The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Suk-kyu Chang - One of the best experts on this subject based on the ideXlab platform.
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convenient office scanner based au3 analysis using dual signaling of Resorufin dimethylthiocarbamate
Dyes and Pigments, 2021Co-Authors: Myung Gil Choi, Sunbum Kwon, Suk-kyu ChangAbstract:Abstract We developed an office-scanner-based colorimetric and fluorescent Au3+ determination method by exploiting the Au3+-induced hydrolysis of Resorufin dimethylthiocarbamate (GP-1). Probe GP-1 was readily synthesized and exhibited colorimetric as well as turn-on type fluorogenic responses toward Au3+ ions. GP-1 exhibited no perceptible colorimetric or fluorescence response toward representative oxidants (hydrogen peroxide, hypochlorite, peracetic acid, and superoxide) or common metal ions. The optical responses of GP-1 were caused by the Au3+-promoted cleavage of the thiocarbamate moiety to generate the color and fluorescence of Resorufin. Au3+ analysis of GP-1 was not affected by the coexisting common metal ions. The analytical response was completely acquired in less than 10 min, and the limit of detection was 8.0 × 10−8 M (16 ppb). To realize the convenient and straightforward Au3+ determination, Au3+-selective colorimetric and fluorescence analysis by GP-1 was investigated using an office scanner as one of the readily available information-technology-based devices by excitation with LED bars.
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A simple hypochlorous acid signaling probe based on Resorufin carbonodithioate and its biological application.
The Analyst, 2019Co-Authors: Myung Gil Choi, Yu Jeong Lee, Kang Min Lee, Kyoung Yeol Park, Tae Jung Park, Suk-kyu ChangAbstract:A novel hypochlorous-acid-selective signaling probe based on the carbonodithioate derivative of Resorufin (RT-1) was developed. Probe RT-1 showed prominent colorimetric and turn-on type fluorescence signaling behavior exclusively toward hypochlorous acid, induced by oxidative hydrolysis, to regenerate Resorufin dye. Hypochlorous acid signaling was not affected by the presence of common metal ions and anions as background, except for the redox active bromide and iodide anions. The detection limit of RT-1 for hypochlorous acid was found to be 2.18 × 10−9 M (0.11 ppb), and the signaling was completed within 3 min. It was also confirmed that hypochlorous acid signaling by the carbonodithioate-based probe RT-1 was superior to that of the closely related carbonothioate derivative RT-2. This was rationalized by density functional theory calculations, which demonstrated that the CS sulfur atom of the former is more negatively charged than that of the latter. Finally, as a biological application of the probe, visualization of hypochlorous acid in RAW 264.7 murine macrophages and HeLa cells was successfully conducted to detect the cellular response to hypochlorous acid.
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novel hg2 selective signaling probe based on Resorufin thionocarbonate and its μpad application
Scientific Reports, 2019Co-Authors: Myung Gil Choi, So Young Park, Ka Young Park, Suk-kyu ChangAbstract:In this study, a novel Resorufin thionocarbonate-based Hg2+-selective signaling probe (RT) for microfluidic paper-based analytical device (μPAD) applications is reported. The designed probe, RT, was readily synthesized by the one-step reaction of Resorufin with phenyl thionochloroformate. The RT probe displayed a prominent color change from yellow to pink and a marked turn-on fluorescence signaling behavior exclusively toward the Hg2+ ion. The signaling of RT was due to Hg2+-induced hydrolysis of the phenyl thionocarbonate moiety to form the parent Resorufin dye, which restored its spectroscopic properties. In addition, RT exhibited the Hg2+-selective signaling behavior without interference by coexisting environmentally relevant metal ions. The detection limit for Hg2+ in simulated wastewater samples was estimated to be 5.8 × 10−8 M. In particular, an RT-equipped μPAD prepared using a wax printing technique enabled simple and convenient determination of Hg2+ ions in simulated wastewater samples, with a detection limit of 5.9 × 10−6 M.
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Dual signaling of hydrazine by selective deprotection of dichlorofluorescein and Resorufin acetates.
