA-PGMA probe could enrich the content of glycosyl-5-hydroxymethyl-2-deoxycytidine from a complex ground substance, it will broaden the linear detection range and improve sensitivity. The limit of detection was calculated to be 0.167nM after enrichment. Furthermore, the method was successfully used to detect 5-hydroxymethylcytosine from mouse tissues. Copyright © 2016 Elsevier B.V. All rights reserved.

A novel NBD-based fluorescent turn-on probe for the detection of cysteine and homocysteine in living cells

Science.gov (United States)

Wang, Jiamin; Niu, Linqiang; Huang, Jing; Yan, Zhijie; Wang, Jianhong

2018-03-01

Biothiols, such as cysteine (Cys), homocysteine (Hcy) and glutathione (GSH), are involved in a number of biological processes and play crucial roles in biological systems. Thus, the detection of biothiols is highly important for early diagnosis of diseases and evaluation of disease progression. Herein, we developed a new turn-on fluorescent probe 1 based on 7-nitro-2,1,3-benzoxadiazole (NBD) with high selectivity and sensitivity for Cys/Hcy on account of nucleophilic substitution and Smiles rearrangement reaction. The probe could sense Cys/Hcy rapidly, the intensity of fluorescence increased immediately within 1 min. Furthermore, the probe is low toxic and has been successfully applied to detect intracellular Cys/Hcy by cell fluorescence imaging in living normal and cancer cells.

Molecular Imaging of β-Amyloid Plaques with Near-Infrared Boron Dipyrromethane (BODIPY-Based Fluorescent Probes

Directory of Open Access Journals (Sweden)

Hiroyuki Watanabe

2013-07-01

Full Text Available The formation of β-amyloid (Aβ plaques is a critical neurodegenerative change in Alzheimer disease (AD. We designed and synthesized novel boron dipyrromethane (BODIPY-based Aβ probes (BAPs and evaluated their utility for near-infrared fluorescence imaging of Aβ plaques in the brain. In binding experiments in vitro, BAPs showed high affinity for synthetic Aβ aggregates (Kd = 18–149 nM. Furthermore, BAPs clearly stained Aβ plaques in sections of Tg2576 mice. In mouse brain tissue, BAPs showed sufficient uptake for optical imaging. In addition, ex vivo fluorescent staining of brain sections from Tg2576 mice after the injection of BAP-2 showed selective binding of Aβ plaques with little nonspecific binding. BAPs may be useful as a near-infrared fluorescent probe for imaging Aβ plaques.

Fluorescent water-Soluble Probes Based on Ammonium Cation Peg Substituted Perylenepisimides: Synthesis, Photophysical Properties, and Live Cell Images

Science.gov (United States)

Yang, Wei; Cai, Jiaxuan; Zhang, Shuchen; Yi, Xuegang; Gao, Baoxiang

2018-01-01

To synthesize perylenbisimides (PBI) fluorescent probes that will improve the water-soluble ability and the cytocompatibility, the synthesis and properties of fluorescent water-soluble probes based on dendritic ammonium cation polyethylene glycol (PEG) substituted perylenebisimides(GPDIs) are presented. As we expected, with increased ammonium cation PEG, the aggregation of the PBI in an aqueous solution is completely suppressed by the hydrophilic ammonium cation PEG groups. And the fluorescence quantum yield increases from 25% for GPDI-1 to 62% for GPDI-2. When incubated with Hela cells for 48 h, the viabilities are 71% (for GPDI-1) and 76% (for GPDI-2). Live cell imaging shows that these probes are efficiently internalized by HeLa cells. The study of the photophysical properties indicated increasing the ammonium cation PEG generation can increase the fluorescence quantum yield. Live cell imaging shows that with the ammonium cation PEG chains of perylenebisimides has high biocompatibility. The exceptionally low cytotoxicity is ascribed to the ammonium cation PEG chains, which protect the dyes from nonspecifically interacting with the extracellular proteins. Live cell imaging shows that ammonium cations PEG chains can promote the internalization of these probes.

Determination of ATP as a fluorescence probe with europium(III)-doxycycline.

Science.gov (United States)

Hou, Faju; Wang, Xiaolei; Jiang, Chongqiu

2005-03-01

A new spectrofluorimetric method has been developed for the determination of adenosine disodium triphosphate (ATP). We studied the interactions between the doxycycline (DC)-Eu3+ complex and adenosine disodium triphosphate (ATP) by using UV-visible absorption and fluorescence spectra. Using doxycycline (DC)-Eu3+ as a fluorescence probe, under the optimum conditions, ATP could remarkably enhance the fluorescence intensity of the DC-Eu3+ complex at lambda = 612 nm. The enhanced fluorescence intensity of the Eu3+ ion was in proportion to the concentration of ATP. The optimum conditions for the determination of ATP were also investigated. The linear ranges for ATP were 1.00 x 10(-7) - 2.00 x 10(-6) mol L(-1) with detection limits of 4.07 x 10(-8) mol L(-1). This method is simple, practical and relatively free of interference from coexisting substances, and can be successfully applied to the determination of ATP in samples. The mechanism of fluorescence enhancement between the doxycycline (DC)-Eu3+ complex and ATP was also studied.

Design of mitochondria-targeted colorimetric and ratiometric fluorescent probes for rapid detection of SO2 derivatives in living cells

Science.gov (United States)

Yang, Yutao; Zhou, Tingting; Bai, Bozan; Yin, Caixia; Xu, Wenzhi; Li, Wei

2018-05-01

Two mitochondria-targeted colorimetric and ratiometric fluorescent probes for SO2 derivatives were constructed based on the SO2 derivatives-triggered Michael addition reaction. The probes exhibit high specificity toward HSO3-/SO32- by interrupting their conjugation system resulting in a large ratiometric blue shift of 46-121 nm in their emission spectrum. The two well-resolved emission bands can ensure accurate detection of HSO3-. The detection limits were calculated to be 1.09 and 1.35 μM. Importantly, probe 1 and probe 2 were successfully used to fluorescence ratiometric imaging of endogenous HSO3- in BT-474 cells.

d-PET-controlled “off-on” Polarity-sensitive Probes for Reporting Local Hydrophilicity within Lysosomes

Science.gov (United States)

Zhu, Hao; Fan, Jiangli; Mu, Huiying; Zhu, Tao; Zhang, Zhen; Du, Jianjun; Peng, Xiaojun

2016-10-01

Polarity-sensitive fluorescent probes are powerful chemical tools for studying biomolecular structures and activities both in vitro and in vivo. However, the lack of “off-on” polarity-sensing probes has limited the accurate monitoring of biological processes that involve an increase in local hydrophilicity. Here, we design and synthesize a series of “off-on” polarity-sensitive fluorescent probes BP series consisting of the difluoroboron dippyomethene (BODIPY) fluorophore connected to a quaternary ammonium moiety via different carbon linkers. All these probes showed low fluorescence quantum yields in nonpolar solution but became highly fluorescent in polar media. BP-2, which contains a two-carbon linker and a trimethyl quaternary ammonium, displayed a fluorescence intensity and quantum yield that were both linearly correlated with solvent polarity. In addition, BP-2 exhibited high sensitivity and selectivity for polarity over other environmental factors and a variety of biologically relevant species. BP-2 can be synthesized readily via an unusual Mannich reaction followed by methylation. Using electrochemistry combined with theoretical calculations, we demonstrated that the “off-on” sensing behavior of BP-2 is primarily due to the polarity-dependent donor-excited photoinduced electron transfer (d-PET) effect. Live-cell imaging established that BP-2 enables the detection of local hydrophilicity within lysosomes under conditions of lysosomal dysfunction.

A novel “Turn-On” fluorescent probe for F− detection in aqueous solution and its application in live-cell imaging

International Nuclear Information System (INIS)

Xu, Jian; Sun, Shaobo; Li, Qian; Yue, Ying; Li, Yingdong; Shao, Shijun

2014-01-01

Highlights: • A novel BODIPY-based “Turn-On” fluorescent probe was synthesized. • Highly selective detection of fluoride ions in 100% aqueous solution. • Study of sensing mechanism using density functional theory (DFT) calculations. • Fluorescent bioimaging of F − ion in A549 and ATII cells. - Abstract: A novel probe incorporating quaternized 4-pyridinium group into a BODIPY molecule was synthesized and studied for the selective detection of fluoride ions (F − ) in aqueous solution. The design was based on a fluoride-specific desilylation reaction and the “Turn-On” fluorescent response of probe 1 to F − was ascribed to the inhibition of photoinduced electron transfer (PET) process. The probe displayed many desired properties such as high specificity, appreciable solubility, desirable response time and low toxicity to mammalian cells. There was a good linearity between the fluorescence intensity and the concentrations of F − in the range of 0.1–1 mM with a detection limit of 0.02 mM. The sensing mechanism was confirmed by the NMR, electrospray ionization mass spectrum, optical spectroscopy and the mechanism of “Turn-On” fluorescent response was also determinated by a density functional theory (DFT) calculation using Gaussian 03 program. Moreover, the probe was successfully applied for the fluorescence imaging of F − in human epithelial lung cancer (A549) cells and alveolar type II (ATII) cells under physiological conditions

Dual-Color Fluorescence Imaging of Magnetic Nanoparticles in Live Cancer Cells Using Conjugated Polymer Probes

Science.gov (United States)

Sun, Minjie; Sun, Bin; Liu, Yun; Shen, Qun-Dong; Jiang, Shaojun

2016-01-01

Rapid growth in biological applications of nanomaterials brings about pressing needs for exploring nanomaterial-cell interactions. Cationic blue-emissive and anionic green-emissive conjugated polymers are applied as dual-color fluorescence probes to the surface of negatively charged magnetic nanoparticles through sequentially electrostatic adsorption. These conjugated polymers have large extinction coefficients and high fluorescence quantum yield (82% for PFN and 62% for ThPFS). Thereby, one can visualize trace amount (2.7 μg/mL) of fluorescence-labeled nanoparticles within cancer cells by confocal laser scanning microscopy. Fluorescence labeling by the conjugated polymers is also validated for quantitative determination of the internalized nanoparticles in each individual cell by flow cytometry analysis. Extensive overlap of blue and green fluorescence signals in the cytoplasm indicates that both conjugated polymer probes tightly bind to the surface of the nanoparticles during cellular internalization. The highly charged and fluorescence-labeled nanoparticles non-specifically bind to the cell membranes, followed by cellular uptake through endocytosis. The nanoparticles form aggregates inside endosomes, which yields a punctuated staining pattern. Cellular internalization of the nanoparticles is dependent on the dosage and time. Uptake efficiency can be enhanced three-fold by application of an external magnetic field. The nanoparticles are low cytotoxicity and suitable for simultaneously noninvasive fluorescence and magnetic resonance imaging application. PMID:26931282

Quinoline Fluorescent Probes for Zinc - from Diagnostic to Therapeutic Molecules in Treating Neurodegenerative Diseases.

Science.gov (United States)

Czaplinska, Barbara; Spaczynska, Ewelina; Musiol, Robert

2018-01-01

Fluorescent compounds had gained strong attention due to their wide and appealing applications. Microscopic techniques and visualization are good examples among others. Introduction of fluorescent dyes into microbiology opens the possibility to observe tissues, organisms or organelle with exceptional sensitivity and resolution. Probes for detection of biologically relevant metals as zinc, iron or copper seems to be particularly important for drug design and pharmaceutical sciences. Quinoline derivatives are well known for their good metal affinity and wide spectrum of biological activity. In this regard, molecular sensors built on this scaffold may be useful not only as analytical but also as therapeutic agents. In the present review, application of quinoline moiety in designing of novel fluorescent probes for zinc is presented and discussed. Zinc cations are relevant for vast majority of processes and recently attract a great deal of attention for their role in neurodegenerative diseases. Compounds interacting with Zn2+ may be used for early diagnosis of such disorders, for example the Alzheimer disease. Quinoline-based zinc probes may exert some beneficial role in organism acting as theranostic agents. First preliminary drugs for Alzheimer therapy that are based on quinoline moiety are good example of this trend. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Photobleaching kinetics and time-integrated emission of fluorescent probes in cellular membranes

DEFF Research Database (Denmark)

Wüstner, Daniel; Christensen, Tanja; Solanko, Lukasz Michal

2014-01-01

Since the pioneering work of Hirschfeld, it is known that time-integrated emission (TiEm) of a fluorophore is independent of fluorescence quantum yield and illumination intensity. Practical implementation of this important result for determining exact probe distribution in living cells is often h...

A quinoline-based Cu2 + ion complex fluorescence probe for selective detection of inorganic phosphate anion in aqueous solution and its application to living cells

Science.gov (United States)

Dai, Yanpeng; Wang, Peng; Fu, Jiaxin; Yao, Kun; Xu, Kuoxi; Pang, Xiaobin

2017-08-01

A quinaldine functionalized probe QP has been designed and synthesized. It exhibited selective turn-off fluorescence response toward Cu2 + ion over most of the biologically important ions at physiological pH. The binding ratio of the probe QP and Cu2 + ion was determined to be 1:1 through fluorescence titration, Job's plot and ESI-MS. The binding constant (K) of Cu2 + to probe QP was found to be 2.12 × 104 M- 1. Further, the Cu2 + ensemble of probe QP was found to respond H2PO4- and HPO42 - among other important biological anions via fluorescence turn-on response at physiological pH. Fluorescence microscopy imaging using living Hela cells showed that probe QP could be used as an effective fluorescent probe for detecting Cu2 + cation and H2PO4- and HPO42 - anions in living cells.

Fluorescence detection of glutathione and oxidized glutathione in blood with a NIR-excitable cyanine probe

Science.gov (United States)

Liu, Chang-hui; Qi, Feng-pei; Wen, Fu-bin; Long, Li-ping; Liu, Ai-juan; Yang, Rong-hua

2018-04-01

Cyanine has been widely utilized as a near infrared (NIR) fluorophore for detection of glutathione (GSH). However, the excitation of most of the reported cyanine-based probes was less than 800 nm, which inevitably induce biological background absorption and lower the sensitivity, limiting their use for detection of GSH in blood samples. To address this issue, here, a heptamethine cyanine probe (DNIR), with a NIR excitation wavelength at 804 nm and a NIR emission wavelength at 832 nm, is employed for the detection of GSH and its oxidized form (GSSG) in blood. The probe displays excellent selectivity for GSH over GSSG and other amino acids, and rapid response to GSH, in particular a good property for indirect detection of GSSG in the presence of enzyme glutathione reductase and the reducing agent nicotinamideadenine dinucleotide phosphate, without further separation prior to fluorescent measurement. To the best of our knowledge, this is the first attempt to explore NIR fluorescent approach for the simultaneous assay of GSH and GSSG in blood. As such, we expect that our fluorescence sensors with both NIR excitation and NIR emission make this strategy suitable for the application in complex physiological systems.

Determination of the activity of telomerase in cancer cells by using BSA-protected gold nanoclusters as a fluorescent probe.

Science.gov (United States)

Xu, Yujuan; Zhang, Peng; Wang, Zhen; Lv, Shaoping; Ding, Caifeng

2018-02-27

Gold nanoclusters (AuNCs) protected with a bovine serum albumin (BSA) coating are known to emit red fluorescence (peaking at 650 nm) on photoexcitation with ultraviolet light (365 nm). On addition of Cu(II) ions, fluorescence is quenched because Cu(II) complexes certain amino acid units in the BSA chain. Fluorescence is, however, restored if pyrophosphate (PPi) is added because it will chelate Cu(II) and remove it from the BSA coating on the AuNCs. Because PPi is involved in the function of telomerase, the BSA@AuNCs loaded with Cu(II) can act as a fluorescent probe for determination of the activity of telomerase. A fluorescent assay was worked out for telomerase that is highly sensitive and has a wide linear range (10 nU to 10 fM per mL). The fluorescent probe was applied to the determination of telomerase activity in cervix carcinoma cells via imaging. It is shown that tumor cells can be well distinguished from normal cells by monitoring the differences in intracellular telomerase activity. Graphical abstract Gold nanoclusters (AuNCs) protected by bovine serum albumin (BSA) and displaying red photoluminescence were prepared as fluorescent probe for the determination of telomerase activity and used for imaging of cervix carcinoma (HeLa) cells.

A spirobifluorene-based two-photon fluorescence probe for mercury ions and its applications in living cells

Energy Technology Data Exchange (ETDEWEB)

Xiao, Haibo, E-mail: xiaohb@shnu.edu.cn; Zhang, Yanzhen; Zhang, Wu; Li, Shaozhi; Tan, Jingjing; Han, Zhongying

2017-05-01

A novel spirobifluorene derivative SPF-TMS, which containing dithioacetal groups and triphenylamine units, was synthesized. The probing behaviors toward various metal ions were investigated via UV/Vis absorption spectra as well as one-photon fluorescence changes. The results indicated that SPF-TMS exhibits high sensitivity and selectivity for mercury ions. The detection limit was at least 8.6 × 10{sup −8}M, which is excellent comparing with other optical sensors for Hg{sup 2+}. When measured by two-photon excited fluorescence technique in THF at 800 nm, the two-photon cross-section of SPF-TMS is 272 GM. Especially, upon reaction with mercury species, SPF-TMS yielded another two-photon dye SPF-DA. Both SPF-TMS and SPF-DA emit strong two-photon induced fluorescence and can be applied in cell imaging by two-photon microscopy. - Highlights: • We report a spirobifluorene-based molecule as two-photon fluorescent probe with large two-photon cross-section. • The molecule has exclusive selectivity and sensitivity for mercury species. • The molecule has large two-photon emission changes before and after addition of Hg{sup 2+}. • Both the probe and the mercury ion-promoted reaction product can be applied in cell imaging by two-photon microscopy.

Synthesis of novel fluorescent probe Tb(III)-7-carboxymethoxy-4-methylcoumarin complex for sensing of DNA

International Nuclear Information System (INIS)

Hussein, Belal H.M.; Azab, Hassan A.; Fathalla, Walid; Ali, Sherin A.M.

2013-01-01

New fluorescent probe Tb(III) (7-carboxymethoxy-4-methylcoumarin)2(SCN) (C2H5OH)(H2O) was synthesized and characterized by spectroscopy and thermal analysis. The absorption and fluorescence spectra of 7-carboxymethoxy-4-methylcoumarin (CMMC) and Tb(III)–CMMC complex have been measured in different solvents. The interactions of Tb(III)–CMMC complex with calf thymus nucleic acid (CT-DNA) have been investigated using steady state fluorescence measurements. The changes in the fluorescence intensity have been used for the quantitative determination of DNA with LOD of 3.45 ng in methanol–water (9:1, v/v). The association constants of DNA with Tb(III)–CMMC complex was found to be 2.62×1010 M −1 . - Highlights: ► New fluorescent probe Terbium (III)-7-carboxy methoxy-4-methylcoumarin complex has been synthesized and characterized. ► FTIR spectrum of Tb(III)-complex shows a characteristic band for thiocyanate group. ► DNA interaction with Terbium (III)-7-carboxy methoxy-4-methylcoumarin has been studied by fluorescence techniques. ► The change in the fluorescence intensity has been used for the quantitative determination of DNA. ► The result was better than most of the well-known methods including the ethidium bromide method.

A subnanomolar fluorescent probe for protein kinase CK2 interaction studies

DEFF Research Database (Denmark)

Enkvist, Erki; Viht, Kaido; Bischoff, Nils

2012-01-01

of the functions of CK2 could be facilitated by the application of small-molecule fluorescent probes that bind to the active site of the enzyme with high affinity and selectivity. We have used a bisubstrate approach for the development of a highly potent inhibitor of CK2. 4,5,6,7-Tetrabromo-1H-benzimidazole...

Amino acid detection using fluoroquinolone–Cu{sup 2+} complex as a switch-on fluorescent probe by competitive complexation without derivatization

Energy Technology Data Exchange (ETDEWEB)

Farokhcheh, Alireza; Alizadeh, Naader, E-mail: alizaden@modares.ac.ir

2014-01-15

In this work, we describe the use of fluoroquinolone–Cu{sup 2+} complex as a competitive switch-on fluorescence probe for amino acid determination without derivatization. The fluorescence intensity of this probe, which has been reduced due to effective quenching by Cu{sup 2+} ion, increases drastically by an addition of amino acid (glycine, phenylalanine, sarcosine, aspargine, alanine, proline, arginine, aspartic acid, glutamic acid, lysine, leucine and isoleucine). The overall stability constants of Cu{sup 2+} ion complexes with amino acids were determined by fluorometric titration of fluoroquinolone-Cu{sup 2+} complex with the amino acid solution. Furthermore, the probe shows high calibration sensitivity toward aspartic acid. The fluorescence signal depends linearly on the amino acid concentration within the range of concentration from 1.2×10{sup −7} to 1.1×10{sup −5} mol L{sup −1} for aspartic acid. The detection limit was found 2.7×10{sup −8} mol L{sup −1} with the relative standard deviation (RSD%) about 2.1% (five replicate). -- Highlights: • Amino acids are detected by using fluoroquinolone–Cu{sup 2+} complex as fluorescent probe. • Amino acids were detected based on a competitive complexation reaction. • Probe has been able to recognize amino acids through switch-on fluorescence behavior. • Ultra-trace level of aspartic and glutamic acid is determined without derivatization.

Dual fluorescence excitation spectra of methyl salicylate in a free jet

Science.gov (United States)

Heimbrook, Lou Ann; Kenny, Jonathan E.; Kohler, Bryan E.; Scott, Gary W.

1981-11-01

Separate fluorescence excitation spectra of the blue- and UV-emitting forms of methyl salicylate cooled in a free-jet expansion are reported. This study represents the first observation of the detailed vibrational structure of these transitions. The two excitation spectra have no features in common, and their intensity patterns are very different. Many individual lines are ˜2 cm-1 wide (nearly laser limited), although in the excitation spectrum of the UV emission, spectral congestion persists at high energies despite the high degree of cooling. (AIP)

Synthesis of improved upconversion nanoparticles as ultrasensitive fluorescence probe for mycotoxins

Energy Technology Data Exchange (ETDEWEB)

Chen, Quansheng, E-mail: q.s.chen@hotmail.com; Hu, Weiwei; Sun, Cuicui; Li, Huanhuan; Ouyang, Qin

2016-09-28

Rare earth-doped upconversion nanoparticles (UCNPs) have promising potentials in biodetection due to their unique frequency upconverting capability and high detection sensitivity. This paper reports an improved UCNPs-based fluorescence probe for dual-sensing of Aflatoxin B1 (AFB1) and Deoxynivalenol (DON) using a magnetism-induced separation and the specific formation of antibody-targets complex. Herein, the improved UCNPs, which were namely NaYF{sub 4}:Yb/Ho/Gd and NaYF{sub 4}:Yb/Tm/Gd, were systematically studied based on the optimization of reaction time, temperature and the concentration of dopant ions with simultaneous phase and size controlled NaYF{sub 4} nanoparticles; and the targets were detected using the pattern of competitive combination assay. Under an optimized condition, the advanced fluorescent probes revealed stronger fluorescent properties, broader biological applications and better storage stabilities compared to traditional UCNPs-based ones; and ultrasensitive determinations of AFB1 and DON were achieved under a wide sensing range of 0.001–0.1 ng ml{sup −1} with the limit of detection (LOD) of 0.001 ng ml{sup −1}. Additionally, the applicability of the improved nanosensor for the detection of mycotoxins was also confirmed in adulterated oil samples. - Highlights: • Improved rare earth-doped upconversion nanoparticles were prepared with detailed optimizations. • Setup of an upconversion fluorescence spectrometer. • An advanced UCNPs-based immunosensor for dual-sensing mycotoxins was developed with a LOD of 0.001 ng ml{sup −1}. • Application of this biosensor to detect targets in real samples were confirmed with satisfied results.

Construction of an efficient two-photon fluorescent probe for imaging nitroreductase in live cells and tissues

Science.gov (United States)

Zhou, Liyi; Gong, Liang; Hu, Shunqin

2018-06-01

Compared with traditional confocal microscopy, two-photon fluorescence microscopy (TPFM), which excites a two-photon (TP) fluorophore by near-infrared light, provides improved three-dimensional image resolution with increased tissue-image depth (>500 μm) and an extended observation time. Therefore, the development of novel functional TP fluorophores has attracted great attention in recent years. Herein, a novel TP fluorophore CM-NH2, which have the donor-π-acceptor (D-π-A)-structure, was designed and synthesized. We further used this dye developed a new type of TP fluorescent probe CM-NO2 for detecting nitroreductase (NTR). Upon incubated with NTR for 15 min, CM-NO2 displayed a 90-fold fluorescence enhancement at 505 nm and the maximal TP action cross-section value after reaction was detected and calculated to be 200 GM at 760 nm. The probe exhibited excellent properties such as high sensitivity, high selectivity, low cytotoxicity, and high photostability. Moreover, the probe was utilized to image the tumor hypoxia in live HeLa cells. Finally, using the CM-NO2 to image NTR in tissues was demonstrated.

A novel pH-sensitive polymeric fluorescent probe: Synthesis, characterization and optical properties

Energy Technology Data Exchange (ETDEWEB)

Chen Dongyun; Xu Qingfeng; Xia Xuewei; Ge Jianfeng [Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Material Science, Soochow University, Suzhou, Jiangsu, 215123 (China); Lu Jianmei, E-mail: lujm@suda.edu.cn [Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Material Science, Soochow University, Suzhou, Jiangsu, 215123 (China); Li Najun, E-mail: linajun@sina.com [Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Material Science, Soochow University, Suzhou, Jiangsu, 215123 (China)

2010-04-15

A novel initiator containing proflavine derivative moiety, 3,6-dibromo-isobutyramide acridine (DIA), was synthesized and initiated the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA). A water-soluble monomer, N,N-dimethylacrylamide (DMAA) was also initiated by DIA for comparison. The obtained fluorescent polymers, PMMA-DIA and PDMAA-DIA, were characterized by {sup 1}H NMR, GPC and TGA. The emission spectra of the fluorescent polymers exhibit obvious changes in color and fluorescence intensity along with pH varied in range of 3.0-9.0. In addition, the obtained polymers present good film-forming capacity and the films also have a high quantum yield and pH response. Both oil-soluble PMMA-DIA and water-soluble PDMAA-DIA have steady optical and chemical properties by containing proflavine moiety in the main chain.

Smart near-infrared fluorescence probes with donor-acceptor structure for in vivo detection of β-amyloid deposits.

Science.gov (United States)

Cui, Mengchao; Ono, Masahiro; Watanabe, Hiroyuki; Kimura, Hiroyuki; Liu, Boli; Saji, Hideo

2014-03-05

The deposition of β-amyloid (Aβ) plaques in the parenchymal and cortical brain is accepted as the main pathological hallmark of Alzheimer's disease (AD); however, early detection of AD still presents a challenge. With the assistance of molecular imaging techniques, imaging agents specifically targeting Aβ plaques in the brain may lead to the early diagnosis of AD. Herein, we report the design, synthesis, and evaluation of a series of smart near-infrared fluorescence (NIRF) imaging probes with donor-acceptor architecture bridged by a conjugated π-electron chain for Aβ plaques. The chemical structure of these NIRF probes is completely different from Congo Red and Thioflavin-T. Probes with a longer conjugated π system (carbon-carbon double bond) displayed maximum emission in PBS (>650 nm), which falls in the best range for NIRF probes. These probes were proved to have affinity to Aβ plaques in fluorescent staining of brain sections from an AD patient and double transgenic mice, as well as in an in vitro binding assay using Aβ(1-42) aggregates. One probe with high affinity (K(i) = 37 nM, K(d) = 27 nM) was selected for in vivo imaging. It can penetrate the blood-brain barrier of nude mice efficiently and is quickly washed out of the normal brain. Moreover, after intravenous injection of this probe, 22-month-old APPswe/PSEN1 mice exhibited a higher relative signal than control mice over the same period of time, and ex vivo fluorescent observations confirmed the existence of Aβ plaques. In summary, this probe meets most of the requirements for a NIRF contrast agent for the detection of Aβ plaques both in vitro and in vivo.

A novel fluorescence probe based on triphenylamine Schiff base for bioimaging and responding to pH and Fe{sup 3+}

Energy Technology Data Exchange (ETDEWEB)

Wang, Lei; Yang, Xiaodong; Chen, Xiuli [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China); Zhou, Yuping [Guangdong Provincial key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515 (China); Lu, Xiaodan; Yan, Chenggong; Xu, Yikai [Medical Imaging Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515 (China); Liu, Ruiyuan, E-mail: ruiyliu@smu.edu.cn [Guangdong Provincial key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515 (China); Qu, Jinqing, E-mail: cejqqu@scut.edu.cn [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China)

2017-03-01

A novel fluorescence probe 1 based on triphenylamine was synthesized and characterized by NMR, IR, high resolution mass spectrometry and elemental analysis. Its fluorescence was quenched when pH below 2. There was a linear relationship between the fluorescence intensity and pH value ranged from 2 to 7. And its fluorescence emission was reversibility in acidic and alkaline solution. Furthermore, it exhibited remarkable selectivity and high sensitivity to Fe{sup 3+} and was able to detect Fe{sup 3+} in aqueous solution with low detection limit of 0.511 μM. Job plot showed that the binding stoichiometry of 1 with Fe{sup 3+} was 1:1. Further observations of {sup 1}H NMR titration suggested that coordination interaction between Fe{sup 3+} and nitrogen atom on C =N bond promoted the intramolecular charge transfer (ICT) or energy transfer process causing fluorescence quenching. Additionally, 1 was also able to be applied for detecting Fe{sup 3+} in living cell and bioimaging. - Graphical abstract: Triphenylamine based fluorescence probe can detect pH and Fe{sup 3+} simultaneously in aqueous solution and be applied for detecting Fe{sup 3+} in living cell and bioimaging. - Highlights: • The fluorescence probe is sensitive to pH in strong acid conditions. • The fluorescence chemosensor can detect pH and Fe{sup 3+} simultaneously. • The recognition is able to carry out in aqueous solution. • The probe can also be applied for detecting Fe{sup 3+} in living cell and bioimaging. • The sensor is synthesized easily with one step.

Usability of human Infinium MethylationEPIC BeadChip for mouse DNA methylation studies.

Science.gov (United States)

Needhamsen, Maria; Ewing, Ewoud; Lund, Harald; Gomez-Cabrero, David; Harris, Robert Adam; Kular, Lara; Jagodic, Maja

2017-11-15

The advent of array-based genome-wide DNA methylation methods has enabled quantitative measurement of single CpG methylation status at relatively low cost and sample input. Whereas the use of Infinium Human Methylation BeadChips has shown great utility in clinical studies, no equivalent tool is available for rodent animal samples. We examined the feasibility of using the new Infinium MethylationEPIC BeadChip for studying DNA methylation in mouse. In silico, we identified 19,420 EPIC probes (referred as mEPIC probes), which align with a unique best alignment score to the bisulfite converted reference mouse genome mm10. Further annotation revealed that 85% of mEPIC probes overlapped with mm10.refSeq genes at different genomic features including promoters (TSS1500 and TSS200), 1st exons, 5'UTRs, 3'UTRs, CpG islands, shores, shelves, open seas and FANTOM5 enhancers. Hybridization of mouse samples to Infinium Human MethylationEPIC BeadChips showed successful measurement of mEPIC probes and reproducibility between inter-array biological replicates. Finally, we demonstrated the utility of mEPIC probes for data exploration such as hierarchical clustering. Given the absence of cost and labor convenient genome-wide technologies in the murine system, our findings show that the Infinium MethylationEPIC BeadChip platform is suitable for investigation of the mouse methylome. Furthermore, we provide the "mEPICmanifest" with genomic features, available to users of Infinium Human MethylationEPIC arrays for mouse samples.

Imaging of Fluoride Ion in Living Cells and Tissues with a Two-Photon Ratiometric Fluorescence Probe

Directory of Open Access Journals (Sweden)

Xinyue Zhu

2015-01-01

Full Text Available A reaction-based two-photon (TP ratiometric fluorescence probe Z2 has been developed and successfully applied to detect and image fluoride ion in living cells and tissues. The Z2 probe was designed designed to utilize an ICT mechanism between n-butylnaphthalimide as a fluorophore and tert-butyldiphenylsilane (TBDPS as a response group. Upon addition of fluoride ion, the Si-O bond in the Z2 would be cleaved, and then a stronger electron-donating group was released. The fluorescent changes at 450 and 540 nm, respectively, made it possible to achieve ratiometric fluorescence detection. The results indicated that the Z2 could ratiometrically detect and image fluoride ion in living cells and tissues in a depth of 250 μm by two-photon microscopy (TPM.

Towards Fluorescence In Vivo Hybridization (FIVH) Detection of H. pylori in Gastric Mucosa Using Advanced LNA Probes

Science.gov (United States)

Fontenete, Sílvia; Leite, Marina; Guimarães, Nuno; Madureira, Pedro; Ferreira, Rui Manuel; Figueiredo, Céu; Wengel, Jesper; Azevedo, Nuno Filipe

2015-01-01

In recent years, there have been several attempts to improve the diagnosis of infection caused by Helicobacter pylori. Fluorescence in situ hybridization (FISH) is a commonly used technique to detect H. pylori infection but it requires biopsies from the stomach. Thus, the development of an in vivo FISH-based method (FIVH) that directly detects and allows the visualization of the bacterium within the human body would significantly reduce the time of analysis, allowing the diagnosis to be performed during endoscopy. In a previous study we designed and synthesized a phosphorothioate locked nucleic acid (LNA)/ 2’ O-methyl RNA (2’OMe) probe using standard phosphoramidite chemistry and FISH hybridization was then successfully performed both on adhered and suspended bacteria at 37°C. In this work we simplified, shortened and adapted FISH to work at gastric pH values, meaning that the hybridization step now takes only 30 minutes and, in addition to the buffer, uses only urea and probe at non-toxic concentrations. Importantly, the sensitivity and specificity of the FISH method was maintained in the range of conditions tested, even at low stringency conditions (e.g., low pH). In conclusion, this methodology is a promising approach that might be used in vivo in the future in combination with a confocal laser endomicroscope for H. pylori visualization. PMID:25915865

Towards Fluorescence In Vivo Hybridization (FIVH Detection of H. pylori in Gastric Mucosa Using Advanced LNA Probes.

