Faculty Profiles - HAYAKAWA Satoshi

MISC - HAYAKAWA Satoshi

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Molecular Structure Analysis (2) (NMR) -Structural Nalaysis of Inorganic Materials by Solid-state NMR Invited

Satoshi Hayakawa

Ceramics Japan (Bulletin of the Ceramics Society of Japan) 59 ( 1 ) 36 - 41 2024.1

Incorporation of enzyme into silica gels by the sol-gel reaction using AC electrolysis and evaluation of the enzyme activity

吉岡朋彦, 谷口功治, 片岡卓也, 早川聡

日本セラミックス協会年会講演予稿集(Web) 2024 2024

バイオセラミックスの最新の研究動向と将来展望

橋本雅美, 澤村武憲, 早川聡

セラミックス 51 ( 12 ) 836 - 840 2016

The State of Art of Research and Development in Bioceramics

Masami Hashimoto, Takenori Sawamura, Satoshi Hayakawa

CERAMICS JAPAN BULLETIN OF THE CERAMICS SOCIETY OF JAPAN 51 ( 12 ) 836 - 840 2016

In vitro degradation behavior of hydroxyapatite

S. Hayakawa

Hydroxyapatite (HAp) for Biomedical Applications 85 - 105 2015.2

Language：English Publisher：Elsevier Ltd

This chapter discusses in vitro degradation behaviors of calcium phosphate particles, such as nano-crystalline hydroxyapatite (HAp) and ion-substituted HAp synthesized by the wet-chemical processing method, and how their microstructure affects their initial dissolution profiles and kinetics. The chapter reviews several in vitro evaluation techniques for biodegradability of calcium phosphate ceramics and several models representing dissolution profiles and kinetics. The chapter then discusses the relationship between the heterogeneous structure of nano-crystalline HAp and the initial dissolution behaviors in acidic buffer solution.

DOI： 10.1016/B978178242033000004-3

NMR structural characterization of Mg-containing nano-apatite

Satoshi Hayakawa, Toshiisa Konishi, Tomohiko Yoshioka, Eiji Fujii, Kouji Kawabata

Key Engineering Materials 631 57 - 60 2015

Language：English Publisher：Trans Tech Publications Ltd

Nano-meter scale Ca-deficient hydroxyapatite (nano-apatite) is a potential candidate as artificial bone substitute materials owing to its similarity to the bone with respect to composition, morphology and osteoclastic degradation or adsorbent materials for blood purification therapy to remove pathogenic substances. The initial biodegradation behaviors, the initial cell-material interaction and the protein adsorption properties of nano-apatite must depend on the microstructure. The purpose of this study is the preparation of nano-apatite particles and their structural characterization by using X-ray diffraction (XRD) and solid-state NMR spectroscopy. The nano-apatite particles were prepared by precipitation processing method, and the effects of magnesium ions on the precipitation of calcium phosphate were examined, because Mg ions are well-known to play a role of inhibition of crystal growth. The addition of Mg ions led to the precipitation of nano-meter scale Ca-deficient apatite crystals having 1.33-1.63 of the molar ratio (Mg+Ca)/P. NMR analyses showed that the microstructure of Mg•HAp particles can be explained by a crystalline HAp core covered with a thin amorphous hydrated calcium phosphate layer.

DOI： 10.4028/www.scientific.net.KEM.631.57

USE OF INTER-FIBRIL SPACES AMONG ELECTROSPUN FIBRILS AS ION-FIXATION AND NANO-CRYSTALLIZATION

Yuki Shirosaki, Satoshi Hayakawa, Yuri Nakamura, Hiroki Yoshihara, Akiyoshi Osaka, Artemis Stamboulis

ADVANCES IN BIOCERAMICS AND POROUS CERAMICS VII 35 33 - 38 2015

Language：English Publisher：AMER CERAMIC SOC

When solution of a polymer with some inorganic ions is electrospun, the polymer fibrils will be elongated within the spinning direction and those ions are held in the inter-fibril spaces. When those electrospun fibers are calcined, ceramic fibers will be obtained. The present study has attempted to employ such spaces formed in poly(vinyl alcohol) (PVA) as nano- or micro-reactor spaces for precipitation of nano-crystalline particles. Exposing the spun PVA mats to ammonia vapor fixed metal ions in the form of hydroxide and, induced apatitic calcium phosphate crystallites when the precursor solution involved calcium and hydrogen orthophosphate ions.

