The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Naoki Matsuda - One of the best experts on this subject based on the ideXlab platform.
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Kinetics of competitive adsorption of β-casein and methylene blue on Hydrophilic Glass.
The journal of physical chemistry. A, 2012Co-Authors: Lin Deng, Naoki MatsudaAbstract:The competitive adsorption of methylene blue (MB) and β-casein on Hydrophilic Glass from an aqueous mixed solution was directly detected at the solution pH smaller than the protein isoelectric poin...
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In situ investigation of coadsorption of myoglobin and methylene blue to Hydrophilic Glass by broadband time-resolved optical waveguide spectroscopy.
Langmuir : the ACS journal of surfaces and colloids, 2004Co-Authors: Naoki Matsuda, And Akiko Takatsu, Kenji KatoAbstract:Recently, we have developed a broadband optical waveguide (OWG) spectrometer by using commercially available Glass plates of tens of micrometers in thickness as the substrate-free multimode waveguides (Qi et al. Opt. Lett. 2002, 27, 2001-2003). The spectrometer having a bandwidth from 360 to 800 nm is capable of simultaneously detecting the Soret-band absorption of heme proteins and the visible absorption of organic dyes. In this article, the spectrometer was used to in situ investigate coadsorption of methylene blue (MB) and myoglobin from the mixed aqueous solution onto bare Glass. Both MB and myoglobin in the mixed solution are positively charged, which makes them not only avoid the chemical interaction between each other but also easy to adsorb to Hydrophilic Glass. It was found that the coadsorption of MB and myoglobin occurred just in the early stage and the Glass surface was finally occupied by myoglobin. The OWG spectroscopic investigation into the respective MB and myoglobin adsorptions shows that MB adsorption is reversible to some degree but that of myoglobin is irreversible. It reveals that the electrostatic binding of myoglobin to bare Glass is stronger than the case of MB. Therefore, the adsorbed MB can be substituted by myoglobin. Moreover, via the electrostatic repulsion the tightly immobilized myoglobin prevents bulk MB from occupying the empty surface sites. It is the reason MB is absent from the Hydrophilic Glass coated with a submonolayer of myoglobin. In the article, we explained both the strong dimerization of MB at the interface and a slow decrease with time of the Soret-band absorbance after its maximum was reached. We also estimated the myoglobin coverage based on the waveguide theory. The study shows the distinguished applicability of the broadband OWG spectroscopy for in situ, real-time monitoring of the dye-protein coadsorption to silica from the mixed solution.
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Time-Resolved Optical Waveguide Spectroscopy for Studying Protein Adsorption Kinetics
MATERIALS TRANSACTIONS, 2004Co-Authors: Jose H. Santos, Naoki Matsuda, Takamitsu Yoshida, Akiko Takatsu, Kenji KatoAbstract:A time-resolved evanescent wave absorption technique is employed in studying the adsorption of a mammalian protein (cytochrome c) from an electrolyte-free solution on a Hydrophilic Glass surface. The method combines the sensitivity of a fast-scan spectral analyzer and surface specificity of slab optical waveguide (SOWG) technique. While proteins are viewed to undergo an overall irreversible adsorption process brought about by structural changes that occur after the initial adsorption phase, we have used an SOWG technique to investigate the first stage of the adsorption process while no noticeable changes have taken place. Absorbance data within the first two seconds after contact fit well into the reversible adsorption model characteristic of Langmuir-type adsorption but the goodness-of-fit diminishes as the protein molecules spend more time on the surface.
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A Kinetic Study of Cytochrome c Adsorption to Hydrophilic Glass by Broad-Band, Time-Resolved Optical Waveguide Spectroscopy
The Journal of Physical Chemistry B, 2003Co-Authors: Zhi-mei Qi† And, Naoki Matsuda, Akiko Takatsu And, Kenji KatoAbstract:The adsorption process of cytochrome c from aqueous solution onto Glass and its desorption process from Glass into water were investigated by broad-band, time-resolved optical waveguide spectroscop...
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Multimode Optical Waveguide Spectrscopy of Aqueous Gold Sol
Micro Total Analysis Systems 2002, 2002Co-Authors: Naoki Matsuda, Takamitsu Yoshida, J. Santos, A. Takatsu, Kenji KatoAbstract:Optical waveguide (OWG) spectroscopy of aqueous Au sol was performed using 50-µm-thick Glass plates as multimode waveguides. Measurements of the TE- and TM-polarized absorbance spectra in the wavelength range 400 – 800 nm demonstrated that Au nanoparticles in water were surface-inactive for Hydrophilic Glass waveguides due to electrostatic repulsion but they could be easily immobilized on the silanized and protein-modified Glass surfaces to form the aggregated monolayer.