Directory of Open Access Journals (Sweden)

Sílvia Fontenete

Full Text Available In recent years, there have been several attempts to improve the diagnosis of infection caused by Helicobacter pylori. Fluorescence in situ hybridization (FISH is a commonly used technique to detect H. pylori infection but it requires biopsies from the stomach. Thus, the development of an in vivo FISH-based method (FIVH that directly detects and allows the visualization of the bacterium within the human body would significantly reduce the time of analysis, allowing the diagnosis to be performed during endoscopy. In a previous study we designed and synthesized a phosphorothioate locked nucleic acid (LNA/ 2' O-methyl RNA (2'OMe probe using standard phosphoramidite chemistry and FISH hybridization was then successfully performed both on adhered and suspended bacteria at 37°C. In this work we simplified, shortened and adapted FISH to work at gastric pH values, meaning that the hybridization step now takes only 30 minutes and, in addition to the buffer, uses only urea and probe at non-toxic concentrations. Importantly, the sensitivity and specificity of the FISH method was maintained in the range of conditions tested, even at low stringency conditions (e.g., low pH. In conclusion, this methodology is a promising approach that might be used in vivo in the future in combination with a confocal laser endomicroscope for H. pylori visualization.

Thermodynamic and Kinetic Behavior of the Polystyrene/Poly(vinyl methyl ether) Blend as Studied by Excimer Fluorescence.

Science.gov (United States)

1986-01-02

AD-A±63 895 THERMODYNAMIC AND KINETIC BEHAVIOR OF THE / POLYSTYRENE/POLY(YINYL METHYL E..(U) STANFORD UNIY CALIFDEPT OF CHEMICAL ENGINEERING C N...Polystyrene/Poly(vinyl methyl ether) Blend 7. DEcFRMN 81 toOR 30USptE8 00~ as Studied by Excimer Fluorescence 6 EFRIGOG EOTNME *AUTHOR() a. CONTRACT OR GRANT...werea fondoare ihemoriisof * ~ Ex e sp fluodecositionsdu to deud Gen e and hoog Pinus Florsneis shownhase migrationprocSECURITY CLASIFICTIO OFd

Synthesis and characterization of a novel nitric oxide fluorescent probe CdS-PMMA nanocomposite via in-situ bulk polymerization.

Science.gov (United States)

Ding, Liyun; Li, Tao; Zhong, Yunming; Fan, Chao; Huang, Jun

2014-02-01

A novel nitric oxide (NO) fluorescent probe CdS-poly(methyl methacrylate) (PMMA) nanocomposites with different molar ratios of CdS quantum dots (QDs) to PMMA are developed successfully via in-situ bulk polymerization method. The optical properties of CdS/PMMA nanocomposites are studied by UV-Vis absorption spectra and fluorescence (FL) spectra in detail. It is demonstrated that the optical properties from such nanocomposite solution are tuned and stabilized by simply varying the concentration of CdS in the final product. X-ray diffraction (XRD) patterns of CdS-PMMA nanocomposite with higher loading of CdS show broad pattern for cubic CdS, which has narrow particle size distribution with less than 5 nm in PMMA observed by transmission electron microscopy (TEM). The surface morphological characterization of the CdS-PMMA nanocomposite has been done through atomic force microscopy (AFM). The thermo-gravimetric analyses (TGA) and differential scanning calorimetry (DSC) confirm the enhanced thermal stability of CdS-PMMA nanocomposites than PMMA. NO can coordinate with Cd(2+) as a ligand for transition metal complexes, which will cause a quenching effect on the fluorescence of CdS QDs. Therefore, a significant quenching effect on the fluorescence of the CdS-PMMA nanocomposite is observed in the presence of NO. The fluorescence responses are concentration-dependent and can be well described by the typical Stern-Volmer equation, and a linear calibration I0/I=1.0021+0.1944[NO] (R(2)=0.96052) is obtained in the range from 1.4×10(-5) to 9.3×10(-3) mol/L NO with a detection limit of 1.0×10(-6) mol/L (S/N=3). © 2013.

Double-labeled donor probe can enhance the signal of fluorescence resonance energy transfer (FRET) in detection of nucleic acid hybridization

Science.gov (United States)

Okamura, Yukio; Kondo, Satoshi; Sase, Ichiro; Suga, Takayuki; Mise, Kazuyuki; Furusawa, Iwao; Kawakami, Shigeki; Watanabe, Yuichiro

2000-01-01

A set of fluorescently-labeled DNA probes that hybridize with the target RNA and produce fluorescence resonance energy transfer (FRET) signals can be utilized for the detection of specific RNA. We have developed probe sets to detect and discriminate single-strand RNA molecules of plant viral genome, and sought a method to improve the FRET signals to handle in vivo applications. Consequently, we found that a double-labeled donor probe labeled with Bodipy dye yielded a remarkable increase in fluorescence intensity compared to a single-labeled donor probe used in an ordinary FRET. This double-labeled donor system can be easily applied to improve various FRET probes since the dependence upon sequence and label position in enhancement is not as strict. Furthermore this method could be applied to other nucleic acid substances, such as oligo RNA and phosphorothioate oligonucleotides (S-oligos) to enhance FRET signal. Although the double-labeled donor probes labeled with a variety of fluorophores had unexpected properties (strange UV-visible absorption spectra, decrease of intensity and decay of donor fluorescence) compared with single-labeled ones, they had no relation to FRET enhancement. This signal amplification mechanism cannot be explained simply based on our current results and knowledge of FRET. Yet it is possible to utilize this double-labeled donor system in various applications of FRET as a simple signal-enhancement method. PMID:11121494

Dual-Modal Colorimetric/Fluorescence Molecular Probe for Ratiometric Sensing of pH and Its Application.

Science.gov (United States)

Wu, Luling; Li, Xiaolin; Huang, Chusen; Jia, Nengqin

2016-08-16

As traditional pH meters cannot work well for minute regions (such as subcellular organelles) and in harsh media, molecular pH-sensitive devices for monitoring pH changes in diverse local heterogeneous environments are urgently needed. Here, we report a new dual-modal colorimetric/fluorescence merocyanine-based molecular probe (CPH) for ratiometric sensing of pH. Compared with previously reported pH probes, CPH bearing the benzyl group at the nitrogen position of the indolium group and the phenol, which is used as the acceptor for proton, could respond to pH changes immediately through both the ratiometric fluorescence signal readout and naked-eye colorimetric observation. The sensing process was highly stable and reversible. Most importantly, the suitable pKa value (6.44) allows CPH to presumably accumulate in lysosomes and become a lysosome-target fluorescent probe. By using CPH, the intralysosomal pH fluctuation stimulated by antimalaria drug chloroquine was successfully tracked in live cells through the ratiometric fluorescence images. Additionally, CPH could be immobilized on test papers, which exhibited a rapid and reversible colorimetric response to acid/base vapor through the naked-eye colorimetric analysis. This proof-of-concept study presents the potential application of CPH as a molecular tool for monitoring intralysosomal pH fluctuation in live cells, as well as paves the way for developing the economic, reusable, and fast-response optical pH meters for colorimetric sensing acid/base vapor with direct naked-eye observation.

Fluorescence enhancement of samarium complex co-doped with terbium complex in a poly(methyl methacrylate) matrix

International Nuclear Information System (INIS)

Jiu Hongfang; Zhang Lixin; Liu Guode; Fan Tao

2009-01-01

The fluorescence property of Sm(DBM) 3 phen- (DBM-dibenzoylmethide, phen-1,10-phenanthroline) and Tb(DBM) 3 phen-co-doped poly(methyl methacrylate) (PMMA) was investigated. The excitation, emission spectra and fluorescence lifetime of the co-doped samples were examined. In the co-doped samples, the luminescence intensities of Sm 3+ enhance with an increase of the Tb(DBM) 3 phen content and with a decrease of the Sm(DBM) 3 phen content. The reason for the fluorescence enhancement effect in the co-doped polymer is the intermolecular energy transfer. To give a vivid picture for this co-doped system, a model for the fluorescence enhancement of Sm(DBM) 3 phen- and Tb(DBM) 3 phen-co-doped PMMA is presented

An image fiber based fluorescent probe with associated signal processing scheme for biomedical diagnostics

International Nuclear Information System (INIS)

Vaishakh, M; Murukeshan, V M; Seah, L K

2008-01-01

A dual-modality image fiber based fluorescent probe that can be used for depth sensitive imaging and suppression of fluorescent emissions with nanosecond lifetime difference is proposed and illustrated in this paper. The system can give high optical sectioning and employs an algorithm for obtaining phase sensitive images. The system can find main application in in vivo biomedical diagnostics for detecting biochemical changes for distinguishing malignant tissue from healthy tissue

Tissue classification and diagnostics using a fiber probe for combined Raman and fluorescence spectroscopy

Science.gov (United States)

Cicchi, Riccardo; Anand, Suresh; Crisci, Alfonso; Giordano, Flavio; Rossari, Susanna; De Giorgi, Vincenzo; Maio, Vincenza; Massi, Daniela; Nesi, Gabriella; Buccoliero, Anna Maria; Guerrini, Renzo; Pimpinelli, Nicola; Pavone, Francesco S.

2015-07-01

Two different optical fiber probes for combined Raman and fluorescence spectroscopic measurements were designed, developed and used for tissue diagnostics. Two visible laser diodes were used for fluorescence spectroscopy, whereas a laser diode emitting in the NIR was used for Raman spectroscopy. The two probes were based on fiber bundles with a central multimode optical fiber, used for delivering light to the tissue, and 24 surrounding optical fibers for signal collection. Both fluorescence and Raman spectra were acquired using the same detection unit, based on a cooled CCD camera, connected to a spectrograph. The two probes were successfully employed for diagnostic purposes on various tissues in a good agreement with common routine histology. This study included skin, brain and bladder tissues and in particular the classification of: malignant melanoma against melanocytic lesions and healthy skin; urothelial carcinoma against healthy bladder mucosa; brain tumor against dysplastic brain tissue. The diagnostic capabilities were determined using a cross-validation method with a leave-one-out approach, finding very high sensitivity and specificity for all the examined tissues. The obtained results demonstrated that the multimodal approach is crucial for improving diagnostic capabilities. The system presented here can improve diagnostic capabilities on a broad range of tissues and has the potential of being used for endoscopic inspections in the near future.

Synthesis of novel fluorescent probe Tb(III)-7-carboxymethoxy-4-methylcoumarin complex for sensing of DNA

Energy Technology Data Exchange (ETDEWEB)

Hussein, Belal H.M., E-mail: belalhussein102@yahoo.com [Department of Chemistry, Faculty of Science, Suez Canal University, Ismailia (Egypt); Azab, Hassan A. [Department of Chemistry, Faculty of Science, Suez Canal University, Ismailia (Egypt); Fathalla, Walid [Department of Mathematical and Physical Sciences, Faculty of Engineering, Port-Said University, Port-Said (Egypt); Ali, Sherin A.M. [Department of Mathematical and Physical Sciences, Faculty of Engineering, Suez Canal University, Ismailia (Egypt)

2013-02-15

New fluorescent probe Tb(III) (7-carboxymethoxy-4-methylcoumarin)2(SCN) (C2H5OH)(H2O) was synthesized and characterized by spectroscopy and thermal analysis. The absorption and fluorescence spectra of 7-carboxymethoxy-4-methylcoumarin (CMMC) and Tb(III)-CMMC complex have been measured in different solvents. The interactions of Tb(III)-CMMC complex with calf thymus nucleic acid (CT-DNA) have been investigated using steady state fluorescence measurements. The changes in the fluorescence intensity have been used for the quantitative determination of DNA with LOD of 3.45 ng in methanol-water (9:1, v/v). The association constants of DNA with Tb(III)-CMMC complex was found to be 2.62 Multiplication-Sign 1010 M{sup -1}. - Highlights: Black-Right-Pointing-Pointer New fluorescent probe Terbium (III)-7-carboxy methoxy-4-methylcoumarin complex has been synthesized and characterized. Black-Right-Pointing-Pointer FTIR spectrum of Tb(III)-complex shows a characteristic band for thiocyanate group. Black-Right-Pointing-Pointer DNA interaction with Terbium (III)-7-carboxy methoxy-4-methylcoumarin has been studied by fluorescence techniques. Black-Right-Pointing-Pointer The change in the fluorescence intensity has been used for the quantitative determination of DNA. Black-Right-Pointing-Pointer The result was better than most of the well-known methods including the ethidium bromide method.

Sensitive determination of nucleic acids using organic nanoparticle fluorescence probes

Science.gov (United States)

Zhou, Yunyou; Bian, Guirong; Wang, Leyu; Dong, Ling; Wang, Lun; Kan, Jian

2005-06-01

This paper describes the preparation of organic nanoparticles by reprecipitation method under sonication and vigorous stirring. Transmission electron microscopy (TEM) was used to characterize the size and size distribution of the luminescent nanoparticles. Their average diameter was about 25 nm with a size variation of ±18%. The fluorescence decay lifetime of the nanoparticles also was determined on a self-equipped fluorospectrometer with laser light source. The lifetime (˜0.09 μs) of nanoparticles is about three times long as that of the monomer. The nanoparticles were in abundant of hydrophilic groups, which increased their miscibility in aqueous solution. These organic nanoparticles have high photochemical stability, excellent resistance to chemical degradation and photodegradation, and a good fluorescence quantum yield (25%). The fluorescence can be efficiently quenched by nucleic acids. Based on the fluorescence quenching of nanoparticles, a fluorescence quenching method was developed for determination of microamounts of nucleic acids by using the nanoparticles as a new fluorescent probe. Under optimal conditions, maximum fluorescence quenching is produced, with maximum excitation and emission wavelengths of 345 and 402 nm, respectively. Under optimal conditions, the calibration graphs are linear over the range 0.4-19.0 μg ml -1 for calf thymus DNA (ct-DNA) and 0.3-19.0 μg ml -1 for fish sperm DNA (fs-DNA). The corresponding detection limits are 0.25 μg ml -1 for ct-DNA and 0.17 μg ml -1 for fs-DNA. The relative standard deviation of six replicate measurements is 1.3-2.1%. The method is simple, rapid and sensitive with wide linear range. The recovery and relative standard deviation are very satisfactory.

In-vivo fluorescence detection of breast cancer growth factor receptors by fiber-optic probe

Science.gov (United States)

Bustamante, Gilbert; Wang, Bingzhi; DeLuna, Frank; Sun, LuZhe; Ye, Jing Yong

2018-02-01

Breast cancer treatment options often include medications that target the overexpression of growth factor receptors, such as the proto-oncogene human epidermal growth factor receptor 2 (HER2/neu) and epidermal growth factor receptor (EGFR) to suppress the abnormal growth of cancerous cells and induce cancer regression. Although effective, certain treatments are toxic to vital organs, and demand assurance that the pursued receptor is present at the tumor before administration of the drug. This requires diagnostic tools to provide tumor molecular signatures, as well as locational information. In this study, we utilized a fiber-optic probe to characterize in vivo HER2 and EGFR overexpressed tumors through the fluorescence of targeted dyes. HER2 and EGFR antibodies were conjugated with ICG-Sulfo-OSu and Alexa Fluor 680, respectively, to tag BT474 (HER2+) and MDA-MB-468 (EGFR+) tumors. The fiber was inserted into the samples via a 30-gauge needle. Different wavelengths of a supercontinuum laser were selected to couple into the fiber and excite the corresponding fluorophores in the samples. The fluorescence from the dyes was collected through the same fiber and quantified by a time-correlated single photon counter. Fluorescence at different antibody-dye concentrations was measured for calibration. Mice with subcutaneous HER2+ and/or EGFR+ tumors received intravenous injections of the conjugates and were later probed at the tumor sites. The measured fluorescence was used to distinguish between tumor types and to calculate the concentration of the antibody-dye conjugates, which were detectable at levels as low as 40 nM. The fiber-optic probe presents a minimally invasive instrument to characterize the molecular signatures of breast cancer in vivo.

Hyaluronan functionalizing QDs as turn-on fluorescent probe for targeted recognition CD44 receptor

Science.gov (United States)

Zhou, Shang; Huo, Danqun; Hou, Changjun; Yang, Mei; Fa, Huanbao

2017-09-01

The recognition of tumor markers in living cancer cells has attracted increasing interest. In the present study, the turn-on fluorescence probe was designed based on the fluorescence of thiolated chitosan-coated CdTe QDs (CdTe/TCS QDs) quenched by hyaluronan, which could provide the low background signal for sensitive cellular imaging. This system is expected to offer specific recognition of CD44 receptor over other substances owing to the specific affinity of hyaluronan and CD44 receptor ( 8-9 kcal/mol). The probe is stable in aqueous and has little toxicity to living cells; thus, it can be utilized for targeted cancer cell imaging. The living lung cancer cell imaging experiments further demonstrate its value in recognizing cell-surface CD44 receptor with turn-on mode. In addition, the probe can be used to recognize and differentiate the subtypes of lung cancer cells based on the difference of CD44 expression on the surface of lung cancer cells. And, the western blot test further confirmed that the expression level of the CD44 receptor in lung cancer cells is different. Therefore, this probe may be potentially applied in recognizing lung cancer cells with higher contrast and sensitivity and provide new tools for cancer prognosis and therapy. [Figure not available: see fulltext.

Reaction-based small-molecule fluorescent probes for dynamic detection of ROS and transient redox changes in living cells and small animals.

Science.gov (United States)

Lü, Rui

2017-09-01

Dynamic detection of transient redox changes in living cells and animals has broad implications for human health and disease diagnosis, because intracellular redox homeostasis regulated by reactive oxygen species (ROS) plays important role in cell functions, normal physiological functions and some serious human diseases (e.g., cancer, Alzheimer's disease, diabetes, etc.) usually have close relationship with the intracellular redox status. Small-molecule ROS-responsive fluorescent probes can act as powerful tools for dynamic detection of ROS and redox changes in living cells and animals through fluorescence imaging techniques; and great advances have been achieved recently in the design and synthesis of small-molecule ROS-responsive fluorescent probes. This article highlights up-to-date achievements in designing and using the reaction-based small-molecule fluorescent probes (with high sensitivity and selectivity to ROS and redox cycles) in the dynamic detection of ROS and transient redox changes in living cells and animals through fluorescence imaging. Copyright © 2017. Published by Elsevier Ltd.

A lysosome-targetable turn-on fluorescent probe for the detection of thiols in living cells based on a 1,8-naphthalimide derivative

Science.gov (United States)

Liang, Beibei; Wang, Baiyan; Ma, Qiujuan; Xie, Caixia; Li, Xian; Wang, Suiping

2018-03-01

Biological thiols, like cysteine (Cys), homocysteine (Hcy) and glutathione (GSH), play crucial roles in biological systems and in lysosomal processes. Highly selective probes for detecting biological thiols in lysomes of living cells are rare. In this work, a lysosome-targetable turn-on fluorescent probe for the detection of thiols in living cells was designed and synthesized based on a 1,8-naphthalimide derivative. The probe has a 4-(2-aminoethyl)morpholine unit as a lysosome-targetable group and an acrylate group as the thiol recognition unit as well as a fluorescence quencher. In the absence of biothiols, the probe displayed weak fluorescence due to the photoinduced electron transfer (PET) process. Upon the addition of biothiols, the probe exhibited an enhanced fluorescence emission centered at 550 nm due to cleavage of the acrylate moiety. The probe had high selectivity toward biothiols. Moreover, the probe features fast response time, excitation in the visible region and ability of working in a wide pH range. The linear response range covers a concentration range of Cys from 1.5 × 10- 7 to 1.0 × 10- 5 mol·L- 1 and the detection limit is 6.9 × 10- 8 mol·L- 1 for Cys. The probe has been successfully applied to the confocal imaging of biothiols in lysosomes of A549 cells with low cell toxicity. Furthermore, the method was successfully applied to the determination of thiols in a complex multicomponent mixture such as human serum, which suggests our proposed method has great potential for diagnostic purposes. All of such good properties prove it can be used to monitor biothiols in lysosomes of living cells and to be a good fluorescent probe for the selective detection of thiols.

Fluorescent probe for turn-on sensing of L-cysteine by ensemble of AuNCs and polymer protected AuNPs.

Science.gov (United States)

Xu, Xiaozhe; Qiao, Juan; Li, Nan; Qi, Li; Zhang, Shufeng

2015-06-16

A new fluorescent probe based on ensemble of gold nanoclusters (AuNCs) and polymer protected gold nanoparticles (AuNPs) for turn-on sensing of L-cysteine was designed and prepared. The AuNCs were protected by bovine serum albumin and had strong fluorescence. The polymer protected AuNPs were synthesized by a facile in situ strategy at room temperature and could quench the fluorescence of AuNCs due to the Förster resonance energy transfer. Interestingly, it has been observed that the quenched fluorescence of AuNCs was recovered by L-cysteine, which could induce the aggregation of polymer protected AuNPs by sulfur group. Then the prepared fluorescent probe was successfully used for determination of L-Cys in human urines, which would have an evolving aspect and promote the subsequent exploration. Copyright © 2015 Elsevier B.V. All rights reserved.

Monitoring membrane hydration with 2-(dimethylamino)-6-acylnaphtalenes fluorescent probes

DEFF Research Database (Denmark)

Bagatolli, Luis

2015-01-01

of LAURDAN and PRODAN are exquisitely sensitive to cholesterol effects, allowing interpretations that correlate changes in membrane packing with membrane hydration. Different membrane model systems as well as innate biological membranes have been studied with this family of probes allowing interesting...... comparative studies. This chapter presents a short historical overview about these fluorescent reporters, discusses on different models proposed to explain their sensitivity to membrane hydration, and includes relevant examples from experiments performed in artificial and biological membranes....

Highly selective and sensitive detection of Cu2+ with lysine enhancing bovine serum albumin modified-carbon dots fluorescent probe.

Science.gov (United States)

Liu, Jia-Ming; Lin, Li-ping; Wang, Xin-Xing; Lin, Shao-Qin; Cai, Wen-Lian; Zhang, Li-Hong; Zheng, Zhi-Yong

2012-06-07

Based on the ability of lysine (Lys) to enhance the fluorescence intensity of bovine serum albumin modified-carbon dots (CDs-BSA) to decrease surface defects and quench fluorescence of the CDs-BSA-Lys system in the presence of Cu(2+) under conditions of phosphate buffer (PBS, pH = 5.0) at 45 °C for 10 min, a sensitive Lys enhancing CDs-BSA fluorescent probe was designed. The environment-friendly, simple, rapid, selective and sensitive fluorescent probe has been utilized to detect Cu(2+) in hair and tap water samples and it achieved consistent results with those obtained by inductively coupled plasma mass spectroscopy (ICP-MS). The mechanism of the proposed assay for the detection of Cu(2+) is discussed.

Conception, synthesis and evaluation of fluorescent probes and PET radioligands for the oxytocin and vasopressin receptors

International Nuclear Information System (INIS)

Karpenko, Iuliia

2014-01-01

In order to better understand the role of OTR and AVPR in ASD, to reveal new features in its pharmacology and signaling and to establish high-throughput screening method on wild-type G protein-coupled receptors, we developed imaging probes for the oxytocin-vasopressin receptors family, namely radiotracers for positron emission tomography and optical probes for fluorescence detection and imaging. The fluorescent ligands have been used to establish TR-FRET binding assay for OTR and to initiate the development the screening assay for the wild-type oxytocin receptor. The PET radiotracers will be shortly tested in mice and monkeys to evaluate their potency in detecting the central oxytocin receptors. (author)

A highly selective turn-on fluorescent probe for Al3+ in aqueous solution based on quinoline Schiff-base

Science.gov (United States)

Huang, Peng-Cheng; Fang, Hao; Xiong, Jing-Jing; Wu, Fang-Ying

2017-06-01

A new Al3+-specific fluorescent probe NQ was designed and synthesized from 2-hydroxy-1-naphthaldehyde and 2-aminoquinoline. Upon the addition of Al3+, the fluorescent intensity of NQ was significantly enhanced compared with other examined metal ions in aqueous solution. The result of a Job’s plot indicated the formation of a 1:1 complex between the probe and Al3+, and the possible binding mode of the system between NQ and Al3+ was clarified by IR analysis and 1H NMR titration. Moreover, other metal ions examined had little effect on the detection of Al3+. The detection limit of NQ for Al3+ detection was 1.98 μM, which is lower than the level (7.4 μM) in drinking water defined by the World Health Organization. In addition, the fluorescent probe NQ could be recyclable simply through treatment with a proper reagent such as F-, and could also be used for the detection of Al3+ in real samples.

Hydrazine selective dual signaling chemodosimetric probe in physiological conditions and its application in live cells

Energy Technology Data Exchange (ETDEWEB)

Nandi, Sandip; Sahana, Animesh; Mandal, Sandip [Department of Chemistry, The University of Burdwan, Burdwan, 713104 West Bengal (India); Sengupta, Archya; Chatterjee, Ansuman [Department of Zoology, Visva Bharati University, Santiniketan, West Bengal (India); Safin, Damir A., E-mail: damir.a.safin@gmail.com [Institute of Condensed Matter and Nanosciences, Molecules, Solids and Reactivity (IMCN/MOST), Université catholique de Louvain, Place L. Pasteur 1, 1348 Louvain-la-Neuve (Belgium); Babashkina, Maria G.; Tumanov, Nikolay A.; Filinchuk, Yaroslav [Institute of Condensed Matter and Nanosciences, Molecules, Solids and Reactivity (IMCN/MOST), Université catholique de Louvain, Place L. Pasteur 1, 1348 Louvain-la-Neuve (Belgium); Das, Debasis, E-mail: ddas100in@yahoo.com [Department of Chemistry, The University of Burdwan, Burdwan, 713104 West Bengal (India)

2015-09-17

A rhodamine–cyanobenzene conjugate, (E)-4-((2-(3′,6′-bis(diethylamino)-3-oxospiro[isoindoline-1,9′-xanthene] -2-yl)ethylimino)methyl)benzonitrile (1), which structure has been elucidated by single crystal X-ray diffraction, was synthesized for selective fluorescent “turn-on” and colorimetric recognition of hydrazine at physiological pH 7.4. It was established that 1 detects hydrazine up to 58 nM. The probe is useful for the detection of intracellular hydrazine in the human breast cancer cells MCF-7 using a fluorescence microscope. Spirolactam ring opening of 1, followed by its hydrolysis, was established as a probable mechanism for the selective sensing of hydrazine. - Highlights: • A selective rhodamine–cyanobenzene conjugate is synthesized. • The conjugate is a selective dual signaling chemodosimetric probe towards hydrazine. • Spirolactam ring opening of the probe, followed by its hydrolysis, is the sensing mechanism. • The probe detects hydrazine in the human breast cancer cells MCF-7 imaging.

A novel “Turn-On” fluorescent probe for F{sup −} detection in aqueous solution and its application in live-cell imaging

Energy Technology Data Exchange (ETDEWEB)

Xu, Jian [Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Sun, Shaobo [Institute of Integrated Traditional and Western Medicine, Gansu University of Chinese Medicine, Lanzhou 730000 (China); Li, Qian; Yue, Ying [Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Li, Yingdong [Institute of Integrated Traditional and Western Medicine, Gansu University of Chinese Medicine, Lanzhou 730000 (China); Shao, Shijun, E-mail: sjshao@licp.cas.cn [Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2014-11-07

Highlights: • A novel BODIPY-based “Turn-On” fluorescent probe was synthesized. • Highly selective detection of fluoride ions in 100% aqueous solution. • Study of sensing mechanism using density functional theory (DFT) calculations. • Fluorescent bioimaging of F{sup −} ion in A549 and ATII cells. - Abstract: A novel probe incorporating quaternized 4-pyridinium group into a BODIPY molecule was synthesized and studied for the selective detection of fluoride ions (F{sup −}) in aqueous solution. The design was based on a fluoride-specific desilylation reaction and the “Turn-On” fluorescent response of probe 1 to F{sup −} was ascribed to the inhibition of photoinduced electron transfer (PET) process. The probe displayed many desired properties such as high specificity, appreciable solubility, desirable response time and low toxicity to mammalian cells. There was a good linearity between the fluorescence intensity and the concentrations of F{sup −} in the range of 0.1–1 mM with a detection limit of 0.02 mM. The sensing mechanism was confirmed by the NMR, electrospray ionization mass spectrum, optical spectroscopy and the mechanism of “Turn-On” fluorescent response was also determinated by a density functional theory (DFT) calculation using Gaussian 03 program. Moreover, the probe was successfully applied for the fluorescence imaging of F{sup −} in human epithelial lung cancer (A549) cells and alveolar type II (ATII) cells under physiological conditions.

Dual Mechanism of an Intramolecular Charge Transfer (ICT)-FRET-Based Fluorescent Probe for the Selective Detection of Hydrogen Peroxide.

Science.gov (United States)

Liang, Xiao; Xu, Xiaoyi; Qiao, Dan; Yin, Zheng; Shang, Luqing

2017-12-14

A dual-mechanism intramolecular charge transfer (ICT)-FRET fluorescent probe for the selective detection of H 2 O 2 in living cells has been designed and synthesized. This probe used a coumarin-naphthalimide hybrid as the FRET platform and a boronate moiety as the recognition group. Upon the addition of H 2 O 2 , the probe exhibited a redshifted (73 nm) fluorescence emission, and the ratio of fluorescence intensities at λ=558 and 485 nm (F 558 /F 485 ) shifted notably (up to 100-fold). Moreover, there was a good linearity (R 2 =0.9911) between the ratio and concentration of H 2 O 2 in the range of 0 to 60 μm, with a limit of detection of 0.28 μm (signal to noise ratio (S/N)=3). This probe could also detect enzymatically generated H 2 O 2 . Importantly, it could be used to visualize endogenous H 2 O 2 produced by stimulation from epidermal growth factor. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fluorescent and colorimetric molecular recognition probe for hydrogen bond acceptors.

Science.gov (United States)

Pike, Sarah J; Hunter, Christopher A

2017-11-22

The association constants for formation of 1 : 1 complexes between a H-bond donor, 1-naphthol, and a diverse range of charged and neutral H-bond acceptors have been measured using UV/vis absorption and fluorescence emission titrations. The performance of 1-naphthol as a dual colorimetric and fluorescent molecular recognition probe for determining the H-bond acceptor (HBA) parameters of charged and neutral solutes has been investigated in three solvents. The data were employed to establish self-consistent H-bond acceptor parameters (β) for benzoate, azide, chloride, thiocyanate anions, a series of phosphine oxides, phosphate ester, sulfoxide and a tertiary amide. The results demonstrate both the transferability of H-bond parameters between different solvents and the utility of the naphthol-based dual molecular recognition probe to exploit orthogonal spectroscopic techniques to determine the HBA properties of neutral and charged solutes. The benzoate anion is the strongest HBA studied with a β parameter of 15.4, and the neutral tertiary amide is the weakest H-bond acceptor investigated with a β parameter of 8.5. The H-bond acceptor strength of the azide anion is higher than that of chloride (12.8 and 12.2 respectively), and the thiocyanate anion has a β value of 10.8 and thus is a significantly weaker H-bond acceptor than both the azide and chloride anions.

A NBD-based simple but effective fluorescent pH probe for imaging of lysosomes in living cells.

Science.gov (United States)

Cao, Xiang-Jian; Chen, Li-Na; Zhang, Xuan; Liu, Jin-Ting; Chen, Ming-Yu; Wu, Qiu-Rong; Miao, Jun-Ying; Zhao, Bao-Xiang

2016-05-12

NBDlyso with lysosome-locating morpholine moiety has been developed as a high selective and sensitive fluorescent pH probe. This probe can respond to acidic pH (2.0-7.0) in a short time (less than 1 min) and not almost change after continuously illuminated for an extended period by ultraviolet light. The fluorescence intensity of NBDlyso enhanced 100-fold in acidic solution, with very good linear relationship (R(2) = 0.996). The pKa of probe NBDlyso is 4.10. Therefore, NBDlyso was used to detect lysosomal pH changes successfully. Besides, X-ray crystallography was used to verify the structure of NBDlyso, and the recognition mechanism involving photo-induced electron transfer was interpreted theoretically by means of DFT and TDDFT calculations skillfully when NBDlyso comes into play under the acidic condition. This probe showed good ability to sense pH change in living cell image. Copyright © 2016 Elsevier B.V. All rights reserved.

Beveled fiber-optic probe couples a ball lens for improving depth-resolved fluorescence measurements of layered tissue: Monte Carlo simulations

International Nuclear Information System (INIS)

Jaillon, Franck; Zheng Wei; Huang Zhiwei

2008-01-01

In this study, we evaluate the feasibility of designing a beveled fiber-optic probe coupled with a ball lens for improving depth-resolved fluorescence measurements of epithelial tissue using Monte Carlo (MC) simulations. The results show that by using the probe configuration with a beveled tip collection fiber and a flat tip excitation fiber associated with a ball lens, discrimination of fluorescence signals generated in different tissue depths is achievable. In comparison with a flat-tip collection fiber, the use of a large bevel angled collection fiber enables a better differentiation between the shallow and deep tissue layers by changing the excitation-collection fiber separations. This work suggests that the beveled fiber-optic probe coupled with a ball lens has the potential to facilitate depth-resolved fluorescence measurements of epithelial tissues

NONINVASIVE OPTICAL IMAGING OF STAPHYLOCOCCUS AUREUS INFECTION IN VIVO USING AN ANTIMICROBIAL PEPTIDE FRAGMENT BASED NEAR-INFRARED FLUORESCENT PROBES

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CUICUI LIU

2013-07-01

Full Text Available The diagnosis of bacterial infections remains a major challenge in medicine. Optical imaging of bacterial infection in living animals is usually conducted with genetic reporters such as light-emitting enzymes or fluorescent proteins. However, there are many circumstances where genetic reporters are not applicable, and there is an urgent need for exogenous synthetic probes that can selectively target bacteria. Optical imaging of bacteria in vivo is much less developed than methods such as radioimaging and MRI. Furthermore near-infrared (NIR dyes with emission wavelengths in the region of 650–900 nm can propagate through two or more centimeters of tissue and may enable deeper tissue imaging if sensitive detection techniques are employed. Here we constructed an antimicrobial peptide fragment UBI29-41-based near-infrared fluorescent imaging probe. The probe is composed of UBI29-41 conjugated to a near infrared dye ICG-Der-02. UBI29-41 is a cationic antimicrobial peptide that targets the anionic surfaces of bacterial cells. The probe allows detection of Staphylococcus aureus infection (5 × 107 cells in a mouse local infection model using whole animal near-infrared fluorescence imaging. Furthermore, we demonstrate that the UBI29-41-based imaging probe can selectively accumulate within bacteria. The significantly higher accumulation in bacterial infection suggests that UBI29-41-based imaging probe may be a promising imaging agent to detect bacterial infections.

