Faculty Profiles - HAYAKAWA Satoshi

Papers - HAYAKAWA Satoshi

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Improvement of caffeine adsorption on octacalcium phosphate through suberate ion incorporation

Takuya Kataoka, Ayumi Koga, Seita Nishiyama, Tomohiko Yoshioka, Satoshi Hayakawa

Materials Letters 385 138188 - 138188 2025.4

Comparative study of the effects of fluoride treatment with cyclic variations in pH on the structures of stoichiometric, calcium-deficient, and carbonated hydroxyapatites

Satoshi Hayakawa, Yu Okada, Tomohiko Yoshioka

Journal of the Ceramic Society of Japan 133 ( 1 ) 15 - 24 2025.1

Electrochemically assisted sol-gel deposition of bioactive gels for biomedical applications Reviewed

Tomohiko Yoshioka, Naoki Miyamoto, Satoshi Hayakawa

Journal of Sol-Gel Science and Technology 112 ( 2 ) 419 - 424 2024.9

Authorship：Last author Publishing type：Research paper (scientific journal) Publisher：Springer Science and Business Media LLC

Abstract

So far, the sol-gel process has been available to prepare precursor gels of bioactive glasses with various compositions. In this report, we described a novel coating method of bioactive gels on a titanium substrate where the sol-gel transition is controlled by applying external electric fields. The application of a constant current of 10 mA/cm² in an acidic sol containing pre-hydrolyzed tetraethoxysilane, calcium nitrate, and ammonium dihydrogen phosphate led to the deposition of gels on the titanium cathodes due to the generation of OH^– by water electrolysis as a catalyst of the sol-gel transition. The obtained gels, which were characterized to be amorphous and consisted of Si, Ca, and P, covered the titanium substrates as a coating. The bioactivity of the gels deposited was confirmed by soaking in a simulated body fluid (SBF) up to 7 days, suggesting that the electrochemically assisted sol-gel process is promising for providing bioactive coatings on metallic implants.

Graphical Abstract

DOI： 10.1007/s10971-024-06530-6

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Other Link： https://link.springer.com/article/10.1007/s10971-024-06530-6/fulltext.html

Synthesis and structural characterization of Sr(II) ion-containing octacalcium phosphate incorporated with both 2,6-pyridinedicarboxylate and succinate ions as a bone defect filler with multiple drug loading capability Reviewed

Takuya Kataoka, Seita Nishiyama, Eiji Fujii, Tomohiko Yoshioka, Satoshi Hayakawa

Colloids and Surfaces A: Physicochemical and Engineering Aspects 134001 - 134001 2024.4

Effect of chitosan content on protein adsorption capacity of Mg(II) ion-containing apatite/chitosan composite particles Reviewed

Takuya Kataoka, Wataru Nishizaki, Yuhi Yasuhira, Eiji Fujii, Tomohiko Yoshioka, Satoshi Hayakawa

Journal of the Ceramic Society of Japan 2024

Incorporation behavior of Mg(II) ion into hydroxyapatite in the presence of chitosan Reviewed

Takuya Kataoka, Yuhi Yasuhira, Eiji Fujii, Tomohiko Yoshioka, Satoshi Hayakawa

Journal of the Ceramic Society of Japan 131 ( 9 ) 569 - 574 2023.9

Functional evaluation of mineral trioxide aggregate cement with choline dihydrogen phosphate. Reviewed

Kazuhisa Tabira, Noboru Kajimoto, Hirogo Minamisawa, Taira Sato, Michito Maruta, Kyoko Oka, Takuya Kataoka, Tomohiko Yoshioka, Satoshi Hayakawa, Kanji Tsuru

Dental materials journal 2023.4

Language：English Publishing type：Research paper (scientific journal)

To improve the cytocompatibility of mineral trioxide aggregate (MTA) cement and its ability for reparative dentin formation, the effect of adding choline dihydrogen phosphate (CDHP), which is reported to be biocompatible, to MTA cement was investigated. The L929 cell proliferation showed that the addition of CDHP improved cell viability. The addition of CDHP shortened the setting time of MTA cement, with a significant decrease in consistency above 0.4 g/mL. Diametral tensile strength of the set cement was improved by the addition of 0.4 g/mL CDHP. Solubility was judged to be within the range of clinical application. The spontaneous precipitation of low crystalline hydroxyapatite was examined by immersing the set cement in phosphate buffer saline, and it was found that the ability of the cement with 0.4 g/mL of CDHP was significantly improved compared with that of the cement without CDHP.

