Browsing by Author "Hamaguchi, Hiro-o"

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1064 nm Deep Near-Infrared (NIR) Excited Raman Microspectroscopy for Studying Photolabile Organisms
(2011-05-01)
Ando, Masahiro
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Sugiura, Miwa
;
Hayashi, Hidenori
;
Hamaguchi, Hiro-o
;
應用化學系
We have constructed a 1064 nm deep near-infrared (NIR) excited multichannel Raman microspectrometer using an InP/InGaAsP multichannel detector. This microspectrometer achieves high sensitivity suitable for in vivo measurements of single living cells with lateral resolution of 0.7 mu m and depth resolution of 3.1 mu m. It has been applied to the structural analysis of living cyanobacterial cells, well-known model organisms for photosynthesis research, which are too photolabile to be measured with visible laser excitation. High signal-to-noise ratio (SIN) Raman spectra have been obtained from carotenoid, chlorophyll a, and phycocyanin in a single living cyanobacterial cell with no appreciable interference from autofluorescence or photodamage. Sub-micrometer mapping of Raman intensities provides clear distribution images of the three pigments inside the cell.
A General Approach for Estimating Lamella-Thickness Distribution in Polymers with Low-Frequency Raman Spectroscopy: Application to Lamella Formation in Crystallizing Polyethylene
(2018-07-02)
Samuel, Ashok Zachariah
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Hamaguchi, Hiro-o
;
應用化學系
;
應用化學系分子科學碩博班
;
Department of Applied Chemistry
A general method for estimating lamella-thickness distribution in semicrystalline polymers has been developed and applied to polyethylene (PE). The longitudinal acoustic mode (LAM) of PE appears at very low frequencies (i.e., (v) over tilde8-20 cm(-1)) in the Raman spectrum. It represents a distribution of lamellae of varying thicknesses. We propose a distribution function that converts a low-frequency LAM Raman band into the corresponding lamellae-thickness distribution. By using this distribution function, we can study lamella formation in crystallizing PE to elucidate the influence of supercooling and determine critical lamella thickness, the minimum chain length at which folding occurs, and the associated thermodynamic parameters accurately. This method has a general applicability toward the examination of polymer crystallization in an accurate and straightforward manner. Understanding the molecular details of polymer crystallization has applications, particularly in polymer thin-film photovoltaics and polymer processing, beyond its fundamental academic significance.
Accurate intensity calibration for low wavenumber (-150 to 150cm(-1)) Raman spectroscopy using the pure rotational spectrum of N-2
(2015-11-01)
Okajima, Hajime
;
Hamaguchi, Hiro-o
;
應用化學系
;
應用化學系分子科學碩博班
;
Department of Applied Chemistry
We report on an accurate intensity calibration method for low wavenumber Raman spectroscopy. It uses the rotational Raman spectrum of N-2. The intensity distributions in the rotational Raman spectra of diatomic molecules are theoretically well established. They can be used as primary intensity standards for intensity calibration. The intensity ratios of the Stokes and anti-Stokes transitions originating from the same rotational levels are not affected by thermal population. Taking the effect of rotation-vibration interactions appropriately into account, we are able to calculate these intensity ratios theoretically. The comparison between the observed and calculated ratios of the N-2 pure rotational spectrum provides an accurate relative sensitivity curve (error similar to 5 x 10(-4)) in the wavenumber region of -150 to 150 cm(-1). We determine the temperature of water solely from the low wavenumber Raman spectra, using a thus calibrated spectrometer. The Raman temperature shows an excellent agreement with the thermocouple temperature, with only 0.5 K difference. The present calibration technique will be highly useful in many applications of low wavenumber quantitative Raman spectroscopy. Copyright (C) 2015 John Wiley & Sons, Ltd.
