The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform
Tatsuhiro Okada - One of the best experts on this subject based on the ideXlab platform.
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study of adsorption of Methylene Blue and New Methylene Blue in liquid solid interface by slab optical waveguide spectroscopy
Talanta, 2005Co-Authors: Naoki Matsuda, Akiko Takatsu, Kenji Kato, Tatsuhiro OkadaAbstract:Abstract A slab optical waveguide (SOWG) has been used for study of adsorption of both Methylene Blue (MB) and New Methylene Blue (NMB) in liquid–solid interface. Adsorption characteristics of MB and NMB on both bare SOWG and silanized SOWG by octadecyltrichlorosilane (ODS) were compared. Effect of pH on adsorption on MB and NMB was investigated. Binding rate constant analysis showed that both MB and NMB on bare SOWG demonstrates larger association constants than those on ODS-SOWG. Interactions of MB and NMB on bare SOWG and ODS-SOWG were analyzed by molecular mechanics calculation method. The binding energy change was in the following order: E NMB–bare > E MB–bare > E NMB–ODS > E MB–ODS .
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Simultaneous determination of Methylene Blue and New Methylene Blue by slab optical waveguide spectroscopy and artificial neural networks
Analytica Chimica Acta, 2003Co-Authors: Lixian Sun, Naoki Matsuda, Akiko Takatsu, Kenji Kato, A.mahipal Reddy, Tatsuhiro OkadaAbstract:Abstract A slab optical waveguide (SOWG) has been used for study of adsorption of both Methylene Blue (MB) and New Methylene Blue (NMB) in liquid–solid interface. Adsorption characteristics of MB and NMB on both bare SOWG and silanized SOWG by octadecyltrichlorosilane (ODS) were compared. The simultaneous determinations of both MB and NMB were explored by flow injection SOWG spectrophotometric analysis and artificial neural networks (ANNs) for the first time. Concentrations of MB and NMB were estimated simultaneously with the ANNs. Results obtained with SOWG were compared with those got by conventional UV-visible spectrophotometry.
Jiaqi Deng - One of the best experts on this subject based on the ideXlab platform.
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Immobilization of horseradish peroxidase onto a composite membrane of regenerated silk fibroin and polyvinyl alcohol and its application to a New Methylene Blue-mediating sensor for hydrogen peroxide
Enzyme and Microbial Technology, 1997Co-Authors: Yongcheng Liu, Haiying Liu, Jianghong Qian, Jiaqi DengAbstract:Abstract Horseradish peroxidase (HRP) was effectively entrapped in a novel composite membrane of polyvinyl alcohol (PVA) and regenerated silk fibroin (RSF). IR and scanning electron microscopy were employed to provide a useful insight into the structure and morphology of the immobilized HRP composite membrane. A New Methylene Blue-mediating sensor for hydrogen peroxide was constructed which was based on the composite membrane as an immobilization matrix for HRP. Cyclic voltammetry and amperometric measurements were used to demonstrate the efficiency of the New Methylene Blue mediating an electron transfer between the immobilized HRP and a glassy carbon electrode in bioelectrocatalytic reduction of hydrogen peroxide. Performance and characteristics of the sensor were evaluated with regard to response time, detection limit, selectivity, and dependences on temperature and pH as well as operating and storage stabilities. The sensor has a variety of characteristics including good sensitivity, rapid response time, and low detection limit of 5.0 μ m .
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An Amperometric New Methylene Blue N-Mediating Sensor for Hydrogen Peroxide Based on Regenerated Silk Fibroin as an Immobilization Matrix for Peroxidase
Analytical biochemistry, 1996Co-Authors: Jianghong Qian, Haiying Liu, Yongcheng Liu, Jiaqi DengAbstract:A simple and effective procedure was described for the immobilization of peroxidase in regenerated silk fibroin membrane prepared from waste silk. The membranes of regenerated silk fibroin with or without peroxidase, before or after the ethanol treatment, were characterized by ir spectra. An amperometric H202 sensor, based on the immobilized peroxidase in regenerated silk fibroin membrane, in the use of New Methylene Blue N as an electron transfer mediator, was fabricated. The characteristics of the sensor with respect to linearity, response time, effect of pH and temperature, stability, and reproducibility were investigated. Dependences of Michaelis-Menten constant KMapp on the concentration of the mediator, and the applied potential were also studied and the results were presented. The sensor was highly sensitive to H2O2 with a detection limit of 1.0 x 10(-7)M and with response time of less than 40 s.