Preparation of α-Tricalcium Phosphate Powders Surface-modified with Inositol Phosphate for Cement Fabrication

Toshiisa Konishi, Michiyo Honda, Tomohiko Yoshioka, Satoshi Hayakawa, Mamoru Aizawa

Key Engineering Materials 631 113 - 118 2015

Language：English Publisher：Trans Tech Publications Ltd

We have previously developed biodegradable β-tricalcium phosphate (β-TCP) cement based on the chelate-setting mechanism of inositol phosphate (IP6). The β-TCP cement powder for the cement fabrication was prepared via a novel powder preparation process, in which the starting β-TCP powders were prepared by simultaneous ball-milling and surface-modification in the IP6 solution. In the present study, the novel powder preparation process was applied to an α-TCP powder, and effect of milling time and beads size for ball-milling on the material properties of the a-TCP powders was investigated. The α-TCP powder ball-milled in 1000 ppm IP6 solution for 4 h with 2 mm-diameter beads was composed of single phase α-TCP with the smallest particle size of 2.2 um. Dissolution of 4 h-milled α-TCP powder was approximately twice higher than that of starting α-TCP powder before ball-milling. The α-TCP powder with high dissolution property prepared via the novel powder preparation process is potential candidate for fabrication of the chelate-setting cement.

DOI： 10.4028/www.scientific.net.KEM.631.113

ジルコニア表面に対するリン酸モノマー処理の検討

長岡紀幸, 玉田宜之, 入江正郎, 吉原久美子, 吉田靖弘, 西川悟郎, 丸尾幸憲, 松本卓也, 皆木省吾, 早川聡

日本歯科理工学会誌 32 ( 5 ) 354 - 354 2013.9

Sol-Gel Preparation of Silica-Based Nano-Fibers for Biomédical Applications

Song Chen, Hiroki Yoshihara, Nobutaka Hanagata, Yuki Shirosaki, Mark Blevins, Yuri Nakamura, Satoshi Hayakawa, Artemis Stamboulis, Akiyoshi Osaka

Biomaterials Science: Processing, Properties and Applications III 242 55 - 62 2013.8

Language：English Publisher：wiley

Silica nanotube sponges and solid silica fiber mats were fabricated using a collagen and electrospun poly(vinylalcohol) as the templates via the sol-gel route. In vitro reassembled collagen fibrils were treated in the Stöber sol-gel precursor mixture of tetraethoxysilane (TEOS), ethanol, water, and ammonia to produce the silica-coated collagen fibrils. The electrospun PVA fiber mats were soaked in the Stöber type as well as acid-catalyzed silica oligomer sol from TEOS. Those were calcined to yield apparently silica nano- or micro-fibers, but transmission and scanning electron microscope observations showed that the Stöber sol treatment resulted in silica nano- or micro-fibers with hollow structure, or nanotubes (silica NTs), while the acid-catalyzed sol yielded solid fibrous mats.

DOI： 10.1002/9781118751015.ch7

UV-Irradiation modifies chemistry of anatase layer associated with in vitro apatite nucleation

Keita Uetsuki, Shinsuke Nakai, Yuki Shirosaki, Satoshi Hayakawa, Akiyoshi Osaka

Ceramic Engineering and Science Proceedings 33 79 - 84 2013.4

Anatase layer was derived on pure titanium substrates by the H 2O2 treatment and calcination, on which UV was irradiated in air (UVa) and in ultra pure water (UVw). The effects of the UV irradiation on in vitro apatite formation in Kokubo's simulated body fluid were interpreted in terms of the modified chemistry of the anatase layer. The UVa treatment reduced apatite formation while the contrary effects were observed for the UVw treatment. From Ols X-ray photoelectron spectroscopic (XPS) analysis, those results were correlated to the change in the relative amount of Ti-OH (basic TiOH) and Ti-O(H)-Ti (acidic Ti-OH). Combining the XPS analysis and the apatite growth characteristics, i.e., the number and size of the semi-spherical particles and their surface-coverage, derived a plausible model: proper assembly of those sites (Ti-OH and Ti-O(H)-Ti) that collect both calcium and phosphate ions together should only give rise to induction of apatite nucleation.

