Browsing by Author "Tsurui, Hiromichi"

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Biological imaging with nonlinear photothermal microscopy using a compact supercontinuum fiber laser source
(2015-04-20)
He, Jinping
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Miyazaki, Jun
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Wang, Nan
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Tsurui, Hiromichi
;
Kobayashi, Takayoshi
Nonlinear photothermal microscopy is applied in the imaging of biological tissues stained with chlorophyll and hematoxylin. Experimental results show that this type of organic molecules, which absorb light but transform dominant part of the absorbed energy into heat, may be ideal probes for photothermal imaging without photochemical toxicity. Picosecond pump and probe pulses, with central wavelengths of 488 and 632 nm, respectively, are spectrally filtered from a compact supercontinuum fiber laser source. Based on the light source, a compact and sensitive super-resolution imaging system is constructed. Further more, the imaging system is much less affected by thermal blurring than photothermal microscopes with continuous-wave light sources. The spatial resolution of nonlinear photothermal microscopy is similar to 188 nm. It is similar to 23% higher than commonly utilized linear photothermal microscopy experimentally and similar to 43% than conventional optical microscopy theoretically. The nonlinear photothermal imaging technology can be used in the evaluation of biological tissues with high-resolution and contrast. (C) 2015 Optical Society of America
Further resolution enhancement of high-sensitivity laser scanning photothermal microscopy applied to mouse endogenous
(2016-12-07)
Nakata, Kazuaki
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Tsurui, Hiromichi
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Kobayashi, Takayoshi
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電子物理學系
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Department of Electrophysics
Photothermal microscopy has intrinsically super resolution capability due to the bilinear dependence of signal intensity of pump and probe. In the present paper, we have made further resolution improvement of high-sensitivity laser scanning photothermal microscopy by applying non-linear detection. By this, the new method has the following advantages: (1) super resolution with 61% and 42% enhancement from the diffraction limit values of the probe and pump wavelengths, respectively, by a second-order non-linear scheme, (2) compact light source using inexpensive conventional diode lasers, (3) wide applicability to nonfluorescent materials such as gold nanoparticles (GNPs) and hematoxylin-eosin stained biological samples, (4) relative robustness to optical damage, and (5) a high-frame rate using a Galvano mirror. The maximum resolution is determined to be 160 nm in the second-order non-linear detection mode and 270 nm in the linear detection mode by the PT signal of GNPs. The pixel rate and frame rate for 300 x 300 pixel image are 50 mu s and 4.5 s, respectively. The pixel and frame rate are shorter than the rates, which are 1ms and 100 s, respectively, using the piezo-driven stage system. Published by AIP Publishing.
Gray-level co-occurrence matrix analysis of several cell types in mouse brain using resolution-enhanced photothermal microscopy
(2017-03-01)
Kobayashi, Takayoshi
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Sundaram, Durga
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Nakata, Kazuaki
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Tsurui, Hiromichi
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電子物理學系
Qualifications of intracellular structure were performed for the first time using the gray-level co-occurrence matrix (GLCM) method for images of cells obtained by resolution-enhanced photothermal imaging. The GLCM method has been used to extract five parameters of texture features for five different types of cells in mouse brain; pyramidal neurons and glial cells in the basal nucleus (BGl), dentate gyrus granule cells, cerebellar Purkinje cells, and cerebellar granule cells. The parameters are correlation, contrast, angular second moment (ASM), inverse difference moment (IDM), and entropy for the images of cells of interest in a mouse brain. The parameters vary depending on the pixel distance taken in the analysis method. Based on the obtained results, we identified that the most suitable GLCM parameter is IDM for pyramidal neurons and BGl, granule cells in the dentate gyrus, Purkinje cells and granule cells in the cerebellum. It was also found that the ASM is the most appropriate for neurons in the basal nucleus. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License.