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Biosensoring of hydrogen peroxide using New Methylene Blue N incorporated in a montmorillonite-modified horseradish peroxidase immobilization matrix as an electron shuttle
Analytica Chimica Acta, 1996Co-Authors: Chenghong Lei, Haiying Liu, Zhanen Zhang, Jilie Kong, Jiaqi DengAbstract:Abstract A novel H 2 O 2 sensor is described. New Methylene Blue N, a cation dye mediator, was incorporated in the montmorillonite-horseradish peroxidase (HRP) hydrogel cross-linked on a glassy carbon electrode surface via bovine serum albumin (BSA)-glutaraldehyde to construct the sensor. The interaction of the dye with sodium montmorillonite colloidal particles was investigated by employing visible spectrometry, X-ray photoelectron spectroscopy (XPS), and electrochemical measurements. The coimmobilization matrix of the mediator and the enzyme was formed from the pretreated sodium montmorillonite colloid in which horseradish peroxidase was dissolved. Immobilization of New Methylene Blue N involved its interaction with the montmorillonite colloidal particles while that of horseradish peroxidase involved the cross-linking via BSA-glutaraldehyde as usual. Cyclic voltammetry and amperometric measurements demonstrated that New Methylene Blue N coimmobilized with HRP in this way displayed good stability and efficiently shuttled electrons between immobilized HRP and the electrode. The sensor responded rapidly to H 2 O 2 in the linear range from 5.0 μM to 2.2 mM with detection limit of 6.0 × 10 −7 M.
Naoki Matsuda - One of the best experts on this subject based on the ideXlab platform.
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study of adsorption of Methylene Blue and New Methylene Blue in liquid solid interface by slab optical waveguide spectroscopy
Talanta, 2005Co-Authors: Naoki Matsuda, Akiko Takatsu, Kenji Kato, Tatsuhiro OkadaAbstract:Abstract A slab optical waveguide (SOWG) has been used for study of adsorption of both Methylene Blue (MB) and New Methylene Blue (NMB) in liquid–solid interface. Adsorption characteristics of MB and NMB on both bare SOWG and silanized SOWG by octadecyltrichlorosilane (ODS) were compared. Effect of pH on adsorption on MB and NMB was investigated. Binding rate constant analysis showed that both MB and NMB on bare SOWG demonstrates larger association constants than those on ODS-SOWG. Interactions of MB and NMB on bare SOWG and ODS-SOWG were analyzed by molecular mechanics calculation method. The binding energy change was in the following order: E NMB–bare > E MB–bare > E NMB–ODS > E MB–ODS .
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Simultaneous determination of Methylene Blue and New Methylene Blue by slab optical waveguide spectroscopy and artificial neural networks
Analytica Chimica Acta, 2003Co-Authors: Lixian Sun, Naoki Matsuda, Akiko Takatsu, Kenji Kato, A.mahipal Reddy, Tatsuhiro OkadaAbstract:Abstract A slab optical waveguide (SOWG) has been used for study of adsorption of both Methylene Blue (MB) and New Methylene Blue (NMB) in liquid–solid interface. Adsorption characteristics of MB and NMB on both bare SOWG and silanized SOWG by octadecyltrichlorosilane (ODS) were compared. The simultaneous determinations of both MB and NMB were explored by flow injection SOWG spectrophotometric analysis and artificial neural networks (ANNs) for the first time. Concentrations of MB and NMB were estimated simultaneously with the ANNs. Results obtained with SOWG were compared with those got by conventional UV-visible spectrophotometry.
Gopinatha Suresh Kumar - One of the best experts on this subject based on the ideXlab platform.
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Insights on the interaction of phenothiazinium dyes Methylene Blue and New Methylene Blue with synthetic duplex RNAs through spectroscopy and modeling
Journal of photochemistry and photobiology. B Biology, 2020Co-Authors: Puja Paul, Soumya Sundar Mati, Gopinatha Suresh KumarAbstract:The ubiquitous influence of double stranded RNAs in biological events makes them imperative to gather data based on specific binding procedure of small molecules to various RNA conformations. Particular interest may be attributed to situations wherein small molecules target RNAs altering their structures and causing functional modifications. The main focus of this study is to delve into the interactive pattern of two small molecule phenothiazinium dyes, Methylene Blue and New Methylene Blue, with three duplex RNA polynucleotides-poly(A).poly(U), poly(C).poly(G) and poly(I).poly(C) by spectroscopic and molecular modeling techniques. Analysis of data as per Scatchard and Benesi-Hildebrand methodologies revealed highest affinity of these dyes to poly(A).poly(U) and least to poly(I).poly(C). In addition to fluorescence quenching, viscometric studies also substantiated that the dyes follow different modes of binding to different RNA polynucleotides. Distortion in the RNA structures with induced optical activity in the otherwise optically inactive dye molecules was evidenced from circular dichroism results. Dye-induced RNA structural modification occurred from extended conformation to compact particles visualized by atomic force microscopy. Molecular docking results revealed different binding patterns of the dye molecules within the RNA duplexes. The novelty of the present work lies towards a New contribution of the phenothiazinium dyes in dysfunctioning double stranded RNAs, advancing our knowledge to their potential use as RNA targeted small molecules.