Excited state hydrogen bonding fluorescent probe: Role of structure and environment

Energy Technology Data Exchange (ETDEWEB)

Dey, Debarati, E-mail: debaratidey07@gmail.com [Department of Chemistry, Vidyasagar College, 39 Sankar Ghosh Lane, Kolkata 700006 (India); Sarangi, Manas Kumar [Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India); Ray, Angana; Bhattacharyya, Dhananjay [Computational Science Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India); Maity, Dilip Kumar [Department of Chemistry, University College of Science and Technology, 92 A.P.C. Road, Kolkata 700009 (India)

2016-05-15

An environment sensitive fluorescent probe, 11-benzoyl-dibenzo[a,c]phenazine (BDBPZ), has been synthesized and characterized that acts via excited state hydrogen bonding (ESHB). On interaction with hydrogen bond donating solvents the fluorescence intensity of BDBPZ increases abruptly with a concomitant bathochromic shift. The extent of fluorescence increment and the red-shift of λ{sub max} depend on hydrogen bond donating ability of the solvent associated. ESHB restricts the free rotation of the benzoyl group and hence blocks the non-radiative deactivation pathway. BDBPZ forms an exciplex with organic amine in nonpolar medium that readily disappears on increasing the polarity of the solvent. In polar environment the fluorescence of both the free molecule and excited state hydrogen bonded species are quenched on addition of amine unlike its parent dibenzo[a,c]phenazine (DBPZ), that remains very much inaccessible towards the solvent as well as quencher molecules due to its structure. This newly synthesized derivative BDBPZ is much more interactive due to the benzoyl group that is flanked outside the skeletal aromatic rings of DBPZ, which helps to sense the environment properly and thus shows better ESHB capacity than DBPZ.

Label-free fluorescence strategy for sensitive detection of adenosine triphosphate using a loop DNA probe with low background noise.

Science.gov (United States)

Lin, Chunshui; Cai, Zhixiong; Wang, Yiru; Zhu, Zhi; Yang, Chaoyong James; Chen, Xi

2014-07-15

A simple, rapid, label-free, and ultrasensitive fluorescence strategy for adenosine triphosphate (ATP) detection was developed using a loop DNA probe with low background noise. In this strategy, a loop DNA probe, which is the substrate for both ligation and digestion enzyme reaction, was designed. SYBR green I (SG I), a double-stranded specific dye, was applied for the readout fluorescence signal. Exonuclease I (Exo I) and exonuclease III (Exo III), sequence-independent nucleases, were selected to digest the loop DNA probe in order to minimize the background fluorescence signal. As a result, in the absence of ATP, the loop DNA was completely digested by Exo I and Exo III, leading to low background fluorescence owing to the weak electrostatic interaction between SG I and mononucleotides. On the other hand, ATP induced the ligation of the nicking site, and the sealed loop DNA resisted the digestion of Exo I and ExoIII, resulting in a remarkable increase of fluorescence response. Upon background noise reduction, the sensitivity of the ATP determination was improved significantly, and the detection limitation was found to be 1.2 pM, which is much lower than that in almost all the previously reported methods. This strategy has promise for wide application in the determination of ATP.

Real-Time Tracking the Synthesis and Degradation of Albumin in Complex Biological Systems with a near-Infrared Fluorescent Probe.

Science.gov (United States)

Jin, Qiang; Feng, Lei; Zhang, Shui-Jun; Wang, Dan-Dan; Wang, Fang-Jun; Zhang, Yi; Cui, Jing-Nan; Guo, Wen-Zhi; Ge, Guang-Bo; Yang, Ling

2017-09-19

In this study, a novel fluorescent detection system for biological sensing of human albumin (HA) was developed on the basis of the pseudoesterase activity and substrate preference of HA. The designed near-infrared (NIR) fluorescent probe (DDAP) could be effectively hydrolyzed by HA, accompanied by significant changes in both color and fluorescence spectrum. The sensing mechanism was fully investigated by fluorescence spectroscopy, NMR, and mass spectra. DDAP exhibited excellent selectivity and sensitivity toward HA over a variety of human plasma proteins, hydrolases, and abundant biomolecules found in human body. The probe has been successfully applied to measure native HA in diluted plasma samples and the secreted HA in the hepatocyte culture supernatant. DDAP has also been used for fluorescence imaging of HA reabsorption in living renal cells, and the results show that the probe exhibits good cell permeability, low cytotoxicity and high imaging resolution. Furthermore, DDAP has been successfully used for real-time tracking the uptaking and degradation of albumin in ex vivo mouse kidney models for the first time. All these results clearly demonstrated that DDAP-based assay held great promise for real-time sensing and tracking HA in complex biological systems, which would be very useful for basic researches and clinical diagnosis of HA-associated diseases.

A ratiometric fluorescent probe based on boron dipyrromethene and rhodamine Förster resonance energy transfer platform for hypochlorous acid and its application in living cells

International Nuclear Information System (INIS)

Liu, Ying; Zhao, Zhi-Min; Miao, Jun-Ying; Zhao, Bao-Xiang

2016-01-01

We have developed a ratiometric fluorescent probe BRT based on boron dipyrromethene (BODIPY) and rhodamine-thiohydrazide Förster resonance energy transfer (FRET) platform for sensing hypochlorous acid (HOCl) with high selectivity and sensitivity. The probe can detect HOCl in 15 s with the detection limit of 38 nM. Upon mixing with HOCl the fluorescence colour of probe BRT changed from green to orange. Moreover, probe BRT was applied to successfully monitor HOCl in living RAW 264.7 cells. - Highlights: • A probe based on BODIPY and rhodamine was developed for sensing HOCl. • The probe could sense HOCl in a ratiometric manner based on the FRET platform in PBS buffer solution. • The probe can detect HOCl in 15 s accompanied with a fluorescence colour change. • This probe was successfully used to monitor HOCl in living RAW 264.7 cells.

Synthesis of strongly fluorescent carbon quantum dots modified with polyamidoamine and a triethoxysilane as quenchable fluorescent probes for mercury(II)

International Nuclear Information System (INIS)

Tang, Wenjie; Wang, Yan; Wang, Panpan; Di, Junwei; Wu, Ying; Yang, Jianping

2016-01-01

This article reports on the synthesis of water dispersible carbon quantum dots (CDs) by a one-step hydrothermal method using polyamidoamine (PAMAM) and (3-aminopropyl)triethoxysilane (APTES) as a platform and passivant. The resulting CDs are highly uniform and finely dispersed. The synergistic effect between PAMAM and APTES on the surface of the CDs results in a fluorescence that is much brighter than that of CDs modified with either APTES or PAMAM only. The fluorescence of the co-modified CDs is quenched by Hg(II) ions at fairly low concentrations. Under the optimum conditions, the intensity of quenched fluorescence drops with Hg(II) concentration in the range from 0.2 nM to 10 μM, and the detection limit is 87 fM. The effect of potentially interfering cations on the fluorescence revealed a high selectivity for Hg 2+ . The fluorescent probe was applied to the determination of Hg(II) in (spiked) waters and milk and gave recoveries between 95.6 and 107 %, with relative standard deviation between 4.4 and 6.0 %. (author)

A novel water-soluble 1,8-naphthalimide as a fluorescent pH-probe and a molecular logic circuit

International Nuclear Information System (INIS)

Georgiev, Nikolai I.; Dimitrova, Margarita D.; Krasteva, Paoleta V.; Bojinov, Vladimir B.

2017-01-01

A novel highly water-soluble fluorescence sensing 1,8-naphthalimide is synthesized and investigated. The novel compound is designed on the “fluorophore-receptor 1 -spacer-receptor 2 ” model as a molecular fluorescence probe for determination of ions in 100% aqueous media. The novel probe comprising hydrazide and N-methylpiperazine substituents is capable of operating simultaneously via ICT and PET signaling mechanism and of recognizing selectively protons and hydroxyl anions over the representative metal ions and anions. Due to the remarkable fluorescence changes as a function of pH the system is able to act as a three output combinatorial logic circuit with two chemical inputs. Two INHIBIT gates in fluorescence and absorption mode as well as an IMPLICATION logic gate are obtained. Because of the parallel action of both INHIBIT gates a magnitude digital comparator is achieved for the first time in this way.

CdTe/ZnS quantum dots as fluorescent probes for ammonium determination.

Science.gov (United States)

Yi, Kui-Yu

2016-06-01

Novel CdTe/ZnS quantum dot (QD) probes based on the quenching effect were proposed for the simple, rapid, and specific determination of ammonium in aqueous solutions. The QDs were modified using 3-mercaptopropionic acid, and the fluorescence responses of the CdTe/ZnS QD probes to ammonium were detected through regularity quenching. The quenching levels of the CdTe/ZnS QDs and ammonium concentration showed a good linear relationship between 4.0 × 10(-6) and 5.0 × 10(-4) mol/L; the detection limit was 3.0 × 10(-7) mol/L. Ammonium contents in synthetic explosion soil samples were measured to determine the practical applications of the QD probes and a probable quenching mechanism was described. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Preparation of a Two-Photon Fluorescent Probe for Imaging H2O2 in Lysosomes in Living Cells and Tissues.

Science.gov (United States)

Ren, Mingguang; Deng, Beibei; Kong, Xiuqi; Tang, Yonghe; Lin, Weiying

2017-01-01

Hydrogen peroxide (H 2 O 2 ) plays important roles in many physiological and pathological processes. At the cellular organelle level, the abnormal concentrations of H 2 O 2 in the lysosomes may cause redox imbalance and the loss of the critical functions of the lysosomes. Herein, we describe the preparation of a potent lysosome-targeted two-photon fluorescent probe (Lyso-HP) for the detection of H 2 O 2 in the lysosomes in the living cells. This unique fluorescent probe can also be employed to effectively detect H 2 O 2 in the living tissues using two-photon fluorescence microscopy.

Multiplex fluorescence melting curve analysis for mutation detection with dual-labeled, self-quenched probes.

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Qiuying Huang

2011-04-01

Full Text Available Probe-based fluorescence melting curve analysis (FMCA is a powerful tool for mutation detection based on melting temperature generated by thermal denaturation of the probe-target hybrid. Nevertheless, the color multiplexing, probe design, and cross-platform compatibility remain to be limited by using existing probe chemistries. We hereby explored two dual-labeled, self-quenched probes, TaqMan and shared-stem molecular beacons, in their ability to conduct FMCA. Both probes could be directly used for FMCA and readily integrated with closed-tube amplicon hybridization under asymmetric PCR conditions. Improved flexibility of FMCA by using these probes was illustrated in three representative applications of FMCA: mutation scanning, mutation identification and mutation genotyping, all of which achieved improved color-multiplexing with easy probe design and versatile probe combination and all were validated with a large number of real clinical samples. The universal cross-platform compatibility of these probes-based FMCA was also demonstrated by a 4-color mutation genotyping assay performed on five different real-time PCR instruments. The dual-labeled, self-quenched probes offered unprecedented combined advantage of enhanced multiplexing, improved flexibility in probe design, and expanded cross-platform compatibility, which would substantially improve FMCA in mutation detection of various applications.

Blue emitting copper nanoclusters as colorimetric and fluorescent probe for the selective detection of bilirubin

Science.gov (United States)

R. S., Aparna; J. S., Anjali Devi; John, Nebu; Abha, K.; S. S., Syamchand; George, Sony

2018-06-01

Hurdles to develop point of care diagnostic methods restrict the translation of progress in the health care sector from bench side to bedside. In this article a simple, cost effective fluorescent as well as colorimetric nanosensor was developed for the early and easy detection of hyperbilirubinemia. A stable, water soluble bovine serum albumin stabilised copper nanocluster (BSA CuNC) was used as the fluorescent probe which exhibited strong blue emission (404 nm) upon 330 nm excitation. The fluorescence of the BSA CuNC can be effectively quenched by the addition of bilirubin by the formation of copper-bilirubin complex. Meanwhile the copper-bilirubin complex resulted in an observable colour change from pale violet to green facilitating colorimetric detection. The prepared sensor displayed good selectivity and sensitivity over other co-existing molecules, and can be used for quantifying bilirubin with a detection limit down to 257 fM. Additionally, the as-prepared probe was coated on a paper strip to develop a portable paper strip sensor of bilirubin. Moreover, the method was successfully applied in real sample analysis and obtained promising result.

Turn-on Fluorescent Probe for Exogenous and Endogenous Imaging of Hypochlorous Acid in Living Cells and Quantitative Application in Flow Cytometry.

Science.gov (United States)

Zhan, Zixuan; Liu, Rui; Chai, Li; Li, Qiuyan; Zhang, Kexin; Lv, Yi

2017-09-05

Hypochlorous acid (HClO) acts as a dominant microbicidal mediator in the natural immune system, and the excess production of hypochlorites is related to a series of diseases. Thus, it is vitally important and necessary to develop a highly sensitive and selective method for HClO detection in living systems, and most of fluorescent probes are mainly focused on cells imaging. Besides, accurate HClO quantitative information about individual cells in a large cell population is extremely important for understanding inflammation and cellular apoptosis as well. In our work, a turn-on fluorescent probe has been synthesized, which can selectively and sensitively detect HClO with fast response time. The probe is almost nonfluorescent possibly due to both the spirolactam form of fluorescein and unbridged C═N bonds which can undergo a nonradiative decay process in the excited state. Upon the addition of ClO - , the probe was oxidized to ring-opened fluorescent form and the fluorescence intensity was greatly enhanced. In live cell experiments, the probe was successfully applied to image exogenous ClO - in HeLa cells and endogenous HClO in RAW 264.7 macrophage cells. In particular, the quantitative information on exogenous and endogenous HClO can also be acquired in flow cytometry. Therefore, the probe not only can image exogenous and endogenous HClO but also provides a new and promising platform to quantitatively detect HClO in flow cytometry.

A Conjugate of Pentamethine Cyanine and 18F as a Positron Emission Tomography/Near-Infrared Fluorescence Probe for Multimodality Tumor Imaging

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Fei-Fei An

2017-06-01

Full Text Available The novel synthesis of a dual-modality, pentamethine cyanine (Cy5 fluorescent, 18F positron emission tomography (PET imaging probe is reported. The probe shows a large extinction coefficient and large quantum yield in the biologically transparent, near-infrared window (650–900 nm for in vivo fluorescent imaging. This fluorophore bears the isotope, 18F, giving a 18F-PET/near-infrared fluorescent (NIRF, bi-modal imaging probe, that combines the long-term stability of NIRF and the unlimited penetration depth of PET imaging. The bi-modal probe is labeled with 18F in a quick, one-step reaction, which is important in working with the rapid decay of 18F. The bi-modal probe bears a free carboxyl group, highlighting a PET/NIRF synthon that can be conjugated onto many advanced biomolecules for biomarker-specific in vivo dual-modal PET/NIR tumor imaging, confocal histology, and utility in multi-fluorophore, fluorescence-guided surgery. Its potential in vivo biocompatibility is explored in a quick proof-of-principal in vivo study. The dye is delivered to A549 xenograft flank-tumors to generate PET and NIRF signals at the tumor site. The tumor distribution is confirmed in ex vivo gamma counting and imaging. Pentamethine cyanine (Cy5 has the ability to preferentially accumulate in tumor xenografts. We substitute the PET/NIRF probe for Cy5, and explore this phenomenon.

Calix[2]pyreno[2]pyrrole as a Fluorescence Chemical Probe for Polynitroaromatics

International Nuclear Information System (INIS)

Park, Kyung Hwa; Yoo, Jae Duk; Lee, Chang Hee; Ka, Jae Won

2012-01-01

We have demonstrated that the new, readily synthesized and well characterized calix pyreno pyrrole fluorescence molecular probe can detect polynitroaromatic compounds with high affinity. In addition, this highly fluorescent neutral molecular receptor also exhibits enhanced binding affinity towards TNT which is associated with the formation of a pi-complex. The dynamic nature of the current system may enable it to serve as an excellent scaffold for electron-deficient guest molecular binding. Studies for other neutral molecules including metal ions are under in active progress. The elevated selectivity and sensitivity for specific analytes are the core requirements for an ideal chemical probes. A signal induced by guest binding must be sensitive enough so that accurate real time monitoring could be satisfactorily achieved. Introduction of signaling units at suitable places in which they can directly interact with the recognition events is critical in designing chemosensors. Among various signaling events, fluorescence changes are often applied for the sensitive detection of various analytes. An easy modulation of the photochemical properties of the signaling units is an additional advantage in compatibility and applications. Chemosensors for the detection of explosives becomes important due to their immediate applications in remedation of explosive manufacturing sites, homeland security or forensic sciences. With that in mind, numerous methods for the explosive detection have been reported in recent years. Nevertheless, some detection methods sometimes require sophisticated instrumentation which is not easy for on-site testing

Development of tumor-targeted near infrared probes for fluorescence guided surgery.

Science.gov (United States)

Kelderhouse, Lindsay E; Chelvam, Venkatesh; Wayua, Charity; Mahalingam, Sakkarapalayam; Poh, Scott; Kularatne, Sumith A; Low, Philip S

2013-06-19

Complete surgical resection of malignant disease is the only reliable method to cure cancer. Unfortunately, quantitative tumor resection is often limited by a surgeon's ability to locate all malignant disease and distinguish it from healthy tissue. Fluorescence-guided surgery has emerged as a tool to aid surgeons in the identification and removal of malignant lesions. While nontargeted fluorescent dyes have been shown to passively accumulate in some tumors, the resulting tumor-to-background ratios are often poor, and the boundaries between malignant and healthy tissues can be difficult to define. To circumvent these problems, our laboratory has developed high affinity tumor targeting ligands that bind to receptors that are overexpressed on cancer cells and deliver attached molecules selectively into these cells. In this study, we explore the use of two tumor-specific targeting ligands (i.e., folic acid that targets the folate receptor (FR) and DUPA that targets prostate specific membrane antigen (PSMA)) to deliver near-infrared (NIR) fluorescent dyes specifically to FR and PSMA expressing cancers, thereby rendering only the malignant cells highly fluorescent. We report here that all FR- and PSMA-targeted NIR probes examined bind cultured cancer cells in the low nanomolar range. Moreover, upon intravenous injection into tumor-bearing mice with metastatic disease, these same ligand-NIR dye conjugates render receptor-expressing tumor tissues fluorescent, enabling their facile resection with minimal contamination from healthy tissues.

Cellular Activation of the Self-Quenched Fluorescent Reporter Probe in Tumor Microenvironment

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Alexei A. Bogdanov, Jr.

2002-01-01

Full Text Available The effect of intralysosomal proteolysis of near-infrared fluorescent (NIRF self-quenched macromolecular probe (PGC-Cy5.5 has been previously reported and used for tumor imaging. Here we demonstrate that proteolysis can be detected noninvasively in vivo at the cellular level. A codetection of GFP fluorescence (using two-photon excitation and NIRF was performed in tumor-bearing animals injected with PGC-Cy5.5. In vivo microscopy of tumor cells in subdermal tissue layers (up to 160 μm showed a strong Cy5.5 dequenching effect in GFP-negative cells. This observation was corroborated by flow cytometry, sorting, and reverse transcription polymerase chain reaction analysis of tumor-isolated cells. Both GFP-positive (81% total and GFP-negative (19% total populations contained Cy5.5-positive cells. The GFP-negative cells were confirmed to be host mouse cells by the absence of rat cathepsin mRNA signal. The subfraction of GFPnegative cells (2.5-3.0% had seven times higher NIRF intensity than the majority of GFP-positive or GFPnegative cells (372 and 55 AU, respectively. Highly NIRF-positive, FP-negative cells were CD45-and MAC3-positive. Our results indicate that: 1 intracellular proteolysis can be imaged in vivo at the cellular level using cathepsin-sensitive probes; 2 tumor-recruited cells of hematopoetic origin participate most actively in uptake and degradation of long-circulating macromolecular probes.

Rational design of reversible fluorescent probes for live-cell imaging and quantification of fast glutathione dynamics

Science.gov (United States)

Umezawa, Keitaro; Yoshida, Masafumi; Kamiya, Mako; Yamasoba, Tatsuya; Urano, Yasuteru

2017-03-01

Alterations in glutathione (GSH) homeostasis are associated with a variety of diseases and cellular functions, and therefore, real-time live-cell imaging and quantification of GSH dynamics are important for understanding pathophysiological processes. However, existing fluorescent probes are unsuitable for these purposes due to their irreversible fluorogenic mechanisms or slow reaction rates. In this work, we have successfully overcome these problems by establishing a design strategy inspired by Mayr's work on nucleophilic reaction kinetics. The synthesized probes exhibit concentration-dependent, reversible and rapid absorption/fluorescence changes (t1/2 = 620 ms at [GSH] = 1 mM), as well as appropriate Kd values (1-10 mM: within the range of intracellular GSH concentrations). We also developed FRET-based ratiometric probes, and demonstrated that they are useful for quantifying GSH concentration in various cell types and also for real-time live-cell imaging of GSH dynamics with temporal resolution of seconds.

Mass amplifying probe for sensitive fluorescence anisotropy detection of small molecules in complex biological samples.

Science.gov (United States)

Cui, Liang; Zou, Yuan; Lin, Ninghang; Zhu, Zhi; Jenkins, Gareth; Yang, Chaoyong James

2012-07-03

Fluorescence anisotropy (FA) is a reliable and excellent choice for fluorescence sensing. One of the key factors influencing the FA value for any molecule is the molar mass of the molecule being measured. As a result, the FA method with functional nucleic acid aptamers has been limited to macromolecules such as proteins and is generally not applicable for the analysis of small molecules because their molecular masses are relatively too small to produce observable FA value changes. We report here a molecular mass amplifying strategy to construct anisotropy aptamer probes for small molecules. The probe is designed in such a way that only when a target molecule binds to the probe does it activate its binding ability to an anisotropy amplifier (a high molecular mass molecule such as protein), thus significantly increasing the molecular mass and FA value of the probe/target complex. Specifically, a mass amplifying probe (MAP) consists of a targeting aptamer domain against a target molecule and molecular mass amplifying aptamer domain for the amplifier protein. The probe is initially rendered inactive by a small blocking strand partially complementary to both target aptamer and amplifier protein aptamer so that the mass amplifying aptamer domain would not bind to the amplifier protein unless the probe has been activated by the target. In this way, we prepared two probes that constitute a target (ATP and cocaine respectively) aptamer, a thrombin (as the mass amplifier) aptamer, and a fluorophore. Both probes worked well against their corresponding small molecule targets, and the detection limits for ATP and cocaine were 0.5 μM and 0.8 μM, respectively. More importantly, because FA is less affected by environmental interferences, ATP in cell media and cocaine in urine were directly detected without any tedious sample pretreatment. Our results established that our molecular mass amplifying strategy can be used to design aptamer probes for rapid, sensitive, and selective

[Sentinel node detection using optonuclear probe (gamma and fluorescence) after green indocyanine and radio-isotope injections].

Science.gov (United States)

Poumellec, M-A; Dejode, M; Figl, A; Darcourt, J; Haudebourg, J; Sabah, Y; Voury, A; Martaens, A; Barranger, E

2016-04-01

Assess the biopsy's feasibility of the sentinel lymph node biopsy (SLNB) using optonuclear probe after of indocyanine green (ICG) and radio-isotope (RI) injections. Twenty-one patients with a localized breast cancer and unsuspicious axillary nodes underwent a SLNB after both injections of ICG and radio-isotope. One or more SLN were identified on the 21 patients (identification rate of 100%). The median number SLN was 2 (1-3). Twenty SLN were both radio-actives and fluorescents (54.1%), 11 fluorescent only (29.7%) and 6 were only radio-actives (16.2%). Seven patients had a metastatic SLN (8 SLN overall). Among them, only one had a micrometastasic SLN, 5 others had a macrometastatic SLN and one patient had two macrometastatic SLNs. Among the 8 metastatic SLN, 5 were both fluorescent and radioactive, 2 were only fluorescent and 1 was only radioactive. Detection SLN using optonuclear probe after indocyanine green and radio-isotope injections is effective and could be, after validation by randomized trial, a reliable alternative to the blue dye injection for teams who consider that combined detection as the reference. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Synthesis and characterization of a novel nitric oxide fluorescent probe CdS-PMMA nanocomposite via in-situ bulk polymerization

Energy Technology Data Exchange (ETDEWEB)

Ding, Liyun, E-mail: dlyw@whut.edu.cn; Li, Tao; Zhong, Yunming; Fan, Chao; Huang, Jun

2014-02-01

A novel nitric oxide (NO) fluorescent probe CdS-poly(methyl methacrylate) (PMMA) nanocomposites with different molar ratios of CdS quantum dots (QDs) to PMMA are developed successfully via in-situ bulk polymerization method. The optical properties of CdS/PMMA nanocomposites are studied by UV–Vis absorption spectra and fluorescence (FL) spectra in detail. It is demonstrated that the optical properties from such nanocomposite solution are tuned and stabilized by simply varying the concentration of CdS in the final product. X-ray diffraction (XRD) patterns of CdS-PMMA nanocomposite with higher loading of CdS show broad pattern for cubic CdS, which has narrow particle size distribution with less than 5 nm in PMMA observed by transmission electron microscopy (TEM). The surface morphological characterization of the CdS-PMMA nanocomposite has been done through atomic force microscopy (AFM). The thermo-gravimetric analyses (TGA) and differential scanning calorimetry (DSC) confirm the enhanced thermal stability of CdS-PMMA nanocomposites than PMMA. NO can coordinate with Cd{sup 2+} as a ligand for transition metal complexes, which will cause a quenching effect on the fluorescence of CdS QDs. Therefore, a significant quenching effect on the fluorescence of the CdS-PMMA nanocomposite is observed in the presence of NO. The fluorescence responses are concentration-dependent and can be well described by the typical Stern–Volmer equation, and a linear calibration I{sub 0}/I = 1.0021 + 0.1944[NO] (R{sup 2} = 0.96052) is obtained in the range from 1.4 × 10{sup −5} to 9.3 × 10{sup −3} mol/L NO with a detection limit of 1.0 × 10{sup −6} mol/L (S/N = 3). - Highlights: • CdS-PMMA nanocomposite was developed by in-situ bulk polymerization for NO detection. • The fluorescence quenching mechanism relies on the interaction between NO and Cd{sup 2+}. • The fluorescence response shows a good linear reproducibility with NO concentrations. • A linear calibration is

Synthesis and characterization of a novel nitric oxide fluorescent probe CdS-PMMA nanocomposite via in-situ bulk polymerization

International Nuclear Information System (INIS)

Ding, Liyun; Li, Tao; Zhong, Yunming; Fan, Chao; Huang, Jun

2014-01-01

A novel nitric oxide (NO) fluorescent probe CdS-poly(methyl methacrylate) (PMMA) nanocomposites with different molar ratios of CdS quantum dots (QDs) to PMMA are developed successfully via in-situ bulk polymerization method. The optical properties of CdS/PMMA nanocomposites are studied by UV–Vis absorption spectra and fluorescence (FL) spectra in detail. It is demonstrated that the optical properties from such nanocomposite solution are tuned and stabilized by simply varying the concentration of CdS in the final product. X-ray diffraction (XRD) patterns of CdS-PMMA nanocomposite with higher loading of CdS show broad pattern for cubic CdS, which has narrow particle size distribution with less than 5 nm in PMMA observed by transmission electron microscopy (TEM). The surface morphological characterization of the CdS-PMMA nanocomposite has been done through atomic force microscopy (AFM). The thermo-gravimetric analyses (TGA) and differential scanning calorimetry (DSC) confirm the enhanced thermal stability of CdS-PMMA nanocomposites than PMMA. NO can coordinate with Cd 2+ as a ligand for transition metal complexes, which will cause a quenching effect on the fluorescence of CdS QDs. Therefore, a significant quenching effect on the fluorescence of the CdS-PMMA nanocomposite is observed in the presence of NO. The fluorescence responses are concentration-dependent and can be well described by the typical Stern–Volmer equation, and a linear calibration I 0 /I = 1.0021 + 0.1944[NO] (R 2 = 0.96052) is obtained in the range from 1.4 × 10 −5 to 9.3 × 10 −3 mol/L NO with a detection limit of 1.0 × 10 −6 mol/L (S/N = 3). - Highlights: • CdS-PMMA nanocomposite was developed by in-situ bulk polymerization for NO detection. • The fluorescence quenching mechanism relies on the interaction between NO and Cd 2+ . • The fluorescence response shows a good linear reproducibility with NO concentrations. • A linear calibration is obtained in the range from 1.4 × 10 �

Studies of bio-mimetic medium of ionic and non-ionic micelles by a simple charge transfer fluorescence probe N,N-dimethylaminonapthyl-(acrylo)-nitrile

Science.gov (United States)

Samanta, Anuva; Paul, Bijan Kumar; Guchhait, N.

2011-05-01

In this report we have studied micellization process of anionic, cationic and non-ionic surfactants using N,N-dimethylaminonapthyl-(acrylo)-nitrile (DMANAN) as an external fluorescence probe. Micropolarity, microviscosity, critical micellar concentration of these micelles based on steady state absorption and fluorescence and time resolved emission spectroscopy of the probe DMANAN show that the molecule resides in the micelle-water interface for ionic micelles and in the core for the non-ionic micelle. The effect of variation of pH of the micellar solution as well as fluorescence quenching measurements of DMANAN provide further support for the location of the probe in the micelles.

Fluorescent eosin probe in investigations of structural changes in glycated proteins

Science.gov (United States)

Pravdin, A. B.; Kochubey, V. I.; Mel'Nikov, A. G.

2010-08-01

The possibility of using the luminescent-kinetic probe method to investigate structural changes in bovine serum albumin (BSA) upon nonenzymatic thermal glycation is studied. An increase in the glycation time lead to a decrease in the intensity of the probe (eosin) fluorescence and to a long-wavelength shift of its maximum, as well as to an increase in the eosin phosphorescence intensity, which indicates that eosin binds to hydrophobic regions of protein at any times of incubation of BSA with glucose. From a decrease in the rate constant of the triplet-triplet energy transfer between the donor (eosin) and acceptor (anthracene) bound to proteins, it is found that the changes observed in the spectral characteristics of eosin are caused by structural changes in albumin globules as a result of glycosylation.

A novel fluorescent probe (dtpa-bis(cytosine)) for detection of Eu(III) in rare earth metal ions

Science.gov (United States)

Yang, Fan; Ren, Peipei; Liu, Guanhong; Song, Youtao; Bu, Naishun; Wang, Jun

2018-03-01

In this paper, a novel fluorescent probe, dtpa-bis(cytosine), was designed and synthesized for detecting europium (Eu3 +) ion. Upon addition of Eu3 + ions into the dtpa-bis(cytosine) solution, the fluorescence intensity can strongly be enhanced. Conversely, adding other rare earth metal ions, such as Y3 +, Ce3 +, Pr3 +, Nd3 +, Sm3 +, Gd3 +, Tb3 +, Dy3 +, Ho3 +, Er3 +, Yb3 + and Lu3 +, into dtpa-bis(cytosine) solution, the fluorescence intensity is decreased slightly. Some parameters affecting the fluorescence intensity of dtpa-bis(cytosine) solution in the presence of Eu3 + ions were investigated, including solution pH value, Eu3 + ion concentration and interfering substances. The detection mechanism of Eu3 + ion using dtpa-bis(cytosine) as fluorescent probe was proposed. Under optimum conditions, the fluorescence emission intensities of EuIII-dtpa-bis(cytosine) at 375 nm in the concentration range of 0.50 × 10- 5 mol • L- 1-5.00 × 10- 5 mol • L- 1 of Eu3 + ion display a better linear relationship. The limit of detection (LOD) was determined as 8.65 × 10- 7 mol • L- 1 and the corresponding correlation coefficient (R2) of the linear equation is 0.9807. It is wished that the proposed method could be applied for sensitively and selectively detecting Eu3 + ion.

A Novel “Off-On” Fluorescent Probe Based on Carbon Nitride Nanoribbons for the Detection of Citrate Anion and Live Cell Imaging

Directory of Open Access Journals (Sweden)

Yanling Hu

2018-04-01

Full Text Available A novel fluorescent “off-on” probe based on carbon nitride (C3N4 nanoribbons was developed for citrate anion (C6H5O73− detection. The fluorescence of C3N4 nanoribbons can be quenched by Cu2+ and then recovered by the addition of C6H5O73−, because the chelation between C6H5O73− and Cu2+ blocks the electron transfer between Cu2+ and C3N4 nanoribbons. The turn-on fluorescent sensor using this fluorescent “off-on” probe can detect C6H5O73− rapidly and selectively, showing a wide detection linear range (1~400 μM and a low detection limit (0.78 μM in aqueous solutions. Importantly, this C3N4 nanoribbon-based “off-on” probe exhibits good biocompatibility and can be used as fluorescent visualizer for exogenous C6H5O73− in HeLa cells.

Time-resolved spectroscopy of the probe fluorescence in the study of human blood protein dynamic structure on SR beam

International Nuclear Information System (INIS)

Dobretsov, G.E.; Kurek, N.K.; Syrejshchikova, T.I.; Yakimenko, M.N.; Clarke, D.T.; Jones, G.R.; Munro, I.H.

2000-01-01

Time-resolved spectroscopy on the SRS of the Daresbury Laboratory was used for the study of the human serum lipoproteins and human blood albumins with fluorescent probes K-37 and K-35, developed in Russia. The probe K-37 was found sensitive to the difference in dynamic properties of the lipid objects. Two sets of the parameters were used for the description of lipid dynamic structure: (1) time-resolved fluorescence spectra and (2) time-resolved fluorescence depolarization as a function of rotational mobility of lipid molecules. Each measured dynamic parameter reflected the monotonous changes of dynamic properties in the range: lipid spheres-very low density lipoproteins-low density lipoproteins-high density lipoproteins-phospholipid liposomes. The range is characterized by the increase of the ratio polar/ nonpolar lipids. Thus, time-resolved fluorescence could be used to detect some structural modifications in lipoproteins related to atherosclerosis and subsequent cardiovascular diseases development

X-ray Pump–Probe Investigation of Charge and Dissociation Dynamics in Methyl Iodine Molecule

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Li Fang

2017-05-01

Full Text Available Molecular dynamics is of fundamental interest in natural science research. The capability of investigating molecular dynamics is one of the various motivations for ultrafast optics. We present our investigation of photoionization and nuclear dynamics in methyl iodine (CH3I molecule with an X-ray pump X-ray probe scheme. The pump–probe experiment was realized with a two-mirror X-ray split and delay apparatus. Time-of-flight mass spectra at various pump–probe delay times were recorded to obtain the time profile for the creation of high charge states via sequential ionization and for molecular dissociation. We observed high charge states of atomic iodine up to 29+, and visualized the evolution of creating these high atomic ion charge states, including their population suppression and enhancement as the arrival time of the second X-ray pulse was varied. We also show the evolution of the kinetics of the high charge states upon the timing of their creation during the ionization-dissociation coupled dynamics. We demonstrate the implementation of X-ray pump–probe methodology for investigating X-ray induced molecular dynamics with femtosecond temporal resolution. The results indicate the footprints of ionization that lead to high charge states, probing the long-range potential curves of the high charge states.