Kenji Kato - One of the best experts on this subject based on the ideXlab platform.
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In situ investigation of coadsorption of myoglobin and methylene blue to Hydrophilic Glass by broadband time-resolved optical waveguide spectroscopy.
Langmuir : the ACS journal of surfaces and colloids, 2004Co-Authors: Naoki Matsuda, And Akiko Takatsu, Kenji KatoAbstract:Recently, we have developed a broadband optical waveguide (OWG) spectrometer by using commercially available Glass plates of tens of micrometers in thickness as the substrate-free multimode waveguides (Qi et al. Opt. Lett. 2002, 27, 2001-2003). The spectrometer having a bandwidth from 360 to 800 nm is capable of simultaneously detecting the Soret-band absorption of heme proteins and the visible absorption of organic dyes. In this article, the spectrometer was used to in situ investigate coadsorption of methylene blue (MB) and myoglobin from the mixed aqueous solution onto bare Glass. Both MB and myoglobin in the mixed solution are positively charged, which makes them not only avoid the chemical interaction between each other but also easy to adsorb to Hydrophilic Glass. It was found that the coadsorption of MB and myoglobin occurred just in the early stage and the Glass surface was finally occupied by myoglobin. The OWG spectroscopic investigation into the respective MB and myoglobin adsorptions shows that MB adsorption is reversible to some degree but that of myoglobin is irreversible. It reveals that the electrostatic binding of myoglobin to bare Glass is stronger than the case of MB. Therefore, the adsorbed MB can be substituted by myoglobin. Moreover, via the electrostatic repulsion the tightly immobilized myoglobin prevents bulk MB from occupying the empty surface sites. It is the reason MB is absent from the Hydrophilic Glass coated with a submonolayer of myoglobin. In the article, we explained both the strong dimerization of MB at the interface and a slow decrease with time of the Soret-band absorbance after its maximum was reached. We also estimated the myoglobin coverage based on the waveguide theory. The study shows the distinguished applicability of the broadband OWG spectroscopy for in situ, real-time monitoring of the dye-protein coadsorption to silica from the mixed solution.
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Time-Resolved Optical Waveguide Spectroscopy for Studying Protein Adsorption Kinetics
MATERIALS TRANSACTIONS, 2004Co-Authors: Jose H. Santos, Naoki Matsuda, Takamitsu Yoshida, Akiko Takatsu, Kenji KatoAbstract:A time-resolved evanescent wave absorption technique is employed in studying the adsorption of a mammalian protein (cytochrome c) from an electrolyte-free solution on a Hydrophilic Glass surface. The method combines the sensitivity of a fast-scan spectral analyzer and surface specificity of slab optical waveguide (SOWG) technique. While proteins are viewed to undergo an overall irreversible adsorption process brought about by structural changes that occur after the initial adsorption phase, we have used an SOWG technique to investigate the first stage of the adsorption process while no noticeable changes have taken place. Absorbance data within the first two seconds after contact fit well into the reversible adsorption model characteristic of Langmuir-type adsorption but the goodness-of-fit diminishes as the protein molecules spend more time on the surface.
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A Kinetic Study of Cytochrome c Adsorption to Hydrophilic Glass by Broad-Band, Time-Resolved Optical Waveguide Spectroscopy
The Journal of Physical Chemistry B, 2003Co-Authors: Zhi-mei Qi† And, Naoki Matsuda, Akiko Takatsu And, Kenji KatoAbstract:The adsorption process of cytochrome c from aqueous solution onto Glass and its desorption process from Glass into water were investigated by broad-band, time-resolved optical waveguide spectroscop...
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Multimode Optical Waveguide Spectrscopy of Aqueous Gold Sol
Micro Total Analysis Systems 2002, 2002Co-Authors: Naoki Matsuda, Takamitsu Yoshida, J. Santos, A. Takatsu, Kenji KatoAbstract:Optical waveguide (OWG) spectroscopy of aqueous Au sol was performed using 50-µm-thick Glass plates as multimode waveguides. Measurements of the TE- and TM-polarized absorbance spectra in the wavelength range 400 – 800 nm demonstrated that Au nanoparticles in water were surface-inactive for Hydrophilic Glass waveguides due to electrostatic repulsion but they could be easily immobilized on the silanized and protein-modified Glass surfaces to form the aggregated monolayer.
