研究者詳細 - 今村　維克

ニードル刺激によるfoaming誘導を利用した低真空下における真空foam乾燥の乾燥履歴の制御査読

日高史博, 佐藤朋, 藤岡亜希穂, 竹田昂司, 今中洋行, 石田尚之, 今村維克

37 ( 12 ) 1520 - 1527 2019年9月

アモルファス固体分散体としてメタノールから乾燥した糖類アモルファスマトリクスの物理的安定性と熱処理の影響査読

竹田昂司, 関藤孝成, 藤岡亜希穂, 山本佳代子, 岡本崇, 松浦傳史, 今中洋行, 石田尚之, 今村維克

Journal of Pharmaceutical Sciences 108 ( 6 ) 2056 - 2062 2019年6月

Nanofluidic enzyme reactor exceeding limit of bulk reaction rate

Koki Yamamoto, Kyojiro Morikawa, Koreyoshi Imamura, Hiroyuki Imanaka, Takehiko Kitamori

23rd International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2019 113 - 114 2019年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Chemical and Biological Microsystems Society

We development a nanofluidic enzyme reactor exceeding the limitation of bulk enzyme reaction. The limit concentration of bulk trypsin solution is approximately 0.5 PM because self-digestion occurs over 0.5 PM solution, which complicates analysis of target proteins by digestion trypsin itself. Using extremely high surface/volume ration of nanospace, trypsin concentration, which indicates number of immobilized trypsin molecules on the nanochannel surface for liquid phase volume, exceed to bulk limit of concentration. As a result, 31 times higher concentration and 33 times faster enzyme reaction compared to bulk was realized. This reactor will be powerful tools which overcomes limitation in bulk and microfluidic method.

Scopus

Adsorption characteristics of various proteins on a metal surface in the presence of an external electric potential 査読

Colloids and Surfaces B: Biointerfaces 166 262 - 268 2018年6月

Hydrophobic Attraction Measured between Asymmetric Hydrophobic Surfaces 査読

Naoyuki Ishida, Kohei Matsuo, Koreyoshi Imamura, Vincent S. J. Craig

Langmuir 34 ( 12 ) 3588 - 3596 2018年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：American Chemical Society

The interaction forces between silica surfaces modified to different degrees of hydrophobicity were measured using colloidal probe atomic force microscopy (AFM). A highly hydrophobic silica particle was prepared with octadecyltrichlorosilane (OTS), and the interaction forces were measured against silica substrates modified to produce surfaces of varying hydrophobicity. The interaction forces between the highly hydrophobic particle and a completely hydrophilic silicon wafer surface fitted well to the DLVO theory, indicating that no additional (non-DLVO) forces act between the surfaces. When the silicon wafer surface was treated to produce a contact angle of water on surface of 40°, an additional attractive force that is longer ranged than the van der Waals force was observed between the surfaces. The range and magnitude of the attractive force increase with the contact angle of water on the substrate. Beyond the effect on the contact angle, the hydrocarbon chain length and the terminal groups of hydrophobic layer on the substrate only have a minor effect on the magnitude of the force, even when the substrate is terminated with polar carboxyl groups, provided the hydrophobicity of the other surface is high.

DOI： 10.1021/acs.langmuir.7b04246

Influence of an external electric field on removal of protein fouling on a stainless steel surface by proteolytic enzymes 査読

COLLOIDS AND SURFACES B-BIOINTERFACES 159 118 - 124 2017年11月

Characteristics of proteinaceous additives in stabilizing enzymes during freeze-thawing and -drying 査読

Takanori Shimizu, Tamayo Korehisa, Hiroyuki Imanaka, Naoyuki Ishida, Koreyoshi Imamura

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 81 ( 4 ) 687 - 697 2017年4月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：TAYLOR & FRANCIS LTD

Protein-stabilizing characteristics of sixteen proteins during freeze-thawing and freeze-drying were investigated. Five enzymes, each with different instabilities against freezing and dehydration, were employed as the protein to be stabilized. Proteinaceous additives generally resulted in greater enzyme stabilization during freeze-thawing than sugars while the degree of stabilization for basic lysozyme and protamine were inferior to that of neutral and acidic proteins. Freeze-drying-induced inactivation of enzyme was also reduced by the presence of a proteinaceous additive, the extent of which was lower than that for a sugar. In both freeze thawing and freeze drying, the enzymes stabilization by the proteinaceous additive increased with increasing additive concentration. The enhancement of enzyme inactivation caused by pH change was also reduced in the presence of proteinaceous additives. The combined use of a sugar such as sucrose and dextran tended to increase the stabilizing effect of the proteinaceous additive.