Heterogeneous structure of hydroxyapatite and in vitro degradability

Satoshi Hayakawa, Yuki Shirosaki, Akiyoshi Osaka, Christian Jäger

Ceramic Engineering and Science Proceedings 33 49 - 56 2013.4

Hydroxyapatite (HAp) particles were synthesized by two processing methods such as solid-state reaction and wet chemical reaction, and were characterized in terms of their chemical composition, disordered structure and in vitro biodegradability. XRD revealed that the prepared HAp particles were composed of single phase HAp, while 1D and 2D solid-state NMR analysis showed that the prepared HAp particles consisted of not only crystalline HAp but also disordered phase. The in vitro biodegradability was discussed by using a structure model for nano-crystalline HAp, in which the nano-crystals consist of a crystalline HAp core covered with a disordered surface layer (core-shell model).

Nerve regeneration by using of chitosan-silicate hybrid porous membranes

Yuki Shirosaki, Satoshi Hayakawa, Akiyoshi Osaka, José D. Santos, Ana C. Maurício

Key Engineering Materials 529-530 ( 1 ) 361 - 364 2013

Language：English

The treatment of peripheral nerve injuries is still one of the most challenging tasks in neurosurgery, as functional recovery is rarely satisfactory in these patients. The concept behind the use of biodegradable nerve guides is that no foreign material should be left in place after the device has fulfilled its task, so as to spare a second surgical intervention. In a previous study, flexible and biodegradable chitosan-γ-glycidoxypropyltrimethoxysilane (GPTMS) hybrid membranes exhibited better cytocompatibility in terms of osteoblastic cells than chitosan membrane. Porous chitosan hybrid membranes, derived by freeze-drying the hybrid gels, showed that the cells were attached and proliferated both on the surface and into pores. The aim of the present study was to evaluate the influence of these chitosan hybrid membranes in terms of their inflammatory response and remodeling of connective tissue during wound-healing processes before use as a periphery nerve graft. The porous chitosan hybrid membranes showed good biocompatibility and improved posttraumatic axonal regrowth and functional recovery. © (2013) Trans Tech Publications, Switzerland.

DOI： 10.4028/www.scientific.net/KEM.529-530.361

Heterogeneous structure of hydroxyapatite and in vitro biodegradability

Satoshi Hayakawa, Yuki Shirosaki, Akiyoshi Osaka, Christian Jäger

Key Engineering Materials 529-530 ( 1 ) 70 - 73 2013

Language：English

Hydroxyapatite (HAp) particles were synthesized by solid-state reaction and wet chemical reaction, and were characterized in terms of their chemical composition, disordered structure and in vitro biodegradability. An X-ray diffraction study revealed that the prepared HAp particles were composed of single phase HAp, while 1D and 2D solid-state NMR analysis showed that they consisted of not only crystalline HAp but also a disordered phase. An in vitro biodegradability test showed that wet chemically derived HAp particles were degraded quicker than commercially available HAP-100. The in vitro biodegradability was discussed by using a structure model for nano-crystalline HAp, in which the nano-crystals consist of a crystalline HAp core covered with a disordered surface layer (core-shell model). Although the specific surface area was the predominant factor on the rate of Ca ion dissolution, the disordered surface layer enhanced the release of Ca ions in the initial stage within 1 min, while the crystalline core of HAp also gave different release rate of Ca ions, depending on the chemical distribution in the P (V) environment. © (2013) Trans Tech Publications, Switzerland.