Label-free imaging of melanoma with nonlinear photothermal microscopy
(2015-04-01)
He, Jinping
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Miyazaki, Jun
;
Wang, Nan
;
Tsurui, Hiromichi
;
Kobayashi, Takayoshi
Nonlinear photothermal microscopy, in which the intensity of the pump heating beam is modulated at f and the photothermal signal is extracted from the probe beam with a lock-in amplifier referred to 2f, is applied to the imaging of mouse melanoma without any staining. The pump and probe pulses, with central wavelengths of 488 and 632 nm, and a pulse duration of similar to 100 ps, are filtered from a compact commercial supercontinuum fiber laser source. An auto-balanced detector is applied to accumulate the signal and remove the laser noise of the probe. The spatial resolution of the nonlinear photothermal imaging is enhanced by similar to 18% in both theoretical calculations and experiments, compared with a linear photothermal mechanism, and the resolution enhancement is theoretically similar to 42% compared with conventional optical microscopy. This imaging technique shows possibilities for the clinical evaluation of melanoma with a high contrast and spatial resolution. (C) 2015 Optical Society of America
Noninvasive, label-free, three-dimensional imaging of melanoma with confocal photothermal microscopy: Differentiate malignant melanoma from benign tumor tissue
(2016-07-22)
He, Jinping
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Wang, Nan
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Tsurui, Hiromichi
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Kato, Masashi
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Iida, Machiko
Skin cancer is one of the most common cancers. Melanoma accounts for less than 2% of skin cancer cases but causes a large majority of skin cancer deaths. Early detection of malignant melanoma remains the key factor in saving lives. However, the melanoma diagnosis is still clinically challenging. Here, we developed a confocal photothermal microscope for noninvasive, label-free, three-dimensional imaging of melanoma. The axial resolution of confocal photothermal microscope is similar to 3 times higher than that of commonly used photothermal microscope. Three-dimensional microscopic distribution of melanin in pigmented lesions of mouse skin is obtained directly with this setup. Classic morphometric and fractal analysis of sixteen 3D images (eight for benign melanoma and eight for malignant) showed a capability of pathology of melanoma: melanin density and size become larger during the melanoma growth, and the melanin distribution also becomes more chaotic and unregulated. The results suggested new options for monitoring the melanoma growth and also for the melanoma diagnosis.
Optimal detection angle in sub-diffraction resolution photothermal microscopy: application for high sensitivity imaging of biological tissues
(2014-08-11)
Miyazaki, Jun
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Tsurui, Hiromichi
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Kawasumi, Koshi
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Kobayashi, Takayoshi
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電子物理學系
We evaluated the optimal detection angle for maximizing the signal to noise ratio (SNR) in sub-diffraction resolution photothermal microscopy. The angular dependent photothermal signal was calculated based on scattering theory using the temporally modulated Yukawa potential, and its detection angle and modulation frequency dependencies were analyzed. We verified the theoretical findings by imaging gold nanoparticles using laser diode based photothermal microscopy with balanced detection scheme. High-sensitivity (SNR similar to 40) photothermal biological imaging of a mouse brain was also demonstrated.
Optimal detection angle in sub-diffraction resolution photothermal microscopy: application for high sensitivity imaging of biological tissues
(2014-08-11)
Miyazaki, Jun
;
Tsurui, Hiromichi
;
Kawasumi, Koshi
;
Kobayashi, Takayoshi
;
電子物理學系
We evaluated the optimal detection angle for maximizing the signal to noise ratio (SNR) in sub-diffraction resolution photothermal microscopy. The angular dependent photothermal signal was calculated based on scattering theory using the temporally modulated Yukawa potential, and its detection angle and modulation frequency dependencies were analyzed. We verified the theoretical findings by imaging gold nanoparticles using laser diode based photothermal microscopy with balanced detection scheme. High-sensitivity (SNR similar to 40) photothermal biological imaging of a mouse brain was also demonstrated. (C) 2014 Optical Society of America
"Optimal detection angle in sub-diffraction resolution photothermal microscopy: application for high sensitivity imaging of biological tissues": reply
(2015-03-09)
Miyazaki, Jun
;
Tsurui, Hiromichi
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Kawasumi, Koshi
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Kobayashi, Takayoshi
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電子物理學系
The differences between our model and existing models are rationalized in terms of the experimental conditions. The theory in [Opt. Express 22(16), 18833-18842 (2014)] is applicable when the temperature increase is moderate (similar to 1 K) and the spatial extend of refractive index being modulated is comparable to or smaller than the wavelength, which are in accordance with our experiment. (C) 2014 Optical Society of America
Reduction of distortion in photothermal microscopy and its application to the high-resolution three-dimensional imaging of nonfluorescent tissues
(2015-09-01)
Miyazaki, Jun
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Tsurui, Hiromichi
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Kobayashi, Takayoshi
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電子物理學系
;
Department of Electrophysics