Anharmonic coupling of the CH-stretch and CH-bend vibrations of chloroform as studied by near-infrared electroabsorption spectroscopy
(2012-12-21)
Nishida, Jun
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Shigeto, Shinsuke
;
Yabumoto, Sohshi
;
Hamaguchi, Hiro-o
;
應用化學系
Combination bands that involve CH- or OH-stretch vibrations appear in the near-infrared (NIR) region (4000-10 000 cm(-1)). Because they arise from anharmonic coupling between the component fundamentals, detailed analysis of the frequency and intensity of NIR combination bands allows one to elucidate the mechanisms behind the vibrational coupling in the condensed phase in terms of mechanical and electrical anharmonicities. Nevertheless, little has been studied, in particular experimentally, on the origin of the combination band intensity. Here, we show that NIR electroabsorption (EA) spectroscopy, which directly probes the effects of an externally applied electric field on a combination band, can shed new light on anharmonic vibrational coupling through determination of the direction of the transition moment for the combination band. We studied the combination band of the CH-stretch (nu(1)) and CH-bend (nu(4)) modes of liquid chloroform. The electric-field induced absorbance change of the nu(1) + nu(4) combination band caused by reorientation of the chloroform molecule was measured at various chi angles, where chi is the angle between the direction of the applied electric field and the polarization of the incident IR light. We were able to detect an absorbance change as small as 5 x 10(-8) for the combination band. Using the NIR EA spectra of the combination band together with those of the CH-stretch and bend fundamentals, the angle between the transition moment for the combination band and the permanent dipole moment was determined experimentally for the first time to be (79 +/- 14)degrees. The present investigation indicates that the contribution of the CH-stretch mode to the mechanical anharmonicity is minor and that the CH-bend mode plays a dominant role in the mechanical part of the vibrational coupling between the two fundamentals. Furthermore, density functional theory calculations show that both the mechanical anharmonicity of the CH-bend mode and the electrical anharmonicity may contribute equally to the anharmonic coupling. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4770264]
Carbon structure in nanodiamonds elucidated from Raman spectroscopy
(2017-09-01)
Korepanov, Vitaly I.
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Hamaguchi, Hiro-o
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Osawa, Eiji
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Ermolenkov, Vladimir
;
Lednev, Igor K.
Despite their name, nanodiamonds (ND) are comprised of a complex interplay of different carbon phases. The diamond core is surrounded by the shell consisting mostly of disordered sp(3) carbon and graphene-like carbon (GLC). The complex structure makes the characterization of nanodiamonds (ND) a difficult challenge. Recent development of many varieties of NDs for different applications demands quick and reliable characterization of the content of various carbon fragments, as well as the estimation of the diamond core size. In this work, we apply Raman spectroscopy to study the structure of nanodiamonds from different origins, including those produced by detonation (DND), high pressure high temperature synthesis (HPHT), and pulsed laser irradiation (LND). The relative content of GLC, disordered and surface carbon can be easily determined from Raman spectra. In particular, we show how the content of different structure fragments is changed upon de-agglutination, surface oxidation and ion irradiation. We also compare the different ND production methods in terms of the structural uniformity of the nanoparticles. Raman spectroscopy provides unique quantitative tool for ND characterization; we believe that the present data will be useful for understanding the structure of diamond nanoparticles, and will provide the background for obtaining the NDs with desired properties. (C) 2017 Elsevier Ltd. All rights reserved.
CARS Microspectroscopic Study of Human Hair Using a Nanosecond White Light Laser Source
(2010)
Bito, Kotatsu
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Tokuhara, Shihomi
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Naito, Satoru
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Masukawa, Yoshinori
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Okuno, Masanari
Casting New Physicochemical Light on the Fundamental Biological Processes in Single Living Cells by Using Raman Microspectroscopy
(2012-12-01)
Kaliaperumal, Venkatesh
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Hamaguchi, Hiro-o
;
應用化學系
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應用化學系分子科學碩博班
;
Department of Applied Chemistry
This Personal Account highlights the capabilities of spontaneous Raman microspectroscopy for studying fundamental biological processes in a single living cell. Raman microspectroscopy provides time- and space-resolved vibrational Raman spectra that contain detailed information on the structure and dynamics of biomolecules in a cell. By using yeast as a model system, we have made great progress in the development of this methodology. The results that we have obtained so far are described herein with an emphasis placed on how three cellular processes, that is, cell-division, respiration, and cell-death, are traced and elucidated with the use of time- and space-resolved structural information that is extracted from the Raman spectra. For cell-division, compositional- and structural changes of various biomolecules are observed during the course of the whole cell cycle. For respiration, the redox state of mitochondrial cytochromes, which is inferred from the resonance Raman bands of cytochromes, is used to evaluate the respiration activity of a single cell, as well as that of isolated mitochondrial particles. Special reference is made to the Raman spectroscopic signature of life, which is a characteristic Raman band at 1602?cm-1 that is found in yeast cells. This signature reflects the cellular metabolic activity and may serve as a measure of mitochondrial dysfunction. For cell-death, cross-talk between the mitochondria and the vacuole in a dying cell is suggested. DOI 10.1002/tcr.201200008
