Browsing by Author "Okuno, Masanari"

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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
;
Masukawa, Yoshinori
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Okuno, Masanari
Label-free tetra-modal molecular imaging of living cells with CARS, SHG, THG and TSFG (coherent anti-Stokes Raman scattering, second harmonic generation, third harmonic generation and third-order sum frequency generation)
(2012-04-23)
Segawa, Hiroki
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Okuno, Masanari
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Kano, Hideaki
;
Leproux, Philippe
;
Couderc, Vincent
We have developed a new multimodal molecular imaging system that combines CARS (coherent anti-Stokes Raman scattering), SHG (second harmonic generation), THG (third harmonic generation) and multiplex TSFG (third-order sum frequency generation) using a subnanosecond white-light laser source. Molecular composition and their distribution in living cells are clearly visualized with different contrast enhancements through different mechanisms of CARS, SHG, THG and TSFG. A correlation image of CARS and TSF reveals that the TSF signal is generated predominantly from lipid droplets inside a cell as well as the peripheral cell wall. (C) 2012 Optical Society of America
Multifocus confocal Raman microspectroscopy for fast multimode vibrational imaging of living cells
(2010-12-15)
Okuno, Masanari
;
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 have developed a multifocus confocal Raman microspectroscopic system for the fast multimode vibrational imaging of living cells. It consists of an inverted microscope equipped with a microlens array, a pinhole array, a fiber bundle, and a multichannel Raman spectrometer. Forty-eight Raman spectra from 48 foci under the microscope are simultaneously obtained by using multifocus excitation and image-compression techniques. The multifocus confocal configuration suppresses the background generated from the cover glass and the cell culturing medium so that high-contrast images are obtainable with a short accumulation time. The system enables us to obtain multimode (10 different vibrational modes) vibrational images of living cells in tens of seconds with only 1 mW laser power at one focal point. This image acquisition time is more than 10 times faster than that in conventional single-focus Raman microspectroscopy. (C) 2010 Optical Society of America
Observation of Raman Optical Activity by Heterodyne-Detected Polarization-Resolved Coherent Anti-Stokes Raman Scattering
(2012-08-24)
Hiramatsu, Kotaro
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Okuno, Masanari
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Kano, Hideaki
;
Leproux, Philippe
;
Couderc, Vincent
We report the first observation of Raman optical activity (ROA) by coherent anti-Stokes Raman scattering. Thanks to the more freedom of polarization configurations in coherent anti-Stokes Raman scattering than in spontaneous Raman spectroscopy, the contrast ratio of the chiral signal to the achiral background has been improved markedly. For (-)-beta-pinene, it is 2 orders of magnitude better than that in the reported spontaneous ROA measurement. This is also the first measurement of ROA signal using a pulsed laser source.
Protein Secondary Structure Imaging with Ultrabroadband Multiplex Coherent Anti-Stokes Raman Scattering (CARS) Microspectroscopy
(2012-02-02)
Bito, Kotatsu
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Okuno, Masanari
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Kano, Hideaki
;
Tokuhara, Shihomi
;
Naito, Satoru
Protein secondary structures in human hair have been studied with ultrabroadband multiplex coherent anti-Stokes Raman scattering (CARS) microspectroscopy. The CARS peak-shift mapping method has been developed and applied to hair samples with and without treatments by chemical reduction and mechanical extension. It clearly visualizes the treatment induced changes in protein secondary structures and their spatial distributions. Using the new imaging technique, we found a multilayered structure in the human hair cortex.
Quantitative analysis of the redox states of cytochromes in a living L929 (NCTC) cell by resonance Raman microspectroscopy
(2013-03-01)
Kakita, Minoru
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Okuno, Masanari
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Hamaguchi, Hiro-o
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應用化學系
;
應用化學系分子科學碩博班
Raman spectra and images of a living L929 (NCTC) cell have been measured with 532 nm excitation. Both reduced and oxidized forms of cytochromes b and c (cyt b and cyt c) have been observed in situ without any pretreatment. The redox states of cyts b and c have been assessed quantitatively with a spectral analysis. It has been found that reduced cyt c is more abundant than oxidized cyt c, while oxidized cyt b is slightly more abundant than reduced cyt b in a living cell. ((c) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantitative CARS Molecular Fingerprinting of Single Living Cells with the Use of the Maximum Entropy Method
(2010)
Okuno, Masanari
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Kano, Hideaki
;
Leproux, Philippe
;
Couderc, Vincent
;
Day, James P. R.
Quantitative CARS Spectral Imaging of a Single Living Cell in the Fingerprint Region
(2010)
Okuno, Masanari
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Kano, Hideaki
;
Leproux, Philippe
;
Couderc, Vincent
;
Day, James P. R.