DOI： 10.4012/dmj.2022-283

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Effects of the silicon-containing chemical species dissolved from chitosan–siloxane hybrids on nerve cells Reviewed

Kosei Hattori, Satoshi Hayakawa, Yuki Shirosaki

Journal of Sol-Gel Science and Technology 104 ( 3 ) 606 - 616 2022.12

Publishing type：Research paper (scientific journal)

Silicic acid components from bioactive glass activate osteoblasts gene for bone generation. Many studies have been reported on osteoblast compatibility and bone regeneration using composites and hybrids, including silica or siloxane units. We previously synthesized chitosan−siloxane hybrids via a sol-gel method and observed bone and nerve regeneration. However, it is not clear the structure of molecules involving silicon atoms that has a more effective role in the cell activity and their mechanisms of cell activation. In this study, we prepared hybrid materials from chitosan and different types of alkoxysilane, 3-glycidoxypropyltrimethoxysilane (GPTMS), 3-glycidoxypropyldimethoxymethylsilane (GPDMS), and tetraethoxysilane (TEOS), and investigated the structures of the silicon-containing species dissolved from each hybrid and their effect on the proliferation of nerve cells. The silicon-containing species in the extraction were mainly 100–600 molecular weight, indicating they were chitin/chitosan units and monomeric hydrolyzed GPTMS, GPDMS, and TEOS. The nerve cell proliferation was inhibited by the chitosan–GPTMS and GPDMS hybrid extractions. The silicon-containing species were not taken up by the cells. The silicon-containing species dissolved from the hybrids were adsorbed to the cells or they inactivated biomolecules in the culture medium, suppressing cell proliferation. [Figure not available: see fulltext.]

DOI： 10.1007/s10971-022-05814-z

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Preparation and Drug Release Profile of Chitosan–Siloxane Hybrid Capsules Coated with Hydroxyapatite Reviewed

Yuki Shirosaki, Yasuyo Tsukatani, Kohei Okamoto, Satoshi Hayakawa, Akiyoshi Osaka

Pharmaceutics 14 ( 5 ) 2022.5

Publishing type：Research paper (scientific journal)

Chitosan is a cationic polymer that forms polymerized membranes upon reaction with anionic polymers. Chitosan−carboxymethyl cellulose (CMC) capsules are drug delivery carrier candidates whose mechanical strength and permeability must be controlled to achieve sustained release. In this study, the capsules were prepared from chitosan−γ-glycidoxypropyltrimethoxysilane (GPTMS)−CMC. The mechanical stability of the capsules was improved by crosslinking the chitosan with GPTMS. The capsules were then coated with hydroxyapatite (HAp) by alternately soaking them in calcium chloride solution and disodium hydrogen phosphate solution to prevent rapid initial drug release. Cytochrome C (CC), as a model drug, was introduced into the capsules via two routes, impregnation and injection, and then the CC released from the capsules was examined. HAp was found to be deposited on the internal and external surfaces of the capsules. The amount of CC introduced, and the release rate were reduced by the HAp coating. The injection method was found to result in the greatest CC loading.