Real-Time Discrimination and Versatile Profiling of Spontaneous Reactive Oxygen Species in Living Organisms with a Single Fluorescent Probe.

Science.gov (United States)

Zhang, Ruilong; Zhao, Jun; Han, Guangmei; Liu, Zhengjie; Liu, Cui; Zhang, Cheng; Liu, Bianhua; Jiang, Changlong; Liu, Renyong; Zhao, Tingting; Han, Ming-Yong; Zhang, Zhongping

2016-03-23

Fluorescent probes are powerful tools for the investigations of reactive oxygen species (ROS) in living organisms by visualization and imaging. However, the multiparallel assays of several ROS with multiple probes are often limited by the available number of spectrally nonoverlapping chromophores together with large invasive effects and discrepant biological locations. Meanwhile, the spontaneous ROS profilings in various living organs/tissues are also limited by the penetration capability of probes across different biological barriers and the stability in reactive in vivo environments. Here, we report a single fluorescent probe to achieve the effective discrimination and profiling of hydroxyl radicals (•OH) and hypochlorous acid (HClO) in living organisms. The probe is constructed by chemically grafting an additional five-membered heterocyclic ring and a lateral triethylene glycol chain to a fluorescein mother, which does not only turn off the fluorescence of fluorescein, but also create the dual reactive sites to ROS and the penetration capability in passing through various biological barriers. The reactions of probe with •OH and HClO simultaneously result in cyan and green emissions, respectively, providing the real-time discrimination and quantitative analysis of the two ROS in cellular mitochondria. Surprisingly, the accumulation of probes in the intestine and liver of a normal-state zebrafish and the transfer pathway from intestine-to-blood-to-organ/tissue-to-kidney-to-excretion clearly present the profiling of spontaneous •OH and HClO in these metabolic organs. In particular, the stress generation of •OH at the fresh wound of zebrafish is successfully visualized for the first time, in spite of its extremely short lifetime.

Fluorescent quenching-based quantitative detection of specific DNA/RNA using a BODIPY® FL-labeled probe or primer

Science.gov (United States)

Kurata, Shinya; Kanagawa, Takahiro; Yamada, Kazutaka; Torimura, Masaki; Yokomaku, Toyokazu; Kamagata, Yoichi; Kurane, Ryuichiro

2001-01-01

We have developed a simple method for the quantitative detection of specific DNA or RNA molecules based on the finding that BODIPY® FL fluorescence was quenched by its interaction with a uniquely positioned guanine. This approach makes use of an oligonucleotide probe or primer containing a BODIPY® FL-modified cytosine at its 5′-end. When such a probe was hybridized with a target DNA, its fluorescence was quenched by the guanine in the target, complementary to the modified cytosine, and the quench rate was proportional to the amount of target DNA. This widely applicable technique will be used directly with larger samples or in conjunction with the polymerase chain reaction to quantify small DNA samples. PMID:11239011

Fluorescent Protein Voltage Probes Derived from ArcLight that Respond to Membrane Voltage Changes with Fast Kinetics

Science.gov (United States)

Han, Zhou; Jin, Lei; Platisa, Jelena; Cohen, Lawrence B.; Baker, Bradley J.; Pieribone, Vincent A.

2013-01-01

We previously reported the discovery of a fluorescent protein voltage probe, ArcLight, and its derivatives that exhibit large changes in fluorescence intensity in response to changes of plasma membrane voltage. ArcLight allows the reliable detection of single action potentials and sub-threshold activities in individual neurons and dendrites. The response kinetics of ArcLight (τ1-on ~10 ms, τ2-on ~ 50 ms) are comparable with most published genetically-encoded voltage probes. However, probes using voltage-sensing domains other than that from the Ciona intestinalis voltage sensitive phosphatase exhibit faster kinetics. Here we report new versions of ArcLight, in which the Ciona voltage-sensing domain was replaced with those from chicken, zebrafish, frog, mouse or human. We found that the chicken and zebrafish-based ArcLight exhibit faster kinetics, with a time constant (τ) less than 6ms for a 100 mV depolarization. Although the response amplitude of these two probes (8-9%) is not as large as the Ciona-based ArcLight (~35%), they are better at reporting action potentials from cultured neurons at higher frequency. In contrast, probes based on frog, mouse and human voltage sensing domains were either slower than the Ciona-based ArcLight or had very small signals. PMID:24312287

Fluorescent protein voltage probes derived from ArcLight that respond to membrane voltage changes with fast kinetics.

Directory of Open Access Journals (Sweden)

Zhou Han

Full Text Available We previously reported the discovery of a fluorescent protein voltage probe, ArcLight, and its derivatives that exhibit large changes in fluorescence intensity in response to changes of plasma membrane voltage. ArcLight allows the reliable detection of single action potentials and sub-threshold activities in individual neurons and dendrites. The response kinetics of ArcLight (τ1-on ~10 ms, τ2-on ~ 50 ms are comparable with most published genetically-encoded voltage probes. However, probes using voltage-sensing domains other than that from the Ciona intestinalis voltage sensitive phosphatase exhibit faster kinetics. Here we report new versions of ArcLight, in which the Ciona voltage-sensing domain was replaced with those from chicken, zebrafish, frog, mouse or human. We found that the chicken and zebrafish-based ArcLight exhibit faster kinetics, with a time constant (τ less than 6 ms for a 100 mV depolarization. Although the response amplitude of these two probes (8-9% is not as large as the Ciona-based ArcLight (~35%, they are better at reporting action potentials from cultured neurons at higher frequency. In contrast, probes based on frog, mouse and human voltage sensing domains were either slower than the Ciona-based ArcLight or had very small signals.

Two rhodamine lactam modulated lysosome-targetable fluorescence probes for sensitively and selectively monitoring subcellular organelle pH change

Energy Technology Data Exchange (ETDEWEB)

Li, Hongmei [Ministry of Education Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069 (China); Wang, Cuiling [Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, Xi' an 710069 (China); She, Mengyao; Zhu, Yuelu; Zhang, Jidong; Yang, Zheng [Ministry of Education Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069 (China); Liu, Ping, E-mail: liuping@nwu.edu.cn [Ministry of Education Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069 (China); Wang, Yaoyu [Ministry of Education Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069 (China); Li, Jianli, E-mail: lijianli@nwu.edu.cn [Ministry of Education Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069 (China)

2015-11-05

Be a powerful technique for convenient detection of pH change in living cells, especially at subcellular level, fluorescent probes has attracted more and more attention. In this work, we designed and synthesized three rhodamine lactam modulated fluorescent probes RS1, RS2 and RS3, which all respond sensitively toward weak acidity (pH range 4–6) via the photophysical property in buffer solution without interference from the other metal ions, and they also show ideal pKa values and excellent reversibility. Particularly, by changing the lone pair electrons distribution of lactam-N atom with different conjugations, RS2 and RS3 exhibit high quantum yield, negligible cytotoxicity and excellent permeability. They are suitable to stain selectively lysosomes of tumor cells and monitor its pH changes sensitively via optical molecular imaging. The above findings suggest that the probes we designed could act as ideal and easy method for investigating the pivotal role of H{sup +} in lysosomes and are potential pH detectors in disease diagnosis through direct intracellular imaging. - Highlights: • Two probes for sensitively and selectively monitoring weak acidic pH change. • The pKa of the probes was highly suitable for staining lysosomes in tumor cells. • The properties of those probes were changed by different conjugate system. • These probes have negligible cytotoxicity and good sensitivity in vivo.

Two rhodamine lactam modulated lysosome-targetable fluorescence probes for sensitively and selectively monitoring subcellular organelle pH change

International Nuclear Information System (INIS)

Li, Hongmei; Wang, Cuiling; She, Mengyao; Zhu, Yuelu; Zhang, Jidong; Yang, Zheng; Liu, Ping; Wang, Yaoyu; Li, Jianli

2015-01-01

Be a powerful technique for convenient detection of pH change in living cells, especially at subcellular level, fluorescent probes has attracted more and more attention. In this work, we designed and synthesized three rhodamine lactam modulated fluorescent probes RS1, RS2 and RS3, which all respond sensitively toward weak acidity (pH range 4–6) via the photophysical property in buffer solution without interference from the other metal ions, and they also show ideal pKa values and excellent reversibility. Particularly, by changing the lone pair electrons distribution of lactam-N atom with different conjugations, RS2 and RS3 exhibit high quantum yield, negligible cytotoxicity and excellent permeability. They are suitable to stain selectively lysosomes of tumor cells and monitor its pH changes sensitively via optical molecular imaging. The above findings suggest that the probes we designed could act as ideal and easy method for investigating the pivotal role of H + in lysosomes and are potential pH detectors in disease diagnosis through direct intracellular imaging. - Highlights: • Two probes for sensitively and selectively monitoring weak acidic pH change. • The pKa of the probes was highly suitable for staining lysosomes in tumor cells. • The properties of those probes were changed by different conjugate system. • These probes have negligible cytotoxicity and good sensitivity in vivo.

DHA-fluorescent probe is sensitive to membrane order and reveals molecular adaptation of DHA in ordered lipid microdomains☆

Science.gov (United States)

Teague, Heather; Ross, Ron; Harris, Mitchel; Mitchell, Drake C.; Shaikh, Saame Raza

2012-01-01

Docosahexaenoic acid (DHA) disrupts the size and order of plasma membrane lipid microdomains in vitro and in vivo. However, it is unknown how the highly disordered structure of DHA mechanistically adapts to increase the order of tightly packed lipid microdomains. Therefore, we studied a novel DHA-Bodipy fluorescent probe to address this issue. We first determined if the DHA-Bodipy probe localized to the plasma membrane of primary B and immortal EL4 cells. Image analysis revealed that DHA-Bodipy localized into the plasma membrane of primary B cells more efficiently than EL4 cells. We then determined if the probe detected changes in plasma membrane order. Quantitative analysis of time-lapse movies established that DHA-Bodipy was sensitive to membrane molecular order. This allowed us to investigate how DHA-Bodipy physically adapted to ordered lipid microdomains. To accomplish this, we employed steady-state and time-resolved fluorescence anisotropy measurements in lipid vesicles of varying composition. Similar to cell culture studies, the probe was highly sensitive to membrane order in lipid vesicles. Moreover, these experiments revealed, relative to controls, that upon incorporation into highly ordered microdomains, DHA-Bodipy underwent an increase in its fluorescence lifetime and molecular order. In addition, the probe displayed a significant reduction in its rotational diffusion compared to controls. Altogether, DHA-Bodipy was highly sensitive to membrane order and revealed for the first time that DHA, despite its flexibility, could become ordered with less rotational motion inside ordered lipid microdomains. Mechanistically, this explains how DHA acyl chains can increase order upon formation of lipid microdomains in vivo. PMID:22841541

A turn-on supramolecular fluorescent probe for sensing benzimidazole fungicides and its application in living cell imaging

Science.gov (United States)

Tang, Qing; Zhang, Jing; Sun, Tao; Wang, Cheng-Hui; Huang, Ying; Zhou, Qingdi; Wei, Gang

2018-02-01

A cucurbit[8]uril-based turn-on supramolecular fluorescent probe between cucurbit[8]uril (Q[8]) and pyronine Y (PyY) (designated 2PyY@Q[8]) in acidic aqueous solution showed a remarkable fluorescence 'turn-on' response to benzimidazole fungicides such as thiabendazole, fuberidazole and carbendazim. The 2PyY@Q[8] fluorescent probe can be used to detect benzimidazole fungicides with high sensitivity and selectivity with a detection limit of 10- 8 mol/L. A good linear relationship of emission intensity at 580 nm for benzimidazole fungicides at concentrations of 0.4-5.0 μmol/L was observed. The proposed sensing mechanism was investigated using 1H NMR spectroscopy combined with density functional theory calculations at the B3LYP/6-31G(d) level. The cell imaging study showed that the 2PyY@Q[8] complex could be used to image benzimidazole fungicide in prostate cancer (PC3) cells, which may help to elucidate relevant biological processes at the molecular level.

Phenotypical characteristics of leukocyte membranes in Chernobyl clean-up workers from Latvia: use of the fluorescent probe ABM

International Nuclear Information System (INIS)

Kalnina, I.; Meirovics, I.; Garbuseva, N.; Bruvere, R.; Heisele, O.; Zvagule, T.; Volrate, A.; Feldmane, G.

2001-01-01

A fluorescent probe - aminoderivative of benzanthrone, AMB (developed at the Riga Technical University, Riga, Latvia) - has been previously shown to localise within the phospholipid bilayer of the cell membrane, and shown to affect the structural and functional properties of peripheral blood mononuclear cells (PBMC). The probe ABM was used to characterise the PBMC membranes of 97 Chernobyl clean-up workers from Latvia. The study was conducted in the years 1997-1998. After addition of the probe to PBMC, fluorescence intensity of ABM (F) was measured, the depolarisation value P was calculated, and emission spectra were recorded. Screening of all individuals showed 5 different patterns of fluorescence spectra. Four of the patterns had never been previously observed in healthy individuals or patients with tuberculosis, multiple sclerosis, oncologic patients, etc., examined by us. The spectral patterns of ABM suspensions were associated with ability of leukocytes to produce interferons, with the levels of immunoglobulins A, G, and M, the concentration of lead in peripheral blood, and with several neurologic diseases. The use of ABM allowed to show phenotypic differences in PBMC between Chernobyl clean-up workers and individuals who had never had professional contact with radioactivity. (author)

Development of species-specific rDNA probes for Giardia by multiple fluorescent in situ hybridization combined with immunocytochemical identification of cyst wall antigens.

Science.gov (United States)

Erlandsen, Stanley L; Jarroll, Edward; Wallis, Peter; van Keulen, Harry

2005-08-01

In this study, we describe the development of fluorescent oligonucleotide probes to variable regions in the small subunit of 16S rRNA in three distinct Giardia species. Sense and antisense probes (17-22 mer) to variable regions 1, 3, and 8 were labeled with digoxygenin or selected fluorochomes (FluorX, Cy3, or Cy5). Optimal results were obtained with fluorochome-labeled oligonucleotides for detection of rRNA in Giardia cysts. Specificity of fluorescent in situ hybridization (FISH) was shown using RNase digestion and high stringency to diminish the hybridization signal, and oligonucleotide probes for rRNA in Giardia lamblia, Giardia muris, and Giardia ardeae were shown to specifically stain rRNA only within cysts or trophozoites of those species. The fluorescent oligonucleotide specific for rRNA in human isolates of Giardia was positive for ten different strains. A method for simultaneous FISH detection of cysts using fluorescent antibody (genotype marker) and two oligonucleotide probes (species marker) permitted visualization of G. lamblia and G. muris cysts in the same preparation. Testing of an environmental water sample revealed the presence of FISH-positive G. lamblia cysts with a specific rDNA probe for rRNA, while negative cysts were presumed to be of animal or bird origin.

Fluorescent Bisphosphonate and Carboxyphosphonate Probes: A Versatile Imaging Toolkit for Applications in Bone Biology and Biomedicine.

Science.gov (United States)

Sun, Shuting; Błażewska, Katarzyna M; Kadina, Anastasia P; Kashemirov, Boris A; Duan, Xuchen; Triffitt, James T; Dunford, James E; Russell, R Graham G; Ebetino, Frank H; Roelofs, Anke J; Coxon, Fraser P; Lundy, Mark W; McKenna, Charles E

2016-02-17

A bone imaging toolkit of 21 fluorescent probes with variable spectroscopic properties, bone mineral binding affinities, and antiprenylation activities has been created, including a novel linking strategy. The linking chemistry allows attachment of a diverse selection of dyes fluorescent in the visible to near-infrared range to any of the three clinically important heterocyclic bisphosphonate bone drugs (risedronate, zoledronate, and minodronate or their analogues). The resultant suite of conjugates offers multiple options to "mix and match" parent drug structure, fluorescence emission wavelength, relative bone affinity, and presence or absence of antiprenylation activity, for bone-related imaging applications.

Fluorescent Sterols and Cholesteryl Esters as Probes for Intracellular Cholesterol Transport

Science.gov (United States)

Solanko, Katarzyna A.; Modzel, Maciej; Solanko, Lukasz M.; Wüstner, Daniel

2015-01-01

Cholesterol transport between cellular organelles comprised vesicular trafficking and nonvesicular exchange; these processes are often studied by quantitative fluorescence microscopy. A major challenge for using this approach is producing analogs of cholesterol with suitable brightness and structural and chemical properties comparable with those of cholesterol. This review surveys currently used fluorescent sterols with respect to their behavior in model membranes, their photophysical properties, as well as their transport and metabolism in cells. In the first part, several intrinsically fluorescent sterols, such as dehydroergosterol or cholestatrienol, are discussed. These polyene sterols (P-sterols) contain three conjugated double bonds in the steroid ring system, giving them slight fluorescence in ultraviolet light. We discuss the properties of P-sterols relative to cholesterol, outline their chemical synthesis, and explain how to image them in living cells and organisms. In particular, we show that P-sterol esters inserted into low-density lipoprotein can be tracked in the fibroblasts of Niemann–Pick disease using high-resolution deconvolution microscopy. We also describe fluorophore-tagged cholesterol probes, such as BODIPY-, NBD-, Dansyl-, or Pyrene-tagged cholesterol, and eventual esters of these analogs. Finally, we survey the latest developments in the synthesis and use of alkyne cholesterol analogs to be labeled with fluorophores by click chemistry and discuss the potential of all approaches for future applications. PMID:27330304

A convenient colorimetric and ratiometric fluorescent probe for detection of cyanide based on BODIPY derivative in aqueous media

Directory of Open Access Journals (Sweden)

Yanhua Yu

2017-06-01

Full Text Available A convenient colorimetric and ratiometric fluorescent probe based on BODIPY derivative for cyanide detection has been synthesized, whose structural contains a dicyanovinyl group used as a sensing unit. Among the tested analytes, such as CN−, F−, Cl−, Br−, I−, ClO4−, AcO−, NO3−, H2PO4− HSO4−, S2− and N3−, only CN− could react with dicyanovinyl moiety by nucleophilic addition, which disrupted the π-conjugation of the probe and hindered the intramolecular charge transfer (ICT, leading a blue shift of absorption and fluorescence spectrum and a concomitant color change from yellow to light pink. The detection limit of this probe was calculated to be 0.98 μM, which is lower than the maximum concentration in drinking water (1.9 μM permitted by the World Health Organization (WHO. Moreover, the probe showed excellent selectivity and anti-interference ability towards CN− over other anions. The reaction mechanism was fully supported by 1H NMR and MS spectrum.

Folic acid-targeted magnetic Tb-doped CeF3 fluorescent nanoparticles as bimodal probes for cellular fluorescence and magnetic resonance imaging.

Science.gov (United States)

Ma, Zhi-Ya; Liu, Yu-Ping; Bai, Ling-Yu; An, Jie; Zhang, Lin; Xuan, Yang; Zhang, Xiao-Shuai; Zhao, Yuan-Di

2015-10-07

Magnetic fluorescent nanoparticles (NPs) have great potential applications for diagnostics, imaging and therapy. We developed a facile polyol method to synthesize multifunctional Fe3O4@CeF3:Tb@CeF3 NPs with small size (CA) to obtain carboxyl-functionalized NPs (Fe3O4@CeF3:Tb@CeF3-COOH). Folic acid (FA) as an affinity ligand was then covalently conjugated onto NPs to yield Fe3O4@CeF3:Tb@CeF3-FA NPs. They were then applied as multimodal imaging agents for simultaneous in vitro targeted fluorescence imaging and magnetic resonance imaging (MRI) of HeLa cells with overexpressed folate receptors (FR). The results indicated that these NPs had strong luminescence and enhanced T2-weighted MR contrast and would be promising candidates as multimodal probes for both fluorescence and MRI imaging.

ICT-Isomerization-Induced Turn-On Fluorescence Probe with a Large Emission Shift for Mercury Ion: Application in Combinational Molecular Logic.

Science.gov (United States)

Bhatta, Sushil Ranjan; Mondal, Bijan; Vijaykumar, Gonela; Thakur, Arunabha

2017-10-02

A unique turn-on fluorescent device based on a ferrocene-aminonaphtholate derivative specific for Hg 2+ cation was developed. Upon binding with Hg 2+ ion, the probe shows a dramatic fluorescence enhancement (the fluorescence quantum yield increases 58-fold) along with a large red shift of 68 nm in the emission spectrum. The fluorescence enhancement with a red shift may be ascribed to the combinational effect of C═N isomerization and an extended intramolecular charge transfer (ICT) mechanism. The response was instantaneous with a detection limit of 2.7 × 10 -9 M. Upon Hg 2+ recognition, the ferrocene/ferrocenium redox peak was anodically shifted by ΔE 1/2 = 72 mV along with a "naked eye" color change from faint yellow to pale orange for this metal cation. Further, upon protonation of the imine nitrogen, the present probe displays a high fluorescence output due to suppression of the C═N isomerization process. Upon deprotonation using strong base, the fluorescence steadily decreases, which indicates that H + and OH - can be used to regulate the off-on-off fluorescence switching of the present probe. Density functional theory studies revealed that the addition of acid leads to protonation of the imine N (according to natural bond orbital analysis), and the resulting iminium proton forms a strong H-bond (2.307 Å) with one of the triazole N atoms to form a five-membered ring, which makes the molecule rigid; hence, enhancement of the ICT process takes place, thereby leading to a fluorescence enhancement with a red shift. The unprecedented combination of H + , OH - , and Hg 2+ ions has been used to generate a molecular system exhibiting the INHIBIT-OR combinational logic operation.

Determination of adenosine disodium triphosphate using prulifloxacin-terbium(III) as a fluorescence probe by spectrofluorimetry

International Nuclear Information System (INIS)

Yu Fengshan; Li Lin; Chen Fang

2008-01-01

A new spectrofluorimetric method is developed for determination of adenosine disodium triphosphate (ATP). The interactions between prulifloxacin (PUFX)-Tb 3+ complex and adenosine disodium triphosphate has been studied by using UV-vis absorption and fluorescence spectra. Using prulifloxacin-Tb 3+ as a fluorescence probe, under the optimum conditions, ATP can remarkably enhance the fluorescence intensity of the prulifloxacin-Tb 3+ complex at λ = 545 nm and the enhanced fluorescence intensity is in proportion to the concentration of ATP. Optimum conditions for the determination of ATP were also investigated. The dynamic range for the determination of ATP is 4.0 x 10 -7 to 2.0 x 10 -5 mol L -1 , and the detection limit (3 σ/k) is 1.7 x 10 -8 mol L -1 . This method is simple, practical and relatively free interference from coexisting substances and can be successfully applied to determination of ATP in real pharmaceutical samples. The mechanism of fluorescence enhancement of prulifloxacin-Tb 3+ complex by ATP was also discussed

“Turn-on” fluorescence probe integrated polymer nanoparticles for sensing biological thiol molecules

Science.gov (United States)

Ang, Chung Yen; Tan, Si Yu; Lu, Yunpeng; Bai, Linyi; Li, Menghuan; Li, Peizhou; Zhang, Quan; Selvan, Subramanian Tamil; Zhao, Yanli

2014-11-01

A ``turn-on'' thiol-responsive fluorescence probe was synthesized and integrated into polymeric nanoparticles for sensing intracellular thiols. There is a photo-induced electron transfer process in the off state of the probe, and this process is terminated upon the reaction with thiol compounds. Configuration interaction singles (CIS) calculation was performed to confirm the mechanism of this process. A series of sensing studies were carried out, showing that the probe-integrated nanoparticles were highly selective towards biological thiol compounds over non-thiolated amino acids. Kinetic studies were also performed to investigate the relative reaction rate between the probe and the thiolated amino acids. Subsequently, the Gibbs free energy of the reactions was explored by means of the electrochemical method. Finally, the detection system was employed for sensing intracellular thiols in cancer cells, and the sensing selectivity could be further enhanced with the use of a cancer cell-targeting ligand in the nanoparticles. This development paves a path for the sensing and detection of biological thiols, serving as a potential diagnostic tool in the future.

Biophysical characterization of the fluorescent protein voltage probe VSFP2.3 based on the voltage-sensing domain of Ci-VSP

DEFF Research Database (Denmark)

Lundby, Alicia; Akemann, Walther; Knöpfel, Thomas

2010-01-01

A voltage sensitive phosphatase was discovered in the ascidian Ciona intestinalis. The phosphatase, Ci-VSP, contains a voltage-sensing domain homologous to those known from voltage-gated ion channels, but unlike ion channels, the voltage-sensing domain of Ci-VSP can reside in the cell membrane...... as a monomer. We fused the voltage-sensing domain of Ci-VSP to a pair of fluorescent reporter proteins to generate a genetically encodable voltage-sensing fluorescent probe, VSFP2.3. VSFP2.3 is a fluorescent voltage probe that reports changes in membrane potential as a FRET (fluorescence resonance energy....... Neutralization of an arginine in S4, previously suggested to be a sensing charge, and measuring associated sensing currents indicate that this charge is likely to reside at the membrane-aqueous interface rather than within the membrane electric field. The data presented give us insights into the voltage-sensing...

Thioglycolic acid-capped CuInS2/ZnS quantum dots as fluorescent probe for cobalt ion detection

International Nuclear Information System (INIS)

Zi, Lili; Huang, Yu; Yan, Zhengyu; Liao, Shenghua

2014-01-01

A novel sensing fluorescent probe based on the fluorescence quenching of the thioglycolic acid-capped CuInS 2 /ZnS quantum dots (CuInS 2 /ZnS/TGA QDs) was established for cobalt ions detection. The fluorescence quenching of CuInS 2 /ZnS/TGA QDs was due to the increasing surface deficiency and the inner-filter effect, which were attributed to the reaction between Co 2+ and sulfur bonds on the surface of QDs. The quenching curve could be fitted by a typical Stern–Volmer-type equation, with a linear relationship between the quenching efficiency and the concentration of cobalt ions in the range of 0.3012–90.36 μmol L −1 . And the detection limit (S/N=3) for Co 2+ was 0.16 μmol L −1 . Therefore, the established probe provided a simple, rapid, cheap and sensitive method for Co 2+ detection. In a word, this method can be used to detect Co 2+ in the environment. -- Highlights: • The CuInS2/ZnS QDs were used for the first time as a fluorescent probe for Co 2+ detection. • The dramatic color change could be observed when Co 2+ was added into the QDs solution. • The quenching of QDs was due to the increasing surface deficiency and the inner-filter effect. • This rapid, cheap and sensitive method was applied to the detection of Co 2+ in simulated water

Fluorescent peptide biosensor for probing the relative abundance of cyclin-dependent kinases in living cells.

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Laetitia Kurzawa

Full Text Available Cyclin-dependant kinases play a central role in coordinating cell growth and division, and in sustaining proliferation of cancer cells, thereby constituting attractive pharmacological targets. However, there are no direct means of assessing their relative abundance in living cells, current approaches being limited to antigenic and proteomic analysis of fixed cells. In order to probe the relative abundance of these kinases directly in living cells, we have developed a fluorescent peptide biosensor with biligand affinity for CDKs and cyclins in vitro, that retains endogenous CDK/cyclin complexes from cell extracts, and that bears an environmentally-sensitive probe, whose fluorescence increases in a sensitive fashion upon recognition of its targets. CDKSENS was introduced into living cells, through complexation with the cell-penetrating carrier CADY2 and applied to assess the relative abundance of CDK/Cyclins through fluorescence imaging and ratiometric quantification. This peptide biosensor technology affords direct and sensitive readout of CDK/cyclin complex levels, and reports on differences in complex formation when tampering with a single CDK or cyclin. CDKSENS further allows for detection of differences between different healthy and cancer cell lines, thereby enabling to distinguish cells that express high levels of these heterodimeric kinases, from cells that present decreased or defective assemblies. This fluorescent biosensor technology provides information on the overall status of CDK/Cyclin complexes which cannot be obtained through antigenic detection of individual subunits, in a non-invasive fashion which does not require cell fixation or extraction procedures. As such it provides promising perspectives for monitoring the response to therapeutics that affect CDK/Cyclin abundance, for cell-based drug discovery strategies and fluorescence-based cancer diagnostics.

Sensitive fluorescence on-off probes for the fast detection of a chemical warfare agent mimic.

Science.gov (United States)

Khan, Muhammad Shar Jhahan; Wang, Ya-Wen; Senge, Mathias O; Peng, Yu

2018-01-15

Two highly sensitive probes bearing a nucleophilic imine moiety have been utilized for the selective detection of chemical warfare agent (CWA) mimics. Diethyl chlorophosphate (DCP) was used as mimic CWAs. Both iminocoumarin-benzothiazole-based probes not only demonstrated a remarkable fluorescence ON-OFF response and good recognition, but also exhibited fast response times (10s) along with color changes upon addition of DCP. Limits of detection for the two sensors 1 and 2 were calculated as 0.065μM and 0.21μM, respectively, which are much lower than most other reported probes. These two probes not only show high sensitivity and selectivity in solution, but can also be applied for the recognition of DCP in the gas state, with significant color changes easily observed by the naked eye. Copyright © 2017 Elsevier B.V. All rights reserved.

Sets of RNA repeated tags and hybridization-sensitive fluorescent probes for distinct images of RNA in a living cell.

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Takeshi Kubota

Full Text Available BACKGROUND: Imaging the behavior of RNA in a living cell is a powerful means for understanding RNA functions and acquiring spatiotemporal information in a single cell. For more distinct RNA imaging in a living cell, a more effective chemical method to fluorescently label RNA is now required. In addition, development of the technology labeling with different colors for different RNA would make it easier to analyze plural RNA strands expressing in a cell. METHODOLOGY/PRINCIPAL FINDINGS: Tag technology for RNA imaging in a living cell has been developed based on the unique chemical functions of exciton-controlled hybridization-sensitive oligonucleotide (ECHO probes. Repetitions of selected 18-nucleotide RNA tags were incorporated into the mRNA 3'-UTR. Pairs with complementary ECHO probes exhibited hybridization-sensitive fluorescence emission for the mRNA expressed in a living cell. The mRNA in a nucleus was detected clearly as fluorescent puncta, and the images of the expression of two mRNAs were obtained independently and simultaneously with two orthogonal tag-probe pairs. CONCLUSIONS/SIGNIFICANCE: A compact and repeated label has been developed for RNA imaging in a living cell, based on the photochemistry of ECHO probes. The pairs of an 18-nt RNA tag and the complementary ECHO probes are highly thermostable, sequence-specifically emissive, and orthogonal to each other. The nucleotide length necessary for one tag sequence is much shorter compared with conventional tag technologies, resulting in easy preparation of the tag sequences with a larger number of repeats for more distinct RNA imaging.

Curcumin-Based "Enhanced SNAr" Promoted Ultrafast Fluorescent Probe for Thiophenols Detection in Aqueous Solution and in Living Cells.

Science.gov (United States)

Yue, Yongkang; Huo, Fangjun; Zhang, Yongbin; Chao, Jianbin; Martínez-Máñez, Ramón; Yin, Caixia

2016-11-01

We report herein a highly selective and sensitive turn-on fluorescent probe (compound 1) with a fast response time (less than 2 min) for thiophenol detection based on an "enhanced S N Ar" reaction between thiophenols and a sulfonyl-ester moiety covalently attach to curcumin. Reaction of 1 in Hepes-MeOH (1:1, v/v, pH 7.4) in the presence of 4-methylthiophenol (MTP) resulted in a remarkable enhancement of the fluorescence. A linear response in the presence of MTP of the relative fluorescent intensity (F - F 0 ) of 1 at 536 nm in the 0-40 μM MTP concentration range was found. A limit of detection (LOD) for the detection of MTP of 26 nM, based on the definition by IUPAC (C DL = 3 Sb/m), was calculated. Probe 1 was applied to monitor and imaging exogenous MTP in live cells and to the detection of MTP in real water samples.

A highly sensitive, single selective, fluorescent sensor for Al3+ detection and its application in living cell imaging

International Nuclear Information System (INIS)

Ye, Xing-Pei; Sun, Shao-bo; Li, Ying-dong; Zhi, Li-hua; Wu, Wei-na; Wang, Yuan

2014-01-01

A new o-aminophenol-based fluorogenic chemosensor methyl 3,5-bis((E)-(2-hydroxyphenylimino)methyl)-4-hydroxybenzoate 1 have been synthesized by Schiff base condensation of methyl 3,5-diformyl-4-hydroxybenzoate with o-aminophenol, which exhibits high selectivity and sensitivity toward Al 3+ . Fluorescence titration studies of receptors 1 with different metal cations in CH 3 OH medium showed highly selective and sensitive towards Al 3+ ions even in the presence of other commonly coexisting metal ions. The detection limit of Al 3+ ions is at the parts per billion level. Interestingly, the Al(III) complex of 1 offered a large Stokes shift (>120 nm), which can miximize the selfquenching effect. In addition, possible utilization of this receptor as bio-imaging fluorescent probe to detect Al 3+ in human cervical HeLa cancer cell lines was also investigated by confocal fluorescence microscopy. - Highlights: • A new Schiff base chemosensor is reported. • The sensor for Al 3+ offers large Stokes shift. • The detection limit of Al 3+ in CH 3 OH solution is at the parts per billion level. • The utilization of sensor for the monitoring of Al 3+ levels in living cells was examined

A Fluorescent Molecular Probe for the Detection of Hydrogen Based on Oxidative Addition Reactions with Crabtree-Type Hydrogenation Catalysts.

Science.gov (United States)

Kos, Pavlo; Plenio, Herbert

2015-11-02

A Crabtree-type Ir(I) complex tagged with a fluorescent dye (bodipy) was synthesized. The oxidative addition of H2 converts the weakly fluorescent Ir(I) complex (Φ=0.038) into a highly fluorescent Ir(III) species (Φ=0.51). This fluorogenic reaction can be utilized for the detection of H2 and to probe the oxidative addition step in the catalytic hydrogenation of olefins. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Use of selenium to detect mercury in water and cells: an enhancement of the sensitivity and specificity of a seleno fluorescent probe.