Organic & biomolecular chemistry, 2013Co-Authors: Myung Gil Choi, Jung Ok Moon, Jihee Bae, Jung Woo Lee, Suk-kyu ChangAbstract:The highly selective chemosignaling behaviors for hydrazine by a reaction-based probe of dichlorofluorescein and Resorufin acetates were investigated. Hydrazinolysis of latent dichlorofluorescein and Resorufin acetate fluorochromes caused prominent chromogenic and fluorescent turn-on type signals. The probes selectively detected hydrazine in the presence of commonly encountered metal ions and anions as background. Dichlorofluorescein and Resorufin acetates selectively detected hydrazine with detection limits of 9.0 × 10−8 M and 8.2 × 10−7 M, respectively. Furthermore, hydrazine was selectively detected over other closely related compounds, such as hydroxylamine, ethylenediamine, and ammonia. As a possible application of the acetate probes, hydrazine signaling in tap water was tested.
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reaction based dual signaling of fluoride ions by Resorufin sulfonates
Organic and Biomolecular Chemistry, 2013Co-Authors: Hong Yeong Kim, Myung Gil Choi, Suk-kyu ChangAbstract:We developed new reaction-based probes for the dual signaling of fluoride ions. Selective fluoride-assisted deprotection of Resorufin nosylate to generate Resorufin fluorochrome was used for signaling. Resorufin nosylate exhibited selective colorimetric and fluorogenic signaling of fluoride ions in acetonitrile. The response from sulfide ions was effectively masked by using the TPEN–Cu2+ complex as a source of Cu2+ ions for masking sulfide. Selective optical signaling of fluoride was possible in the presence of commonly encountered anions with a detection limit of 1.9 × 10−6 M.
Yu G Vainer - One of the best experts on this subject based on the ideXlab platform.
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nanosecond spectral diffusion and optical dephasing in organic glasses over a wide temperature range incoherent photon echo study of Resorufin in d and d6 ethanol
Journal of Luminescence, 1993Co-Authors: N V Gruzdev, Yu G VainerAbstract:Abstract Incoherent photon echoes (IPE) decay curve of two differently deuterated ethanol glasses: Resorufin in d-ethanol (r/d-e) and Resorufin in d 6 -ethanol (r/d 6 -e) have been measured in wide temperature interval (1.7–35 K). At low temperatures the difference in decay times between results of IPE and two-pulse picosecond photon echoes (2PE) were observed and attributed to nanosecond spectral diffusion (SD). The T -dependence of the SD contribution in IPE data was defined and analyzed using Bai-Fayer theory. IPE high temperature results have shown that high-temperature dephasing in r/d-e is caused mainly by interaction with single low frequency mode (LFM). LFM dephasing was analyzed using Osad'ko nonperturbative dynamical theory. The difference in temperature dependencies of dephasing time between r/d-e and r/d 6 -e was observed: the deuteration influenced both on LFM and two-level systems (TLS) contribution to dephasing.
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ultrafast dephasing of Resorufin in d ethanol glass from 1 7 to 40 k studied by incoherent photon echo
Journal of The Optical Society of America B-optical Physics, 1992Co-Authors: N V Gruzdev, E G Silkis, V D Titov, Yu G VainerAbstract:The temperature dependence of the electronic dephasing of Resorufin in d-ethanol glass was measured from 1.7 to 40 K by incoherent photon echo (IPE) techniques. At T = 8–11 K good agreement between IPE and two-pulse picosecond photon echo (PPE) results was observed. For T 11 K confirm the hypothesis that high-temperature dephasing in this system is due mainly to interaction with a pseudolocal mode.
Stephane Arbault - One of the best experts on this subject based on the ideXlab platform.