DOI： 10.3390/pharmaceutics14051111

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Antibacterial Chitosan Nanofiber Thin Films with Bacitracin Zinc Salt. Reviewed International journal

Kazutaka Kumamoto, Toshinari Maeda, Satoshi Hayakawa, Nurul Asyifah Binti Mustapha, Meng-Jiy Wang, Yuki Shirosaki

Polymers 13 ( 7 ) 2021.3

Language：English Publishing type：Research paper (scientific journal)

Chitosan nanofiber has a highly uniform structure of 20-50 nm in diameter and shows high dispersibility in water due to its submicron size and high surface-to-volume ratio. The stacked nanofibers film is useful for breathability because it has a gap with a size of several tens of nm or more. However, the chemical bonds between the nanofibers cannot be broken during use. In this study, the thin films were obtained by filtration of chitosan nanofibers and 3-glycidoxypropyltrimethoxysilane (GPTMS) mixture. The addition of GPTMS changed the wettability, mechanical property and stability in water of the thin films. Bacitracin zinc salt (BZ) has been used for the localized dermatological medicines and loaded in the films. BZ interacted electrostatically with the thin films matrix and the release of BZ was controlled by the amount of GPTMS. A higher released amount of BZ showed higher antibacterial effects toward S. aureus. The film was also tested their toxicity by L929 fibroblasts. The release of less than 11.9 μg of BZ showed antibacterial effects, but were not toxic for fibroblast cells.

DOI： 10.3390/polym13071104

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Blood-compatible ceramic particles, coating layers, and macrospheres for blood purification and related applications

Takuji Asano, Tomohiko Yoshioka, Yuki Shirosaki, Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka

Bioceramics 195 - 243 2021

Three-dimensional observation and analysis of remineralization in dentinal caries lesions Reviewed

Kumiko Yoshihara, Noriyuki Nagaoka, Akiko Nakamura, Toru Hara, Satoshi Hayakawa, Yasuhiro Yoshida, Bart Van Meerbeek

Scientific Reports 10 ( 1 ) 2020.12

Conversion of sub-µm calcium carbonate (calcite) particles to hollow hydroxyapatite agglomerates in K2HPO4 solutions Reviewed

Sun Yanyan, Wang Guangxin, Li Wuhui, Wang Yaming, Satoshi Hayakawa, Akiyoshi Osaka

Nanotechnology Reviews 9 ( 1 ) 945 - 960 2020.9

Language：English Publishing type：Research paper (scientific journal) Publisher：Walter de Gruyter GmbH

<title>Abstract</title>
Sub-µm CaCO₃ (calcite; CC) particles were converted to calcium monohydrogenphosphate dihydrate (DCPD) and hydroxyapatite (HAp) via soaking treatments in K₂HPO₄ solutions with varied pH (3–12) and concentrations (0.1–1.5 M) at 37°C for up to 10 days. DCPD was derived from the solutions with pH ≤ 6; while hollow HAp was yielded when pH ≥ 7 in assemblies of petal-like crystallites. Results of magic angle spinning (MAS) and cross-polarization magic angle spinning (CP-MAS) NMR studies have shown that the HAp lattice has only PO₄
²⁻ but no HPO₄
²⁻ at B (phosphate) sites. Trace amounts of CO₃
²⁻ have occupied both A (OH) and B (PO₄) sites, and H₂O is adsorbed on surface crystallites. The primary crystallite size of HAp derived from Scherrer equation increases quickly in a 12 h period and becomes gradually stable afterward. Samples of particles soaked within 3 h in a temperature range of 20–80°C were analyzed by X-ray diffraction. It is shown that the rate constant of 1 M solution is about an order of magnitude greater than that of 0.1 M solution and the apparent activation energy is 33 kJ/mol. In this work, the conversion of CC to HAp can be quantitatively controlled to solve the problem of slow degradation of HAp.