Science.gov (United States)

Tang, Bo; Ding, Baiyu; Xu, Kehua; Tong, Lili

2009-01-01

Seleno fluorescent probe: An organoselenium fluorescent probe (FSe-1) for mercury was designed based on the irreversible deselenation mechanism. FSe-1 exhibits an ultrahigh selectivity and sensitivity for Hg(2+) detection only for reactive selenium atom sites, due the strong affinity between Se and Hg. Furthermore, the new probe has been successfully used for imaging mercury ions in RAW 264.7 cells (a mouse macrophage cell line; see figure).Inspired by the antitoxic function of selenium towards heavy-metal ions, we designed an organoselenium fluorescent probe (FSe-1) for mercury. The reaction of FSe-1 and Hg(2+) is an irreversible deselenation mechanism based on the selenophilic character of mercury. FSe-1 exhibits an ultrahigh selectivity and sensitivity for Hg(2+) detection only for reactive selenium atom sites due to the strong affinity between Se and Hg. The experimental results proved that FSe-1 was selective for Hg(2+) ions over other relevant metal ions and bioanalytes, and also showed an enhancement in sensitivity of up to 1.0 nM, which is lower than the current Environmental Protection Agency standard for drinking water. Furthermore, the new probe has been successfully applied to the imaging of mercury ions in RAW 264.7 cells (a mouse macrophage cell line) with high sensitivity and selectivity.

A dual-emission and large Stokes shift fluorescence probe for real-time discrimination of ROS/RNS and imaging in live cells.

Science.gov (United States)

Guo, Ting; Cui, Lei; Shen, Jiaoning; Wang, Rui; Zhu, Weiping; Xu, Yufang; Qian, Xuhong

2013-03-04

A novel dual-emission fluorescence probe has been developed for specific and sensitive detection of hypochlorite (ClO(-)). Upon addition of ClO(-), significant changes in fluorescence emission intensity at two discrete wavelengths were observed. Meanwhile OONO(-) led to only a single-channel fluorescence enhancement. This feature makes it a clear advantage in distinguishing ClO(-), RNS from other ROS.

Molecularly Imprinted Core-Shell CdSe@SiO2/CDs as a Ratiometric Fluorescent Probe for 4-Nitrophenol Sensing

Science.gov (United States)

Liu, Mingyue; Gao, Zhao; Yu, Yanjun; Su, Rongxin; Huang, Renliang; Qi, Wei; He, Zhimin

2018-01-01

4-Nitrophenol (4-NP) is a priority pollutant in water and is both carcinogenic and genotoxic to humans and wildlife even at very low concentrations. Thus, we herein fabricated a novel molecularly imprinted core-shell nanohybrid as a ratiometric fluorescent sensor for the highly sensitive and selective detection of 4-NP. This sensor was functioned by the transfer of fluorescence resonance energy between photoluminescent carbon dots (CDs) and 4-NP. This sensor was synthesized by linking organosilane-functionalized CDs to silica-coated CdSe quantum dots (CdSe@SiO2) via Si-O bonds. The nanohybrids were further modified by anchoring a molecularly imprinted polymer (MIP) layer on the ratiometric fluorescent sensor through a facile sol-gel polymerization method. The morphology, chemical structure, and optical properties of the resulting molecularly imprinted dual-emission fluorescent probe were characterized by transmission electron microscopy and spectroscopic analysis. The probe was then applied in the detection of 4-NP and exhibited good linearity between 0.051 and 13.7 μg/mL, in addition to a low detection limit of 0.026 μg/mL. Furthermore, the simplicity, reliability, high selectivity, and high sensitivity of the developed sensor demonstrate that the combination of MIPs and ratiometric fluorescence allows the preparation of excellent fluorescent sensors for the detection of trace or ultra-trace analytes.

Dual lanthanide-doped complexes: the development of a time-resolved ratiometric fluorescent probe for anthrax biomarker and a paper-based visual sensor.

Science.gov (United States)

Wang, Qi-Xian; Xue, Shi-Fan; Chen, Zi-Han; Ma, Shi-Hui; Zhang, Shengqiang; Shi, Guoyue; Zhang, Min

2017-08-15

In this work, a novel time-resolved ratiometric fluorescent probe based on dual lanthanide (Tb: terbium, and Eu: europium)-doped complexes (Tb/DPA@SiO 2 -Eu/GMP) has been designed for detecting anthrax biomarker (dipicolinic acid, DPA), a unique and major component of anthrax spores. In such complexes-based probe, Tb/DPA@SiO 2 can serve as a stable reference signal with green fluorescence and Eu/GMP act as a sensitive response signal with red fluorescence for ratiometric fluorescent sensing DPA. Additionally, the probe exhibits long fluorescence lifetime, which can significantly reduce the autofluorescence interferences from biological samples by using time-resolved fluorescence measurement. More significantly, a paper-based visual sensor for DPA has been devised by using filter paper embedded with Tb/DPA@SiO 2 -Eu/GMP, and we have proved its utility for fluorescent detection of DPA, in which only a handheld UV lamp is used. In the presence of DPA, the paper-based visual sensor, illuminated by a handheld UV lamp, would result in an obvious fluorescence color change from green to red, which can be easily observed with naked eyes. The paper-based visual sensor is stable, portable, disposable, cost-effective and easy-to-use. The feasibility of using a smartphone with easy-to-access color-scanning APP as the detection platform for quantitative scanometric assays has been also demonstrated by coupled with our proposed paper-based visual sensor. This work unveils an effective method for accurate, sensitive and selective monitoring anthrax biomarker with backgroud-free and self-calibrating properties. Copyright © 2017 Elsevier B.V. All rights reserved.

Fluorescent probes for understanding soil water repellency: the novel application of a chemist's tool to soil science

Science.gov (United States)

Balshaw, Helen M.; Davies, Matthew L.; Doerr, Stefan H.; Douglas, Peter

2015-04-01

Food security and production is one of the key global issues faced by society. It has become essential to work the land efficiently, through better soil management and agronomy whilst protecting the environment from air and water pollution. The failure of soil to absorb water - soil water repellency can lead to major environmental problems such as increased overland flow and soil erosion, poor uptake of agricultural chemicals, and increased risk of groundwater pollution due to the rapid transfer of contaminants and nutrient leaching through uneven wetting and preferential flow pathways. Understanding the causes of soil hydrophobicity is essential for the development of effective methods for its amelioration, supporting environmental stability and food security. Organic compounds deposited on soil mineral or aggregate surfaces have long been recognised as a major factor in causing soil water repellency. It is widely accepted that the main groups of compounds responsible are long-chain acids, alkanes and other organic compounds with hydrophobic properties. However, when reapplied to sands and soils, the degree of water repellency induced by these compounds and mixtures varied widely with compound type, amount, and mixture, in a seemingly unpredictable way. Fluorescent and phosphorescent probes are widely used in chemistry and biochemistry due to their sensitive response to their physical and chemical environment, such as polarity, and viscosity. However, they have to-date not been used to study soil water repellency. Here we present preliminary work on the evaluation of fluorescent probes as tools to study two poorly understood features that determine the degree of wettability for water repellent soils: (i) the distribution of organics on soils; (ii) the changes in polarity at soil surfaces required for water drops to infiltrate. In our initial work we have examined probes adsorbed onto model soils, prepared by adsorption of specific organics onto acid washed sand

A highly selective and sensitive photoswitchable fluorescent probe for Hg2+ based on bisthienylethene-rhodamine 6G dyad and for live cells imaging.

Science.gov (United States)

Xu, Li; Wang, Sheng; Lv, Yingnian; Son, Young-A; Cao, Derong

2014-07-15

A new photochromic diarylethene derivative bearing rhodamine 6G dimmer as a fluorescent molecular probe is designed and synthesized successfully. All the compounds are characterized by nuclear magnetic resonance and mass spectrometry. The bisthienylethene-rhodamine 6G dyad exhibit excellent phtochromism with reversibly color and fluorescence changes alternating irradiation with ultraviolet and visible light. Upon addition of Hg(2+), its color changes from colorless to red and its fluorescence is remarkably enhanced. Whereas other ions including K(+), Na(+), Ca(2+), Mg(2+), Fe(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Mn(2+), Pb(2+), Ni(2+), Fe(3+), Al(3+), Cr(3+) and so on induce basically no spectral changes, which constitute a highly selective and sensitive photoswitchable fluorescent probe toward Hg(2+). Furthermore, by means of laser confocal scanning microscopy experiments, it is demonstrated that this probe can be applied for live cell imaging and monitoring Hg(2+) in living lung cancer cells with satisfying results, which shows its value of potential application in environmental and biological systems. Copyright © 2014 Elsevier B.V. All rights reserved.

Single-cell resolution imaging of retinal ganglion cell apoptosis in vivo using a cell-penetrating caspase-activatable peptide probe.

Directory of Open Access Journals (Sweden)

Xudong Qiu

Full Text Available Peptide probes for imaging retinal ganglion cell (RGC apoptosis consist of a cell-penetrating peptide targeting moiety and a fluorophore-quencher pair flanking an effector caspase consensus sequence. Using ex vivo fluorescence imaging, we previously validated the capacity of these probes to identify apoptotic RGCs in cell culture and in an in vivo rat model of N-methyl- D-aspartate (NMDA-induced neurotoxicity. Herein, using TcapQ488, a new probe designed and synthesized for compatibility with clinically-relevant imaging instruments, and real time imaging of a live rat RGC degeneration model, we fully characterized time- and dose-dependent probe activation, signal-to-noise ratios, and probe safety profiles in vivo. Adult rats received intravitreal injections of four NMDA concentrations followed by varying TcapQ488 doses. Fluorescence fundus imaging was performed sequentially in vivo using a confocal scanning laser ophthalmoscope and individual RGCs displaying activated probe were counted and analyzed. Rats also underwent electroretinography following intravitreal injection of probe. In vivo fluorescence fundus imaging revealed distinct single-cell probe activation as an indicator of RGC apoptosis induced by intravitreal NMDA injection that corresponded to the identical cells observed in retinal flat mounts of the same eye. Peak activation of probe in vivo was detected 12 hours post probe injection. Detectable fluorescent RGCs increased with increasing NMDA concentration; sensitivity of detection generally increased with increasing TcapQ488 dose until saturating at 0.387 nmol. Electroretinography following intravitreal injections of TcapQ488 showed no significant difference compared with control injections. We optimized the signal-to-noise ratio of a caspase-activatable cell penetrating peptide probe for quantitative non-invasive detection of RGC apoptosis in vivo. Full characterization of probe performance in this setting creates an important in

Nitrogen-Doped Carbon Quantum Dots as Fluorescent Probes for Sensitive and Selective Detection of Nitrite

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Zhibiao Feng

2017-11-01

Full Text Available Nitrites are the upstream precursors of the carcinogenic nitrosamines, which are widely found in the natural environment and many food products. It is important to develop a simple and sensitive sensor for detecting nitrites. In this work, a fluorescence probe based on nitrogen-doped carbon quantum dots (N-CQDs was developed for the sensitive and selective determination of nitrites. At pH 2, the fluorescence of N-CQDs can be selectively quenched by nitrite due to the fact N-nitroso compounds can be formed in the reaction of amide groups with nitrous acid, which results in fluorescence static quenching. Under optimal conditions, fluorescence intensity quenching upon addition of nitrite gives a satisfactory linear relationship covering the linear range of 0.2–20 μM, and the limit of detection (LOD is 40 nM. Moreover, this method has been successfully applied to the determination of nitrites in tap water, which indicates its great potential for monitoring of nitrites in environmental samples.

Thermodynamics of poly(7-methoxy-2-acetylbenzofurane methyl methacrylate-co-styrene) and poly(2-acetylbenzofurane methyl methacrylate-co-styrene)-probe interactions at different temperatures by inverse gas chromatography

International Nuclear Information System (INIS)

İlter, Zülfiye; Demir, Abdullah; Kaya, İsmet

2016-01-01

Highlights: • Thermodynamic of methacrylate-co-styrene polymers were studied by the inverse gas chromatography. • The sorption parameters of polymer-solute systems were determined under glass transition temperature of polymers. • The solubility parameter (δ 2 ) of the polymer was obtained from the slope and intercepts. • Flory-Huggins interaction parameter (χ 12 ∞ ) were determined for polymer-solute systems. - Abstract: In this study, some thermodynamic properties of poly(7-methoxy-2-acetylbenzofurane methyl methacrylate-co-styrene) Poly(MABMM-co-St) and poly(2-acetylbenzofurane methyl methacrylate-co-styrene) Poly(ABMM-co-St) were studied by the inverse gas chromatography (IGC) technique. The retention times (t r ) of selected organic probes were determined from the interactions with Poly(MABMM-co-St) and Poly(ABMM-co-St) of four groups of solvents with different chemical natures and polarities. Then, specific volume (V g 0 ) values of probes were calculated at different column temperatures. The glass transition temperatures (T g ) of Poly(MABMM-co-St) and Poly(ABMM-co-St) were found as 393, 413 K from inverse gas chromatography measurements, respectively. Under the glass transition temperatures adsorption heat (ΔH a ) and above the glass transition molar heat (ΔH 1 S ), free energies (ΔG 1 S ) and entropies (ΔS 1 S ) belonging to sorption for every probe were calculated from inverse gas chromatography measurements. The partial molar heat (ΔH 1 ∞ ), partial molar free energy (ΔG 1 ∞ ), Flory-Huggins interaction parameter (χ 12 ∞ ) and weight fraction activity coefficient (a 1 /w 1 ) ∞ , values for infinite dilute solutions were calculated for polymer-probe systems. The solubility parameter (δ 2 ) of the polymer was obtained from the slope and intercepts of Flory-Huggins interaction parameter (χ 12 ∞ ) graphs with solubility parameters (δ 1 ) of probes.

An evanescent wave biosensor--Part I: Fluorescent signal acquisition from step-etched fiber optic probes.

Science.gov (United States)

Anderson, G P; Golden, J P; Ligler, F S

1994-06-01

A fiber-optic biosensor capable of remote continuous monitoring has recently been designed. To permit sensing at locations separate from the optoelectronic instrumentation, long optical fibers are utilized. An evanescent wave immuno-probe is prepared by removing the cladding near the distal end of the fiber and covalently attaching antibodies to the core. Probes with a radius unaltered from that of the original core inefficiently returned the signal produced upon binding the fluorescent-labelled antigen. To elucidate the limiting factors in signal acquisition, a series of fibers with increasingly reduced probe core radius was examined. The results were consistent with the V-number mismatch, the difference in mode carrying capacity between the clad and unclad fiber, being a critical factor in limiting signal coupling from the fiber probe. However, it was also delineated that conditions which conserve excitation power, such that power in the evanescent wave is optimized, must also be met to obtain a maximal signal. The threshold sensitivity for the optimal step-etched fiber probe was improved by over 20-fold in an immunoassay, although, it was demonstrated that signal acquisition decreased along the probe length, suggesting that a sensor region of uniform radius is not ideal.

A Rotational BODIPY Nucleotide: An Environment-Sensitive Fluorescence-Lifetime Probe for DNA Interactions and Applications in Live-Cell Microscopy

Czech Academy of Sciences Publication Activity Database

Dziuba, Dmytro; Jurkiewicz, Piotr; Cebecauer, Marek; Hof, Martin; Hocek, Michal

2016-01-01

Roč. 55, č. 1 (2016), s. 174-178 ISSN 1433-7851 R&D Projects: GA ČR GBP206/12/G151; GA ČR(CZ) GC14-03141J Institutional support: RVO:61388963 ; RVO:61388955 Keywords : DNA * fluorescence spectroscopy * fluorescent probes * nucleosides * time-resolved spectroscopy Subject RIV: CC - Organic Chemistry ; BO - Biophysics (UFCH-W) Impact factor: 11.994, year: 2016

Analysis of DNA methylation in various swine tissues.

Directory of Open Access Journals (Sweden)

Chun Yang

Full Text Available DNA methylation is known to play an important role in regulating gene expression during biological development and tissue differentiation in eukaryotes. In this study, we used the fluorescence-labeled methylation-sensitive amplified polymorphism (F-MSAP method to assess the extent and pattern of cytosine methylation in muscle, heart, liver, spleen, lung, kidney and stomach from the swine strain Laiwu, and we also examined specific methylation patterns in the seven tissues. In total, 96,371 fragments, each representing a recognition site cleaved by either or both EcoRI + HpaII and EcoRI + MspI, the HpaII and MspI are isoschizomeric enzymes, were amplified using 16 pairs of selective primers. A total of 50,094 sites were found to be methylated at cytosines in seven tissues. The incidence of DNA methylation was approximately 53.99% in muscle, 51.24% in the heart, 50.18% in the liver, 53.31% in the spleen, 51.97% in the lung, 51.15% in the kidney and 53.39% in the stomach, as revealed by the incidence of differential digestion. Additionally, differences in DNA methylation levels imply that such variations may be related to specific gene expression during tissue differentiation, growth and development. Three types of bands were generated in the F-MSAP profile, the total numbers of these three types of bands in the seven tissues were 46,277, 24,801 and 25,293, respectively.In addition, different methylation patterns were observed in seven tissues from pig, and almost all of the methylation patterns detected by F-MSAP could be confirmed by Southern analysis using the isolated amplified fragments as probes. The results clearly demonstrated that the F-MSAP technique can be adapted for use in large-scale DNA methylation detection in the pig genome.

Development of a Novel Fiber Optic Sensor Combined with a Fluorescence Turn-on Probe for Cu (II Detection

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Ma J.

2013-04-01

Full Text Available Existing staining-based methodology for the detection of metal ions is not well suited for real-time or in situ use. This is a significant problem, given that these ions can have a considerable impact on both human health and the environment. Thus, there is growing interest and need for simple, rapid and in-situ monitoring techniques for the purpose of detecting various target analytes (e.g. heavy metals, which is of a significant importance in many fields ranging from environmental monitoring to the study of intracellular processes. Among various sensors developed, optical fiber-optic sensors (FOS, based on fluorescence, are one class of sensors that address this goal [1]. Optical fibers are ideal for environmental sensing applications because of their ability to transmit optical signals to and from the sensing region without the use of free-space optics. In this work, we present, for the first time, a simple FOS incorporating novel fluorescence turn-on mechanism [2] that could detect Cu (II as low as 10−4 M. Traditionally, fluorescence quenching or “turn-off” was used to detect Cu (II [3]. In recent years, fluorescence “turn-on” emerges as a preferable tool. The developed fiber-optic sensor has two fiber leads and one probe head. One fiber lead includes 6 fibers for He-Ne laser excitation light delivery (e-fibers. Another fiber lead has one receiving fiber (r-fiber connected to an Ocean Optics QE65000 scientific grade spectrometer, which is interrogated by a computer via USB connection. The SpectroSuite software is used to observe and to record all spectra. The probe head combines all fibers together to form a coaxial structure with the r-fiber placed in the center. The key component in the proposed fluorescent sensing system is a probe prepared by binding a receptor containing a zwitterionic chromophore (M1, through noncovalent interactions, to the fluorescent polymer (P1 resulting in quenching its emission. The sensing mechanism

Far-Red Fluorescent Probe for Imaging of Vicinal Dithiol-Containing Proteins in Living Cells Based on a pKa Shift Mechanism.

Science.gov (United States)

Zhang, Shengrui; Chen, Guojun; Wang, Yuanyuan; Wang, Qin; Zhong, Yaogang; Yang, Xiao-Feng; Li, Zheng; Li, Hua

2018-02-20

Vicinal dithiol-containing proteins (VDPs) play fundamental roles in intracellular redox homeostasis and are responsible for many diseases. In this work, we report a far-red fluorescence turn-on probe MCAs for VDPs exploiting the pK a shift of the imine functionality of the probe. MCAs is composed of a merocyanine Schiff base as the fluorescent reporter and a cyclic 1,3,2-dithiarsenolane as the specific ligand for VDPs. The imine pK a of MCAs is 4.8, and it exists predominantly in the Schiff base (SB) form at physiological pH. Due to the absence of a resonating positive charge, it absorbs at a relatively short wavelength and is essentially nonfluorescent. Upon selective binding to reduced bovine serum albumin (rBSA, selected as the model protein), MCAs was brought from aqueous media to the binding pockets of the protein, causing a large increase in pK a value of MCAs (pK a = 7.1). As a result, an increase in the protonated Schiff base (PSB) form of MCAs was observed at the physiological pH conditions, which in turn leads to a bathochromically shifted chromophore (λ abs = 634 nm) and a significant increase in fluorescence intensity (λ em = 657 nm) simultaneously. Furthermore, molecular dynamics simulations indicate that the salt bridges formed between the iminium in MCAs and the residues D72 and D517 in rBSA resist the dissociation of proton from the probe, thus inducing an increase of the pK a value. The proposed probe shows excellent sensitivity and specificity toward VDPs over other proteins and biologically relevant species and has been successfully applied for imaging of VDPs in living cells. We believe that the present pK a shift switching strategy may facilitate the development of new fluorescent probes that are useful for a wide range of applications.

Rotational and translational diffusions of fluorescent probes during gelation process

Science.gov (United States)

Hattori, Yusuke; Panizza, Pascal; Letamendia, Louis; Ushiki, Hideharu

2006-04-01

Gelation process has been investigated by using light scattering techniques in recent years. We measured both of rotational and translational motions of fluorescent probes during gelation process. The measurements were performed after the temperature quenched at 30 °C. As the results, rotational diffusion coefficient of fluorescein was decreased after 6.0 × 10 4 s and energy transfer rate was reduced after 2.0 × 10 4 s. We sorted the gelation process into the following three parts, (I) pre-gelation, (II) reduction of translational diffusion (aging), and (III) reduction of rotational diffusion with saturating translational diffusion (post-gelation). The time scale of the process was completely different from the results of other methods.

TaqMan MGB probe fluorescence real-time quantitative PCR for rapid detection of Chinese Sacbrood virus.

Directory of Open Access Journals (Sweden)

Ma Mingxiao

Full Text Available Sacbrood virus (SBV is a picorna-like virus that affects honey bees (Apis mellifera and results in the death of the larvae. Several procedures are available to detect Chinese SBV (CSBV in clinical samples, but not to estimate the level of CSBV infection. The aim of this study was develop an assay for rapid detection and quantification of this virus. Primers and probes were designed that were specific for CSBV structural protein genes. A TaqMan minor groove binder (MGB probe-based, fluorescence real-time quantitative PCR was established. The specificity, sensitivity and stability of the assay were assessed; specificity was high and there were no cross-reactivity with healthy larvae or other bee viruses. The assay was applied to detect CSBV in 37 clinical samples and its efficiency was compared with clinical diagnosis, electron microscopy observation, and conventional RT-PCR. The TaqMan MGB-based probe fluorescence real-time quantitative PCR for CSBV was more sensitive than other methods tested. This assay was a reliable, fast, and sensitive method that was used successfully to detect CSBV in clinical samples. The technology can provide a useful tool for rapid detection of CSBV. This study has established a useful protocol for CSBV testing, epidemiological investigation, and development of animal models.

Accumulation of polyunsaturated aldehydes in the gonads of the copepod Acartia tonsa revealed by tailored fluorescent probes.

Science.gov (United States)

Wolfram, Stefanie; Nejstgaard, Jens C; Pohnert, Georg

2014-01-01

Polyunsaturated aldehydes (PUAs) are released by several diatom species during predation. Besides other attributed activities, these oxylipins can interfere with the reproduction of copepods, important predators of diatoms. While intensive research has been carried out to document the effects of PUAs on copepod reproduction, little is known about the underlying mechanistic aspects of PUA action. Especially PUA uptake and accumulation in copepods has not been addressed to date. To investigate how PUAs are taken up and interfere with the reproduction in copepods we developed a fluorescent probe containing the α,β,γ,δ-unsaturated aldehyde structure element that is essential for the activity of PUAs as well as a set of control probes. We developed incubation and monitoring procedures for adult females of the calanoid copepod Acartia tonsa and show that the PUA derived fluorescent molecular probe selectively accumulates in the gonads of this copepod. In contrast, a saturated aldehyde derived probe of an inactive parent molecule was enriched in the lipid sac. This leads to a model for PUAs' teratogenic mode of action involving accumulation and covalent interaction with nucleophilic moieties in the copepod reproductive tissue. The teratogenic effect of PUAs can therefore be explained by a selective targeting of the molecules into the reproductive tissue of the herbivores, while more lipophilic but otherwise strongly related structures end up in lipid bodies.

Accumulation of polyunsaturated aldehydes in the gonads of the copepod Acartia tonsa revealed by tailored fluorescent probes.

Directory of Open Access Journals (Sweden)

Stefanie Wolfram

Full Text Available Polyunsaturated aldehydes (PUAs are released by several diatom species during predation. Besides other attributed activities, these oxylipins can interfere with the reproduction of copepods, important predators of diatoms. While intensive research has been carried out to document the effects of PUAs on copepod reproduction, little is known about the underlying mechanistic aspects of PUA action. Especially PUA uptake and accumulation in copepods has not been addressed to date. To investigate how PUAs are taken up and interfere with the reproduction in copepods we developed a fluorescent probe containing the α,β,γ,δ-unsaturated aldehyde structure element that is essential for the activity of PUAs as well as a set of control probes. We developed incubation and monitoring procedures for adult females of the calanoid copepod Acartia tonsa and show that the PUA derived fluorescent molecular probe selectively accumulates in the gonads of this copepod. In contrast, a saturated aldehyde derived probe of an inactive parent molecule was enriched in the lipid sac. This leads to a model for PUAs' teratogenic mode of action involving accumulation and covalent interaction with nucleophilic moieties in the copepod reproductive tissue. The teratogenic effect of PUAs can therefore be explained by a selective targeting of the molecules into the reproductive tissue of the herbivores, while more lipophilic but otherwise strongly related structures end up in lipid bodies.

Hydrothermal synthesis of functionalized CdS nanoparticles and their application as fluorescence probes in the determination of uracil and thymine

International Nuclear Information System (INIS)

Lu Yaxiang; Li Li; Ding Yaping; Zhang Fenfen; Wang Yaping; Yu Weijun

2012-01-01

A novel, sensitive, and convenient method for the determination of uracil and thymine by functionalized CdS nanoparticles (NPs) was proposed. CdS NPs were prepared by hydrothermal process and modified with thioglycollic acid (TGA) in aqueous solution. The fluorescence intensity of functionalized CdS NPs was quenched in the presence of uracil or thymine. Under optimal conditions, the relative fluorescence intensity (F 0 /F) was proportional to the concentration in the range of 9.0x10 -6 -1.0x10 -4 mol/L for uracil (r=0.9985) and 8.8x10 -7 -1.5x10 -4 mol/L for thymine (r=0.9960). The corresponding detection limits were 9.6x10 -7 mol/L and 3.2x10 -7 mol/L, respectively. In addition, the possible quenching mechanism was also discussed. - Highlights: → Nano-CdS fluorescence probes were synthesized with good optical properties. → Uracil and thymine were successfully detected by CdS fluorescence probes. → Wide linear ranges and low detection limits were obtained.

Synthesis and evaluation of [{sup 14}C]-Labelled and fluorescent-Tagged paclitaxel derivatives as new biological probes

Energy Technology Data Exchange (ETDEWEB)

Rao, C.S.; Chu, J.-J.; Lai, Y.-K. [Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan (China); Liu, R.-S. [Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan (China)

1998-11-01

Our present report deals with the preparation of hitherto unreported 7-([carbonyl-{sup 14}C]-acetyl)paclitaxel 4 and two new bioactive 7-substituted fluorescent taxoids (FITC 9 and rhodamine 11), as well as evaluation towards their applications as biological probes. The results in this report demonstrate that (a) the new paclitaxel derivatives 4, 9, 11 could be prepared with good yields starting from paclitaxel; (b) the [{sup 14}C]acetylation step was found to be better by using [{sup 14}C]acetic anhydride rather than [{sup 14}C]sodium acetate; (c) the radiochemical purity of 4 was 96% and its specific activity was 48 mCi/mmol; (d) the cytotoxicity of 4 was close to that of paclitaxel whereas 9, 11 were far less active than paclitaxel, but these cytotoxic levels were good enough for their biological applications; (e) the drug-quantitation by flow cytometric analysis using 9 and 11 was proved to be equally efficient with respect to the radioactivity-based determination employing 4; (f) the intracellular fluorescence mapping by 9 and 11 was found to be effective and the microtubule network pattern was visible in both the cases; (g) the overall fluorescence imaging efficiency was better with 11 while the intensity of fluorescence was higher with 9; (h) staining of nucleolus was observed in fluorescence studies of both 9 and 11. Based on these results, the newly prepared paclitaxel derivatives can be considered as efficient biological probes and should find further use in relevant applications. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

Dissociation dynamics of methylal

Energy Technology Data Exchange (ETDEWEB)

Beaud, P; Frey, H -M; Gerber, T; Mischler, B; Radi, P P; Tzannis, A -P [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1999-08-01

The dissociation of methylal is investigated using mass spectrometry, combined with a pyrolytic radical source and femtosecond pump probe experiments. Based on preliminary results two reaction paths of methylal dissociation are proposed and discussed. (author) 4 fig., 3 refs.

Characterisation of corrosion processes of using electron micro-probe, scanning probe microscopy and synchrotron-generated x-ray fluorescence imaging

International Nuclear Information System (INIS)

Neufeld, A.K.; Cole, I.S.; Furman, S.A.; Isaacs, H.S.

2002-01-01

Full text: With recent advances in computerized technology, the study of chemical reactions can now be visualized as they occur in real time and has resulted in analytical techniques with orders of magnitude greater sensitivity and resolution. This ability offers the corrosion scientist a unique opportunity to study the processes relevant to degradation science which could only be theoretically considered. Neufeld el al (1,2) have attempted to explain in great detail the mechanism of corrosion initiation of zinc by using X-ray micro-probe, Scanning Kelvin probe, and more recently by using synchrotron-generated X-rays and X-ray fluorescence imaging. New results are presented from the synchrotron studies where the transport of ions in-situ has been investigated. The synthesis of information from the techniques will also be discussed in its relevance to atmospheric corrosion processes. Copyright (2002) Australian Society for Electron Microscopy Inc

Binding-Induced Fluorescence of Serotonin Transporter Ligands: A Spectroscopic and Structural Study of 4-(4-(Dimethylamino)phenyl)-1-methylpyridinium (APP+) and APP+ Analogues

Science.gov (United States)

2014-01-01

The binding-induced fluorescence of 4-(4-(dimethylamino)-phenyl)-1-methylpyridinium (APP+) and two new serotonin transporter (SERT)-binding fluorescent analogues, 1-butyl-4-[4-(1-dimethylamino)phenyl]-pyridinium bromide (BPP+) and 1-methyl-4-[4-(1-piperidinyl)phenyl]-pyridinium (PPP+), has been investigated. Optical spectroscopy reveals that these probes are highly sensitive to their chemical microenvironment, responding to variations in polarity with changes in transition energies and responding to changes in viscosity or rotational freedom with emission enhancements. Molecular docking calculations reveal that the probes are able to access the nonpolar and conformationally restrictive binding pocket of SERT. As a result, the probes exhibit previously not identified binding-induced turn-on emission that is spectroscopically distinct from dyes that have accumulated intracellularly. Thus, binding and transport dynamics of SERT ligands can be resolved both spatially and spectroscopically. PMID:24460204

Fluorescence-Guided Probes of Aptamer-Targeted Gold Nanoparticles with Computed Tomography Imaging Accesses for in Vivo Tumor Resection.

Science.gov (United States)

Li, Cheng-Hung; Kuo, Tsung-Rong; Su, Hsin-Jan; Lai, Wei-Yun; Yang, Pan-Chyr; Chen, Jinn-Shiun; Wang, Di-Yan; Wu, Yi-Chun; Chen, Chia-Chun

2015-10-28

Recent development of molecular imaging probes for fluorescence-guided surgery has shown great progresses for determining tumor margin to execute the tissue resection. Here we synthesize the fluorescent gold nanoparticles conjugated with diatrizoic acid and nucleolin-targeted AS1411 aptamer. The nanoparticle conjugates exhibit high water-solubility, good biocompatibility, visible fluorescence and strong X-ray attenuation for computed tomography (CT) contrast enhancement. The fluorescent nanoparticle conjugates are applied as a molecular contrast agent to reveal the tumor location in CL1-5 tumor-bearing mice by CT imaging. Furthermore, the orange-red fluorescence emitting from the conjugates in the CL1-5 tumor can be easily visualized by the naked eyes. After the resection, the IVIS measurements show that the fluorescence signal of the nanoparticle conjugates in the tumor is greatly enhanced in comparison to that in the controlled experiment. Our work has shown potential application of functionalized nanoparticles as a dual-function imaging agent in clinical fluorescence-guided surgery.

A new fluorescence/PET probe for targeting intracellular human telomerase reverse transcriptase (hTERT) using Tat peptide-conjugated IgM

International Nuclear Information System (INIS)

Jung, Kyung oh; Youn, Hyewon; Kim, Seung Hoo; Kim, Young-Hwa; Kang, Keon Wook; Chung, June-Key

2016-01-01

Despite an increasing need for methods to visualize intracellular proteins in vivo, the majority of antibody-based imaging methods available can only detect membrane proteins. The human telomerase reverse transcriptase (hTERT) is an intracellular target of great interest because of its high expression in several types of cancer. In this study, we developed a new probe for hTERT using the Tat peptide. An hTERT antibody (IgG or IgM) was conjugated with the Tat peptide, a fluorescence dye and "6"4Cu. HT29 (hTERT+) and U2OS (hTERT−) were used to visualize the intracellular hTERT. The hTERT was detected by RT-PCR and western blot. Fluorescence signals for hTERT were obtained by confocal microscopy, live cell imaging, and analyzed by Tissue-FAXS. In nude mice, tumors were visualized using the fluorescence imaging devices Maestro™ and PETBOX. In RT-PCR and western blot, the expression of hTERT was detected in HT29 cells, but not in U2OS cells. Fluorescence signals were clearly observed in HT29 cells and in U2OS cells after 1 h of treatment, but signals were only detected in HT29 cells after 24 h. Confocal microscopy showed that 9.65% of U2OS and 78.54% of HT29 cells had positive hTERT signals. 3D animation images showed that the probe could target intranuclear hTERT in the nucleus. In mice models, fluorescence and PET imaging showed that hTERT in HT29 tumors could be efficiently visualized. In summary, we developed a new method to visualize intracellular and intranuclear proteins both in vitro and in vivo. - Highlights: • We developed new probes for imaging hTERT using Tat-conjugated IgM antibodies labeled with a fluorescent dye and radioisotope. • This probes could be used to overcome limitation of conventional antibody imaging system in live cell imaging. • This system could be applicable to monitor intracellular and intranuclear proteins in vitro and in vivo.