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coupling electrochemistry with fluorescence confocal microscopy to investigate electrochemical reactivity a case study with the resazurin Resorufin fluorogenic couple
Analytical Chemistry, 2016Co-Authors: Thomas Doneux, Laurent Bouffier, Bertrand Goudeau, Stephane ArbaultAbstract:The redox couple resazurin-Resorufin exhibits electrofluorochromic properties which are investigated herein by absorption and fluorescence spectroelectrochemistry and by electrochemically coupled-fluorescence confocal laser scanning microscopy (EC-CLSM). At pH 10, the highly fluorescent Resorufin dye is generated at the electrode surface by the electrochemical reduction of the poorly fluorescent resazurin. Performing EC-CLSM at electrode surfaces allows to monitor spatially resolved electrochemical processes in situ and in real time. Using a small (315 μm diameter) cylindrical electrode, a steady-state diffusion layer builds up under potentiostatic conditions at −0.45 V vs Ag|AgCl. Mapping the fluorescence intensity in 3D by CLSM enables us to reconstruct the relative concentration profile of Resorufin around the electrode. The comparison of the experimental diffusion-profile with theoretical predictions demonstrates that spontaneous convection has a direct influence on the actual thickness of the diffusi...
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coupling electrochemistry with fluorescence confocal microscopy to investigate electrochemical reactivity a case study with the resazurin Resorufin fluorogenic couple
Analytical Chemistry, 2016Co-Authors: Thomas Doneux, Laurent Bouffier, Bertrand Goudeau, Stephane ArbaultAbstract:The redox couple resazurin-Resorufin exhibits electrofluorochromic properties which are investigated herein by absorption and fluorescence spectroelectrochemistry and by electrochemically coupled-fluorescence confocal laser scanning microscopy (EC-CLSM). At pH 10, the highly fluorescent Resorufin dye is generated at the electrode surface by the electrochemical reduction of the poorly fluorescent resazurin. Performing EC-CLSM at electrode surfaces allows to monitor spatially resolved electrochemical processes in situ and in real time. Using a small (315 μm diameter) cylindrical electrode, a steady-state diffusion layer builds up under potentiostatic conditions at -0.45 V vs Ag|AgCl. Mapping the fluorescence intensity in 3D by CLSM enables us to reconstruct the relative concentration profile of Resorufin around the electrode. The comparison of the experimental diffusion-profile with theoretical predictions demonstrates that spontaneous convection has a direct influence on the actual thickness of the diffusion layer, which is smaller than the value predicted for a purely diffusional transport. This study shows that combining fluorescence CLSM with electrochemistry is a powerful tool to study electrochemical reactivity at a spatially resolved level.
Trevor M Kitson - One of the best experts on this subject based on the ideXlab platform.
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the oxidative addition reaction between compounds of Resorufin 7 hydroxy 3h phenoxazin 3 one and 2 mercaptoethanol
Bioorganic Chemistry, 1998Co-Authors: Trevor M KitsonAbstract:Abstract 2-Mercaptoethanol reacts with the methanesulphonate, the dimethylcarbamate, and the ethyl ether of Resorufin (7-hydroxy-3 H -phenoxazin-3-one) at 25°C and pH 7.4 to give colored products with maximal absorbances at 433, 442, and 481 nm, respectively. NMR spectra of the products show that the hydrogen atom on C-2 has been specifically replaced by the -SCH 2 CH 2 OH group. It is concluded that the thiol adds to the quinonimine ring and that the first-formed product then undergoes spontaneous oxidation to reform the Resorufin structure. The implications of these studies toward biochemical work with Resorufin derivatives is discussed.