添付ファイル： TBBB_A_1274637r1.pdf

DOI： 10.1080/09168451.2016.1274637

Surfactant-Free Solid Dispersions of Hydrophobic Drugs in an Amorphous Sugar Matrix Dried from an Organic Solvent 査読

Koji Takeda, Yuto Gotoda, Daichi Hirota, Fumihiro Hidaka, Tomo Sato, Tsutashi Matsuura, Hiroyuki Imanaka, Naoyuki Ishida, Koreyoshi Imamura

MOLECULAR PHARMACEUTICS 14 ( 3 ) 791 - 798 2017年3月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

The technique for homogeneously dispersing hydrophobic drugs in a water-soluble solid matrix (solid dispersion) is a subject that has been extensively investigated in the pharmaceutical industry. Herein, a novel technique for dispersing a solid, without the need to use a surfactant, is reported. A freeze-dried amorphous sugar sample was dissolved in an organic solvent, which contained a soluble model hydrophobic component. The suspension of the sugar and the model hydrophobic component was vacuum foam dried to give a solid powder. Four types of sugars and methanol were used as representative sugars and the organic medium. Four model drugs (indomethacin, ibuprofen, gliclazide, and nifedipine) were employed. Differential scanning calorimetry analyses indicated that the sugar and model drug (100:1) did not undergo segregation during the drying process. The dissolution of the hydrophobic drugs in water from the solid dispersion was then evaluated, and the results indicated that the C-max and AUC(0-60) (min) of the hydrophobic drug in water were increased when the surfactant-free solid dispersion was used. Palatinose and/or alpha-maltose were superior to the other tested carbohydrates in increasing C-max and AUC(0-60 min), for all tested model drugs, and the model drug with a lower water solubility tended to exhibit a greater extent of over-dissolution.

添付ファイル： P0SF-DrugProof.pdf

DOI： 10.1021/acs.molpharmaceut.6b01048

Adsorption of lysozyme on base metal surfaces in the presence of an external electric potential 査読

Ei Ei Htwe, Yuhi Nakama, Hiroshi Tanaka, Hiroyuki Imanaka, Naoyuki Ishida, Koreyoshi Imamura

COLLOIDS AND SURFACES B-BIOINTERFACES 147 9 - 16 2016年11月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

The impact of external electric potential on the adsorption of a protein to base metal surfaces was examined. Hen egg white lysozyme (LSZ) and six types of base metal plates (stainless steel SUS316L (St), Ti, Ta, Zr, Cr, or Ni) were used as the protein and adsorption surface, respectively. LSZ was allowed to adsorb on the surface under different conditions (surface potential, pH, electrolyte type and concentration, surface material), which was monitored using an ellipsometer. LSZ adsorption was minimized in the potential range above a certain threshold and, in the surface potential range below the threshold, decreasing the surface potential increased the amount of protein adsorbed. The threshold potential for LSZ adsorption was shifted toward a positive value with increasing pH and was lower for Ta and Zr than for the others. A divalent anion salt (K2SO4) as an electrolyte exhibited the adsorption of LSZ in the positive potential range while a monovalent salt (KCI) did not. A comprehensive consideration of the obtained results suggests that two modes of interactions, namely the electric force by an external electric field and electrostatic interactions with ionized surface hydroxyl groups, act on the LSZ molecules and determine the extent of suppression of LSZ adsorption, All these findings appear to support the view that a base metal surface can be controlled for the affinity to a protein by manipulating the surface electric potential as has been reported on some electrode materials. (C) 2016 Elsevier B.V. All rights reserved.

添付ファイル： P2LSZ-pub.pdf

DOI： 10.1016/j.colsurfb.2016.07.042

Molecular design of proteinaceous cushion for sensitive biomolecular interaction detection system

Hiroyuki Imanaka, Koki Dare, Koreyoshi Imamura

NEW BIOTECHNOLOGY 33 S72 - S72 2016年7月

Surfactant-free solid dispersion of fat-soluble flavour in an amorphous sugar matrix 査読

Tomo Satoh, Fumihiro Hidaka, Kento Miyake, Natsuki Yoshiyama, Koji Takeda, Tsutashi Matsuura, Hiroyuki Imanaka, Naoyuki Ishida, Koreyoshi Imamura

FOOD CHEMISTRY 197 1136 - 1142 2016年4月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCI LTD

A solid dispersion technique to homogeneously disperse hydrophobic ingredients in a water-soluble solid without using surfactant was examined as follows: first, freeze-dried amorphous sugar was dissolved in an organic medium that contained a soluble model hydrophobic component. Second, the mixed solution of sugar and the model hydrophobic component was vacuum dried into a solid (solid dispersion). Methanol and six fat-soluble flavours, including cinnamaldehyde, were used as organic media and model hydrophobic components. The retention of flavours in the solid dispersion during drying and storage under vacuum was evaluated. The amorphised disaccharides dissolved in methanol up to 100 mg/mL, even temporarily (20 s to 10 days) and could be solidified without any evidence of crystallisation and segregation from flavour. The solid dispersion, prepared using a-maltose usually showed 65-95% flavour retention during drying (and storage for cinnamaldehyde), whereas >= 50% of the flavour was lost when the flavour was O/W emulsified with a surfactant and then freeze-dried with sugar. (C) 2015 Elsevier Ltd. All rights reserved.