A new fluorescence/PET probe for targeting intracellular human telomerase reverse transcriptase (hTERT) using Tat peptide-conjugated IgM

Energy Technology Data Exchange (ETDEWEB)

Jung, Kyung oh [Department of Nuclear Medicine, Seoul National University College of Medicine (Korea, Republic of); Biomedical Sciences, Seoul National University College of Medicine (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine (Korea, Republic of); Tumor Microenvironment Global Core Research Center, Seoul National University (Korea, Republic of); Youn, Hyewon, E-mail: hwyoun@snu.ac.kr [Department of Nuclear Medicine, Seoul National University College of Medicine (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine (Korea, Republic of); Tumor Microenvironment Global Core Research Center, Seoul National University (Korea, Republic of); Cancer Imaging Center, Seoul National University Hospital, Seoul (Korea, Republic of); Kim, Seung Hoo [Department of Nuclear Medicine, Seoul National University College of Medicine (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine (Korea, Republic of); Kim, Young-Hwa [Department of Nuclear Medicine, Seoul National University College of Medicine (Korea, Republic of); Biomedical Sciences, Seoul National University College of Medicine (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine (Korea, Republic of); Kang, Keon Wook [Department of Nuclear Medicine, Seoul National University College of Medicine (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine (Korea, Republic of); Chung, June-Key, E-mail: jkchung@snu.ac.kr [Department of Nuclear Medicine, Seoul National University College of Medicine (Korea, Republic of); Biomedical Sciences, Seoul National University College of Medicine (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine (Korea, Republic of); Tumor Microenvironment Global Core Research Center, Seoul National University (Korea, Republic of)

2016-08-26

Despite an increasing need for methods to visualize intracellular proteins in vivo, the majority of antibody-based imaging methods available can only detect membrane proteins. The human telomerase reverse transcriptase (hTERT) is an intracellular target of great interest because of its high expression in several types of cancer. In this study, we developed a new probe for hTERT using the Tat peptide. An hTERT antibody (IgG or IgM) was conjugated with the Tat peptide, a fluorescence dye and {sup 64}Cu. HT29 (hTERT+) and U2OS (hTERT−) were used to visualize the intracellular hTERT. The hTERT was detected by RT-PCR and western blot. Fluorescence signals for hTERT were obtained by confocal microscopy, live cell imaging, and analyzed by Tissue-FAXS. In nude mice, tumors were visualized using the fluorescence imaging devices Maestro™ and PETBOX. In RT-PCR and western blot, the expression of hTERT was detected in HT29 cells, but not in U2OS cells. Fluorescence signals were clearly observed in HT29 cells and in U2OS cells after 1 h of treatment, but signals were only detected in HT29 cells after 24 h. Confocal microscopy showed that 9.65% of U2OS and 78.54% of HT29 cells had positive hTERT signals. 3D animation images showed that the probe could target intranuclear hTERT in the nucleus. In mice models, fluorescence and PET imaging showed that hTERT in HT29 tumors could be efficiently visualized. In summary, we developed a new method to visualize intracellular and intranuclear proteins both in vitro and in vivo. - Highlights: • We developed new probes for imaging hTERT using Tat-conjugated IgM antibodies labeled with a fluorescent dye and radioisotope. • This probes could be used to overcome limitation of conventional antibody imaging system in live cell imaging. • This system could be applicable to monitor intracellular and intranuclear proteins in vitro and in vivo.

Validation of a simple and fast method to quantify in vitro mineralization with fluorescent probes used in molecular imaging of bone

International Nuclear Information System (INIS)

Moester, Martiene J.C.; Schoeman, Monique A.E.; Oudshoorn, Ineke B.; Beusekom, Mara M. van; Mol, Isabel M.; Kaijzel, Eric L.; Löwik, Clemens W.G.M.; Rooij, Karien E. de

2014-01-01

Highlights: •We validate a simple and fast method of quantification of in vitro mineralization. •Fluorescently labeled agents can detect calcium deposits in the mineralized matrix of cell cultures. •Fluorescent signals of the probes correlated with Alizarin Red S staining. -- Abstract: Alizarin Red S staining is the standard method to indicate and quantify matrix mineralization during differentiation of osteoblast cultures. KS483 cells are multipotent mouse mesenchymal progenitor cells that can differentiate into chondrocytes, adipocytes and osteoblasts and are a well-characterized model for the study of bone formation. Matrix mineralization is the last step of differentiation of bone cells and is therefore a very important outcome measure in bone research. Fluorescently labelled calcium chelating agents, e.g. BoneTag and OsteoSense, are currently used for in vivo imaging of bone. The aim of the present study was to validate these probes for fast and simple detection and quantification of in vitro matrix mineralization by KS483 cells and thus enabling high-throughput screening experiments. KS483 cells were cultured under osteogenic conditions in the presence of compounds that either stimulate or inhibit osteoblast differentiation and thereby matrix mineralization. After 21 days of differentiation, fluorescence of stained cultures was quantified with a near-infrared imager and compared to Alizarin Red S quantification. Fluorescence of both probes closely correlated to Alizarin Red S staining in both inhibiting and stimulating conditions. In addition, both compounds displayed specificity for mineralized nodules. We therefore conclude that this method of quantification of bone mineralization using fluorescent compounds is a good alternative for the Alizarin Red S staining

Validation of a simple and fast method to quantify in vitro mineralization with fluorescent probes used in molecular imaging of bone

Energy Technology Data Exchange (ETDEWEB)

Moester, Martiene J.C. [Department of Radiology, Leiden University Medical Center (Netherlands); Schoeman, Monique A.E. [Department of Orthopedic Surgery, Leiden University Medical Center (Netherlands); Oudshoorn, Ineke B. [Department of Radiology, Leiden University Medical Center (Netherlands); Percuros BV, Leiden (Netherlands); Beusekom, Mara M. van [Department of Radiology, Leiden University Medical Center (Netherlands); Mol, Isabel M. [Department of Radiology, Leiden University Medical Center (Netherlands); Percuros BV, Leiden (Netherlands); Kaijzel, Eric L.; Löwik, Clemens W.G.M. [Department of Radiology, Leiden University Medical Center (Netherlands); Rooij, Karien E. de, E-mail: k.e.de_rooij@lumc.nl [Department of Radiology, Leiden University Medical Center (Netherlands); Percuros BV, Leiden (Netherlands)

2014-01-03

Highlights: •We validate a simple and fast method of quantification of in vitro mineralization. •Fluorescently labeled agents can detect calcium deposits in the mineralized matrix of cell cultures. •Fluorescent signals of the probes correlated with Alizarin Red S staining. -- Abstract: Alizarin Red S staining is the standard method to indicate and quantify matrix mineralization during differentiation of osteoblast cultures. KS483 cells are multipotent mouse mesenchymal progenitor cells that can differentiate into chondrocytes, adipocytes and osteoblasts and are a well-characterized model for the study of bone formation. Matrix mineralization is the last step of differentiation of bone cells and is therefore a very important outcome measure in bone research. Fluorescently labelled calcium chelating agents, e.g. BoneTag and OsteoSense, are currently used for in vivo imaging of bone. The aim of the present study was to validate these probes for fast and simple detection and quantification of in vitro matrix mineralization by KS483 cells and thus enabling high-throughput screening experiments. KS483 cells were cultured under osteogenic conditions in the presence of compounds that either stimulate or inhibit osteoblast differentiation and thereby matrix mineralization. After 21 days of differentiation, fluorescence of stained cultures was quantified with a near-infrared imager and compared to Alizarin Red S quantification. Fluorescence of both probes closely correlated to Alizarin Red S staining in both inhibiting and stimulating conditions. In addition, both compounds displayed specificity for mineralized nodules. We therefore conclude that this method of quantification of bone mineralization using fluorescent compounds is a good alternative for the Alizarin Red S staining.

Analysis of chemical equilibrium of silicon-substituted fluorescein and its application to develop a scaffold for red fluorescent probes.

Science.gov (United States)

Hirabayashi, Kazuhisa; Hanaoka, Kenjiro; Takayanagi, Toshio; Toki, Yuko; Egawa, Takahiro; Kamiya, Mako; Komatsu, Toru; Ueno, Tasuku; Terai, Takuya; Yoshida, Kengo; Uchiyama, Masanobu; Nagano, Tetsuo; Urano, Yasuteru

2015-09-01

Fluorescein is a representative green fluorophore that has been widely used as a scaffold of practically useful green fluorescent probes. Here, we report synthesis and characterization of a silicon-substituted fluorescein, i.e., 2-COOH TokyoMagenta (2-COOH TM), which is a fluorescein analogue in which the O atom at the 10' position of the xanthene moiety of fluorescein is replaced with a Si atom. This fluorescein analogue forms a spirolactone ring via intramolecular nucleophilic attack of the carboxylic group in a pH-dependent manner. Consequently, 2-COOH TM exhibits characteristic large pH-dependent absorption and fluorescence spectral changes: (1) 2-COOH TM is colorless at acidic pH, whereas fluorescein retains observable absorption and fluorescence even at acidic pH, and the absorption maximum is also shifted; (2) the absorption spectral change occurs above pH 7.0 for 2-COOH TM and below pH 7.0 for fluorescein; (3) 2-COOH TM shows a much sharper pH response than fluorescein because of its pKa inversion, i.e., pKa1 > pKa2. These features are also different from those of a compound without the carboxylic group, 2-Me TokyoMagenta (2-Me TM). Analysis of the chemical equilibrium between pH 3.0 and 11.0 disclosed that 2-COOH TM favors the colorless and nonfluorescent lactone form, compared with fluorescein. Substitution of Cl atoms at the 4' and 5' positions of the xanthene moiety of 2-COOH TM to obtain 2-COOH DCTM shifted the equilibrium so that the new derivative exists predominantly in the strongly fluorescent open form at physiological pH (pH 7.4). To demonstrate the practical utility of 2-COOH DCTM as a novel scaffold for red fluorescent probes, we employed it to develop a probe for β-galactosidase.

A homogeneous and “off–on” fluorescence aptamer-based assay for chloramphenicol using vesicle quantum dot-gold colloid composite probes

Energy Technology Data Exchange (ETDEWEB)

Miao, Yang-Bao [State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211 (China); Ren, Hong-Xia [Key Laboratory of Asymmetric Synthesis and Chirotechnology of Sichuan Province, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041 (China); University of Chinese Academy of Sciences, Beijing 10049 (China); Gan, Ning, E-mail: ganning@nbu.edu.cn [State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211 (China); Zhou, You [State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211 (China); Cao, Yuting, E-mail: caoyuting@nbu.edu.cn [State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211 (China); Li, Tianhua [State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211 (China); Chen, Yinji [Faculty of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210000 (China)

2016-07-27

In this work, a novel homogeneous and signal “off–on” aptamer based fluorescence assay was successfully developed to detect chloramphenicol (CAP) residues in food based on the fluorescence resonance energy transfer (FRET). The vesicle nanotracer was prepared through labeling single stranded DNA binding protein (SSB) on limposome-CdSe/ZnS quantum dot (SSB/L-QD) complexes. It was worth mentioning that the signal tracer (SSB/L-QD) with vesicle shape, which was fabricated being encapsulated with a number of quantum dots and SSB. The nanotracer has excellent signal amplification effects. The vesicle composite probe was formed by combining aptamer labeled nano-gold (Au-Apt) and SSB/L-QD. Which based on SSB's specific affinity towards aptamer. This probe can't emit fluoresce which is in “off” state because the signal from SSB/L-QD as donor can be quenched by the Au-aptas acceptor. When CAP was added in the composite probe solution, the aptamer on the Au-Apt can be preferentially bounded with CAP then release from the composite probe, which can turn the “off” signal of SSB/L-QD tracer into “on” state. The assay indicates excellent linear response to CAP from 0.001 nM to 10 nM and detection limit down to 0.3 pM. The vesicle probes with size of 88 nm have strong signal amplification. Because a larger number of QDs can be labeled inside the double phosphorus lipid membrane. Besides, it was employed to detect CAP residues in the milk samples with results being agreed well with those from ELISA, verifying its accuracy and reliability. - Highlights: • Homogeneous and “off–on” fluorescence aptamer-based assay was developed to detect chloramphenicol (CAP) residues in food. • This probe was fabricated based on a vesicle QDs signal tracer (SSB/L-QD) combining with Au-Aptamer. • The detection mechanism was based on FRET with high specificity. • The results for CAP detection in the milk samples agreed well with those from ELISA, while

Thioglycolic acid-capped CuInS{sub 2}/ZnS quantum dots as fluorescent probe for cobalt ion detection

Energy Technology Data Exchange (ETDEWEB)

Zi, Lili; Huang, Yu [Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, 4 Tongjia Lane, Gulou District, Nanjing 210009 (China); Department of Analytical Chemistry, China Pharmaceutical University, 24 Tongjia Lane, Gulou District, Nanjing 210009 (China); Yan, Zhengyu, E-mail: yanzhengyujiang@126.com [Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, 4 Tongjia Lane, Gulou District, Nanjing 210009 (China); Department of Analytical Chemistry, China Pharmaceutical University, 24 Tongjia Lane, Gulou District, Nanjing 210009 (China); Liao, Shenghua, E-mail: liaoshenghuacpu@hotmail.com [Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, 4 Tongjia Lane, Gulou District, Nanjing 210009 (China); Department of Analytical Chemistry, China Pharmaceutical University, 24 Tongjia Lane, Gulou District, Nanjing 210009 (China)

2014-04-15

A novel sensing fluorescent probe based on the fluorescence quenching of the thioglycolic acid-capped CuInS{sub 2}/ZnS quantum dots (CuInS{sub 2}/ZnS/TGA QDs) was established for cobalt ions detection. The fluorescence quenching of CuInS{sub 2}/ZnS/TGA QDs was due to the increasing surface deficiency and the inner-filter effect, which were attributed to the reaction between Co{sup 2+} and sulfur bonds on the surface of QDs. The quenching curve could be fitted by a typical Stern–Volmer-type equation, with a linear relationship between the quenching efficiency and the concentration of cobalt ions in the range of 0.3012–90.36 μmol L{sup −1}. And the detection limit (S/N=3) for Co{sup 2+} was 0.16 μmol L{sup −1}. Therefore, the established probe provided a simple, rapid, cheap and sensitive method for Co{sup 2+} detection. In a word, this method can be used to detect Co{sup 2+} in the environment. -- Highlights: • The CuInS2/ZnS QDs were used for the first time as a fluorescent probe for Co{sup 2+} detection. • The dramatic color change could be observed when Co{sup 2+} was added into the QDs solution. • The quenching of QDs was due to the increasing surface deficiency and the inner-filter effect. • This rapid, cheap and sensitive method was applied to the detection of Co{sup 2+} in simulated water.

L-cysteine-capped core/shell/shell quantum dot-graphene oxide nanocomposite fluorescence probe for polycyclic aromatic hydrocarbon detection.

Science.gov (United States)

Adegoke, Oluwasesan; Forbes, Patricia B C

2016-01-01

Environmental pollutants, such as the polycyclic aromatic hydrocarbons (PAHs), become widely distributed in the environment after emission from a range of sources, and they have potential biological effects, including toxicity and carcinogenity. In this work, we have demonstrated the analytical potential of a covalently linked L-cysteine-capped CdSeTe/ZnSe/ZnS core/shell/shell quantum dot (QD)-graphene oxide (GO) nanocomposite fluorescence probe to detect PAH compounds in aqueous solution. Water-soluble L-cysteine-capped CdSeTe/ZnSe/ZnS QDs were synthesized for the first time and were covalently bonded to GO. The fluorescence of the QD-GO nanocomposite was enhanced relative to the unconjugated QDs. Various techniques including TEM, SEM, HRSEM, XRD, Raman, FT-IR, UV/vis and fluorescence spectrophotometry were employed to characterize both the QDs and the QD-GO nanocomposite. Four commonly found priority PAH analytes namely; phenanthrene (Phe), anthracene (Ant), pyrene (Py) and naphthalene (Naph), were tested and it was found that each of the PAH analytes enhanced the fluorescence of the QD-GO probe. Phe was selected for further studies as the PL enhancement was significantly greater for this PAH. A limit of detection (LOD) of 0.19 µg/L was obtained for Phe under optimum conditions, whilst the LOD of Ant, Py and Naph were estimated to be ~0.26 µg/L. The fluorescence detection mechanism is proposed. Copyright © 2015 Elsevier B.V. All rights reserved.

Development and cytotoxicity of Schiff base derivative as a fluorescence probe for the detection of L-Arginine

Science.gov (United States)

Shang, Xuefang; Li, Jie; Guo, Kerong; Ti, Tongyu; Wang, Tianyun; Zhang, Jinlian

2017-04-01

Inspired from biological counter parts, chemical modification of Schiff base derivatives with function groups may provide a highly efficient method to detect amino acids. Therefore, a fluorescent probe involving Schiff base and hydroxyl group has been designed and prepared, which showed high response and specificity for Arginine (Arg) among normal eighteen standard kinds of amino acids (Alanine, Valine, Leucine, Isoleucine, Methionine, Asparticacid, Glutamicacid, Arginine, Glycine, Serine, Threonine, Asparagine, Phenylalanine, Histidine, Tryptophan, Proline, Lysine, Glutamine, Tyrosine and Cysteine). Furthermore, theoretical investigation further illustrated the possible binding mode in the host-guest interaction and the roles of molecular frontier orbitals in molecular interplay. In addition, the synthesized fluorescent probe exhibited high binding ability for Arg and low cytotoxicity to MCF-7 cells over a concentration range of 0-200 μg mL-1 which can be also used as a biosensor for the Arg detection in vivo.

Probing Contaminant-Induced Alterations in Chlorophyll Fluorescence by AC-Dielectrophoresis-Based 2D-Algal Array

Directory of Open Access Journals (Sweden)

Coralie Siebman

2018-02-01

Full Text Available The investigation of contaminant impact on algae requires rapid and reliable cell collection and optical detection. The capability of alternative current (AC dielectrophoresis (DEP collection of whole cell arrays with combined fluorescence microscopy detection to follow the alterations of chlorophyll fluorescence during environmental contaminant exposure was explored. The application of an AC-field of 100 V cm−1, 100 Hz for 30 min to capture and immobilize the cells of green alga Chlamydomonas reinhardtii in two-dimensional (2D arrays does not induce changes in chlorophyll fluorescence. The results demonstrate that DEP-based 2D-arrays allow non-invasive detection of chlorophyll fluorescence change upon exposure to high concentrations of copper oxide nanoparticles and ionic copper. These results were in agreement with data obtained by flow cytometry used as a comparative method. The tool was also applied to follow the effect of a number of ubiquitous contaminants such as inorganic mercury, methylmercury, and diuron. However, a statistically significant short-term effect was observed only for mercury. Overall, DEP-based 2D-arrays of algal cells with fluorescence detection appear to be suitable for stain-free probing the effects on the photosynthetic microorganisms in highly polluted environment.

Observing Fluorescent Probes in Living Cells using a Low-Cost LED Flashlight Retrofitted to a Common Vintage Light Microscope

Directory of Open Access Journals (Sweden)

G. A. Babbitt

2013-03-01

Full Text Available While the application of molecular biological techniques based upon fluorescent probes has rapidly expanded over recent decades, the equipment cost of fluorescent microscopy has largely prevented its adoption in the college and high school classroom. We offer a simple solution to this problem by describing in detail how to build with simple tools, a fluorescent microscope using a common brand of colored LED flashlights and second-hand components of vintage Nikon microscopes. This extremely low cost solution is qualitatively compared to an expensive modern Zeiss system.

Synthesis and spectral properties of novel chlorinated pH fluorescent probes

International Nuclear Information System (INIS)

Wu Xianglong; Jin Xilang; Wang Yunxia; Mei Qibing; Li Jianli; Shi Zhen

2011-01-01

Eight chlorinated fluoresceins have been synthesized by the reaction of chlorinated resorcinols with 4, 5, 6, 7-tetrachlorophthalic anhydride or 3, 6-dichloro-4-carboxyphthalic anhydride in the presence of methanesulfonic acid. The spectral properties of the chlorinated fluoresceins were studied. It was found that they have absorption and emission maxima at long wavelengths and high fluorescence quantum yields. Emission spectra of chlorinated fluoresceins shifted towards long wavelength with increase in chlorine. pH-dependent properties of chlorinated fluoresceins were studied in detail. These compounds showed a strongly pH-sensitive range of 3.0-7.0. These chlorinated fluoresceins will be used as pH probes for pH measurement of the cell because of the high quantum yield and strong pH-sensitivity. - Research highlights: → Eight chlorinated fluoresceins have been synthesized in the presence of methanesulfonic acid. → Emission spectra of these compounds shifted towards long wavelength with increase in chlorine. → Eight chlorinated fluoresceins showed a strongly pH-sensitive range of 3.0-7.0. → They have emission maxima at long wavelengths and high fluorescence quantum yields.

Functional imaging in bulk tissue specimens using optical emission tomography: fluorescence preservation during optical clearing

International Nuclear Information System (INIS)

Sakhalkar, H S; Dewhirst, M; Oliver, T; Cao, Y; Oldham, M

2007-01-01

Optical emission computed tomography (optical-ECT) is a technique for imaging the three-dimensional (3D) distribution of fluorescent probes in biological tissue specimens with high contrast and spatial resolution. In optical-ECT, functional information can be imaged by (i) systemic application of functional labels (e.g. fluorophore labelled proteins) and/or (ii) endogenous expression of fluorescent reporter proteins (e.g. red fluorescent protein (RFP), green fluorescent protein (GFP)) in vivo. An essential prerequisite for optical-ECT is optical clearing, a procedure where tissue specimens are made transparent to light by sequential perfusion with fixing, dehydrating and clearing agents. In this study, we investigate clearing protocols involving a selection of common fixing (4% buffered paraformaldehyde (PFA), methanol and ethanol), dehydrating (methanol and ethanol) and clearing agents (methyl salicylate and benzyl-alcohol-benzyl-benzoate (BABB)) in order to determine a 'fluorescence friendly' clearing procedure. Cell culture experiments were employed to optimize the sequence of chemical treatments that best preserve fluorescence. Texas red (TxRed), fluorescein isothiocyanate (FITC), RFP and GFP were tested as fluorophores and fluorescent reporter proteins of interest. Fluorescent and control cells were imaged on a microscope using a DSred2 and FITC filter set. The most promising clearing protocols of cell culture experiments were applied to whole xenograft tumour specimens, to test their effectiveness in large unsectioned samples. Fluorescence of TxRed/FITC fluorophores was not found to be significantly affected by any of the test clearing protocols. RFP and GFP fluorescence, however, was found to be significantly greater when cell fixation was in ethanol. Fixation in either PFA or methanol resulted in diminished fluorescence. After ethanol fixation, the RFP and GFP fluorescence proved remarkably robust to subsequent exposure to either methyl salicylate or BABB

Functional imaging in bulk tissue specimens using optical emission tomography: fluorescence preservation during optical clearing

Energy Technology Data Exchange (ETDEWEB)

Sakhalkar, H S [Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710 (United States); Dewhirst, M [Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710 (United States); Oliver, T [Department of Cell Biology, Duke University Medical Center, Durham, NC 27710 (United States); Cao, Y [Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710 (United States); Oldham, M [Department of Radiation Oncology Physics, and Biomedical Engineering, Duke University Medical Center, Durham, NC 27710 (United States)

2007-04-21

Optical emission computed tomography (optical-ECT) is a technique for imaging the three-dimensional (3D) distribution of fluorescent probes in biological tissue specimens with high contrast and spatial resolution. In optical-ECT, functional information can be imaged by (i) systemic application of functional labels (e.g. fluorophore labelled proteins) and/or (ii) endogenous expression of fluorescent reporter proteins (e.g. red fluorescent protein (RFP), green fluorescent protein (GFP)) in vivo. An essential prerequisite for optical-ECT is optical clearing, a procedure where tissue specimens are made transparent to light by sequential perfusion with fixing, dehydrating and clearing agents. In this study, we investigate clearing protocols involving a selection of common fixing (4% buffered paraformaldehyde (PFA), methanol and ethanol), dehydrating (methanol and ethanol) and clearing agents (methyl salicylate and benzyl-alcohol-benzyl-benzoate (BABB)) in order to determine a 'fluorescence friendly' clearing procedure. Cell culture experiments were employed to optimize the sequence of chemical treatments that best preserve fluorescence. Texas red (TxRed), fluorescein isothiocyanate (FITC), RFP and GFP were tested as fluorophores and fluorescent reporter proteins of interest. Fluorescent and control cells were imaged on a microscope using a DSred2 and FITC filter set. The most promising clearing protocols of cell culture experiments were applied to whole xenograft tumour specimens, to test their effectiveness in large unsectioned samples. Fluorescence of TxRed/FITC fluorophores was not found to be significantly affected by any of the test clearing protocols. RFP and GFP fluorescence, however, was found to be significantly greater when cell fixation was in ethanol. Fixation in either PFA or methanol resulted in diminished fluorescence. After ethanol fixation, the RFP and GFP fluorescence proved remarkably robust to subsequent exposure to either methyl salicylate

Synthesis of water-soluble, ring-substituted squaraine dyes and their evaluation as fluorescent probes and labels

Energy Technology Data Exchange (ETDEWEB)

Tatarets, Anatoliy L. [SSI ' Institute for Single Crystals' of the National Academy of Sciences of Ukraine, 60 Lenin Ave., Kharkov 61001 (Ukraine); Fedyunyayeva, Irina A. [SSI ' Institute for Single Crystals' of the National Academy of Sciences of Ukraine, 60 Lenin Ave., Kharkov 61001 (Ukraine); Dyubko, Tatyana S. [SSI ' Institute for Single Crystals' of the National Academy of Sciences of Ukraine, 60 Lenin Ave., Kharkov 61001 (Ukraine); Povrozin, Yevgeniy A. [SSI ' Institute for Single Crystals' of the National Academy of Sciences of Ukraine, 60 Lenin Ave., Kharkov 61001 (Ukraine); Doroshenko, Andrey O. [Institute of Chemistry, V.N. Karazin National University, 4 Svobody Sq., Kharkov 61077 (Ukraine); Terpetschnig, Ewald A. [SETA BioMedicals, LLC, 2014 Silver Ct East, Urbana, IL 61801 (United States) and ISS, Inc., 1602 Newton Drive, Champaign, IL 61822 (United States)]. E-mail: ewaldte@juno.com; Patsenker, Leonid D. [SSI ' Institute for Single Crystals' of the National Academy of Sciences of Ukraine, 60 Lenin Ave., Kharkov 61001 (Ukraine); SETA BioMedicals, LLC, 2014 Silver Ct East, Urbana, IL 61801 (United States)

2006-06-16

A series of ring-substituted squaraines absorbing and emitting in the red and NIR spectral region was synthesized and their spectral and photophysical properties (quantum yields, fluorescence lifetimes) and photostabilities were measured and compared to Cy5, a commonly used fluorescent label. The absorption maxima in aqueous media were found to be between 628 and 667 nm and the emission maxima are between 642 and 685 nm. Squaraine dyes exhibit high extinction coefficients (163,000-265,000 M{sup -1} cm{sup -1}) and lower quantum yields (2-7%) in aqueous buffer but high quantum yields (up to 45%) and long fluorescence lifetimes (up to 3.3 ns) in presence of BSA. Dicyanomethylene- and thio-substituted squaraines exhibit an additional absorption around 400 nm with extinction coefficients between 21,500 and 44,500 M{sup -1} cm{sup -1}. These dyes are excitable not only with red but also with blue diode lasers or light emitting diodes. Due to the favourable spectral and photophysical properties these dyes can be used as fluorescent probes and labels for intensity- and fluorescence lifetime-based biomedical applications.

Synthesis of water-soluble, ring-substituted squaraine dyes and their evaluation as fluorescent probes and labels

International Nuclear Information System (INIS)

Tatarets, Anatoliy L.; Fedyunyayeva, Irina A.; Dyubko, Tatyana S.; Povrozin, Yevgeniy A.; Doroshenko, Andrey O.; Terpetschnig, Ewald A.; Patsenker, Leonid D.

2006-01-01

A series of ring-substituted squaraines absorbing and emitting in the red and NIR spectral region was synthesized and their spectral and photophysical properties (quantum yields, fluorescence lifetimes) and photostabilities were measured and compared to Cy5, a commonly used fluorescent label. The absorption maxima in aqueous media were found to be between 628 and 667 nm and the emission maxima are between 642 and 685 nm. Squaraine dyes exhibit high extinction coefficients (163,000-265,000 M -1 cm -1 ) and lower quantum yields (2-7%) in aqueous buffer but high quantum yields (up to 45%) and long fluorescence lifetimes (up to 3.3 ns) in presence of BSA. Dicyanomethylene- and thio-substituted squaraines exhibit an additional absorption around 400 nm with extinction coefficients between 21,500 and 44,500 M -1 cm -1 . These dyes are excitable not only with red but also with blue diode lasers or light emitting diodes. Due to the favourable spectral and photophysical properties these dyes can be used as fluorescent probes and labels for intensity- and fluorescence lifetime-based biomedical applications

Detection of malachite green in fish based on magnetic fluorescent probe of CdTe QDs/nano-Fe3O4@MIPs

Science.gov (United States)

Wu, Le; Lin, Zheng-Zhong; Zeng, Jun; Zhong, Hui-Ping; Chen, Xiao-Mei; Huang, Zhi-Yong

2018-05-01

A magnetic fluorescent probe of CdTe QDs/nano-Fe3O4@MIPs was prepared using CdTe QDs and Fe3O4 nanoparticles as co-nucleus and molecularly imprinted polymers (MIPs) as specific recognition sites based on a reverse microemulsion method. With the specific enrichment and magnetic separation properties, the probe of CdTe QDs/nano-Fe3O4@MIPs was used to detect malachite green (MG) in fish samples. The TEM analysis showed that the particles of CdTe QDs/nano-Fe3O4@MIPs were spherical with average diameter around 53 nm, and a core-shell structure was well-shaped with several Fe3O4 nanoparticles and CdTe QDs embedded in each of the microsphere. Quick separation of the probes from solutions could be realized with a magnet, indicating the excellent magnetic property of CdTe QDs/nano-Fe3O4@MIPs. The probe exhibited high specific adsorption towards MG and excellent fluorescence emission at λem 598 nm. The fluorescence of CdTe QDs/nano-Fe3O4@MIPs could be linearly quenched by MG at the concentrations from 0.025 to 1.5 μmol L-1. The detection limit was 0.014 μmol L-1. The average recovery of spiked MG in fish samples was 105.2%. The result demonstrated that the as-prepared CdTe QDs/nano-Fe3O4@MIPs could be used as a probe to the detection of trace MG in fish samples.

Dansyl-8-aminoquinoline as a sensitive pH fluorescent probe with dual-responsive ranges in aqueous solutions.

Science.gov (United States)

Zhang, Min; Zheng, Shuyu; Ma, Liguo; Zhao, Meili; Deng, Lengfang; Yang, Liting; Ma, Li-Jun

2014-04-24

A sensitive pH fluorescent probe based on dansyl group, dansyl-8-aminoquinoline (DAQ), has been synthesized. The probe showed dual-responsive ranges to pH changes, one range from 2.00 to 7.95 and another one from 7.95 to 10.87 in aqueous solution, as it showed pKa values of 5.73 and 8.56 under acid and basic conditions, respectively. Furthermore, the pH response mechanism of the probe was explored successfully by using NMR spectra. The results indicated that the responses of DAQ to pH changes should attribute to the protonation of the nitrogen atom in the dimethylamino group and deprotonation of sulfonamide group. Copyright © 2014. Published by Elsevier B.V.

Spectrofluorimetric determination of trace amount of coenzyme II using ciprofloxacin-terbium complex as a fluorescent probe

International Nuclear Information System (INIS)

Bian Weiwei; Wang Yusheng; Zhu Xiaojing; Jiang Chongqiu

2006-01-01

A new spectrofluorimetric method was developed for the determination of trace amount of nicotinamide adenine dinucleotide phosphate (NADP). Using terbium ion (Tb 3+ )-ciprofloxacin (CIP) complex as a fluorescent probe, in the buffer solution of pH=9.00, NADP can remarkably enhance the fluorescence intensity of the Tb 3+ -CIP complex at λ=545nm and the enhanced fluorescence intensity of Tb 3+ ion is in proportion to the concentration of NADP. Optimum conditions for the determination of NADP were also investigated. The dynamic range for the determination of NADP is 4.9x10 -7 -3.7x10 -6 molL -1 with detection limit of 1.3x10 -7 molL -1 . This method is simple, practical and relatively free interference from coexisting substances and can be successfully applied to determination of NADP in synthetic water samples. Moreover, the enhancement mechanisms of the fluorescence intensity in the Tb 3+ -CIP system and the Tb 3+ -CIP-NADP system have been also discussed

Whole-slide imaging is a robust alternative to traditional fluorescent microscopy for fluorescence in situ hybridization imaging using break-apart DNA probes.

Science.gov (United States)

Laurent, Camille; Guérin, Maxime; Frenois, François-Xavier; Thuries, Valérie; Jalabert, Laurence; Brousset, Pierre; Valmary-Degano, Séverine

2013-08-01

Fluorescence in situ hybridization is an indispensable technique used in routine pathology and for theranostic purposes. Because fluorescence in situ hybridization techniques require sophisticated microscopic workstations and long procedures of image acquisition with sometimes subjective and poorly reproducible results, we decided to test a whole-slide imaging system as an alternative approach. In this study, we used the latest generation of Pannoramic 250 Flash digital microscopes (P250 Flash digital microscopes; 3DHISTECH, Budapest, Hungary) to digitize fluorescence in situ hybridization slides of diffuse large B cells lymphoma cases for detecting MYC rearrangement. The P250 Flash digital microscope was found to be precise with better definition of split signals in cells containing MYC rearrangement with fewer truncated signals as compared to traditional fluorescence microscopy. This digital technique is easier thanks to the preview function, which allows almost immediate identification of the tumor area, and the panning and zooming functionalities as well as a shorter acquisition time. Moreover, fluorescence in situ hybridization analyses using the digital technique appeared to be more reproducible between pathologists. Finally, the digital technique also allowed prolonged conservation of photos. In conclusion, whole-slide imaging technologies represent rapid, robust, and highly sensitive methods for interpreting fluorescence in situ hybridization slides with break-apart probes. In addition, these techniques offer an easier way to interpret the signals and allow definitive storage of the images for pathology expert networks or e-learning databases. Copyright © 2013 Elsevier Inc. All rights reserved.