DOI： 10.1515/ntrev-2020-0070

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Other Link： https://www.degruyter.com/document/doi/10.1515/ntrev-2020-0070/xml

Comparative study of in vitro apatite-forming abilities of highly ordered rutile nanorod arrays fabricated on cpTi and Ti6Al4V alloys Reviewed

Xingzhu Liu, Tomohiko Yoshioka, Satoshi Hayakawa

Journal of Asian Ceramic Societies 8 ( 1 ) 29 - 38 2020.1

Cytocompatible and antibacterial properties of chitosan−siloxane hybrid spheres Reviewed

Yuki Shirosaki, Manato Nakatsukasa, Saki Yasutomi, Susana Cruz-Neves, Satoshi Hayakawa, Akiyoshi Osaka, Toshinari Maeda, Toshiki Miyazaki

Polymers 11 1676 - 1686 2019.10

Effect of titanyl sulfate concentration on growth of nanometer-scale rutile rod arrays on the surface of titanium substrate Reviewed

Xing-zhu LIU, Tomohiko YOSHIOKA, Satoshi HAYAKAWA

Journal of the Ceramic Society of Japan 127 ( 8 ) 545 - 550 2019.8

The fabrication of nanostructured titania polymorphs layer with high crystallinity and its apatite-forming ability Reviewed

Xingzhu Liu, Fan Xiao, Satoshi Hayakawa, Akiyoshi Osaka

Surface and Coatings Technology 363 338 - 343 2019.4

© 2019 Elsevier B.V. High crystallinity anatase/rutile layers are prepared on the surface of commercially pure titanium (cpTi) by hydrothermal method at 160 °C for 3 h. The surface morphology of titania layers is changed by adjusting the pH value and Ti 4+ concentration of treating solution (TS). Obtained nanorods on all TS samples are composed of pure rutile and the anatase co-deposited with rutile is found in the dense bottom layer. The possible co-deposition mechanism of polymorphs layers is given in this study. In this study, the rutile nanorods array with high energy (101) facet exposed is found on the TS 3 sample. In vitro apatite forming ability of the TS samples are confirmed by soaking them in Kokubo's simulated body fluid (SBF, pH 7.4, 36.5 °C) for 1 and 3 days. Results show that apatite particles could be obtained on all TS samples within 1 d. After 3 days' immersion in SBF, TS 3 sample shows strongest apatite X-ray diffraction. These results indicate that the ability in inducing apatite on cpTi with TS 3 treatment is excellent. Such excellent apatite-forming ability is ascribed to the existence of thick titania layer with high energy (101) facet exposed on the TS 3 sample.

DOI： 10.1016/j.surfcoat.2019.02.063

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Accelerated induction of in vitro apatite formation by parallel alignment of hydrothermally oxidized titanium substrates separated by sub-millimeter gaps Reviewed

Satoshi Hayakawa, Keigo Okamoto, Tomohiko Yoshioka

Journal of Asian Ceramic Societies 7 ( 1 ) 90 - 100 2019.1

Authorship：Lead author,　Corresponding author Publishing type：Research paper (scientific journal) Publisher：Informa UK Limited

© 2019, © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of The Korean Ceramic Society and The Ceramic Society of Japan. Although autoclaving is a common sterilization method for biomedical devices, the ability to induce deposition of apatite particles on hydrothermally treated titanium is still not fully realized. This is because the induction ability is too weak to be evaluated via in vitro apatite formation in Kokubo’s simulated body fluid (SBF) by the conventional immersion method, i.e. using samples with open and smooth surface. This study reports on the surface structure of hydrothermally treated titanium and the ability to induce deposition of apatite particles on the surface of parallel confined spaces separated by sub-millimeter gaps in Kokubo’s SBF. Thin-film X-ray diffraction and analyses using Fourier transform infra-red (FT-IR) spectroscopy and Raman spectroscopy revealed that a nano-crystalline anatase-type titanium oxide layer was formed on titanium substrates after hydrothermal treatment at 150°C for 2 h. When growth of the titanium oxide layer was moderately suppressed, the hydrothermally treated titanium surface exhibited a characteristic interference color, silver or gold, which does not impair the esthetic appearance of the titanium-based implant. The ability to induce deposition of apatite particles on hydrothermally treated titanium was remarkably amplified by parallel alignment of substrates separated by sub-millimeter gaps.