添付ファイル： P0SurfFree-drft.pdf

DOI： 10.1016/j.foodchem.2015.11.097

The use of a proteinaceous "cushion" with a polystyrene-binding peptide tag to control the orientation and function of a target peptide adsorbed to a hydrophilic polystyrene surface 査読

Hiroyuki Imanaka, Daisuke Yamadzumi, Keisuke Yanagita, Naoyuki Ishida, Kazuhiro Nakanishi, Koreyoshi Imamura

BIOTECHNOLOGY PROGRESS 32 ( 2 ) 527 - 534 2016年3月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-BLACKWELL

In immobilizing target biomolecules on a solid surface, it is essential (i) to orient the target moiety in a preferred direction and (ii) to avoid unwanted interactions of the target moiety including with the solid surface. The preferred orientation of the target moiety can be achieved by genetic conjugation of an affinity peptide tag specific to the immobilization surface. Herein, we report on a strategy for reducing the extent of direct interaction between the target moiety and surface in the immobilization of hexahistidine peptide (6His) and green fluorescent protein (GFP) on a hydrophilic polystyrene (PS) surface: Ribonuclease HII from Thermococcus kodakaraensis (cHII) was genetically inserted as a cushion between the PS-affinity peptide tag and target moiety. The insertion of a cushion protein resulted in a considerably stronger immobilization of target biomolecules compared to conjugation with only a PS affinity peptide tag, resulting in a substantially enhanced accessibility of the detection antibody to the target 6His peptide. The fluorescent intensity of the GFP moiety was decreased by approximately 30% as the result of fusion with cHII and the PS-affinity peptide tag but was fully retained in the immobilization on the PS surface irrespective of the increased binding force. Furthermore, the fusion of cHII did not impair the stability of the target GFP moiety. Accordingly, the use of a proteinaceous cushion appears to be promising for the immobilization of functional biomolecules on a solid surface. (c) 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:527-534, 2016

添付ファイル： BTPR_2232corected.pdf

DOI： 10.1002/btpr.2232

クッションタンパク質の分子デザインによるバイオ分子間相互作用の高感度化

今中洋行, 伊達弘輝, 的場晴香, 石田尚之, 今村維克

表面科学学術講演会要旨集 36 37 - 37 2016年

記述言語：日本語出版者・発行元：公益社団法人日本表面科学会

ELISA，SPRやQCMなどのバイオ分子間相互作用検出系における基板上へのリガンド分子の固定化について，基板親和性ペプチド連結による固定化配向制御ならびにリガンド分子と基板との直接的な相互作用を緩和するクッションタンパク質を用いた機能維持を試みた．そして，クッションタンパク質の様々な分子デザインにより，ペプチド-タンパク質間あるいはタンパク質-タンパク質間相互作用検出を顕著に高感度化できた．

DOI： 10.14886/sssj2008.36.0_37

CiNii Article

Effect of surface hydrophobicity on short-range hydrophobic attraction between silanated silica surfaces 査読

Yuhei Soga, Hiroyuki Imanaka, Koreyoshi Imamura, Naoyuki Ishida

ADVANCED POWDER TECHNOLOGY 26 ( 6 ) 1729 - 1733 2015年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

The interaction forces between silanated silica surfaces without nanobubbles were measured using colloidal probe atomic force microscopy (AFM). To obtain hydrophobic surfaces without nanobubbles, an aqueous solution was introduced between the surfaces following an exchange process involving several solvents. In the obtained approaching force curves, an attractive force was observed from a distance of 10-20 nm, which is an additional attractive force stronger than typical van der Waals attractions. When the surface hydrophobicity decreased, the range of this attraction decreased slightly; the attraction disappeared when the surface contact angle was below 90 degrees. In contrast, measurements in the water-ethanol mixtures revealed that the attraction persisted even when the contact angle was well below 90 degrees. The possible origin of this force was discussed on the basis of the obtained results. (C) 2015 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan.