A scheme for reducing image distortion in photothermal microscopy is presented. In photothermal microscopy, the signal shape exhibits twin peaks corresponding to the focusing or defocusing of the probe beam when a sample is scanned in the axial direction. This causes a distortion when imaging a structured sample in the axial plane. Here, we demonstrate that image distortion caused by the twin peaks is effectively suppressed by providing a small offset between two the focal planes of the pump and the probe beams. Experimental results demonstrate improvement in resolution, especially in the axial direction, over conventional optical microscopy-even with the focal offset. When a dry objective lens with a numerical aperture of 0.95 is used, the full width at half the maximum of the axial point spread function is 0.6 mu m, which is 50% (62%) smaller than the focal spot sizes of the pump (probe) beam. Herein, we present high-resolution three-dimensional imaging of thick biological tissues based on the present scheme. (C) 2015 Optical Society of America
Sensitivity enhancement of photothermal microscopy with radially segmented balanced detection
(2015-02-15)
Miyazaki, Jun
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Tsurui, Hiromichi
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Kawasumi, Koshi
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Kobayashi, Takayoshi
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電子物理學系
A novel detection method is proposed for highly sensitive photothermal microscopic imaging. This method is based on the characteristics of an angular-dependent photothermal signal; it improves signal intensity by up to two times and rejects the intensity noise of the probe beam. The subdiffraction resolution photothermal imaging of mouse skin melanoma is demonstrated using a laser diode-based photothermal microscopy system to evaluate this method. We confirm that the signal intensity is enhanced 1.7 times compared with the conventional detection method. Moreover, the intensity noise of the laser diode used for the probe beam is effectively reduced by approximately 31 dB, even for a sample with non-uniformity of the refractive index and stationary absorption. This method is implemented by means of a commonly used balanced detector and is thus potentially useful for high-speed imaging. (C) 2015 Optical Society of America
Simultaneous dual-wavelength imaging of nonfluorescent tissues with 3D subdiffraction photothermal microscopy
(2015-02-09)
Miyazaki, Jun
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Tsurui, Hiromichi
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Kawasumi, Koshi
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Kobayashi, Takayoshi
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電子物理學系
Multi-wavelength microscopic imaging is essential to visualize a variety of nanoscale cellular components with high specificity and high spatial resolution. However, previous techniques are based on fluorescence, and thus cannot visualize nonfluorescent species, which are much less suffered from photodamage or photobleaching and hence are intrinsically useful in wider range of optical microscopy. Here, we show that simultaneous multi-wavelength imaging of nonfluorescent species can be achieved with the use of a photothermal microscope. Dual-wavelength subdiffraction imaging of biological tissues stained with hematoxylin and eosin is demonstrated. Three-dimensional label-free imaging of mouse melanoma tissue section is also presented to demonstrate the effectiveness of the enhanced spatial resolution. Our technique can be implemented using cost-effective and compact laser diodes and is applicable for various types of both fluorescent and nonfluorescent tissues. (C) 2015 Optical Society of America
Sub-diffraction resolution pump-probe microscopy with shot-noise limited sensitivity using laser diodes
(2014-04-21)
Miyazaki, Jun
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Tsurui, Hiromichi
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Hayashi-Takagi, Akiko
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Kasai, Haruo
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Kobayashi, Takayoshi
We demonstrate the use of intensity-modulated laser diodes to implement pump-probe microscopy and achieved sub-diffraction resolution imaging with shot-noise limited sensitivity with a scheme of balanced detection. This technique has several applications for various types of induced transmission change, including excited-state absorption, ground state absorption bleaching and stimulated emission. By using our technique, biological imaging of mouse T cells and the axons of neurons in the cerebral cortex was demonstrated. (C) 2014 Optical Society of America
Sub-diffraction-limit imaging using mode multiplexing
(2015-01-01)
Wang, Nan
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He, Jinping
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Miyazaki, Jun
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Tsurui, Hiromichi
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Kobayashi, Takayoshi
Simultaneous two-color subtraction microscopy using mode multiplexing is realized experimentally. The samples are irradiated with single laser diode at wavelength of 445 nm. Then the beam split laser spots generate separate solid and donut spatial modes and are multiplexed with modulators for simultaneous excitation. The produced fluorescence signals are back collected and further divided into two color bands with dichroic mirrors. Then they are detected with two photomultipliers and demultiplexed in four lock-in amplifiers. Four fluorescence images are recorded in every scan and resolution enhanced images are obtained in two color channels after applying the subtraction strategy. With this method, imaging results of microspheres stained with organic dyes and mesenteric lymph nodes of a mouse labeled with quantum dots (Q525/650) are realized. Improvement of 20% similar to 30% in resolving power of the two color channels compared with confocal microscopy is achieved in with corresponding subtraction factor of about 0.3.