DOI： 10.4028/www.scientific.net/KEM.529-530.70

Sol-Gel Preparation of HAp-Coated Silica Macrospheres from Water Glass and Their Protein Adsorption

Jie Li, Yuki Shirosaki, Satoshi Hayakawa, Artemis Stamboulis, Akiyoshi Osaka

BIOCERAMICS 24 529-530 637 - + 2013

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Silica gel macrospheres of 2 similar to 4 mm in size, and wrapped with Ca-alginate chelate film were prepared as the substrate for hydroxyapatite coating layer, using water glass as the silica source. Those Ca-SiO2 macrospheres were soaked in a 1:1 (volume) mixture of ethanol and 0.1 M Na2HPO4 to deposit hydroxyapatite layer (HAp-SiO2 macrospheres). Adsorption of bovine serum albumin and egg lysozyme on those Ca-SiO2 and HAp-SiO2 macrospheres under physiological pH (7.2) was well correlated to the Langmuir-type adsorption equation. The electrostatic interactions between the protein molecules and those macrospheres well interpret the adsorption isotherms, while the mesopores in the Ca-SiO2 contributed to some extent. A multi-layer adsorption model was proposed.

DOI： 10.4028/www.scientific.net/KEM.529-530.637

In vitro cytocompatibility of microspheres derived from chitosan-silicate hybrids

Yuki Shirosaki, Kohei Okamoto, Satoshi Hayakawa, Akiyoshi Osaka

2013 INTERNATIONAL SYMPOSIUM ON MICRO-NANOMECHATRONICS AND HUMAN SCIENCE (MHS) 2013

Language：English Publisher：IEEE

Microsphere-based therapy is used to allow drug release to treat the critical site through the choice and formulation of variations drug-polymer combinations. They are also used to control the release of insoluble drug by the biodegradability of polymer. Chitosan is one of the candidates for the polymer matrix because their biodegradability and biocompatibility. Recently, we prepared and characterized the inorganic-organic hybrid derived from chitosan and siloxane units. This hybrid showed the excellent biocompatibility for the osteoblastic cells, fibroblastic cells, and nerve cells, etc. In this study, the microspheres were prepared from this hybrid using the microfluidic systems. The biodegradability, drug releasing behavior and cytocompatibility were investigated.

DOI： 10.1109/MHS.2013.6710442

Advanced Ceramic Science and Technology in the Western Pacific Rim Area Preface

Akiyoshi Osaka, Yoko Suyama, Akira Kishimoto, Nobuhito Imanaka, Tokuro Nanba, Satoshi Hayakawa

JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 120 ( 1407 ) 2012.11

ジルコニアに対するリン酸モノマーの吸着特性

玉田宜之, 長岡紀幸, 早川聡, 入江正郎, 西川悟郎, 丸尾幸憲, 吉田靖弘, 松本卓也, 尾坂明義, 皆木省吾

日本歯科理工学会誌 31 ( 5 ) 479 - 479 2012.9

Preparation of chitosan hydrogel modified with silicate for the bone filling materials

SHIROSAKI Yuki, NAKAMURA Yuri, HAYAKAWA Satoshi, FUJII Eiji, KAWABATA Koji, OSAKA Akiyoshi

18 ( 2 ) 216 - 216 2012.7

Inorganic-Organic Sol-Gel Hybrids

Yuki Shirosaki, Akiyoshi Osaka, Kanji Tsuru, Satoshi Hayakawa

Bio-Glasses: An Introduction 139 - 158 2012.5

ジルコニア表面のリン酸モノマーによる有機化の検討

玉田宜之, 長岡紀幸, 早川聡, 入江正郎, 西川悟郎, 丸尾幸憲, 吉田靖弘, 松本卓也, 尾坂明義, 皆木省吾

日本歯科理工学会誌 31 ( 2 ) 190 - 190 2012.3

Structure of Vanadate Crystals and Glasses : Diversity and Strangeness

New glass 27 ( 1 ) 21 - 26 2012.3

The effect of Si(IV) species derived from chitosan-silicate hydrogels on osteoblast behavior

Yuki Shirosaki, Satoshi Hayakawa, Akiyoshi Osaka

Key Engineering Materials 493-494 698 - 702 2012.1

Chitosan-GPTMS (γ-Glycidoxypropyltrimethoxysilane) hybrid hydrogels were synthesized with β-glycerophosphate (β-GP) as the additive agent. Chitosan-GPTMS sols were fluid at room temperature and transformed to hydrogel at 36.5°C in several min. The gelation time of the hydrogels was shortened by the addition of GPTMS. From NMR experiments, this gelation behavior depended on some factors, namely, electrostatic interaction between the phosphate groups of β-GP and the amino groups of chitosan chains, crosslinking between the epoxy groups of GPTMS and the amino groups of chitosan, and polycondensation of the methoxy groups of GPTMS. The Si(IV) released from the hydrogels promoted the cell adhesion and ALP activity of osteoblastic cells MG63. © (2012) Trans Tech Publications.

