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507 results on '"Fukuhara, Gaku"'

4. Pseudohelicene chemosensor displaying ternary signaling stimulated by hydrostatic pressure and solvent.

Author

Kinoshita, Tomokazu, Watanabe, Kota, Tsurumaki, Eiji, Toyota, Shinji, and Fukuhara, Gaku

Subjects
HYDROSTATIC pressure, SOLVENTS, SPECTROMETRY, SIGNALS & signaling
Abstract

Herein, we report the serendipitous discovery of a racemic chemosensor ([2]HA2) that outputs three signal patterns (1/0/−1) in response to two external stimuli (hydrostatic pressure and solvent); these signals can be observed by hydrostatic pressure spectroscopy. [ABSTRACT FROM AUTHOR]

Published
2025
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9. Recent advances in cancer detection using dynamic, stimuli-responsive supramolecular chemosensors. a focus review.

Author

Matsumoto, Kotaro, Nakagawa, Keiichi, Asanuma, Daisuke, Fukuhara, Gaku, Gorai, Tumpa, Li Shao, and Baihao Shao

Subjects
HYDROSTATIC pressure, CHEMICAL detectors, SUPRAMOLECULAR chemistry, EARLY detection of cancer, CALIXARENES
Abstract

In current chemistry, supramolecular materials that respond to a wide variety of external stimuli, such as solvents, temperature, light excitation, pH, and mechanical forces (pressure, stress, strain, and tension), have attracted considerable attention; for example, we have developed cyclodextrins, cucurbiturils, pillararenes, calixarenes, crown ether-based chemical sensors, or chemosensors. These supramolecular chemosensors have potential applications in imaging, probing, and cancer detection. Recently, we focused on pressure, particularly solution-state hydrostatic pressure, from the viewpoint of cancer therapy. This Mini Review summarizes (i) why hydrostatic pressure is important, particularly in biology, and (ii) what we can do using hydrostatic pressure stimulation. [ABSTRACT FROM AUTHOR]

Published
2024
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21. Sumanene-stacked supramolecular polymers. Dynamic, solvation-directed control.

Author

Mizuno, Hiroaki, Nakazawa, Hironobu, Harada, Makoto, Yakiyama, Yumi, Sakurai, Hidehiro, and Fukuhara, Gaku

Subjects
SUPRAMOLECULAR polymers, POLYMERS, CORANNULENE, SOLVATION
Abstract

In this study, we found that a pristine buckybowl, sumanene, can form solution-state supramolecular polymers. We also demonstrated that sumanene supramolecular polymers can be dynamically controlled by external stimuli, in which solvation plays a significant role. This study not only provides new guidelines for the rational design of supramolecular polymers, particularly for the use of buckybowls, but also presents interesting dynamic behaviors of supramolecular polymerization. [ABSTRACT FROM AUTHOR]

Published
2023
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25. Multiphase Behavior of Tetraphenylethylene Derivatives with Different Polarities at High Pressures

Author

MIYAGAWA, Akihisa, Kinoshita, Tomokazu, Zheng, Yue, Harada, Makoto, Fukuhara, Gaku, and Okada, Tetsuo

Abstract

Although both pressure and temperature are essential parameters governing thermodynamics, the effects of the pressure on solution-phase equilibria have not been well studied compared to those of temperature. Here, we demonstrate the interesting pressure-dependent behavior of tetraphenylethylene (TPE) derivatives in multiphase systems composed of an organic phase and an aqueous phase in the presence and absence of γ-cyclodextrin (γ-CD). In this system, tetraphenylethylene monocarboxylic acid (TPE1H) and its dicarboxylic acid (TPE2H2) are distributed in the aqueous phase and dissociated into the corresponding anions, that is, TPE1– and TPE22–, when the pH is sufficiently high. The distribution ratios of TPE1H/TPE1– and TPE2H/TPE22– show opposing pressure dependencies: the distribution of the former in the organic phase increases with increasing pressure, whereas that of the latter decreases. The 1:1 complexation constants of TPE1– and TPE22– with γ-CD, which can be determined from the distribution ratios in the presence of γ-CD, also show opposing pressure dependencies: the former shows a positive pressure dependence, but the latter exhibits a negative one. These pressure effects on the distribution and complexation of TPE derivatives can be interpreted based on the differences in the molecular polarity of these solutes. The water permittivity is enhanced at high pressure, thus stabilizing the more polar TPE22– in the aqueous phase to a larger extent than TPE1– and, as a result, reducing its distribution in the organic phase, as well as its complexation with γ-CD. Fluorescence spectra in the aqueous phase suggest that the TPE derivatives form aggregates with γ-CD molecules, as detected by the specific fluorescence. In addition, the fluorescence intensities of the γ-CD complexes are enhanced at high pressures because of the restricted rotation of the phenyl rings in the TPE molecules. This study provides new perspectives for multiphase partitioning and an attractive alternative to conventional extraction methods.

Published
2020

39. Hydrostatic Pressure-Regulated Cellular Calcium Responses

Author

Fukuchi, Minami, Oyama, Kotaro, Mizuno, Hiroaki, Miyagawa, Akihisa, Koumoto, Kazuya, Fukuhara, Gaku, Kotaro, Oyama, Fukuchi, Minami, Oyama, Kotaro, Mizuno, Hiroaki, Miyagawa, Akihisa, Koumoto, Kazuya, Fukuhara, Gaku, and Kotaro, Oyama

Abstract

Hydrostatic pressure control has attracted much attention and presents a still challenging objective from mechanobiological viewpoints. Herein, we reveal the calcium entry processes in HeLa cells by means of hydrostatic pressure spectroscopy. The steady-state fluorescence spectral data comprehensively elucidated the factors controlling the outcomes of the hydrostatic pressure-stimulated calcium entry behavior. The present work leads to a new perspective on ion regulations in living cells and an attractive alternative to conventional mechanostimuli.

Published
2021

40. Cyclophane-Based Fluorescence Tuning Induced by Hydrostatic Pressure Changes

Author

Sagara, Yoshimitsu, Tamaoki, Nobuyuki, and Fukuhara, Gaku

Subjects
mechanoresponsive luminescence, hydrostatic pressure, fluorescence, supramolecular chemistry, Cyclophane
Abstract

In contrast to a standard steady fluorescence intensity increase of a chloroform solution of a linear chromophore unit under high pressure, a fluorescent cyclophane solution shows significant fluorescence quenching under elevated pressure. A pressure-induced enhancement of the formation of an intramolecular pi-stacked conformation is proposed to be responsible.

Published
2018

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