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exploring the interaction of phenothiazinium dyes Methylene Blue New Methylene Blue azure a and azure b with trnaphe spectroscopic thermodynamic voltammetric and molecular modeling approach
Physical Chemistry Chemical Physics, 2017Co-Authors: Puja Paul, Soumya Sundar Mati, Subhash Chandra Bhattacharya, Gopinatha Suresh KumarAbstract:This study focuses on the understanding of the interaction of phenothiazinium dyes Methylene Blue (MB), New Methylene Blue (NMB), azure A (AZA) and azure B (AZB) with tRNAPhe with particular emphasis on deciphering the mode and energetics of the binding. Strong intercalative binding to tRNAPhe was observed for MB, NMB and AZB, bound by a partial intercalative mode. AZA has shown groove binding characteristics. From spectroscopic studies binding affinity values of the order of 105 M−1 were deduced for these dyes; the trend varied as MB > NMB > AZB > AZA. The binding was characterized by an increase of thermal melting temperatures and perturbation in the circular dichroism spectrum of tRNA. All the dyes acquired optical activity upon binding to tRNA. The binding was predominantly entropy driven with a favorable enthalpy term that increased with temperature in all the cases. Dissection of the Gibbs energy to polyelectrolytic and non-polyelectrolytic terms revealed a major role of the non-electrostatic forces in the binding. The small but significant heat capacity changes and the observed enthalpy–entropy compensation phenomenon confirmed the involvement of multiple weak non-covalent forces driving the interaction. The mode of binding was confirmed from quenching, viscosity and cyclic voltammetric results. Using density functional theory, ground state optimized structures of the dyes were calculated to provide insight into theoretical docking studies to correlate the experimental approaches. The modeling results verified the binding location as well as the binding energy of complexation. The results may provide New insights into the structure–activity relationship useful in the design of effective RNA targeted therapeutic agents.
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Spectroscopic, calorimetric, cyclic voltammetric and molecular modeling studies of New Methylene Blue-polyadenylic acid interaction and comparison to thionine and toluidine Blue O: Understanding self-structure formation by planar dyes
Dyes and Pigments, 2017Co-Authors: Puja Paul, Soumya Sundar Mati, Subhash Chandra Bhattacharya, Gopinatha Suresh KumarAbstract:Abstract Molecules capable of inducing self-structure in poly(A) may arrest protein synthesis by preventing poly(A) chain elongation thereby inhibiting the function of mRNA. We examined whether New Methylene Blue can induce such structural organization in single stranded poly(A) and compared the results with those of the phenothiazinium dyes thionine and toluidine Blue O. Strong association between the dyes and poly(A) was revealed from the spectroscopy and cyclic voltammetry. Thionine has a higher affinity compared to toluidine Blue O and New Methylene Blue at 50 mM and 100 mM, but at 200 mM [Na + ] New Methylene Blue exhibited the highest binding affinity. Negative enthalpy and positive entropy changes, and enthalpy-entropy compensation behaviour were characteristic features for the complexation. Involvement of hydrophobic forces in the binding process is correlated to the negative heat capacity changes. Differential scanning calorimetry and circular dichroism results revealed that the dyes bind poly(A) and induce a stable secondary structure with a melting temperature of 333.15 K. The binding constants increased in the range of 50–200 mM [Na + ]. Molecular docking results revealed that not only van der Waals forces of attraction but hydrogen bonding also plays a crucial role in dye-poly(A) binding. Recognition and binding of small molecules to single stranded poly(A) may present a New avenue for therapeutic intervention.
Puja Paul - One of the best experts on this subject based on the ideXlab platform.