DOI： 10.4028/www.scientific.net/KEM.493-494.698

Acceleration of apatite nucleation on parallel aligned Ti-substrates with optimum gaps by UV-light Pre-irradiation

Satoshi Hayakawa, Keita Uetsuki, Akinori Kochi, Yuki Shirosaki, Akiyoshi Osaka

Key Engineering Materials 493-494 936 - 939 2012

Language：English

A recently developed "GRAPE® technology" provides titanium or titanium alloy implants with spontaneous apatite-forming ability in vitro, which requires properly designed gaps and optimum heat treatment in air. In this study, pure titanium pieces were thermally oxidized in air and pre-irradiated by UV-light under different environmental conditions such as in air or in ultra-pure water before aligning pairs of specimens in the GRAPE® set-up, i.e., two pieces of titanium substrates were aligned parallel to each other with optimum gap width (spatial design). Then, they were soaked in Kokubo's simulated body fluid (SBF, pH7.4, 36.5°C) for 1-2 days to clarify how the UV-light pre-irradiation affects the in vitro apatite nucleation on the substrates under the specific spatial design. UV-light pre-irradiation in water led to the deposition of a large number of apatite particles within 1 day, and showed apatite X-ray diffraction, although UV-light pre-irradiation in air and non-pretreated specimens gave the deposition of a few apatite particles and did not show any apatite X-ray diffraction. These results indicated that the rate of primary heterogeneous nucleation of apatite increased by UV-light pre-irradiation in ultra-pure water. TFXRD patterns of the surface of the substrates thermally oxidized in air at 500°C showed the peak at 2θ= 27° assignable to the 110 diffraction of rutile phase of titanium dioxide (ICDD-JCPDS data #21-1276). Previous studies reported that the primary heterogeneous nucleation must be induced by Ti-OH groups on titanium oxide layer. Probably, the UV-light pre-irradiation in ultra-pure water can increase the number of Ti-OH groups on the surface, resulting in accelerated primary heterogeneous nucleation of apatite. © (2012) Trans Tech Publications.

DOI： 10.4028/www.scientific.net/KEM.493-494.936

Preparation of injectable hydroxyapatite/collagen nanocomposite artificial bone

Akinori Kochi, Masanori Kikuchi, Yuki Shirosaki, Satoshi Hayakawa, Akiyoshi Osaka

Key Engineering Materials 493-494 689 - 692 2012

Language：English

Injectable hydroxyapatite/collagen nanocomposite (HAp/Col) artificial bone was prepared utilizing gelation of sodium alginate (Na-Alg). Mass ratio of the HAp/Col powder, with or without Ca adsorption treatment and Na-Alg (80-120, 300-400, 500-600 cP in viscosity at 10 g/dm 3) was fixed at 90/10. Injectable HAp/Col was prepared by mixing the HAp/Col powder with Na-Alg solution at several powder (HAp/Col)/liquid (Na-Alg solution) ratios (P/L ratio, g/cm 3). The result of consistency measurement suggested that the operability of injectable HAp/Col paste could be controlled by both the P/L ratio and the viscosity of Na-Alg solution. According to the consistency measurement and practical feelings during mixing, P/L=1/1.67 (80-120 cP) and 1/1.89 (300-400, 500-600 cP) were considered to be the highest P/L ratio allowed to mix the HAp/Col paste with a spatula. At the P/L=1/2.33 (80-120 cP), the paste prepared with the non-treated HAp/Col powder, placed in an incubator (37 °C,relative humidity 100%) for 24h, demonstrated gellike property, while the paste prepared with Ca-treated HAp/Col powder did putty-like property. The difference in their property might be caused by the initial bonding behavior between Alg and Ca 2+ after mixing. The setting time measurement with Gillmore needle was impossible because they were toosoft for this method. Even though, their operability and coalescence/settingproperty could be used as the injectable bone filler. © (2012) Trans Tech Publications.