Development of dual-emission ratiometric probe-based on fluorescent silica nanoparticle and CdTe quantum dots for determination of glucose in beverages and human body fluids.

Science.gov (United States)

Zhai, Hong; Feng, Ting; Dong, Lingyu; Wang, Liyun; Wang, Xiangfeng; Liu, Hailing; Liu, Yuan; Chen, Luan; Xie, MengXia

2016-08-01

A novel dual emission ratiometric fluorescence probe for determination of glucose has been developed. The reference dye fluorescence isothiocyanate (FITC) has been encapsulated in the silica nanoparticles and then the red emission CdTe QDs were grafted on the surface of the silica particles to obtain the fluorescence probe. With glucose and dopamine as substrates, the glucose level was proportional to the fluorescence ratio change of above probe caused by dopamine oxidation, which was produced via bienzyme catalysis (glucose oxidase and horseradish peroxidase). The established approach was sensitive and selective, and has been applied to determine the glucose in beverage, urine and serum samples. The average recoveries of the glucose at various spiking levels ranged from 95.5% to 108.9% with relative standard deviations from 1.5% to 4.3%. The results provided a clue to develop sensors for rapid determination of the target analytes from complex matrices. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fluorescence probes for real-time remote cyanobacteria monitoring: A review of challenges and opportunities.

Science.gov (United States)

Bertone, Edoardo; Burford, Michele A; Hamilton, David P

2018-05-10

In recent years, there has been a widespread deployment of submersible fluorescence sensors by water utilities. They are used to measure diagnostic pigments and estimate algae and cyanobacteria abundance in near real-time. Despite being useful and promising tools, operators and decision-makers often rely on the data provided by these probes without a full understanding of their limitations. As a result, this may lead to wrong and misleading estimations which, in turn, means that researchers and technicians distrust these sensors. In this review paper, we list and discuss the main limitations of such probes, as well as identifying the effect of environmental factors on pigment production, and in turn, the conversion to cyanobacteria abundance estimation. We argue that a comprehensive calibration approach to obtain reliable readings goes well beyond manufacturers' recommendations, and should involve several context-specific experiments. We also believe that if such a comprehensive set of experiments is conducted, the data collected from fluorescence sensors could be used in artificial intelligence modelling approaches to reliably predict, in near real-time, the presence and abundance of different cyanobacteria species. This would have significant benefits for both drinking and recreational water management, given that cyanobacterial toxicity, and taste and odour compounds production, are species-dependent. Copyright © 2018 Elsevier Ltd. All rights reserved.

FLUORESCENCE PROBING OF THE FORMATION OF HYDROPHOBIC MICRODOMAINS BY CROSS-LINKED POLY(ALKYLMETHYLDIALLYLAMMONIUM BROMIDES) IN AQUEOUS-SOLUTION

NARCIS (Netherlands)

WANG, GJ; ENGBERTS, J B F N

Pyrene has been used as a fluorescence probe to investigate the conformational behavior of cross-linked poly(alkylmethyldiallylammonium bromides) in aqueous solutions. Binding of pyrene to hydrophobic microdomains, formed by the polysoaps, is reflected by a change in the ratio I-1/I-3 of the

Interface-Targeting Strategy Enables Two-Photon Fluorescent Lipid Droplet Probes for High-Fidelity Imaging of Turbid Tissues and Detecting Fatty Liver.

Science.gov (United States)

Guo, Lifang; Tian, Minggang; Feng, Ruiqing; Zhang, Ge; Zhang, Ruoyao; Li, Xuechen; Liu, Zhiqiang; He, Xiuquan; Sun, Jing Zhi; Yu, Xiaoqiang

2018-04-04

Lipid droplets (LDs) with unique interfacial architecture not only play crucial roles in protecting a cell from lipotoxicity and lipoapoptosis but also closely relate with many diseases such as fatty liver and diabetes. Thus, as one of the important applied biomaterials, fluorescent probes with ultrahigh selectivity for in situ and high-fidelity imaging of LDs in living cells and tissues are critical to elucidate relevant physiological and pathological events as well as detect related diseases. However, available probes only utilizing LDs' waterless neutral cores but ignoring the unique phospholipid monolayer interfaces exhibit low selectivity. They cannot differentiate neutral cores of LDs from intracellular other lipophilic microenvironments, which results in extensively cloud-like background noise and severely limited their bioapplications. Herein, to design LD probes with ultrahigh selectivity, the exceptional interfacial architecture of LDs is considered adequately and thus an interface-targeting strategy is proposed for the first time. According to the novel strategy, we have developed two amphipathic fluorescent probes (N-Cy and N-Py) by introducing different cations into a lipophilic fluorophore (nitrobenzoxadiazole (NBD)). Consequently, their cationic moiety precisely locates the interfaces through electrostatic interaction and simultaneously NBD entirely embeds into the waterless core via hydrophobic interaction. Thus, high-fidelity and background-free fluorescence imaging of LDs are expectably realized in living cells in situ. Moreover, LDs in turbid tissues like skeletal muscle slices have been clearly imaged (up to 82 μm depth) by a two-photon microscope. Importantly, using N-Cy, we not only intuitively monitored the variations of LDs in number, size, and morphology but also clearly revealed their abnormity in hepatic tissues resulting from fatty liver. Therefore, these unique probes provide excellent imaging tools for elucidating LD

Influence of degree of methyl methacrylate polymerization on spectroscopic properties of ethyl 5-(4-aminophenyl)- and 5-(4-dimethylaminophenyl)-3-amino-2,4-dicyanobenzoate

International Nuclear Information System (INIS)

Józefowicz, M.; Bajorek, A.; Pietrzak, M.; Jędrzejewska, B.; Heldt, J.R.; Heldt, J.

2013-01-01

The influence of degree of methyl methacrylate (MM) polymerization on the both emission modes (LE—locally excited and ICT—intramolecular charge transfer) of the fluorescence spectrum of ethyl 5-(4-aminophenyl)-3-amino-2,4-dicyanobenzoate (EAADCy) and ethyl 5-(4-dimethylaminophenyl)-3-amino-2,4-dicyanobenzoate (EDMAADCy) has been studied using steady-state and time-resolved spectroscopic technique. The purpose of these studies was to find a relationship between the changes in the spectroscopic characteristics (fluorescence intensity, wavelength of maximum intensity, fluorescence full-width at half maximum, emission anisotropy, fluorescence decay time) of the tested compounds and degree of monomer conversion into polymer. On the basis of the experimental results, it was shown that the ICT fluorescence full-width at half maximum for EDMAADCy shows a linear dependence on the time of MM polymerization. Our findings predestine the molecule EDMAADCy to be used as fluorescence probe for monitoring the polymerization process of MM. - Highlights: ► The fluorescence excitation and emission spectra in MM possess a complex nature. ► Fluorescence decay kinetics for different degrees of polymerization of MM were investigated. ► The ICT fluorescence FWHM for EDMAADCy shows a linear dependence on the time of polymerization. ► EDMAADCy can be used as fluorescence probe for monitoring the polymerization process of MM

A highly sensitive, single selective, fluorescent sensor for Al{sup 3+} detection and its application in living cell imaging

Energy Technology Data Exchange (ETDEWEB)

Ye, Xing-Pei [Department of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000 (China); Sun, Shao-bo; Li, Ying-dong [Institute of Integrated Traditional and Western Medicine, Gansu University of Traditional Chinese Medicine, Lanzhou 730000 (China); Zhi, Li-hua [Department of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000 (China); Wu, Wei-na, E-mail: wuwn08@hpu.edu.cn [Department of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000 (China); Wang, Yuan, E-mail: wangyuan08@hpu.edu.cn [Department of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000 (China)

2014-11-15

A new o-aminophenol-based fluorogenic chemosensor methyl 3,5-bis((E)-(2-hydroxyphenylimino)methyl)-4-hydroxybenzoate 1 have been synthesized by Schiff base condensation of methyl 3,5-diformyl-4-hydroxybenzoate with o-aminophenol, which exhibits high selectivity and sensitivity toward Al{sup 3+}. Fluorescence titration studies of receptors 1 with different metal cations in CH{sub 3}OH medium showed highly selective and sensitive towards Al{sup 3+} ions even in the presence of other commonly coexisting metal ions. The detection limit of Al{sup 3+} ions is at the parts per billion level. Interestingly, the Al(III) complex of 1 offered a large Stokes shift (>120 nm), which can miximize the selfquenching effect. In addition, possible utilization of this receptor as bio-imaging fluorescent probe to detect Al{sup 3+} in human cervical HeLa cancer cell lines was also investigated by confocal fluorescence microscopy. - Highlights: • A new Schiff base chemosensor is reported. • The sensor for Al{sup 3+} offers large Stokes shift. • The detection limit of Al{sup 3+} in CH{sub 3}OH solution is at the parts per billion level. • The utilization of sensor for the monitoring of Al{sup 3+} levels in living cells was examined.

Study of probe-sample distance for biomedical spectra measurement

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Li Lei

2011-11-01

Full Text Available Abstract Background Fiber-based optical spectroscopy has been widely used for biomedical applications. However, the effect of probe-sample distance on the collection efficiency has not been well investigated. Method In this paper, we presented a theoretical model to maximize the illumination and collection efficiency in designing fiber optic probes for biomedical spectra measurement. This model was in general applicable to probes with single or multiple fibers at an arbitrary incident angle. In order to demonstrate the theory, a fluorescence spectrometer was used to measure the fluorescence of human finger skin at various probe-sample distances. The fluorescence spectrum and the total fluorescence intensity were recorded. Results The theoretical results show that for single fiber probes, contact measurement always provides the best results. While for multi-fiber probes, there is an optimal probe distance. When a 400- μm excitation fiber is used to deliver the light to the skin and another six 400- μm fibers surrounding the excitation fiber are used to collect the fluorescence signal, the experimental results show that human finger skin has very strong fluorescence between 475 nm and 700 nm under 450 nm excitation. The fluorescence intensity is heavily dependent on the probe-sample distance and there is an optimal probe distance. Conclusions We investigated a number of probe-sample configurations and found that contact measurement could be the primary choice for single-fiber probes, but was very inefficient for multi-fiber probes. There was an optimal probe-sample distance for multi-fiber probes. By carefully choosing the probe-sample distance, the collection efficiency could be enhanced by 5-10 times. Our experiments demonstrated that the experimental results of the probe-sample distance dependence of collection efficiency in multi-fiber probes were in general agreement with our theory.

A study of the compartmentalization of core-shell nanoparticles through fluorescence energy transfer of dopants

Energy Technology Data Exchange (ETDEWEB)

Chavez, Jorge L; Jiang Hui; Duran, Randolph S, E-mail: rduran@lsu.edu [Department of Chemistry, University of Florida, PO Box 117200, Gainesville, FL 32611 (United States)

2010-02-05

Hybrid organic-inorganic templates and core-shell nanoparticles were used as models to study the communication between fluorescent probes placed inside nanoparticles. The hybrid templates were prepared on the basis of a mixed-surfactant system using octadecyltrimethoxysilane as a reactive amphiphile. The core-shell particles were obtained after coating of the templates with a siloxane shell, using the silanol groups on their surface. Atomic force microscopy imaging showed that the templates were made of a flexible material that flattened significantly after deposition on a substrate and evaporation of the solvent. Pyrene was sequestered by the templates in an aqueous suspension, which placed it in a nonpolar environment, as observed by its fluorescence response. Subsequently, double-doped templates were prepared by sequestering coumarin 153 (C153), with pyrene-doped hybrid templates. The communication between these probes was studied on the basis of their spectral properties, by means of fluorescence resonance energy transfer (FRET). Energy transfer between the dyes with efficiencies up to 55% was observed. Similarly, double-doped core-shell particles prepared on the basis of the hybrid templates were doped with this pair of dyes. Despite the presence of the shell, which was intended to increment the average separation between the probes, interaction of the dyes was observed, although with lower efficiencies. A similar study was performed with C153 and 4-(dicyanomethylene)-2-methyl-6-p-(dimethylamino)styryl-4H-pyran (DCM). FRET studies indicated that the probes were placed in proximity to each other. We confirmed these observations by means of fluorescence lifetime measurements, which showed a decrease in the lifetime of the donor upon addition of the acceptor.

Challenges for Super-Resolution Localization Microscopy and Biomolecular Fluorescent Nano-Probing in Cancer Research

Science.gov (United States)

Ilić, Nataša; Pilarczyk, Götz; Lee, Jin-Ho; Logeswaran, Abiramy; Borroni, Aurora Paola; Krufczik, Matthias; Theda, Franziska; Waltrich, Nadine; Bestvater, Felix; Hildenbrand, Georg; Cremer, Christoph; Blank, Michael

2017-01-01

Understanding molecular interactions and regulatory mechanisms in tumor initiation, progression, and treatment response are key requirements towards advanced cancer diagnosis and novel treatment procedures in personalized medicine. Beyond decoding the gene expression, malfunctioning and cancer-related epigenetic pathways, investigations of the spatial receptor arrangements in membranes and genome organization in cell nuclei, on the nano-scale, contribute to elucidating complex molecular mechanisms in cells and tissues. By these means, the correlation between cell function and spatial organization of molecules or molecular complexes can be studied, with respect to carcinogenesis, tumor sensitivity or tumor resistance to anticancer therapies, like radiation or antibody treatment. Here, we present several new applications for bio-molecular nano-probes and super-resolution, laser fluorescence localization microscopy and their potential in life sciences, especially in biomedical and cancer research. By means of a tool-box of fluorescent antibodies, green fluorescent protein (GFP) tagging, or specific oligonucleotides, we present tumor relevant re-arrangements of Erb-receptors in membranes, spatial organization of Smad specific ubiquitin protein ligase 2 (Smurf2) in the cytosol, tumor cell characteristic heterochromatin organization, and molecular re-arrangements induced by radiation or antibody treatment. The main purpose of this article is to demonstrate how nano-scaled distance measurements between bio-molecules, tagged by appropriate nano-probes, can be applied to elucidate structures and conformations of molecular complexes which are characteristic of tumorigenesis and treatment responses. These applications open new avenues towards a better interpretation of the spatial organization and treatment responses of functionally relevant molecules, at the single cell level, in normal and cancer cells, offering new potentials for individualized medicine. PMID:28956810

Challenges for Super-Resolution Localization Microscopy and Biomolecular Fluorescent Nano-Probing in Cancer Research

Directory of Open Access Journals (Sweden)

Michael Hausmann

2017-09-01

Full Text Available Understanding molecular interactions and regulatory mechanisms in tumor initiation, progression, and treatment response are key requirements towards advanced cancer diagnosis and novel treatment procedures in personalized medicine. Beyond decoding the gene expression, malfunctioning and cancer-related epigenetic pathways, investigations of the spatial receptor arrangements in membranes and genome organization in cell nuclei, on the nano-scale, contribute to elucidating complex molecular mechanisms in cells and tissues. By these means, the correlation between cell function and spatial organization of molecules or molecular complexes can be studied, with respect to carcinogenesis, tumor sensitivity or tumor resistance to anticancer therapies, like radiation or antibody treatment. Here, we present several new applications for bio-molecular nano-probes and super-resolution, laser fluorescence localization microscopy and their potential in life sciences, especially in biomedical and cancer research. By means of a tool-box of fluorescent antibodies, green fluorescent protein (GFP tagging, or specific oligonucleotides, we present tumor relevant re-arrangements of Erb-receptors in membranes, spatial organization of Smad specific ubiquitin protein ligase 2 (Smurf2 in the cytosol, tumor cell characteristic heterochromatin organization, and molecular re-arrangements induced by radiation or antibody treatment. The main purpose of this article is to demonstrate how nano-scaled distance measurements between bio-molecules, tagged by appropriate nano-probes, can be applied to elucidate structures and conformations of molecular complexes which are characteristic of tumorigenesis and treatment responses. These applications open new avenues towards a better interpretation of the spatial organization and treatment responses of functionally relevant molecules, at the single cell level, in normal and cancer cells, offering new potentials for individualized medicine.

New fluorescent probes of the hydroxyl radical: characterisation and modelization of the reactivity of coumarin derivatives with HO

International Nuclear Information System (INIS)

Louit, G.

2005-10-01

The hydroxyl radical is involved in a wide range of different fields, from oxidative stress to atmospheric chemistry. In addition to the study of oxidative damage in biological media, the hydroxyl radical detection allows to perform a dosimetry when it is produced by ionising radiation. The aims of this work have been double: - to improve the detection of the hydroxyl radical by the design of new probes - to improve knowledge on the reactive pathways in which the hydroxyl radical is involved. We have studied the coumarin molecule, as well as 6 derivatives that we have synthesised, as fluorescent probes of the hydroxyl radical. Firstly, fluorescence spectroscopy and HPLC chromatography have allowed the evaluation of the sensibility and selectivity of detection of the probes. Consequently to this study, two applications have been developed, concerning the determination of rate constants by competition kinetics and bidimensional dosimetry. Secondly, we have studied the reactivity of the hydroxyl radical through the regioselectivity of its addition on the aromatic cycle. This problem was addressed by the combined use of experimental methods such as time resolved kinetics and HPLC along with interpretation from classical and ab initio modelization. (author)

Comparison of CpG island methylator phenotype (CIMP) frequency in colon cancer using different probe- and gene-specific scoring alternatives on recommended multi-gene panels.

Science.gov (United States)

Berg, Marianne; Hagland, Hanne R; Søreide, Kjetil

2014-01-01

In colorectal cancer a distinct subgroup of tumours demonstrate the CpG island methylator phenotype (CIMP). However, a consensus of how to score CIMP is not reached, and variation in definition may influence the reported CIMP prevalence in tumours. Thus, we sought to compare currently suggested definitions and cut-offs for methylation markers and how they influence CIMP classification in colon cancer. Methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA), with subsequent fragment analysis, was used to investigate methylation of tumour samples. In total, 31 CpG sites, located in 8 different genes (RUNX3, MLH1, NEUROG1, CDKN2A, IGF2, CRABP1, SOCS1 and CACNA1G) were investigated in 64 distinct colon cancers and 2 colon cancer cell lines. The Ogino gene panel includes all 8 genes, in addition to the Weisenberger panel of which only 5 of the 8 genes included were investigated. In total, 18 alternative combinations of scoring of CIMP positivity on probe-, gene-, and panel-level were analysed and compared. For 47 samples (71%), the CIMP status was constant and independent of criteria used for scoring; 34 samples were constantly scored as CIMP negative, and 13 (20%) consistently scored as CIMP positive. Only four of 31 probes (13%) investigated showed no difference in the numbers of positive samples using the different cut-offs. Within the panels a trend was observed that increasing the gene-level stringency resulted in a larger difference in CIMP positive samples than increasing the probe-level stringency. A significant difference between positive samples using 'the most stringent' as compared to 'the least stringent' criteria (20% vs 46%, respectively; pCIMP depending on the cut-offs and genes included in a panel was found, with twice as many positives samples by least compared to most stringent definition used.

Identification of Cannabis sativa L. using the 1-kbTHCA synthase-fluorescence in situ hybridization probe.

Science.gov (United States)

Jeangkhwoa, Pattraporn; Bandhaya, Achirapa; Umpunjun, Puangpaka; Chuenboonngarm, Ngarmnij; Panvisavas, Nathinee

2017-03-01

This study reports a successful application of fluorescence in situ hybridization (FISH) technique in the identification of Cannabis sativa L. cells recovered from fresh and dried powdered plant materials. Two biotin-16-dUTP-labeled FISH probes were designed from the Cannabis-specific tetrahydrocannabinolic acid synthase (THCAS) gene and the ITS region of the 45S rRNA gene. Specificity of probe-target hybridization was tested against the target and 4 non-target plant species, i.e., Humulus lupulus, Mitragyna speciosa, Papaver sp., and Nicotiana tabacum. The 1-kb THCA synthase hybridization probe gave Cannabis-specific hybridization signals, unlike the 700-bp Cannabis-ITS hybridization probe. Probe-target hybridization was also confirmed against 20 individual Cannabis plant samples. The 1-kb THCA synthase and 700-bp Cannabis-ITS hybridization probes clearly showed 2 hybridization signals per cell with reproducibility. The 1-kb THCA synthase probe did not give any FISH signal when tested against H. lupulus, its closely related member of the Canabaceae family. It was also showed that 1-kb THCA synthase FISH probe can be applied to identify small amount of dried powdered Cannabis material with an addition of rehydration step prior to the experimental process. This study provided an alternative identification method for Cannabis trace. Copyright © 2016. Published by Elsevier B.V.

Probing GFP-actin diffusion in living cells using fluorescence correlation spectroscopy

International Nuclear Information System (INIS)

Engelke, Hanna; Heinrich, Doris; Rädler, Joachim O.

2010-01-01

The cytoskeleton of eukaryotic cells is continuously remodeled by polymerization and depolymerization of actin. Consequently, the relative content of polymerized filamentous actin (F-actin) and monomeric globular actin (G-actin) is subject to temporal and spatial fluctuations. Since fluorescence correlation spectroscopy (FCS) can measure the diffusion of fluorescently labeled actin it seems likely that FCS allows us to determine the dynamics and hence indirectly the structural properties of the cytoskeleton components with high spatial resolution. To this end we investigate the FCS signal of GFP-actin in living Dictyostelium discoideum cells and explore the inherent spatial and temporal signatures of the actin cytoskeleton. Using the free green fluorescent protein (GFP) as a reference, we find that actin diffusion inside cells is dominated by G-actin and slower than diffusion in diluted cell extract. The FCS signal in the dense cortical F-actin network near the cell membrane is probed using the cytoskeleton protein LIM and is found to be slower than cytosolic G-actin diffusion. Furthermore, we show that polymerization of the cytoskeleton induced by Jasplakinolide leads to a substantial decrease of G-actin diffusion. Pronounced fluctuations in the distribution of the FCS correlation curves can be induced by latrunculin, which is known to induce actin waves. Our work suggests that the FCS signal of GFP-actin in combination with scanning or spatial correlation techniques yield valuable information about the local dynamics and concomitant cytoskeletal properties

Fluorescent Probes and Fluorescence (Microscopy Techniques — Illuminating Biological and Biomedical Research

Directory of Open Access Journals (Sweden)

Gregor P. C. Drummen

2012-11-01

Full Text Available Fluorescence, the absorption and re-emission of photons with longer wavelengths, is one of those amazing phenomena of Nature. Its discovery and utilization had, and still has, a major impact on biological and biomedical research, since it enables researchers not just to visualize normal physiological processes with high temporal and spatial resolution, to detect multiple signals concomitantly, to track single molecules in vivo, to replace radioactive assays when possible, but also to shed light on many pathobiological processes underpinning disease states, which would otherwise not be possible. Compounds that exhibit fluorescence are commonly called fluorochromes or fluorophores and one of these fluorescent molecules in particular has significantly enabled life science research to gain new insights in virtually all its sub-disciplines: Green Fluorescent Protein. Because fluorescent proteins are synthesized in vivo, integration of fluorescent detection methods into the biological system via genetic techniques now became feasible. Currently fluorescent proteins are available that virtually span the whole electromagnetic spectrum. Concomitantly, fluorescence imaging techniques were developed, and often progress in one field fueled innovation in the other. Impressively, the properties of fluorescence were utilized to develop new assays and imaging modalities, ranging from energy transfer to image molecular interactions to imaging beyond the diffraction limit with super-resolution microscopy. Here, an overview is provided of recent developments in both fluorescence imaging and fluorochrome engineering, which together constitute the “fluorescence toolbox” in life science research.

Development of a 16S rRNA-targeted fluorescence in situ hybridization probe for quantification of the ammonia-oxidizer Nitrosotalea devanaterra and its relatives.

Science.gov (United States)

Restrepo-Ortiz, C X; Merbt, S N; Barrero-Canossa, J; Fuchs, B M; Casamayor, E O

2018-04-28

The Thaumarchaeota SAGMCG-1 group and, in particular, members of the genus Nitrosotalea have high occurrence in acidic soils, the rhizosphere, groundwater and oligotrophic lakes, and play a potential role in nitrogen cycling. In this study, the specific oligonucleotide fluorescence in situ hybridization probe SAG357 was designed for this Thaumarchaeota group based on the available 16S rRNA gene sequences in databases, and included the ammonia-oxidizing species Nitrosotalea devanaterra. Cell permeabilization for catalyzed reporter deposition fluorescence in situ detection and the hybridization conditions were optimized on enrichment cultures of the target species N. devanaterra, as well as the non-target ammonia-oxidizing archaeon Nitrosopumilus maritimus. Probe specificity was improved with a competitor oligonucleotide, and fluorescence intensity and cell visualization were enhanced by the design and application of two adjacent helpers. Probe performance was tested in soil samples along a pH gradient, and counting results matched the expected in situ distributions. Probe SAG357 and the CARD-FISH protocol developed in the present study will help to improve the current understanding of the ecology and physiology of N. devanaterra and its relatives in natural environments. Copyright © 2018 Elsevier GmbH. All rights reserved.

[1,10]Phenanthroline based cyanine dyes as fluorescent probes for ribonucleic acids in live cells

Science.gov (United States)

Kovalska, Vladyslava; Kuperman, Marina; Varzatskii, Oleg; Kryvorotenko, Dmytro; Kinski, Elisa; Schikora, Margot; Janko, Christina; Alexiou, Christoph; Yarmoluk, Sergiy; Mokhir, Andriy

2017-12-01

A series of monomethine, trimethine- and styrylcyanine dyes based on a [1,10]phenanthroline moiety was synthesized, characterized and investigated as potential fluorescent probes for nucleic acids in cell free settings and in cells. The dyes were found to be weakly fluorescent in the unbound state, whereas upon the binding to dsDNA or RNA their emission intensity raised up to 50 times (for monomethine benzothiazole derivative FT1 complexed with RNA). The strongest fluorescence intensity in assemblies with dsDNA and RNA was observed for the trimethine benzothiazole derivative FT4. The quantum yield of FT4 fluorescence in its complex with dsDNA was found to be 1.5% and the binding constant (K b) was estimated to be 7.9 × 104 M-1 that is a typical value for intercalating molecules. The FT4 dye was found to be cell membrane permeable. It stains RNA rich components—the nucleoli and most probably the cytoplasmic RNA. FT4 bound to RNAs delivers a very strong fluorescence signal, which makes this easily accessible dye a potentially useful alternative to known RNA stains, e.g. expensive SYTO® 83. The advantage of FT4 is its easy synthetic access including no chromatographic purification steps, which will be reflected in its substantially lower price.

Metal-organic framework based highly selective fluorescence turn-on probe for hydrogen sulphide

Science.gov (United States)

Nagarkar, Sanjog S.; Saha, Tanmoy; Desai, Aamod V.; Talukdar, Pinaki; Ghosh, Sujit K.

2014-11-01

Hydrogen sulphide (H2S) is known to play a vital role in human physiology and pathology which stimulated interest in understanding complex behaviour of H2S. Discerning the pathways of H2S production and its mode of action is still a challenge owing to its volatile and reactive nature. Herein we report azide functionalized metal-organic framework (MOF) as a selective turn-on fluorescent probe for H2S detection. The MOF shows highly selective and fast response towards H2S even in presence of other relevant biomolecules. Low cytotoxicity and H2S detection in live cells, demonstrate the potential of MOF towards monitoring H2S chemistry in biological system. To the best of our knowledge this is the first example of MOF that exhibit fast and highly selective fluorescence turn-on response towards H2S under physiological conditions.

Pentamethinium fluorescent probes: The impact of molecular structure on photophysical properties and subcellular localization

Czech Academy of Sciences Publication Activity Database

Bříza, T.; Rimpelová, S.; Králová, Jarmila; Záruba, K.; Kejík, Z.; Ruml, T.; Martásek, P.; Král, V.

2014-01-01

Roč. 107, August 2014 (2014), s. 51-59 ISSN 0143-7208 R&D Projects: GA AV ČR KAN200100801; GA ČR(CZ) GAP303/11/1291; GA MŠk(CZ) CZ.01.05/2.1.00/01.00.30; GA MŠk(CZ) CZ.1.07/2.300/30.0060 Institutional support: RVO:68378050 Keywords : Pentamethinium salts * Fluorescent probes * Mitochondria * Cardiolipin Photostability * Organelle imaging Subject RIV: CE - Biochemistry Impact factor: 3.966, year: 2014

A novel single fluorophore-labeled double-stranded oligonucleotide probe for fluorescence-enhanced nucleic acid detection based on the inherent quenching ability of deoxyguanosine bases and competitive strand-displacement reaction.

Science.gov (United States)

Zhang, Yingwei; Tian, Jingqi; Li, Hailong; Wang, Lei; Sun, Xuping

2012-01-01

We develop a novel single fluorophore-labeled double-stranded oligonucleotide (OND) probe for rapid, nanostructure-free, fluorescence-enhanced nucleic acid detection for the first time. We further demonstrate such probe is able to well discriminate single-base mutation in nucleic acid. The design takes advantage of an inherent quenching ability of guanine bases. The short strand of the probe is designed with an end-labeled fluorophore that is placed adjacent to two guanines as the quencher located on the long opposite strand, resulting in great quenching of dye fluorescence. In the presence of a target complementary to the long strand of the probe, a competitive strand-displacement reaction occurs and the long strand forms a more stable duplex with the target, resulting in the two strands of the probe being separated from each other. As a consequence of this displacement, the fluorophore and the quencher are no longer in close proximity and dye fluorescence increases, signaling the presence of target.

A BODIPY-Based Fluorescent Probe to Visually Detect Phosgene: Toward the Development of a Handheld Phosgene Detector.

Science.gov (United States)

Sayar, Melike; Karakuş, Erman; Güner, Tuğrul; Yildiz, Busra; Yildiz, Umit Hakan; Emrullahoğlu, Mustafa

2018-03-02

A boron-dipyrromethene (BODIPY)-based fluorescent probe with a phosgene-specific reactive motif shows remarkable selectivity toward phosgene, in the presence of which the nonfluorescent dye rapidly transforms into a new structure and induces a fluorescent response clearly observable to the naked eye under ultraviolet light. Given that dynamic, a prototypical handheld phosgene detector with a promising sensing capability that expedites the detection of gaseous phosgene without sophisticated instrumentation was developed. The proposed method using the handheld detector involves a rapid response period suitable for issuing early warnings during emergency situations. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Effects of Heteroatoms Si and S on Tuning the Optical Properties of Rhodamine- and Fluorescein-Based Fluorescence Probes: A Theoretical Analysis.

Science.gov (United States)

Zhou, Panwang; Ning, Cai; Alsaedi, Ahmed; Han, Keli

2016-10-05

The effects of the incorporated heteroatoms Si and S on tuning the optical properties of rhodamine- and fluorescein-based fluorescence probes is investigated using DFT and time-dependent DFT with four different functionals. As previously proposed, the large redshift (90 nm) produced by a Si atom in both the absorption and emission spectra can be attributed to the σ*-π* conjugation between the σ* orbital of the Si atom and the π* orbital of the adjacent carbon atoms. However, the presence of a Si atom does not alter the fluorescence quenching mechanism of the nonfluorescent forms of the investigated compounds. For the first time, these theoretical results indicate that the n orbital of the S atom plays an important role in determining the optical properties of the nonfluorescent form of rhodamine-based fluorescence probes. It alters the fluorescence quenching mechanism by lowering the energy of the dark nπ* state, which is due to breakage of the C10-S52 bond upon photoexcitation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kinetics of intercalation of fluorescent probes in magnesium–aluminium layered double hydroxide within a multiscale reaction–diffusion framework

Science.gov (United States)

Saliba, Daniel

2016-01-01

We report the synthesis of magnesium–aluminium layered double hydroxide (LDH) using a reaction–diffusion framework (RDF) that exploits the multiscale coupling of molecular diffusion with chemical reactions, nucleation and growth of crystals. In an RDF, the hydroxide anions are allowed to diffuse into an organic gel matrix containing the salt mixture needed for the precipitation of the LDH. The chemical structure and composition of the synthesized magnesium–aluminium LDHs are determined using powder X-ray diffraction (PXRD), thermo-gravimetric analysis, differential scanning calorimetry, solid-state nuclear magnetic resonance (SSNMR), Fourier transform infrared and energy dispersive X-ray spectroscopy. This novel technique also allows the investigation of the mechanism of intercalation of some fluorescent probes, such as the neutral three-dimensional rhodamine B (RhB) and the negatively charged two-dimensional 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS), using in situ steady-state fluorescence spectroscopy. The incorporation of these organic dyes inside the interlayer region of the LDH is confirmed via fluorescence microscopy, solid-state lifetime, SSNMR and PXRD. The activation energies of intercalation of the corresponding molecules (RhB and HPTS) are computed and exhibit dependence on the geometry of the involved probe (two or three dimensions), the charge of the fluorescent molecule (anionic, cationic or neutral) and the cationic ratio of the corresponding LDH. This article is part of the themed issue ‘Multiscale modelling at the physics–chemistry–biology interface’. PMID:27698034

Kinetics of intercalation of fluorescent probes in magnesium-aluminium layered double hydroxide within a multiscale reaction-diffusion framework

Science.gov (United States)

Saliba, Daniel; Al-Ghoul, Mazen

2016-11-01

We report the synthesis of magnesium-aluminium layered double hydroxide (LDH) using a reaction-diffusion framework (RDF) that exploits the multiscale coupling of molecular diffusion with chemical reactions, nucleation and growth of crystals. In an RDF, the hydroxide anions are allowed to diffuse into an organic gel matrix containing the salt mixture needed for the precipitation of the LDH. The chemical structure and composition of the synthesized magnesium-aluminium LDHs are determined using powder X-ray diffraction (PXRD), thermo-gravimetric analysis, differential scanning calorimetry, solid-state nuclear magnetic resonance (SSNMR), Fourier transform infrared and energy dispersive X-ray spectroscopy. This novel technique also allows the investigation of the mechanism of intercalation of some fluorescent probes, such as the neutral three-dimensional rhodamine B (RhB) and the negatively charged two-dimensional 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS), using in situ steady-state fluorescence spectroscopy. The incorporation of these organic dyes inside the interlayer region of the LDH is confirmed via fluorescence microscopy, solid-state lifetime, SSNMR and PXRD. The activation energies of intercalation of the corresponding molecules (RhB and HPTS) are computed and exhibit dependence on the geometry of the involved probe (two or three dimensions), the charge of the fluorescent molecule (anionic, cationic or neutral) and the cationic ratio of the corresponding LDH. This article is part of the themed issue 'Multiscale modelling at the physics-chemistry-biology interface'.