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studies of the esterase activity of cytosolic aldehyde dehydrogenase with Resorufin acetate as substrate
Biochemical Journal, 1997Co-Authors: Trevor M Kitson, Kathryn E KitsonAbstract:Resorufin acetate is a very good substrate for sheep liver cytosolic aldehyde dehydrogenase, both from the point of view of practical spectrophotometry and in terms of information provided about the nature of the catalysis shown by this enzyme. p-Nitrophenyl (PNP) acetate competes against Resorufin acetate for the enzyme's active site (although relatively weakly as the latter substrate has the lower Michaelis constant), but acetaldehyde (in the presence of NAD+) inhibits the hydrolysis of Resorufin acetate only at very high aldehyde concentration. In the absence of cofactor, the rate-limiting step in the hydrolysis of Resorufin acetate and of PNP acetate is hydrolysis of the common acetyl-enzyme, as shown by the observation of bursts of chromophoric product and very similar values of kcat. In the presence of NAD+ or NADH, however, the deacylation step with Resorufin acetate is greatly accelerated until acylation seems to become rate-limiting, because no burst is seen under these conditions. Millimolar concentrations of Mg2+ activate the hydrolyis of Resorufin acetate both in the presence and absence of cofactors. With both Mg2+ and cofactor the kcat for hydrolysis of Resorufin acetate is 30-35 s-1; this is three orders of magnitude higher than the kcat for aldehyde oxidation in the presence of Mg2+, showing that the enzyme's potential catalytic efficency is very much hampered by the slowness with which NADH dissociates from its binding site. The pH profile for the hydrolysis of Resorufin acetate in the presence of NAD+ or NADH fits well to a theoretical ionization curve of pKa approx. 8.2; it is suggested that this might belong to the enzyme's putative catalytic residue (Cys-302).
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Comparison of Resorufin Acetate andp-Nitrophenyl Acetate as Substrates for Chymotrypsin
Bioorganic Chemistry, 1996Co-Authors: Trevor M KitsonAbstract:Abstract Resorufin acetate is shown to be an attractive substrate to use with chymotrypsin since the absorbance of the product is several times more intense than that formed by the widely used p -nitrophenyl acetate. Furthermore, under the right conditions, Resorufin acetate allows convenient observation of the burst reaction by conventional spectrophotometry. The steady-state k cat values for chymotrypsin-catalyzed hydrolysis of Resorufin acetate and p -nitrophenyl acetate are virtually the same, as expected for a rate-limiting deacylation step involving an identical intermediate from both substrates. Stopped-flow studies show that the maximal bursts of product from both substrates are again (in molar terms) about the same. When chymotrypsin is presented with a mixture of both substrates, the monitoring of reaction with Resorufin acetate (at 571 nm) is not interfered with by simultaneous hydrolysis of p -nitrophenyl acetate. Under these conditions, p -nitrophenyl acetate is shown to increase the burst rate constant for acylation of the enzyme by Resorufin acetate, demonstrating unequivocally that p -nitrophenyl acetate can bind to chymotrypsin elsewhere than in the active site.
Myung Gil Choi - One of the best experts on this subject based on the ideXlab platform.
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convenient office scanner based au3 analysis using dual signaling of Resorufin dimethylthiocarbamate
Dyes and Pigments, 2021Co-Authors: Myung Gil Choi, Sunbum Kwon, Suk-kyu ChangAbstract:Abstract We developed an office-scanner-based colorimetric and fluorescent Au3+ determination method by exploiting the Au3+-induced hydrolysis of Resorufin dimethylthiocarbamate (GP-1). Probe GP-1 was readily synthesized and exhibited colorimetric as well as turn-on type fluorogenic responses toward Au3+ ions. GP-1 exhibited no perceptible colorimetric or fluorescence response toward representative oxidants (hydrogen peroxide, hypochlorite, peracetic acid, and superoxide) or common metal ions. The optical responses of GP-1 were caused by the Au3+-promoted cleavage of the thiocarbamate moiety to generate the color and fluorescence of Resorufin. Au3+ analysis of GP-1 was not affected by the coexisting common metal ions. The analytical response was completely acquired in less than 10 min, and the limit of detection was 8.0 × 10−8 M (16 ppb). To realize the convenient and straightforward Au3+ determination, Au3+-selective colorimetric and fluorescence analysis by GP-1 was investigated using an office scanner as one of the readily available information-technology-based devices by excitation with LED bars.
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A simple hypochlorous acid signaling probe based on Resorufin carbonodithioate and its biological application.