Cylindrical micelles of a POSS amphiphilic dendrimer as nano-reactors for polymerization
(2018-02-21)
Weng, Jing-Ting
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Yeh, Tso-Fan
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Samuel, Ashok Zachariah
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Huang, Yi-Fan
;
Sie, Jyun-Hao
A low generation amphiphilic dendrimer, POSS-AD, which has a POSS core and eight amphiphilic arms, was synthesized and used as a nano-reactor to produce well-defined polymer nano-cylinders. Confirmed by small-angle X-ray scattering (SAXS), Raman and NMR spectrometry, monodispersed cylindrical micelles that contain a hydrophilic cavity with a diameter of 2.09 nm and a length of 4.26 nm were produced via co-assembling POSS-AD with hydrophilic liquids, such as H2O and HEMA in hydrophobic solvents. Taking the HEMA/POSS-AD cylindrical micelles as nano-reactors, polymerization of HEMA within the micelles results in polymer nano-cylinders (POSS-AD NPs) with a diameter of 2.24 nm and a length of 5.02 nm. The study confirmed that despite the inability to maintain specific shape in solution, low generation dendrimers form well-defined nano-containers or nano-reactors, which relies on co-assembling with hydrophilic guest molecules. These nano-reactors are robust enough to maintain their shape during the polymerization of the guest molecules. Polymer nano-cylinders with dimensions less than 10 nm can thus be produced from the HEMA/POSS-AD micelles. Since the chemical structure of low-generation dendrimers and the contents of the co-assembled nano-reactors can be easily adjusted, the concept holds the potential for the further developments of low-generation amphiphilic dendrimers.
Determination of Percent Crystallinity of Side-Chain Crystallized Alkylated-Dextran Derivatives with Raman Spectroscopy and Multivariate Curve Resolution
(2016-05-03)
Samuel, Ashok Zachariah
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Zhou, Mengbo
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Ando, Masahiro
;
Mueller, Robert
;
Liebert, Tim
We demonstrate a methodology to estimate the percent crystallinity of polymers directly with Raman spectroscopy and multivariate curve resolution (MCR) by alternating least-squares (ALS). In this methodology, the Raman spectrum of semicrystalline polymer is separated into two constituent components (crystalline and molten) and their corresponding concentrations. The percent crystallinity can be estimated as the change in area intensity of the molten spectral-component when polymer cools from a temperature above melting point to room temperature. The number of carbons in the crystalline lattice has also been estimated from the position of longitudinal acoustic (LA) Raman bands with the correlation established by Mizushima and Simanouti [Mizushima, S.; Simanouti, T. J. Am. Chem. Soc. 1949, 71, 1320]. The new method allows direct Raman estimation of absolute percent crystallinity of polymers. Until now, Raman spectroscopic estimation of percent crystallinity was possible only in conjunction with other techniques or by using internal standards.
Developments of Raman spectroscopy in the past 40 years: from a molecule to a living cell
(2009-07-25)
Hamaguchi, Hiro-o
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應用化學系
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應用化學系分子科學碩博班
;
Department of Applied Chemistry
;
Institute of Molecular science
This article is based on the opening lecture 'Raman spectroscopy at Tokyo: past 40 years and future' delivered at the symposium entitled '80 years of Raman effect: reflections and the future' held at Bangalore from 8 to 10 December 2008. It reviews four research subjects, including (1) anomalous depolarization ratios in resonance Raman scattering, (2) one- way photoisomerization of retinal by nanosecond time-resolved Raman spectroscopy, (3) dynamic polarization model of photoisomerization of stilbene by picosecond time-resolved Raman spectroscopy, and (4) discovery of the 'Raman spectroscopic signature of life' by timeand space-resolved Raman spectroscopy. The future possibilities of Raman spectroscopy are also briefly addressed.
Energy Transfer Characteristics of Lipid Bilayer Membrane in Liposome Studied with Picosecond Time-Resolved Raman Spectroscopy
(2010)
Nojima, Yuki
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Yoshida, Kyousuke
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Hamaguchi, Hiro-o
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Iwata, Koichi
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應用化學系
Formation of "Nano-Ice" and Density Maximum Anomaly of Water
(2018-06-01)
Okajima, Hajime
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Ando, Masahiro
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Hamaguchi, Hiro-o
;
應用化學系
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應用化學系分子科學碩博班
Water is still mysterious despite intensive and extensive studies over the years. Anomalous behavior of water as a liquid is yet to be fully comprehended. Here we show that the most generally known anomaly of water, the density maximum anomaly, is well accounted for by the formation of nanometer-size ice crystallite at low temperatures. We show spectroscopically that, in cold and super-cooled water, this nanometer-size ice crystallite is formed and coexists with the other two forms of water. Multivariate hyperspectral analysis of 140 temperature dependent Raman spectra in the range of (_)23 similar to 45 degrees C determines the three distinct vibrational spectra of the three forms of water and their fractions at different temperatures. Simulation based on the determined fractions successfully reproduces the temperature dependence of density with a maximum at the right temperature. The mystery of the density maximum of water has thus been given an unequivocal solution. The nanometer-size ice crystallite might well be called "nano-ice".