Midrange affinity fluorescent Zn(II) sensors of the Zinpyr family: syntheses, characterization, and biological imaging applications.

Science.gov (United States)

Nolan, Elizabeth M; Jaworski, Jacek; Racine, Maryann E; Sheng, Morgan; Lippard, Stephen J

2006-11-27

The syntheses and photophysical characterization of ZP9, 2-{2-chloro-6-hydroxy-3-oxo-5-[(2-{[pyridin-2-ylmethyl-(1H-pyrrol-2-ylmethyl)amino]methyl}phenylamino)methyl]-3H-xanthen-9-yl}benzoic acid, and ZP10, 2-{2-chloro-6-hydroxy-5-[(2-{[(1-methyl-1H-pyrrol-2-ylmethyl)pyridin-2-ylmethylamino]methyl}phenylamino)methyl]-3-oxo-3H-xanthen-9-yl}benzoic acid, two asymmetrically derivatized fluorescein-based dyes, are described. These sensors each contain an aniline-based ligand moiety functionalized with a pyridyl-amine-pyrrole group and have dissociation constants for Zn(II) in the sub-micromolar (ZP9) and low-micromolar (ZP10) range, which we define as "midrange". They give approximately 12- (ZP9) and approximately 7-fold (ZP10) fluorescence turn-on immediately following Zn(II) addition at neutral pH and exhibit improved selectivity for Zn(II) compared to the di-(2-picolyl)amine-based Zinpyr (ZP) sensors. Confocal microscopy studies indicate that such asymmetrical fluorescein-based probes are cell permeable and Zn(II) responsive in vivo.

New concepts of fluorescent probes for specific detection of DNA sequences: bis-modified oligonucleotides in excimer and exciplex detection.

Science.gov (United States)

Gbaj, A; Bichenkova, Ev; Walsh, L; Savage, He; Sardarian, Ar; Etchells, Ll; Gulati, A; Hawisa, S; Douglas, Kt

2009-12-01

The detection of single base mismatches in DNA is important for diagnostics, treatment of genetic diseases, and identification of single nucleotide polymorphisms. Highly sensitive, specific assays are needed to investigate genetic samples from patients. The use of a simple fluorescent nucleoside analogue in detection of DNA sequence and point mutations by hybridisation in solution is described in this study. The 5'-bispyrene and 3'-naphthalene oligonucleotide probes form an exciplex on hybridisation to target in water and the 5'-bispyrene oligonucleotide alone is an adequate probe to determine concentration of target present. It was also indicated that this system has a potential to identify mismatches and insertions. The aim of this work was to investigate experimental structures and conditions that permit strong exciplex emission for nucleic acid detectors, and show how such exciplexes can register the presence of mismatches as required in SNP analysis. This study revealed that the hybridisation of 5'-bispyrenyl fluorophore to a DNA target results in formation of a fluorescent probe with high signal intensity change and specificity for detecting a complementary target in a homogeneous system. Detection of SNP mutations using this split-probe system is a highly specific, simple, and accessible method to meet the rigorous requirements of pharmacogenomic studies. Thus, it is possible for the system to act as SNP detectors and it shows promise for future applications in genetic testing.

Fluorescent probes as a tool for labelling and tracking the amphibian chytrid fungus Batrachochytrium dendrobatidis.

Science.gov (United States)

Herbert, Sarah M; Leung, Tommy L F; Bishop, Phillip J

2011-09-09

The dissemination of the virulent pathogen Batrachochytrium dendrobatidis (Bd) has contributed to the decline and extinction of many amphibian species worldwide. Several different strains have been identified, some of which are sympatric. Interactions between co-infecting strains of a pathogen can have significant influences on disease epidemiology and evolution; therefore the dynamics of multi-strain infections is an important area of research. We stained Bd cells with 2 fluorescent BODIPY fatty acid probes to determine whether these can potentially be used to distinguish and track Bd cell lines in multi-strain experiments. Bd cells in broth culture were stained with 5 concentrations of green-fluorescent BODIPY FL and red-fluorescent BODIPY 558/568 and visualised under an epifluorescent microscope for up to 16 d post-dye. Dyed strains were also assessed for growth inhibition. The most effective concentration for both dyes was 10 pM. This concentration of dye produced strong fluorescence for 12 to 16 d in Bd cultures held at 23 degrees C (3 to 4 generations), and did not inhibit Bd growth. Cells dyed with BODIPY FL and BODIPY 558/568 can be distinguished from each other on the basis of their fluorescence characteristics. Therefore, it is likely that this technique will be useful for research into multi-strain dynamics of Bd infections.

Toehold-mediated strand displacement reaction-dependent fluorescent strategy for sensitive detection of uracil-DNA glycosylase activity.

Science.gov (United States)

Wu, Yushu; Wang, Lei; Jiang, Wei

2017-03-15

Sensitive detection of uracil-DNA glycosylase (UDG) activity is beneficial for evaluating the repairing process of DNA lesions. Here, toehold-mediated strand displacement reaction (TSDR)-dependent fluorescent strategy was constructed for sensitive detection of UDG activity. A single-stranded DNA (ssDNA) probe with two uracil bases and a trigger sequence were designed. A hairpin probe with toehold domain was designed, and a reporter probe was also designed. Under the action of UDG, two uracil bases were removed from ssDNA probe, generating apurinic/apyrimidinic (AP) sites. Then, the AP sites could inhibit the TSDR between ssDNA probe and hairpin probe, leaving the trigger sequence in ssDNA probe still free. Subsequently, the trigger sequence was annealed with the reporter probe, initiating the polymerization and nicking amplification reaction. As a result, numerous G-quadruplex (G4) structures were formed, which could bind with N-methyl-mesoporphyrin IX (NMM) to generate enhanced fluorescent signal. In the absence of UDG, the ssDNA probe could hybridize with the toehold domain of the hairpin probe to initiate TSDR, blocking the trigger sequence, and then the subsequent amplification reaction would not occur. The proposed strategy was successfully implemented for detecting UDG activity with a detection limit of 2.7×10 -5 U/mL. Moreover, the strategy could distinguish UDG well from other interference enzymes. Furthermore, the strategy was also applied for detecting UDG activity in HeLa cells lysate with low effect of cellular components. These results indicated that the proposed strategy offered a promising tool for sensitive quantification of UDG activity in UDG-related function study and disease prognosis. Copyright © 2016 Elsevier B.V. All rights reserved.

Development and use of fluorescent 16S rRNA-targeted probes for the specific detection of Methylophaga species by in situ hybridization in marine sediments.

Science.gov (United States)

Janvier, Monique; Regnault, Béatrice; Grimont, Patrick

2003-09-01

Methylotrophic bacteria are widespread in nature. They may play an important role in the cycling of carbon and in the metabolism of dimethylsulfide in a marine environment. Bacteria belonging to the genus Methylophaga are a unique group of aerobic, halophilic, non-methane-utilizing methylotrophs. Two 16S rRNA-targeted oligonucleotide probes were developed for the specific detection of Methylophaga species, marine methylobacteria, by fluorescence in situ hybridization. Probe MPH-730 was highly specific for all members of the genus Methylophaga while probe MPHm-994 targeted exclusively M. marina. The application of these probes were demonstrated by the detection of Methylophaga species in enrichment cultures from various marine sediments. All isolates recovered were visualized by using the genus specific probe MPH-730. The results were confirmed by 16S rDNA sequencing which demonstrated that all selected isolates belong to Methylophaga. Five isolates could be detected by the M. marina-specific probe MPHm-994 and were confirmed by rRNA gene restriction pattern (ribotyping). With the development of these specific probes, fluorescence in situ hybridization shows that the genus Methylophaga is widespread in marine samples.

Combined fluorescence-Raman spectroscopy measurements with an optical fiber probe for the diagnosis of melanocytic lesions

Science.gov (United States)

Cosci, Alessandro; Cicchi, Riccardo; Rossari, Susanna; De Giorgi, Vincenzo; Massi, Daniela; Pavone, Francesco S.

2012-02-01

We have designed and developed an optical fiber-probe for spectroscopic measurements on human tissues. The experimental setup combines fluorescence spectroscopy and Raman spectroscopy in a multidimensional approach. Concerning fluorescence spectroscopy, the excitation is provided by two laser diodes, one emitting in the UV (378 nm) and the other emitting in the visible (445 nm). These two lasers are used to selectively excite fluorescence from NADH and FAD, which are among the brightest endogenous fluorophores in human tissues. For Raman and NIR spectroscopy, the excitation is provided by a third laser diode with 785 nm excitation wavelength. Laser light is delivered to the tissue through the central optical fiber of a fiber bundle. The surrounding 48 fibers of the bundle are used for collecting fluorescence and Raman and for delivering light to the spectrograph. Fluorescence and Raman spectra are acquired on a cooled CCD camera. The instrument has been tested on fresh human skin biopsies clinically diagnosed as malignant melanoma, melanocytic nevus, or healthy skin, finding an optimal correlation with the subsequent histological exam. In some cases our examination was not in agreement with the clinical observation, but it was with the histological exam, demonstrating that the system can potentially contribute to improve clinical diagnostic capabilities and hence reduce the number of unnecessary biopsies.

Structural design of intrinsically fluorescent oxysterols

DEFF Research Database (Denmark)

Nåbo, Lina J; Modzel, Maciej; Krishnan, Kathiresan

2018-01-01

Oxysterols are oxidized derivatives of cholesterol with many important biological functions. Trafficking of oxysterols in and between cells is not well studied, largely due to the lack of appropriate oxysterol analogs. Intrinsically fluorescent oxysterols present a new route towards direct...... observation of intracellular oxysterol trafficking by fluorescence microscopy. We characterize the fluorescence properties of the existing fluorescent 25-hydroxycholesterol analog 25-hydroxycholestatrienol, and propose a new probe with an extended conjugated system. The location of both probes inside...

Comparison of CpG island methylator phenotype (CIMP frequency in colon cancer using different probe- and gene-specific scoring alternatives on recommended multi-gene panels.

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Marianne Berg

Full Text Available BACKGROUND: In colorectal cancer a distinct subgroup of tumours demonstrate the CpG island methylator phenotype (CIMP. However, a consensus of how to score CIMP is not reached, and variation in definition may influence the reported CIMP prevalence in tumours. Thus, we sought to compare currently suggested definitions and cut-offs for methylation markers and how they influence CIMP classification in colon cancer. METHODS: Methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA, with subsequent fragment analysis, was used to investigate methylation of tumour samples. In total, 31 CpG sites, located in 8 different genes (RUNX3, MLH1, NEUROG1, CDKN2A, IGF2, CRABP1, SOCS1 and CACNA1G were investigated in 64 distinct colon cancers and 2 colon cancer cell lines. The Ogino gene panel includes all 8 genes, in addition to the Weisenberger panel of which only 5 of the 8 genes included were investigated. In total, 18 alternative combinations of scoring of CIMP positivity on probe-, gene-, and panel-level were analysed and compared. RESULTS: For 47 samples (71%, the CIMP status was constant and independent of criteria used for scoring; 34 samples were constantly scored as CIMP negative, and 13 (20% consistently scored as CIMP positive. Only four of 31 probes (13% investigated showed no difference in the numbers of positive samples using the different cut-offs. Within the panels a trend was observed that increasing the gene-level stringency resulted in a larger difference in CIMP positive samples than increasing the probe-level stringency. A significant difference between positive samples using 'the most stringent' as compared to 'the least stringent' criteria (20% vs 46%, respectively; p<0.005 was demonstrated. CONCLUSIONS: A statistical significant variation in the frequency of CIMP depending on the cut-offs and genes included in a panel was found, with twice as many positives samples by least compared to most stringent definition

A Conjugated Aptamer-Gold Nanoparticle Fluorescent Probe for Highly Sensitive Detection of rHuEPO-α

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Zhaoyang Zhang

2011-11-01

Full Text Available We present here a novel conjugated aptamer-gold nanoparticle (Apt-AuNPs fluorescent probe and its application for specific detection of recombinant human erythropoietin-α (rHuEPO-α. In this nanobiosensor, 12 nm AuNPs function as both a nano-scaffold and a nano-quencher (fluorescent energy acceptor, on the surface of which the complementary sequences are linked (as cODN-AuNPs and pre-hybridized with carboxymethylfluorescein (FAM-labeled anti-rHuEPO-α aptamers. Upon target protein binding, the aptamers can be released from the AuNP surface and the fluorescence signal is restored. Key variables such as the length of linker, the hybridization site and length have been designed and optimized. Full performance evaluation including sensitivity, linear range and interference substances are also described. This nanobiosensor provides a promising approach for a simple and direct quantification of rHuEPO-α concentrations as low as 0.92 nM within a few hours.

New insights into the dual fluorescence of methyl salicylate: effects of intermolecular hydrogen bonding and solvation.

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Zhou, Panwang; Hoffmann, Mark R; Han, Keli; He, Guozhong

2015-02-12

In this paper, we propose a new and complete mechanism for dual fluorescence of methyl salicylate (MS) under different conditions using a combined experimental (i.e., steady-state absorption and emission spectra and time-resolved fluorescence spectra) and theoretical (i.e., time-dependent density function theory) study. First, our theoretical study indicates that the barrier height for excited state intramolecular proton transfer (ESIPT) reaction of ketoB depends on the solvent polarity. In nonpolar solvents, the ESIPT reaction of ketoB is barrierless; the barrier height will increase with increasing solvent polarity. Second, we found that, in alcoholic solvents, intermolecular hydrogen bonding plays a more important role. The ketoB form of MS can form two hydrogen bonds with alcoholic solvents; one will facilitate ESIPT and produce the emission band in the blue region; the other one precludes ESIPT and produces the emission band in the near-UV region. Our proposed new mechanism can well explain previous results as well as our new experimental results.

Optical Aptamer Probes of Fluorescent Imaging to Rapid Monitoring of Circulating Tumor Cell

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Ji Yeon Hwang

2016-11-01

Full Text Available Fluorescence detecting of exogenous EpCAM (epithelial cell adhesion molecule or muc1 (mucin1 expression correlated to cancer metastasis using nanoparticles provides pivotal information on CTC (circulating tumor cell occurrence in a noninvasive tool. In this study, we study a new skill to detect extracellular EpCAM/muc1 using quantum dot-based aptamer beacon (QD-EpCAM/muc1 ALB (aptamer linker beacon. The QD-EpCAM/muc1 ALB was designed using QDs (quantum dots and probe. The EpCAM/muc1-targeting aptamer contains a Ep-CAM/muc1 binding sequence and BHQ1 (black hole quencher 1 or BHQ2 (black hole quencher2. In the absence of target EpCAM/muc1, the QD-EpCAM/muc1 ALB forms a partial duplex loop-like aptamer beacon and remained in quenched state because the BHQ1/2 quenches the fluorescence signal-on of the QD-EpCAM/muc1 ALB. The binding of EpCAM/muc1 of CTC to the EpCAM/muc1 binding aptamer sequence of the EpCAM/muc1-targeting oligonucleotide triggered the dissociation of the BHQ1/2 quencher and subsequent signal-on of a green/red fluorescence signal. Furthermore, acute inflammation was stimulated by trigger such as caerulein in vivo, which resulted in increased fluorescent signal of the cy5.5-EpCAM/muc1 ALB during cancer metastasis due to exogenous expression of EpCAM/muc1 in Panc02-implanted mouse model.

Xanthines Studied via Femtosecond Fluorescence Spectroscopy

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Pascale Changenet-Barret

2016-12-01

Full Text Available Xanthines represent a wide class of compounds closely related to the DNA bases adenine and guanine. Ubiquitous in the human body, they are capable of replacing natural bases in double helices and give rise to four-stranded structures. Although the use of their fluorescence for analytical purposes was proposed, their fluorescence properties have not been properly characterized so far. The present paper reports the first fluorescence study of xanthine solutions relying on femtosecond spectroscopy. Initially, we focus on 3-methylxanthine, showing that this compound exhibits non-exponential fluorescence decays with no significant dependence on the emission wavelength. The fluorescence quantum yield (3 × 10−4 and average decay time (0.9 ps are slightly larger than those found for the DNA bases. Subsequently, we compare the dynamical fluorescence properties of seven mono-, di- and tri-methylated derivatives. Both the fluorescence decays and fluorescence anisotropies vary only weakly with the site and the degree of methylation. These findings are in line with theoretical predictions suggesting the involvement of several conical intersections in the relaxation of the lowest singlet excited state.

Photophysical properties of a surfactive long-chain styryl merocyanine dye as fluorescent probe

Energy Technology Data Exchange (ETDEWEB)

Ismail, L.F.M., E-mail: Lailafmi@yahoo.com [Al-Azhar University, Faculty of Science, Chemistry Department, Nasr City, 12 Ibrahim El-Nagar, El-Hegaz Sq. Heliopolis, Cairo 11315 (Egypt)

2012-09-15

environment, which have often been used as models for more complex bioaggregates. The results point out to a possible use of this dye as a fluorescence probe for microenvironmental parameters as well as in some micellar systems.

Dynamic, in vivo, real-time detection of retinal oxidative status in a model of elevated intraocular pressure using a novel, reversibly responsive, profluorescent nitroxide probe.

Science.gov (United States)

Rayner, Cassie L; Gole, Glen A; Bottle, Steven E; Barnett, Nigel L

2014-12-01

Changes to the redox status of biological systems have been implicated in the pathogenesis of a wide variety of disorders including cancer, Ischemia-reperfusion (I/R) injury and neurodegeneration. In times of metabolic stress e.g. ischaemia/reperfusion, reactive oxygen species (ROS) production overwhelms the intrinsic antioxidant capacity of the cell, damaging vital cellular components. The ability to quantify ROS changes in vivo, is therefore essential to understanding their biological role. Here we evaluate the suitability of a novel reversible profluorescent probe containing a redox-sensitive nitroxide moiety (methyl ester tetraethylrhodamine nitroxide, ME-TRN), as an in vivo, real-time reporter of retinal oxidative status. The reversible nature of the probe's response offers the unique advantage of being able to monitor redox changes in both oxidizing and reducing directions in real time. After intravitreal administration of the ME-TRN probe, we induced ROS production in rat retina using an established model of complete, acute retinal ischaemia followed by reperfusion. After restoration of blood flow, retinas were imaged using a Micron III rodent fundus fluorescence imaging system, to quantify the redox-response of the probe. Fluorescent intensity declined during the first 60 min of reperfusion. The ROS-induced change in probe fluorescence was ameliorated with the retinal antioxidant, lutein. Fluorescence intensity in non-Ischemia eyes did not change significantly. This new probe and imaging technology provide a reversible and real-time response to oxidative changes and may allow the in vivo testing of antioxidant therapies of potential benefit to a range of diseases linked to oxidative stress. Copyright © 2014 Elsevier Ltd. All rights reserved.

Biophysical characterization of the fluorescent protein voltage probe VSFP2.3 based on the voltage-sensing domain of Ci-VSP.

Science.gov (United States)

Lundby, Alicia; Akemann, Walther; Knöpfel, Thomas

2010-11-01

A voltage sensitive phosphatase was discovered in the ascidian Ciona intestinalis. The phosphatase, Ci-VSP, contains a voltage-sensing domain homologous to those known from voltage-gated ion channels, but unlike ion channels, the voltage-sensing domain of Ci-VSP can reside in the cell membrane as a monomer. We fused the voltage-sensing domain of Ci-VSP to a pair of fluorescent reporter proteins to generate a genetically encodable voltage-sensing fluorescent probe, VSFP2.3. VSFP2.3 is a fluorescent voltage probe that reports changes in membrane potential as a FRET (fluorescence resonance energy transfer) signal. Here we report sensing current measurements from VSFP2.3, and show that VSFP2.3 carries 1.2 e sensing charges, which are displaced within 1.5 ms. The sensing currents become faster at higher temperatures, and the voltage dependence of the decay time constants is temperature dependent. Neutralization of an arginine in S4, previously suggested to be a sensing charge, and measuring associated sensing currents indicate that this charge is likely to reside at the membrane-aqueous interface rather than within the membrane electric field. The data presented give us insights into the voltage-sensing mechanism of Ci-VSP, which will allow us to further improve the sensitivity and kinetics of the family of VSFP proteins.

Probing the photoluminescence properties of gold nanoclusters by fluorescence lifetime correlation spectroscopy

International Nuclear Information System (INIS)

Yuan, C. T.; Lin, T. N.; Shen, J. L.; Lin, C. A.; Chang, W. H.; Cheng, H. W.; Tang, J.

2013-01-01

Gold nanoclusters (Au NCs) have attracted much attention for promising applications in biological imaging owing to their tiny sizes and biocompatibility. So far, most efforts have been focused on the strategies for fabricating high-quality Au NCs and then characterized by conventional ensemble measurement. Here, a fusion single-molecule technique combining fluorescence correlation spectroscopy and time-correlated single-photon counting can be successfully applied to probe the photoluminescence (PL) properties for sparse Au NCs. In this case, the triplet-state dynamics and diffusion process can be observed simultaneously and the relevant time constants can be derived. This work provides a complementary insight into the PL mechanism at the molecular levels for Au NCs in solution

Terbium(III)/gold nanocluster conjugates: the development of a novel ratiometric fluorescent probe for mercury(II) and a paper-based visual sensor.

Science.gov (United States)

Qi, Yan-Xia; Zhang, Min; Zhu, Anwei; Shi, Guoyue

2015-08-21

In this work, a novel ratiometric fluorescent probe was developed for rapid, highly accurate, sensitive and selective detection of mercury(II) (Hg(2+)) based on terbium(III)/gold nanocluster conjugates (Tb(3+)/BSA-AuNCs), in which bovine serum albumin capped gold nanoclusters (BSA-AuNCs) acted as the signal indicator and terbium(III) (Tb(3+)) was used as the build-in reference. Our proposed ratiometric fluorescent probe exhibited unique specificity toward Hg(2+) against other common environmentally and biologically important metal ions, and had high accuracy and sensitivity with a low detection limit of 1 nM. In addition, our proposed probe was effectively employed to detect Hg(2+) in the biological samples from the artificial Hg(2+)-infected rats. More significantly, an appealing paper-based visual sensor for Hg(2+) was designed by using filter paper embedded with Tb(3+)/BSA-AuNC conjugates, and we have further demonstrated its feasibility for facile fluorescent sensing of Hg(2+) in a visual format, in which only a handheld UV lamp is used. In the presence of Hg(2+), the paper-based visual sensor, illuminated by a handheld UV lamp, would undergo a distinct fluorescence color change from red to green, which can be readily observed with naked eyes even in trace Hg(2+) concentrations. The Tb(3+)/BSA-AuNC-derived paper-based visual sensor is cost-effective, portable, disposable and easy-to-use. This work unveiled a facile approach for accurate, sensitive and selective measuring of Hg(2+) with self-calibration.

A fluorescent pH probe for acidic organelles in living cells.

Science.gov (United States)

Chen, Jyun-Wei; Chen, Chih-Ming; Chang, Cheng-Chung

2017-09-26

A water-soluble pH sensor, 2-(6-(4-aminostyryl)-1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)-N, N-dimethylethanamine (ADA), was synthesized based on the molecular design of photoinduced electron transfer (PET) and intramolecular charge transfer (ICT). The fluorescence emission response against a pH value is in the range 3-6, which is suitable for labelling intracellular pH-dependent microenvironments. After biological evolution, ADA is more than a pH biosensor because it is also an endocytosis pathway tracking biosensor that labels endosomes, late endosomes, and lysosome pH gradients. From this, the emissive aggregates of ADA and protonated-ADA in these organs were evaluated to explore how this probe stresses emission colour change to cause these unique cellular images.

Sensitive and rapid detection of endogenous hydrogen sulfide distributing in different mouse viscera via a two-photon fluorescent probe

International Nuclear Information System (INIS)

Chen, Qian; Yang, Jinfeng; Li, Yinhui; Zheng, Jing; Yang, Ronghua

2015-01-01

Development of efficient methods for detection of endogenous H 2 S in living cells and tissues is of considerable significance for better understanding the biological and pathological functions of H 2 S. Two-photon (TP) fluorescent probes are favorable as powerful molecular tools for studying physiological process due to its non-invasiveness, high spatiotemporal resolution and deep-tissues imaging. Up to date, several TP probes for intracellular H 2 S imaging have been designed, but real-time imaging of endogenous H 2 S-related biological processes in tissues is hampered due to low sensitivity, long response time and interference from other biothiols. To address this issue, we herein report a novel two-photon fluorescent probe (TPP-H 2 S) for highly sensitive and fast monitoring and imaging H 2 S levels in living cells and tissues. In the presence of H 2 S, it exhibits obviously improved sensitivity (LOD: 0.12 μM) and fast response time (about 2 min) compared with the reported two-photon H 2 S probes. With two-photon excitation, TPP-H 2 S displays high signal-to-noise ratio and sensitivity even no interference in cell growth media. As further application, TPP-H 2 S is applied for fast imaging of H 2 S in living cells and different fresh tissues by two-photon confocal microscope. Most importantly we first measured the endogenous H 2 S level in different viscera by vivisection and found that the distribution of endogenous H 2 S mostly in brain, liver and lung. The excellent sensing properties of TPP-H 2 S make it a practically useful tool for further studying biological roles of H 2 S. - Highlights: • This two-photon probe exhibits an improved sensitivity and response time to H 2 S. • This probe shows excellent membrane permeability and fast visualization of H 2 S in living cells and tissues. • This probe is successfully applied to measure the endogenously produced H 2 S levels in different viscera of mouse.

Magnetic immunoassay using CdSe/ZnS quantum dots as fluorescent probes to detect the level of DNA methyltransferase 1 in human serum sample

Directory of Open Access Journals (Sweden)

Yu F

2018-01-01

Full Text Available Fei Yu,1,* Ya-min Xiong,1,* Song-cheng Yu,1 Lei-liang He,1 Shan-shan Niu,1 Yu-ming Wu,1 Jie Liu,1 Ling-bo Qu,2 Li-e Liu,1 Yong-jun Wu1 1College of Public Health, 2College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou, Henan, People’s Republic of China *These authors contributed equally to this work Background: DNA methyltransferase 1 (DNMT1, a dominant enzyme responsible for the transfer of a methyl group from the universal methyl donor to the 5-position of cytosine residues in DNA, is essential for mammalian development and closely related to cancer and a variety of age-related chronic diseases. DNMT1 has become a useful biomarker in early disease diagnosis and a potential therapeutic target in cancer therapy and drug development. However, till now, most of the studies on DNA methyltransferase (MTase detection have focused on the prokaryote MTase and its activity.Methods: A magnetic fluorescence-linked immunosorbent assay (FLISA using CdSe/ZnS quantum dots as fluorescent probes was proposed for the rapid and sensitive detection of the DNMT1 level in this study. Key factors that affect the precision and accuracy of the determination of DNMT1 were optimized.Results: Under the optimal conditions, the limit of detection was 0.1 ng/mL, the linear range was 0.1–1,500 ng/mL, the recovery was 91.67%–106.50%, and the relative standard deviations of intra- and inter-assays were respectively 5.45%–11.29% and 7.03%–11.25%. The cross-reactivity rates with DNA methyltransferases 3a and 3b were only 4.0% and 9.4%, respectively. Furthermore, FLISA was successfully used to detect the levels of DNMT1 in human serum samples, and compared with commercial enzyme-linked immunosorbent assay (ELISA kits. The results revealed that there was a good correlation between FLISA and commercial ELISA kits (correlation coefficient r=0.866, p=0.001. The linear scope of FLISA was broader than ELISA, and the measurement time was much shorter

Fluorescent pH-Sensing Probe Based on Biorefinery Wood Lignosulfonate and Its Application in Human Cancer Cell Bioimaging.

Science.gov (United States)

Xue, Yuyuan; Liang, Wanshan; Li, Yuan; Wu, Ying; Peng, Xinwen; Qiu, Xueqing; Liu, Jinbin; Sun, Runcang

2016-12-28

A water-soluble, ratiometric fluorescent pH probe, L-SRhB, was synthesized via grafting spirolactam Rhodamine B (SRhB) to lignosulfonate (LS). As the ring-opening product of L-SRhB, FL-SRhB was also prepared. The pH-response experiment indicated that L-SRhB showed a rapid response to pH changes from 4.60 to 6.20 with a pK a of 5.35, which indicated that L-SRhB has the potential for pH detection of acidic organelle. In addition, the two probes were internalized successfully by living cells through the endocytosis pathway and could distinguish normal cells from cancer cells by different cell staining rates. In addition, L-SRhB showed obvious cytotoxicity to cancer cells, whereas it was nontoxic to normal cells in the same condition. L-SRhB might have potential in cancer therapy. L-SRhB might be a promising ratiometric fluorescent pH sensor and bioimaging dye for the recognition of cancer cells. The results also provided a new perspective to the high-value utilization of lignin.

A turn-on fluorescent probe for endogenous formaldehyde in the endoplasmic reticulum of living cells

Science.gov (United States)

Tang, Yonghe; Ma, Yanyan; Xu, An; Xu, Gaoping; Lin, Weiying

2017-06-01

As the simplest aldehyde compounds, formaldehyde (FA) is implicated in nervous system diseases and cancer. Endoplasmic reticulum is an organelle that plays important functions in living cells. Accordingly, the development of efficient methods for FA detection in the endoplasmic reticulum (ER) is of great biomedical importance. In this work, we developed the first ER-targeted fluorescent FA probe Na-FA-ER. The detection is based on the condensation reaction of the hydrazine group and FA to suppress the photo-induced electron transfer (PET) pathway, resulting in a fluorescence increase. The novel Na-FA-ER showed high sensitivity to FA. In addition, the Na-FA-ER enabled the bio-imaging of exogenous and endogenous FA in living HeLa cells. Most significantly, the new Na-FA-ER was employed to visualize the endogenous FA in the ER in living cells for the first time.

Automated sequence- and stereo-specific assignment of methyl-labeled proteins by paramagnetic relaxation and methyl-methyl nuclear overhauser enhancement spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Venditti, Vincenzo; Fawzi, Nicolas L.; Clore, G. Marius, E-mail: mariusc@mail.nih.gov [National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Laboratory of Chemical Physics (United States)

2011-11-15

Methyl-transverse relaxation optimized spectroscopy is rapidly becoming the preferred NMR technique for probing structure and dynamics of very large proteins up to {approx}1 MDa in molecular size. Data interpretation, however, necessitates assignment of methyl groups which still presents a very challenging and time-consuming process. Here we demonstrate that, in combination with a known 3D structure, paramagnetic relaxation enhancement (PRE), induced by nitroxide spin-labels incorporated at only a few surface-exposed engineered cysteines, provides fast, straightforward and robust access to methyl group resonance assignments, including stereoassignments for the methyl groups of leucine and valine. Neither prior assignments, including backbone assignments, for the protein, nor experiments that transfer magnetization between methyl groups and the protein backbone, are required. PRE-derived assignments are refined by 4D methyl-methyl nuclear Overhauser enhancement data, eliminating ambiguities and errors that may arise due to the high sensitivity of PREs to the potential presence of sparsely-populated transient states.

A light-up fluorescent probe for citrate detection based on bispyridinum amides with aggregation-induced emission feature.

Science.gov (United States)

Liu, Chenchen; Hang, Yandi; Jiang, Tao; Yang, Ji; Zhang, Xiao; Hua, Jianli

2018-02-01

Citrate is an important intermediate in the citric acid cycle, a vital metabolic pathway for animals, plants and bacteria. It is of great significance to detect its levels in human beings because several diseases may cause the abnormal of citrate. In this paper, a new turn-on fluorescent sensor (TPE-Py) using the classic tetraphenylethylene (TPE) as the aggregation-induced emission (AIE) fluorophore and bipyridinium-based amides as the recognition receptor has been synthesized for the detection of citrate. The probe exhibits good selectivity and sensitivity to citrate with a relatively low detection limit (1.0 × 10 -7 M). The enhancement of the fluorescence is relevant with the AIE property based on the complexation of TPE-Py with citrate caused by the hydrogen bonding and electrostatic interactions between the bipyridinium diamides and citrate, which has been proved by 1 H NMR and mass spectra titration, scanning electronic microscope and dynamic light scattering analyses. More importantly, the quantification of citrate in artificial urine may develop TPE-Py fluorometric probe for the citrate detection in real biosystems. Copyright © 2017 Elsevier B.V. All rights reserved.

mathFISH, a web tool that uses thermodynamics-based mathematical models for in silico evaluation of oligonucleotide probes for fluorescence in situ hybridization.

Science.gov (United States)

Yilmaz, L Safak; Parnerkar, Shreyas; Noguera, Daniel R

2011-02-01

Mathematical models of RNA-targeted fluorescence in situ hybridization (FISH) for perfectly matched and mismatched probe/target pairs are organized and automated in web-based mathFISH (http://mathfish.cee.wisc.edu). Offering the users up-to-date knowledge of hybridization thermodynamics within a theoretical framework, mathFISH is expected to maximize the probability of success during oligonucleotide probe design.

Dopamine-functionalized InP/ZnS quantum dots as fluorescence probes for the detection of adenosine in microfluidic chip.

Science.gov (United States)

Ankireddy, Seshadri Reddy; Kim, Jongsung

2015-01-01

Microbeads are frequently used as solid supports for biomolecules such as proteins and nucleic acids in heterogeneous microfluidic assays. Chip-based, quantum dot (QD)-bead-biomolecule probes have been used for the detection of various types of DNA. In this study, we developed dopamine (DA)-functionalized InP/ZnS QDs (QDs-DA) as fluorescence probes for the detection of adenosine in microfluidic chips. The photoluminescence (PL) intensity of the QDs-DA is quenched by Zn(2+) because of the strong coordination interactions. In the presence of adenosine, Zn(2+) cations preferentially bind to adenosine, and the PL intensity of the QDs-DA is recovered. A polydimethylsiloxane-based microfluidic chip was fabricated, and adenosine detection was confirmed using QDs-DA probes.

A fluorescent probe distinguishes between inhibition of early and late steps of lipopolysaccharide biogenesis in whole cells