Katsushika-ku, Japan
Katsushika-ku, Japan

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Kawai K.,Miyoshi Oil and Fat Co. | Kawakami H.,Miyoshi Oil and Fat Co.
Journal of Biomedical Materials Research - Part A | Year: 2015

Matrix metalloprotease (MMP) inhibitors improve the longevity of dental adhesives/tooth bonds; however, biocompatibility is required for their clinical use. This study evaluated the inhibition of MMPs and toxicity of two gold (AuNPs) and platinum nanoparticles (PtNPs) as possible compounds for use in dental adhesives. The MMP assay for studying the interaction of MMPs and nanoparticles (NPs) was evaluated by an MMP assay kit and gelatin zymography. Cultured L929 fibroblast cells or RAW264 macrophages were exposed to NPs. The cellular responses to NPs were examined using cytotoxic (cell viability) and genotoxic assays (comet assay), and transmission electron microscopic (TEM) analysis. The mechanical properties (elastic modulus) of the experimental resin loaded with NPs were examined using thermomechanical analysis. All NPs inhibited MMP activity at relatively low concentrations. The NPs inhibit MMPs by chelating with the Zn2+ bound in the active sites of MMPs. No cytotoxic and genotoxic effects were found in AuNPs, whereas the PtNPs possessed both adverse effects. In TEM analysis, the NPs were localized mainly in lysosomes without penetration into nuclei. The mechanical properties of the resins increased when AuNPs were added in resins, but not by PtNPs. AuNPs are attractive candidates to inhibit MMPs and improve the mechanical properties of resins without cytotoxic/genotoxic effects to cells, and therefore should be suitable for applications in adhesive resin systems. © 2015 Wiley Periodicals, Inc.


Hashimoto M.,Health Sciences University of Hokkaido | Toshima H.,Health Sciences University of Hokkaido | Yonezawa T.,Hokkaido University | Kawai K.,Miyoshi Oil and Fat Co. | And 3 more authors.
Journal of Biomedical Materials Research - Part A | Year: 2014

Nanometals are currently receiving considerable attention for industrial and biomedical applications, but their potentially hazardous and toxic effects have not been extensively studied. This study evaluated the biological responses of novel water-dispersible gold (Au-NPs) and silver nanoparticles (Ag-NPs) stabilized by Au-C or Ag-C σ-bonds in cultured macrophages (RAW264.7), via analysis of the cell viability, the integrity of the plasma membrane, and the inflammatory and morphological properties. The cultured RAW264.7 was exposed to metal-NPs at various concentrations. The Ag-NPs showed cytotoxicity at high NP concentrations, but the cytotoxic effects of the Au-NPs were smaller than those of the Ag-NPs. For the microscopic analysis, both types of particles were internalized into cells, the morphological changes in the cells which manifested as an expansion of the vesicles' volume, were smaller for the Au-NPs compared with the Ag-NPs. For the Ag-NPs, the endocytosis abilities of the macrophages might have induced harmful effects, because of the expansion of the cell vesicles. Although an inflammatory response was observed for both the Au- and Ag-NPs, the harmful effects of the Au-NPs were smaller than those of the Ag-NPs, with minor morphological changes observed even after internalization of the NPs into the cells. © 2013 Society of Plastics Engineers.


Hashimoto M.,Osaka University | Kawai K.,Miyoshi Oil and Fat Co. | Kawakami H.,Miyoshi Oil and Fat Co. | Imazato S.,Osaka University
Journal of Biomedical Materials Research - Part A | Year: 2016

Matrix metalloprotease (MMP) inhibitors improve the longevity of dental adhesives/tooth bonds; however, biocompatibility is required for their clinical use. This study evaluated the inhibition of MMPs and toxicity of two gold (AuNPs) and platinum nanoparticles (PtNPs) as possible compounds for use in dental adhesives. The MMP assay for studying the interaction of MMPs and nanoparticles (NPs) was evaluated by an MMP assay kit and gelatin zymography. Cultured L929 fibroblast cells or RAW264 macrophages were exposed to NPs. The cellular responses to NPs were examined using cytotoxic (cell viability) and genotoxic assays (comet assay), and transmission electron microscopic (TEM) analysis. The mechanical properties (elastic modulus) of the experimental resin loaded with NPs were examined using thermomechanical analysis. All NPs inhibited MMP activity at relatively low concentrations. The NPs inhibit MMPs by chelating with the Zn2+ bound in the active sites of MMPs. No cytotoxic and genotoxic effects were found in AuNPs, whereas the PtNPs possessed both adverse effects. In TEM analysis, the NPs were localized mainly in lysosomes without penetration into nuclei. The mechanical properties of the resins increased when AuNPs were added in resins, but not by PtNPs. AuNPs are attractive candidates to inhibit MMPs and improve the mechanical properties of resins without cytotoxic/genotoxic effects to cells, and therefore should be suitable for applications in adhesive resin systems. © 2015 Wiley Periodicals, Inc.