Hyper-Raman investigation of intermolecular vibrations of water and ice
(2018-11-01)
Korepanov, Vitaly
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Yu, Chun-Chieh
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Hamaguchi, Hiro-o
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應用化學系
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應用化學系分子科學碩博班
We have constructed a hyper-Raman optimized spectrometer using a high repetition rate (200 kHz) picosecond-pulsed Nd:YAG laser. This system has been applied to measure liquid water and ice (H2O and D2O) to obtain their hyper-Raman spectra with high signal-to-noise ratios. Unique vibrational spectra of water and ice, distinct either from infrared absorption and Raman scattering, have been obtained. The intermolecular bands in the low-wavenumber region are observed in the hyper-Raman spectra with intensities higher than those of the intramolecular ones. They show H/D isotope shifts fully consistent with their assignments to the librational and translational motions of assembled water. The librational bands are found to shift to higher wavenumber on going from liquid water to ice, indicating a more confining environment in ice than in water. Hyper-Raman spectroscopy will shed new light, complementary to the traditional infrared and Raman vibrational spectroscopies, on intermolecular interactions in liquid water and ice.
Imaging molecular crystal polymorphs and their polycrystalline microstructures in situ by ultralow-frequency Raman spectroscopy
(2014-01-01)
Chang, Chun-Fu
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Okajima, Hajime
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Hamaguchi, Hiro-o
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Shigeto, Shinsuke
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應用化學系
Ultralow-frequency Raman spectroscopy that can measure vibrational bands at as low as +/- 10 cm(-1) has enabled facile in situ imaging of polycrystalline microstructures such as grains and grain boundaries with high polymorph specificity. We demonstrate this method by investigating microcrystals of two distinct polymorphs of 1,1\'-binaphthyl using a microscope.
Imaging phospholipid conformational disorder and packing in giant multilamellar liposome by confocal Raman microspectroscopy
(2017-12-05)
Noothalapati, Hemanth
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Iwasaki, Keita
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Yoshimoto, Chikako
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Yoshikiyo, Keisuke
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Nishikawa, Tomoe
Liposomes are closed phospholipid bilayer systems that have profound applications in fundamental cell biology, pharmaceutics and medicine. Depending on the composition (pure or mixture of phospholipids, presence of cholesterol) and preparation protocol; intra- and inter-chain molecular interactions vary leading to changes in the quality (order and packing) of liposomes. So far it is not possible to image conformational disorders and packing densities within a liposome in a straightforward manner. In this study, we utilized confocal Raman microspectroscopy to visualize structural disorders and packingefficiency within a giant multilamellar liposome model by focusing mainly on three regions in the vibrational spectrum (C-C stretching, C-H deformation and C-H stretching). We estimated properties such as trans/gauche isomers and lateral packing probability. Interestingly, our Raman imaging studies revealed gel phase rich domains and heterogeneous lateral packing within the giant multilamellar liposome. (C) 2017 Elsevier B.V. All rights reserved.
In Situ Detection of Antibiotic Amphotericin B Produced in Streptomyces nodosus Using Raman Microspectroscopy
(2014-05-01)
Miyaoka, Rimi
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Hosokawa, Masahito
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Ando, Masahiro
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Mori, Tetsushi
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Hamaguchi, Hiro-o
The study of spatial distribution of secondary metabolites within microbial cells facilitates the screening of candidate strains from marine environments for functional metabolites and allows for the subsequent assessment of the production of metabolites, such as antibiotics. This paper demonstrates the first application of Raman microspectroscopy for in situ detection of the antifungal antibiotic amphotericin B (AmB) produced by actinomycetes-Streptomyces nodosus. Raman spectra measured from hyphae of S. nodosus show the specific Raman bands, caused by resonance enhancement, corresponding to the polyene chain of AmB. In addition, Raman microspectroscopy enabled us to monitor the time-dependent change of AmB production corresponding to the growth of mycelia. The Raman images of S. nodosus reveal the heterogeneous distribution of AmB within the mycelia and individual hyphae. Moreover, the molecular association state of AmB in the mycelia was directly identified by observed Raman spectral shifts. These findings suggest that Raman microspectroscopy could be used for in situ monitoring of antibiotic production directly in marine microorganisms with a method that is non-destructive and does not require labeling.