The Analyst, 2019Co-Authors: Myung Gil Choi, Yu Jeong Lee, Kang Min Lee, Kyoung Yeol Park, Tae Jung Park, Suk-kyu ChangAbstract:A novel hypochlorous-acid-selective signaling probe based on the carbonodithioate derivative of Resorufin (RT-1) was developed. Probe RT-1 showed prominent colorimetric and turn-on type fluorescence signaling behavior exclusively toward hypochlorous acid, induced by oxidative hydrolysis, to regenerate Resorufin dye. Hypochlorous acid signaling was not affected by the presence of common metal ions and anions as background, except for the redox active bromide and iodide anions. The detection limit of RT-1 for hypochlorous acid was found to be 2.18 × 10−9 M (0.11 ppb), and the signaling was completed within 3 min. It was also confirmed that hypochlorous acid signaling by the carbonodithioate-based probe RT-1 was superior to that of the closely related carbonothioate derivative RT-2. This was rationalized by density functional theory calculations, which demonstrated that the CS sulfur atom of the former is more negatively charged than that of the latter. Finally, as a biological application of the probe, visualization of hypochlorous acid in RAW 264.7 murine macrophages and HeLa cells was successfully conducted to detect the cellular response to hypochlorous acid.
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novel hg2 selective signaling probe based on Resorufin thionocarbonate and its μpad application
Scientific Reports, 2019Co-Authors: Myung Gil Choi, So Young Park, Ka Young Park, Suk-kyu ChangAbstract:In this study, a novel Resorufin thionocarbonate-based Hg2+-selective signaling probe (RT) for microfluidic paper-based analytical device (μPAD) applications is reported. The designed probe, RT, was readily synthesized by the one-step reaction of Resorufin with phenyl thionochloroformate. The RT probe displayed a prominent color change from yellow to pink and a marked turn-on fluorescence signaling behavior exclusively toward the Hg2+ ion. The signaling of RT was due to Hg2+-induced hydrolysis of the phenyl thionocarbonate moiety to form the parent Resorufin dye, which restored its spectroscopic properties. In addition, RT exhibited the Hg2+-selective signaling behavior without interference by coexisting environmentally relevant metal ions. The detection limit for Hg2+ in simulated wastewater samples was estimated to be 5.8 × 10−8 M. In particular, an RT-equipped μPAD prepared using a wax printing technique enabled simple and convenient determination of Hg2+ ions in simulated wastewater samples, with a detection limit of 5.9 × 10−6 M.
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Dual signaling of hydrazine by selective deprotection of dichlorofluorescein and Resorufin acetates.
Organic & biomolecular chemistry, 2013Co-Authors: Myung Gil Choi, Jung Ok Moon, Jihee Bae, Jung Woo Lee, Suk-kyu ChangAbstract:The highly selective chemosignaling behaviors for hydrazine by a reaction-based probe of dichlorofluorescein and Resorufin acetates were investigated. Hydrazinolysis of latent dichlorofluorescein and Resorufin acetate fluorochromes caused prominent chromogenic and fluorescent turn-on type signals. The probes selectively detected hydrazine in the presence of commonly encountered metal ions and anions as background. Dichlorofluorescein and Resorufin acetates selectively detected hydrazine with detection limits of 9.0 × 10−8 M and 8.2 × 10−7 M, respectively. Furthermore, hydrazine was selectively detected over other closely related compounds, such as hydroxylamine, ethylenediamine, and ammonia. As a possible application of the acetate probes, hydrazine signaling in tap water was tested.
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reaction based dual signaling of fluoride ions by Resorufin sulfonates
Organic and Biomolecular Chemistry, 2013Co-Authors: Hong Yeong Kim, Myung Gil Choi, Suk-kyu ChangAbstract:We developed new reaction-based probes for the dual signaling of fluoride ions. Selective fluoride-assisted deprotection of Resorufin nosylate to generate Resorufin fluorochrome was used for signaling. Resorufin nosylate exhibited selective colorimetric and fluorogenic signaling of fluoride ions in acetonitrile. The response from sulfide ions was effectively masked by using the TPEN–Cu2+ complex as a source of Cu2+ ions for masking sulfide. Selective optical signaling of fluoride was possible in the presence of commonly encountered anions with a detection limit of 1.9 × 10−6 M.