Yangkyu Choi - One of the best experts on this subject based on the ideXlab platform.
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micropatterning polydiacetylene supramolecular vesicles on Glass substrates using a pre patterned hydrophobic thin film
Macromolecular Chemistry and Physics, 2012Co-Authors: Jimin Choi, Bora Yoon, Kyungyong Choi, Myeonglok Seol, Yangkyu ChoiAbstract:A micropatterning method for depositing polydiacetylene (PDA) supramolecular vesicles on Glass substrates, employing a pre-patterned hydrophobic thin film, is presented. The pre-patterned hydrophobic thin film is used to define surface-exposed regions on Hydrophilic Glass substrates where selective immobilization of PDA vesicles takes place. The observation that fluorescent patterns are generated by heat treatment of the deposited PDAs demonstrates that the vesicles are successfully immobilized in the form of micropatterns. Finally, the possibility that this strategy may be used to design a vesicle-based sensor chip system is demonstrated by the observation that fluorescence patterns are generated when the immobilized PDA vesicles interact with cyclodextrin.
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Micropatterning Polydiacetylene Supramolecular Vesicles on Glass Substrates using a Pre‐Patterned Hydrophobic Thin Film
Macromolecular Chemistry and Physics, 2012Co-Authors: Jimin Choi, Bora Yoon, Kyungyong Choi, Myeonglok Seol, Jong-man Kim, Yangkyu ChoiAbstract:A micropatterning method for depositing polydiacetylene (PDA) supramolecular vesicles on Glass substrates, employing a pre-patterned hydrophobic thin film, is presented. The pre-patterned hydrophobic thin film is used to define surface-exposed regions on Hydrophilic Glass substrates where selective immobilization of PDA vesicles takes place. The observation that fluorescent patterns are generated by heat treatment of the deposited PDAs demonstrates that the vesicles are successfully immobilized in the form of micropatterns. Finally, the possibility that this strategy may be used to design a vesicle-based sensor chip system is demonstrated by the observation that fluorescence patterns are generated when the immobilized PDA vesicles interact with cyclodextrin.
Sachin S Velankar - One of the best experts on this subject based on the ideXlab platform.
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aggregation and separation in ternary particle oil water systems with fully wettable particles
Langmuir, 2014Co-Authors: Samantha J Heidlebaugh, Trystan Domenech, Steven V Iasella, Sachin S VelankarAbstract:We report that a variety of ternary particle/liquid/liquid mixtures heavily aggregate or separate completely if (1) the particles are fully or almost fully wetted by one fluid, and (2) if the wetting fluid volume fraction is comparable to the particle volume fraction. Aggregation and separation do not happen if the particles are partially wetted by both fluids, in which case Pickering emulsions appear at all compositions. Rheological and geometric criteria for aggregation are proposed and compared with a state diagram of a ternary system composed of oil, water, and Hydrophilic Glass particles. Analogies are drawn to wet granulation and spherical agglomeration, two particle processing operations in which wetting phenomena are important.
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Aggregation and Separation in Ternary Particle/Oil/Water Systems with Fully Wettable Particles
Langmuir : the ACS journal of surfaces and colloids, 2014Co-Authors: Samantha J Heidlebaugh, Trystan Domenech, Steven V Iasella, Sachin S VelankarAbstract:We report that a variety of ternary particle/liquid/liquid mixtures heavily aggregate or separate completely if (1) the particles are fully or almost fully wetted by one fluid, and (2) if the wetting fluid volume fraction is comparable to the particle volume fraction. Aggregation and separation do not happen if the particles are partially wetted by both fluids, in which case Pickering emulsions appear at all compositions. Rheological and geometric criteria for aggregation are proposed and compared with a state diagram of a ternary system composed of oil, water, and Hydrophilic Glass particles. Analogies are drawn to wet granulation and spherical agglomeration, two particle processing operations in which wetting phenomena are important.
Zhi-mei Qi† And - One of the best experts on this subject based on the ideXlab platform.
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A Kinetic Study of Cytochrome c Adsorption to Hydrophilic Glass by Broad-Band, Time-Resolved Optical Waveguide Spectroscopy
The Journal of Physical Chemistry B, 2003Co-Authors: Zhi-mei Qi† And, Naoki Matsuda, Akiko Takatsu And, Kenji KatoAbstract:The adsorption process of cytochrome c from aqueous solution onto Glass and its desorption process from Glass into water were investigated by broad-band, time-resolved optical waveguide spectroscop...