DOI： 10.4028/www.scientific.net/KEM.493-494.689

第28回日韓国際セラミックスセミナーとその周辺

城崎由紀, 早川聡, 中村有里, 尾坂明義

マテリアルインテグレーション 25 ( 2 ) 9 - 12 2012

Chitosan-silicate hybrids via sol-gel method for scaffold applications

Yuki Shirosaki, Akiyoshi Osaka, Satoshi Hayakawa, Kanji Tsuru

Handbook of Chitosan Research and Applications 327 - 336 2011.2

Novel strategies for regenerating or reconstructing damaged bone tissues are of urgent necessity, because of limitations in conventional therapies for trauma, congenital defects, cancer, and other bone diseases. The tissue engineering approach to repair and regeneration is founded upon the use of biodegradable polymer scaffolds, which may manipulate bone cell functions, encourage the migration of bone cells from border areas to the defect site, and provide a source of inductive factors to support bone cell differentiation. During the past decades, scaffolds from natural biodegradable polymers such as collagen, gelatin, fibrin, and alginates, or synthetic biodegradable polymers such as polyglycolide, polylactides, and copolymers of glycolide with lactides have been extensively explored. On the other hand, it has been confirmed that the bonelike apatite layer, deposited spontaneously on the biomaterial surfaces, can enhance osteoconductivity. The presence of such bone-like apatite layers is also believed to be a prerequisite to conduction of osteogenic cells into various porous scaffolds or onto the surface of bioactive glasses. The formation of such bone-like apatite is favored by the cooperative behavior of a hydrated silica or titania gel surface with many Si-OH or Ti- OH groups, and calcium ions to be released into the body fluid when implanted. Thus, hybrid materials derived from the integration of biodegradable polymers with bioactive inorganic species may construct a new group of scaffolds appropriate for tissue engineering. Moreover, tissue engineering approach depends on the use of porous scaffolds that serve to support and reinforce the regenerating tissue. Controlled porous structures of these scaffolds allow cell attachment and migration, tissue generation, or vascularization. We have been studying the synthesis of novel chitosan-silicate hybrids derived from the integration of chitosan and γ-glycidoxypropyltrimethoxysilane (GPTMS). We introduce some of the results on this hybrid for biomedical application. © 2012 by Nova Science Publishers, Inc. All rights reserved.

Contrary effects of UV-irradiation on in vitro apatite-forming ability of TiO2 layer in simulated body fluid Reviewed

Keita Uetsuki, Yuki Shirosaki, Satoshi Hayakawa, Akiyoshi Osaka

Bioceramics Development and Applications 1 2011.2

Apatite nano-rods array grown on glass substrates in aqueous systems

A. Osaka, Y. Shirosaki, S. Hayakawa, K. Tsuru, E. Fujii, K. Kawabata

Ceramic Transactions 228 83 - 88 2011.1

Fabrication of an assembly of nm-sized rods or wires of hydroxyapatite (HAp) would mimic the structure of dentin or enamel when they are tailored to align each other along a specific crystallographic axis. This study proposed new strategy for self-assembling one-dimensional HAp nano-rods with an organized superstructure. We prepared a nm-scale rod array of HAp having preferred orientation to the c-axis simply by soaking calcium-containing silicate glass substrates in aqueous Na2HPO4 solutions at 80°C for various periods, as inspired by the glass-apatite conversion procedure. Those HAp rods grew up perpendicularly to the glass surface, and the crystallites covered the glass entire surface uniformly, resulting in "dental enamel-like" rod array structure.