DOI： 10.1016/j.apt.2015.10.017

Inhibitory effects of additives and heat treatment on the crystallization of freeze-dried sugar 査読

Kohshi Kinugawa, Mitsunori Kinuhata, Ryo Kagotani, Hiroyuki Imanaka, Naoyuki Ishida, Mizuki Kitamatsu, Kazuhiro Nakanishi, Koreyoshi Imamura

JOURNAL OF FOOD ENGINEERING 155 37 - 44 2015年6月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCI LTD

An amorphous matrix of a sugar is frequently used as a bulk-forming and stabilizing agent in the food industry but tends to crystallize as the result of water uptake and increase in temperature. Additives and methods used to inhibit the crystallization of amorphous sugar (sucrose) were screened in this study. Freeze-dried amorphous sucrose containing 0.5-5 wt% of additive, including salts, different types of sugars, and polymers, the crystallization temperature (T-cry) and isothermal crystallization characteristics were examined. Certain types of salts markedly increased the Tcry and prolonged the induction period for crystal nucleation. The use of 1 wt% MgCl2 was particularly effective in inhibiting sugar crystallization. The heat treatment of crystalline sucrose under appropriate conditions was also found to result in diminished sucrose crystallization. MALDI-TOF mass spectra of the heat-treated sucrose suggested that sucrose derivatives containing multiple pyranose groups were formed, which would closely relate to the crystallization inhibition. Finally, the protein stabilizing effects of the matrices were evaluated. The results indicated that both the addition of additives and the heat treatment resulted in an improvement of the protein stabilizing effect of amorphous sugar matrix, compared to that of sucrose alone. (C) 2015 Elsevier Ltd. All rights reserved.

添付ファイル： P0CryInh-proof.pdf

DOI： 10.1016/j.jfoodeng.2015.01.016

Influence of sugar surfactant structure on the encapsulation of oil droplets in an amorphous sugar matrix during freeze-drying 査読

Shota Nakayama, Yoshifumi Kimura, Sayuri Miki, Jun Oshitani, Takashi Kobayashi, Shuji Adachi, Tsutashi Matsuura, Hiroyuki Imanaka, Naoyuki Ishida, Hiroko Tada, Kazuhiro Nakanishi, Koreyoshi Imamura

FOOD RESEARCH INTERNATIONAL 70 143 - 149 2015年4月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

The encapsulation of O/W emulsion droplets in a freeze-dried amorphous sugar matrix was investigated, focusing on the impact of the molecular structure of the emulsifying surfactant. O/W emulsions, containing various surfactants, were freeze-dried in the presence of a sugar. Thirty types of surfactants, including eighteen different sugar surfactants and ten types of commercially available sugar ester mixtures, were used. Linoleic acid methyl ester and trehalose were used as the oil phase and sugar. The amounts of oil droplets encapsulated in freeze-dried amorphous sugar matrix were analyzed by Fourier transform Infrared spectroscopy. Sugar surfactants were generally superior to the other classes of surfactants for oil droplet encapsulation during freeze-drying, and there was the optimum alkyl chain length of the sugar surfactant. Sugar esters generally exhibited greater oil encapsulation than sugar ethers. Larger sugar head group appeared to result in better encapsulation in the case of sugar esters, but the opposite tendency was found for sugar ethers. A limited combination of sugar surfactants (15% sucrose mono- and 85% di-stearate) resulted in the maximum oil droplet encapsulation efficiency although these surfactants are individually quite poor in the encapsulation and other tested combinations did not improve the encapsulation efficiency relative to their individual effectiveness. (C) 2015 Elsevier Ltd. All rights reserved.

添付ファイル： P1AOex-pub.pdf

DOI： 10.1016/j.foodres.2015.02.003

Effect of Lipid Amount on Surfactant-free Solid Lipid Nanoparticle Formation by Hot Homogenization 査読

Jun Oshitani, Natsumi Murakami, Mikio Yoshida, Naoyuki Ishida, Koreyoshi Imamura, Hideki Ichikawa

CHEMISTRY LETTERS 43 ( 7 ) 1011 - 1013 2014年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：CHEMICAL SOC JAPAN

The yield and size distribution of surfactant-free solid lipid nanoparticles (SF-SLNs) formed by hot homogenization were investigated by changing the amount of lipid (palmitic acid). The yield was 100% and monodispersed same-sized particles of 120-200 nm were formed at the lipid amount <= 2.8 x 10(-4) g-lipid (g-water)(-1). The yield decreased owing to phase separation, and the size increased "step-likely" to be 200 350 nm while keeping the monodispersity when the lipid amount was just above <= 2.8 x 10(-4) g-lipid (g-water)(-1). The size and the lipid amount continued to increase gradually at the lipid amount >2.8 x 10(-4) g-lipid (g-water)(-1). The results indicate that submicron-sized solid lipid particles can be formed without surfactants and that the decrease of yield and the step-like increase of particle size occur at the same lipid amount. The total surface area of the SF-SLNs was estimated using the experimental data. It is suggested that the total surface area and the lipid amount are correlated to each other.

DOI： 10.1246/cl.140279