Quantitative coherent anti-Stokes Raman scattering microspectroscopy using a nanosecond supercontinuum light source
(2012-09-01)
Okuno, Masanari
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Kano, Hideaki
;
Leproux, Philippe
;
Couderc, Vincent
;
Hamaguchi, Hiro-o
We describe and characterize a multiplex CARS microspectroscopic system that uses a nanosecond supercontinuum generated from a photonic crystal fiber and a sub-nanosecond pulse laser. This system has a high spectral resolution (<0.1 cm (1)) and an ultrabroadband spectral coverage (>2500 cm (1)). The estimated spatial resolutions are 0.45 mu m (lateral) and 4.5 mu m (axial), respectively. This system enables us to obtain CARS spectra and corresponding images in the fingerprint region as well in the CH stretch region. Using this system, we have successfully obtained label-free and multi-mode vibrational images of a yeast cell. (C) 2012 Elsevier Inc. All rights reserved.
Surfactant Uptake Dynamics in Mammalian Cells Elucidated with Quantitative Coherent Anti-Stokes Raman Scattering Microspectroscopy
(2014-04-07)
Okuno, Masanari
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Kano, Hideaki
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Fujii, Kenkichi
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Bito, Kotatsu
;
Naito, Satoru
The mechanism of surfactant-induced cell lysis has been studied with quantitative coherent anti-Stokes Raman scattering (CARS) microspectroscopy. The dynamics of surfactant molecules as well as intracellular biomolecules in living Chinese Hamster Lung (CHL) cells has been examined for a low surfactant concentration (0.01 w%). By using an isotope labeled surfactant having CD bonds, surfactant uptake dynamics in living cells has been traced in detail. The simultaneous CARS imaging of the cell itself and the internalized surfactant has shown that the surfactant molecules is first accumulated inside a CHL cell followed by a sudden leak of cytosolic components such as proteins to the outside of the cell. This finding indicates that surfactant uptake occurs prior to the cell lysis, contrary to what has been believed: surface adsorption of surfactant molecules has been thought to occur first with subsequent disruption of cell membranes. Quantitative CARS microspectroscopy enables us to determine the molecular concentration of the surfactant molecules accumulated in a cell. We have also investigated the effect of a drug, nocodazole, on the surfactant uptake dynamics. As a result of the inhibition of tubulin polymerization by nocodazole, the surfactant uptake rate is significantly lowered. This fact suggests that intracellular membrane trafficking contributes to the surfactant uptake mechanism.
Three-pulse multiplex coherent anti-Stokes/Stokes Raman scattering (CARS/CSRS) microspectroscopy using a white-light laser source
(2013-06-20)
Bito, Kotatsu
;
Okuno, Masanari
;
Kano, Hideaki
;
Leproux, Philippe
;
Couderc, Vincent
We have developed a three-pulse non-degenerate multiplex coherent Raman microspectroscopic system using a white-light laser source. The fundamental output (1064 nm) of a Nd: YAG laser is used for the pump radiation with the white-light laser output (1100-1700 nm) for the Stokes radiation to achieve broadband multiplex excitations of vibrational coherences. The second harmonic (532 nm) of the same Nd: YAG laser is used for the probe radiation. Thanks to the large wavelength difference between the pump and probe radiations, coherent anti-Stokes Raman scattering (CARS) and coherent Stokes Raman scattering (CSRS) can be detected simultaneously. Simultaneous detection of CARS and CSRS enables us to obtain information on the electronic resonance effect that affects differently the CARS and CSRS signals. Simultaneous analysis of the CARS and CSRS signals provides us the imaginary part of chi((3)) without introducing any arbitrary parameter in the maximum entropy method (MEM). (C) 2013 Elsevier B. V. All rights reserved.
Time-frequency resolved analysis of a nanosecond supercontinuum source dedicated to multiplex CARS application
(2012-12-31)
De Angelis, Annalisa
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Labruyere, Alexis
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Couderc, Vincent
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Leproux, Philippe
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Tonello, Alessandro
In this paper, we describe and investigate the properties of a broadband source designed from a nanosecond microchip laser operating at high repetition rate and dedicated to multiplex-CARS application. We demonstrate that a strong reshaping of the initial pulse profile drastically affects the Stokes wave and therefore represents an important limitation in CARS experiment. In particular, we emphasize the saturation effect of the peak power of the Stokes wave resulting from supercontinuum generation. However, we show that this type of compact system can be particularly suitable for achieving CARS measurement. (C) 2012 Optical Society of America