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Insights on the interaction of phenothiazinium dyes Methylene Blue and New Methylene Blue with synthetic duplex RNAs through spectroscopy and modeling
Journal of photochemistry and photobiology. B Biology, 2020Co-Authors: Puja Paul, Soumya Sundar Mati, Gopinatha Suresh KumarAbstract:The ubiquitous influence of double stranded RNAs in biological events makes them imperative to gather data based on specific binding procedure of small molecules to various RNA conformations. Particular interest may be attributed to situations wherein small molecules target RNAs altering their structures and causing functional modifications. The main focus of this study is to delve into the interactive pattern of two small molecule phenothiazinium dyes, Methylene Blue and New Methylene Blue, with three duplex RNA polynucleotides-poly(A).poly(U), poly(C).poly(G) and poly(I).poly(C) by spectroscopic and molecular modeling techniques. Analysis of data as per Scatchard and Benesi-Hildebrand methodologies revealed highest affinity of these dyes to poly(A).poly(U) and least to poly(I).poly(C). In addition to fluorescence quenching, viscometric studies also substantiated that the dyes follow different modes of binding to different RNA polynucleotides. Distortion in the RNA structures with induced optical activity in the otherwise optically inactive dye molecules was evidenced from circular dichroism results. Dye-induced RNA structural modification occurred from extended conformation to compact particles visualized by atomic force microscopy. Molecular docking results revealed different binding patterns of the dye molecules within the RNA duplexes. The novelty of the present work lies towards a New contribution of the phenothiazinium dyes in dysfunctioning double stranded RNAs, advancing our knowledge to their potential use as RNA targeted small molecules.
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exploring the interaction of phenothiazinium dyes Methylene Blue New Methylene Blue azure a and azure b with trnaphe spectroscopic thermodynamic voltammetric and molecular modeling approach
Physical Chemistry Chemical Physics, 2017Co-Authors: Puja Paul, Soumya Sundar Mati, Subhash Chandra Bhattacharya, Gopinatha Suresh KumarAbstract:This study focuses on the understanding of the interaction of phenothiazinium dyes Methylene Blue (MB), New Methylene Blue (NMB), azure A (AZA) and azure B (AZB) with tRNAPhe with particular emphasis on deciphering the mode and energetics of the binding. Strong intercalative binding to tRNAPhe was observed for MB, NMB and AZB, bound by a partial intercalative mode. AZA has shown groove binding characteristics. From spectroscopic studies binding affinity values of the order of 105 M−1 were deduced for these dyes; the trend varied as MB > NMB > AZB > AZA. The binding was characterized by an increase of thermal melting temperatures and perturbation in the circular dichroism spectrum of tRNA. All the dyes acquired optical activity upon binding to tRNA. The binding was predominantly entropy driven with a favorable enthalpy term that increased with temperature in all the cases. Dissection of the Gibbs energy to polyelectrolytic and non-polyelectrolytic terms revealed a major role of the non-electrostatic forces in the binding. The small but significant heat capacity changes and the observed enthalpy–entropy compensation phenomenon confirmed the involvement of multiple weak non-covalent forces driving the interaction. The mode of binding was confirmed from quenching, viscosity and cyclic voltammetric results. Using density functional theory, ground state optimized structures of the dyes were calculated to provide insight into theoretical docking studies to correlate the experimental approaches. The modeling results verified the binding location as well as the binding energy of complexation. The results may provide New insights into the structure–activity relationship useful in the design of effective RNA targeted therapeutic agents.
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Spectroscopic, calorimetric, cyclic voltammetric and molecular modeling studies of New Methylene Blue-polyadenylic acid interaction and comparison to thionine and toluidine Blue O: Understanding self-structure formation by planar dyes
Dyes and Pigments, 2017Co-Authors: Puja Paul, Soumya Sundar Mati, Subhash Chandra Bhattacharya, Gopinatha Suresh KumarAbstract:Abstract Molecules capable of inducing self-structure in poly(A) may arrest protein synthesis by preventing poly(A) chain elongation thereby inhibiting the function of mRNA. We examined whether New Methylene Blue can induce such structural organization in single stranded poly(A) and compared the results with those of the phenothiazinium dyes thionine and toluidine Blue O. Strong association between the dyes and poly(A) was revealed from the spectroscopy and cyclic voltammetry. Thionine has a higher affinity compared to toluidine Blue O and New Methylene Blue at 50 mM and 100 mM, but at 200 mM [Na + ] New Methylene Blue exhibited the highest binding affinity. Negative enthalpy and positive entropy changes, and enthalpy-entropy compensation behaviour were characteristic features for the complexation. Involvement of hydrophobic forces in the binding process is correlated to the negative heat capacity changes. Differential scanning calorimetry and circular dichroism results revealed that the dyes bind poly(A) and induce a stable secondary structure with a melting temperature of 333.15 K. The binding constants increased in the range of 50–200 mM [Na + ]. Molecular docking results revealed that not only van der Waals forces of attraction but hydrogen bonding also plays a crucial role in dye-poly(A) binding. Recognition and binding of small molecules to single stranded poly(A) may present a New avenue for therapeutic intervention.