In Vivo Live Cell Imaging for the Quantitative Monitoring of Lipids by Using Raman Microspectroscopy
(2014-08-19)
Hosokawa, Masahito
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Ando, Masahiro
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Mukai, Shoichiro
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Osada, Kyoko
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Yoshino, Tomoko
A straightforward in vivo monitoring technique for biomolecules would be an advantageous approach for understanding their spatiotemporal dynamics in living cells. However, the lack of adequate probes has hampered the quantitative determination of the chemical composition and metabolomics of cellular lipids at single-cell resolution. Here, we describe a method for the rapid, direct, and quantitative determination of lipid molecules from living cells using single-cell Raman imaging. In vivo localization of lipids in the form of triacylglycerol (TAG) within oleaginous microalga and their molecular compositions are monitored with high spatial resolution in a non-destructive and label-free manner. This method can provide quantitative and real-time information on compositions, chain lengths, and degree of unsaturation of fatty acids in living cells for improving the cultivating parameters or for determining the harvest timing during large-scale cultivations for microalgal lipid accumulation toward biodiesel production. Therefore, this technique is a potential tool for in vivo lipidomics for understanding the dynamics of lipid metabolisms in various organisms.
In vivo multimode Raman imaging reveals concerted molecular composition and distribution changes during yeast cell cycle
(2011)
Huang, Chuan-Keng
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Hamaguchi, Hiro-o
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Shigeto, Shinsuke
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應用化學系
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應用化學系分子科學碩博班
In vivo time-lapse Raman imaging reveals highly dynamic and concerted changes in concentration and distribution of phospholipids and proteins during and after cell division of a single living Schizosaccharomyces pombe cell.
In Vivo Resonance Raman Detection of Ferrous Cytochrome c from Mitochondria of Single Living Yeast Cells
(2010-03-05)
Onogi, Chikao
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Hamaguchi, Hiro-o
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應用化學系
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應用化學系分子科學碩博班
;
Department of Applied Chemistry
Raman spectra of mitochondria in living budding yeast cells (zygote of Saccharonlyces cerevisiae and Saccharomyces bayanus) have been recorded with 532 nm excitation. Strong and sharp Raman bands are observed at 1584, 1315, 1129, 749, and 601 cm(-1), in addition to known phospholipid bands. These Raman bands are not observed in the corresponding Raman spectrum of mitochondria obtained with 632.8 nm excitation. Their peak positions and relative intensities agree excellently with the reported resonance-enhanced Raman bands of ferrous cylochrome c, which has a Q-band absorption at 520 nm. We have thus succeeded in detecting ferrous cytochrome c, one of the key intermediates in the electron-transport chain in mitochondria, in vivo without any pretreatment. In vivo resonance Raman detection of ferrous cytochrome c opens up new possibilities for real-time and quantitative tracing of respiration dynamics in mitochondria in a single living cell.
Intensity enhancement and selective detection of proximate solvent molecules by molecular near-field effect in resonance hyper-Raman scattering
(2008-07-14)
Shimada, Rintaro
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Kano, Hideaki
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Hamaguchi, Hiro-o
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應用化學系
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應用化學系分子科學碩博班
A new molecular phenomenon associated with resonance hyper-Raman (HR) scattering in solution has been discovered. Resonance HR spectra of all-trans-beta-carotene and all-trans-lycopene in various solvents exhibited several extra bands that were not assignable to the solute but were unequivocally assigned to the solvents. Neat solvents did not show detectable HR signals under the same experimental conditions. Similar experiments with all-trans-retinal did not exhibit such enhancement either. All-trans-beta-carotene and all-trans-lycopene have thus been shown to induce enhanced HR scattering of solvent molecules through a novel molecular effect that is not associated with all-trans-retinal. We call this new effect the "molecular near-field effect." In order to explain this newly found effect, an extended vibronic theory of resonance HR scattering is developed where the vibronic interaction including the proximate solvent molecule (intermolecular vibronic coupling) is explicitly introduced in the solute hyperpolarizability tensor. The potential of "molecular near-field HR spectroscopy," which selectively detects molecules existing in the close vicinity of a HR probe in complex chemical or biological systems, is discussed. (C) 2008 American Institute of Physics.