PREPARATION AND PROTEIN ADSORPTION OF SILICA-BASED COMPOSITE PARTICLES FOR BLOOD PURIFICATION THERAPY

Jie Li, Yuki Shirosaki, Satoshi Hayakawa, Akiyoshi Osaka

ADVANCES IN BIOCERAMICS AND POROUS CERAMICS IV 32 13 - 18 2011

Language：English Publisher：AMER CERAMIC SOC

Silica gel macrospheres of a few millimeters in diameter were fabricated via the sol-gel route using water glass, calcium chloride, and sodium alginate as the precursor components. TiO2 coating on the silica gel macrosphere surface was conducted by soaking them in titania sol derived from hydrolysis of tetraethylorthotitanate (TEOT) under varied pH (HNO3), and temperature (50 similar to 80 degrees C). X-ray diffraction analysis indicated deposition of anatase, and particular deposition (<1 mu m) on the surface was confirmed by scanning electron microscopy. Protein adsorption behavior was examined as a function of pH of the hydrolysis of TEOT, using bovine serum albumin (BSA) and lysozyme (LSZ) as the model proteins. BSA adsorption was little affected by the pH, while some effects were found for LSZ adsorption. BSA adsorption saturated at 20 similar to 25 min contact, while LSZ adsorption took longer time for the saturation. Moreover, BSA was adsorbed almost twice as much as LSZ, when saturation adsorption was compared. An effect of residual calcium ions with better affinity to BSA was proposed for partial interpretation since surface charge could not account for those adsorption behaviors.

ガラスやガラスセラミックの生体安全性

早川聡, 城﨑由紀, 都留寛治, 尾坂明義

NEW GLASS 26 ( 4 ) 16 - 20 2011

Preparation of injectable artificial bone fabricated from hydroxyapatite/collagen nanocomposite

Akinori Kochi, Masanori Kikuchi, Yuki Shirosaki, Satoshi Hayakawa, Akiyoshi Osaka

World Journal of Engineering 1 585 - 586 2011

空間デザインと熱酸化による骨親和性の向上

尾坂明義, 早川聡, 都留寛治, 城﨑由紀, 大槻主税, 杉野篤史, 藏本孝一

セラミックス 46 ( 4 ) 293 - 297 2011

GRAPE® Technology or bone-like apatite deposition in narrow grooves

A. Sugino, K. Uetsuki, K. Kuramoto, S. Hayakawa, Y. Shirosaki, A. Osaka, K. Tsuru, T. Nakano, C. Ohtsuki

Ceramic Engineering and Science Proceedings 31 57 - 62 2010.12

Among several techniques proposed for fixing titanium bone implant in bone tissues by inducing apatite deposition on the implant surface, "GRAPE® Technology" is the simplest one, where optimum size of macro-grooving and heating in air are provided for pure titanium because samples with such grooves deposit apatite when soaked in an aqueous solution mimicking human blood plasma. The technique is needed to be confirmed by in vivo tests if it is effective for bone tissues, or if it is applicable to newly developed titanium alloy systems. In this study, the validity of GRAPE® Technology for a Ti-15Zr-4Ta-4Nb alloy was assessed with both in vitro and in vivo experiments. Here, alloy pieces with macro-grooves 500 μm in depth and 500 μm in width were heated at 500°C to induce thin titania layers on the surface. In vivo tests confirmed bone-ingrowth within 3 weeks in the samples with the macro-grooves but very less for those without the grooves. Those results indicated that GRAPE® Technology is effective for providing the Ti-15Zr-4Ta-4Nb-based implants with osteoconductivity.

Surface modification of titanium implant: improvement of bioactivity of titania layer by UV light irradiation

Titanium Japan 58 ( 2 ) 146 - 150 2010.4

0932 GRAPE^[○!R] Technology : Novel technique for providing titaniumu-based artificial joint with osteoconductivity by spatial design

SUGINO Atsushi, TSURU Kanji, HAYAKAWA Satoshi, SHIROSAKI Yuki, OHTSUKI Chikara, OSAKA Akiyoshi

2009 ( 22 ) 344 - 344 2010.1

CELL PROLIFERATION ON NANO-STRUCTURED TITANIUM OXIDE LAYER PREPARED ON TITANIUM SUBSTRATES

Satoshi Hayakawa, Koji Kawanishi, Yuki Shirosaki, Akiyoshi Osaka

ADVANCES IN BIOCERAMICS AND BIOTECHNOLOGIES 218 205 - 212 2010

Language：English Publisher：AMER CERAMIC SOC

Effects of nanometer-scale surface roughness of titanium oxide layer on the adhesion and proliferation of osteoblast-like cell were examined. The nano-structured titanium oxide layer was prepared on titanium substrates by chemical treatment and heat-treatment. The anatase or rutile phase of titanium oxide was formed on the titanium substrates. The surface roughness of titanium oxide layer depended on the chemical treatment time or the heat-treatment time. The average roughness (Sa) was controlled in the range from 10 to 70 nm. The cell metabolic activity increased on the substrate with limited surface roughness. It is found that cell proliferation is affected by nanometer-scale surface roughness of titanium oxide layer.