Kawai K.,Hokkaido University | Kawai K.,Miyoshi Oil and Fat Co. | Narushima T.,Hokkaido University | Kaneko K.,Miyoshi Oil and Fat Co. | And 5 more authors.
Applied Surface Science | Year: 2012

The synthesis of 4-diazoniumcarboxylbenzene fluoroborate, a new water-soluble stabilizer for metal nanoparticles (NPs), is described. A stable dispersion of Ag NPs in water was successfully produced by a simultaneous aqueous reduction of this diazonium salt and silver nitrate by NaBH 4. UV-vis spectra, TEM images, XRD patterns, and XPS spectra of the obtained Ag NPs revealed that they were stabilized by Ag-C σ-bonds. These NPs showed excellent antimicrobial properties against Staphylococcus aureus. © 2012 Elsevier B.V. All rights reserved.


Kawai K.,Hokkaido University | Kawai K.,Miyoshi Oil and Fat Co. | Kaneko K.,Miyoshi Oil and Fat Co. | Yonezawa T.,Hokkaido University
Langmuir | Year: 2011

This Letter examines the relationship between the structures of ionic liquids and their water-solubility or osmotic pressure with a number of synthesized quaternary ammonium type ionic liquids and organic salts containing a hydroxyl group as hydrophilic substituted groups on ammonium group cations, and bromide or methylsulfonate as anions. The study found a linear relation between the amount and osmotic pressure of the water-soluble ionic liquids synthesized here, strongly indicating that these water-soluble ionic liquids are perfectly ionized in water like inorganic salts with small diameter ions. © 2011 American Chemical Society.


Kawai K.,Hokkaido University | Kawai K.,Miyoshi Oil and Fat Co. | Kaneko K.,Miyoshi Oil and Fat Co. | Kawakami H.,Miyoshi Oil and Fat Co. | Yonezawa T.,Hokkaido University
Langmuir | Year: 2011

This letter proposes the use of choline-like hydrophilic ionic liquids (ILs) to visualize hydrous samples (e.g., seaweed and other biological or food samples) for scanning electron microscopy (SEM) observation. Some of the water in the samples was successfully replaced with these ILs, which penetrated the cell membranes. The treated samples did not contract much even after drying. The ILs' ionic conductivity decreased the charging of sample surfaces, and good SEM images were obtained. © 2011 American Chemical Society.


Shishino Y.,University of Tokyo | Yonezawa T.,Hokkaido University | Kawai K.,Hokkaido University | Kawai K.,Miyoshi Oil and Fat Co. | Nishihara H.,University of Tokyo
Chemical Communications | Year: 2010

Water-soluble luminescent AuNPs of 1.3 ± 0.3 nm in diameter with a large Stokes shift were facilely synthesized by a new molten matrix sputtering (MMS) method. © 2010 The Royal Society of Chemistry.


Abe S.,Hokkaido University | Hyono A.,Hokkaido University | Kawai K.,Hokkaido University | Kawai K.,Miyoshi Oil and Fat Co. | Yonezawa T.,Hokkaido University
Journal of Nanoscience and Nanotechnology | Year: 2014

In this study, we investigated conductivity preparation for scanning electron microscope (SEM) observation that used novel asymmetrical choline-type room temperature ionic liquids (RTIL). By immersion in only an RTIL solution, clear SEM images of several types of biological samples were successfully observed. In addition, we could visualize protozoans using RTILs without any dilution. These results suggested that the asymmetrical choline-type RTILs used in this study are suitable for visualizing of biological samples by SEM. Treatment without the need for dilution can obviate the need for adjusting the RTIL concentration and provide for a rapid and easy conductivity treatment for insulating samples. Copyright © 2014 American Scientific Publishers.


Kawai K.,Hokkaido University | Kawai K.,Miyoshi Oil and Fat Co. | Kaneko K.,Miyoshi Oil and Fat Co. | Kawakami H.,Miyoshi Oil and Fat Co. | And 2 more authors.
Colloids and Surfaces B: Biointerfaces | Year: 2013

Choline-type ionic liquids (CILs), which have a molecular structure resembling that of the vitamin-like active substance choline, have high water solubility, high osmotic pressure, and high cell membrane permeability. Their physical properties make them a very useful pretreatment agent for scanning electron microscopy (SEM) observation of hydrous samples because they can replace water in the samples, causing them to retain their shapes. SEM images of pollen without dissolution of cell membranes, damage, or deformation were obtained by a simple visualization process using CILs. We also identified an easy pretreatment protocol for SEM observation of hydrous microsamples that uses a membrane filter as a sample stage to ensure correct sample placement. Bacteria were successfully observed by using this protocol. © 2012 Elsevier B.V.


PubMed | Miyoshi Oil and Fat Co., Tokyo University of Pharmacy and Life Science and Tokyo Electron
Type: Journal Article | Journal: Journal of bioscience and bioengineering | Year: 2016

Large quantities of oils and fats are discharged into wastewater from food industries. We evaluated the possibility of using microbial fuel cells (MFCs) for the generation of electricity from food-industry wastewater containing vegetable oils. Single-chamber MFCs were supplied with artificial wastewater containing soybean oil, and oil removal and electric output were examined under several different conditions. We found that MFC performance could be improved by supplementing wastewater with an emulsifier, inoculating MFCs with oil-contaminated soil, and coating the graphite-felt anodes with carbon nanotubes, resulting in a power output of more than 2Wm

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