DOI： 10.1080/21870764.2019.1572690

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Atomic level observation and structural analysis of phosphoric-acid ester interaction at dentin Reviewed International journal

Kumiko Yoshihara, Noriyuki Nagaoka, Yasuhiro Yoshida, Bart Van Meerbeek, Satoshi Hayakawa

Acta Biomaterialia 97 544 - 556 2019.1

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

© 2019 Acta Materialia Inc. The functional monomer 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP), used in many dental adhesives, self-assembles in nano-layers at adhesive-tooth interfaces. Recently, several states of the P[sbnd]OH groups of 10-MDP_Ca salts were suggested, while their actual status has not been elucidated yet. We mechanistically investigated 10-MDP_Ca-salt nano-layering at adhesive-dentin interfaces, correlatively using scanning transmission electron microscopy with energy-dispersive X-ray spectrometry (STEM-EDS), X-ray diffraction (XRD) and solid state nuclear magnetic resonance (NMR). STEM-EDS confirmed the presence of Ca and P in each nano-layer. Both XRD and NMR revealed that the two terminal P[sbnd]OH groups of 10-MDP reacted with Ca. This twofold P[sbnd]OH interaction of 10-MDP with Ca was stable in water and is therefore expected to contribute to durable nano-layering of 10-MDP_Ca salts in the hybrid and adhesive layer. Statement of Significance: The functional monomer 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP), commonly used in dental adhesives with favorable long-term clinical outcome, has been documented to self-assemble into nano-layers at adhesive-tooth interfaces. Characterizing ultra-morphologically (STEM) and chemically (STEM-EDS, XRD, NMR) the mechanisms of interaction of 10-MDP with bulk dentin in a similar manner as what occurs clinically, it was found that the water stable 10-MDP_Ca salts consist of CaRPO4, meaning that the two [sbnd]OH groups of the phosphate group of 10-MDP ionically reacted with Ca. This stable structure is expected to contribute to durable nano-layering of 10-MDP_Ca salts in the hybrid and adhesive layer and hence to clinical longevity of the adhesively bonded tooth restoration.

DOI： 10.1016/j.actbio.2019.08.029

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Conversion of silicate glass to highly oriented divalent ion substituted hydroxyapatite nanorod arrays in alkaline phosphate solutions Reviewed

Satoshi Hayakawa, Yusuke Oshita, Kazuki Yamada, Tomohiko Yoshioka, Noriyuki Nagaoka

Ceramics International 44 ( 15 ) 18719 - 18726 2018.10

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI LTD

© 2018 Elsevier Ltd and Techna Group S.r.l. This study presents a new strategy for preparing highly oriented nanorod array of divalent ion substituted hydroxyapatite (HAp) and factors controlling the rate of glass conversion. HAp nanorod arrays were prepared on a series of alkali/alkaline-earth silicate glasses in the Na2O–CaO–SrO–SiO2 system in phosphate aqueous solutions with different pH values via a glass conversion process. The effects of the substitution of Sr2+ for Ca2+ and the network connectivity (NC) of the silicate glasses on the degree of crystal orientation of the nanorod array of HAp crystals, the crystallite size, and the partial substitution of Sr2+ for Ca2+ in the HAp crystal lattice were investigated using X-ray diffraction, 29Si magic angle spinning nuclear magnetic resonance (NMR) spectroscopy, and field-emission scanning electron microscopy. Sr-free Na2O–CaO–SiO2 glass was converted into HAp nanorod arrays highly-oriented toward the c-axis, whereas the increase in the NC of the glass led to a decrease in the rate of the conversion process from glass to HAp, which resulted in the reduction of the degree of c-axis orientation of the nanorod array of the HAp crystals. However, the rate of the conversion process was remarkably promoted in alkaline phosphate solutions, resulting in an increase of the degree of c-axis orientation of the nanorod array. The Sr/(Sr + Ca) molar fraction of silicate glasses determined the molar fraction of substituted Sr2+ in HAp crystal lattice.

DOI： 10.1016/j.ceramint.2018.07.101

Web of Science

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Papers - HAYAKAWA Satoshi