Browsing by Author "Bito, Kotatsu"

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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
;
Naito, Satoru
;
Masukawa, Yoshinori
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Okuno, Masanari
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
;
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.
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
;
Fujii, Kenkichi
;
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.