ONE-STEP PREPARATION OF ORGANOSILOXANE-DERIVED SILICA PARTICLES

Song Chen, Akiyoshi Osaka, Satoshi Hayakawa, Yuki Shirosaki, Akihiro Matsumoto, Eiji Fujii, Koji Kawabata, Kanji Tsuru

ADVANCES IN BIOCERAMICS AND POROUS CERAMICS II 30 ( 6 ) 3 - + 2010

Language：English Publisher：AMER CERAMIC SOC

Silica particles and their derivatives with meso-structure attracted much attention, but they were synthesized through complicated multi-step procedure. Considering biomedical application, no surfactants, used in almost all cases above, should be employable due to fear of their toxicity. The present study explored one-step sol-gel preparation of silica particles with biomedical functionalities, starting from Stober-type systems, and characterized by Transmission Electron Micrograph or Si-29 MAS NMR spectroscopy. The Ca-containing particles, derived from the precursor system tetraethoxysilane (TEOS)-H2O-C2H5OH (EtOH)-CaCl2-NH4OH, consisted of primary particles of similar to 10 nm, and were spherical in shape with the diameter of similar to 1000 run, where Ca bridged Si-O- on the opposite particle surface. In contrast, the Ca-free particles were smaller with 400 similar to 500 nm in size due to the absence of such bridging effects. In addition, the Ca-containing ones deposited petal-like apatite within one week in Kokubo's simulated body fluid (SBF), which was interpreted in terms of the Ca release from the particles. Amino-modified silica particles were derived from the sol-gel precursor system aminopropyltriethoxysilane (APTES)-TEOS-H2O-EtOH where APTES behaved not only as the catalyst but also a reactant; i.e., this was a self-catalyzed sol-gel system. Hydrogen bonding among the amino group of APTES on one particle surface and with Si-O- on the other was suggested to work in agglomeration of the primary particles. Bovine serum albumin was covalently fixed on the APTES-silica surface, suggesting their applicability of proteins or other growth factor delivery.

SYNTHESIS AND CHARACTERIZATION OF WET CHEMICALLY DERIVED MAGNETITE-HAP HYBRID NANOPARTICLES

S. Hayakawa, K. Tsuru, A. Matsumoto, A. Osaka, E. Fujii, K. Kawabata

ADVANCES IN BIOCERAMICS AND POROUS CERAMICS II 30 ( 6 ) 105 - + 2010

Language：English Publisher：AMER CERAMIC SOC

A new type of hyperthermia or magnetic resonance imaging materials with bone-bonding ability was explored within the framework of magnetic-bone mineral composite ceramics. That is, hydroxyapatite (HAp) nanoparticles, hybridized with ferrous (Fe2+) and ferric (Fe3+) ions (Fe(II) and Fe(III)), were synthesized through the wet chemical procedure, and characterized in terms of crystal structures, magnetic properties and protein adsorption properties. The as-synthesized particles derived from precursor solutions with FeCl2 consisted of hydroxyapatite (JCPDS 09-0432) (20-30 nm in size) and magnetite (JCPDS 19-0629) (2-5 nm in size). They showed super-paramagnetic behavior, yet their saturation magnetization increased with the content of Fe(II) in the solutions up to 4.3 emu/g. From TEM observations, the HAp particles were rod-like, by which the magnetite particles that seemed spherical rather than showing cubic morphology, were surrounded. The particles from the solutions with Fe(III) gave only HAp, and hence Fe(III) was considered to form an amorphous phase.. Moreover, Fe(III) incorporation suppressed HAp crystal growth.

PREPARATION OF HYDROXYAPATITE NANOPARTICLES APPLYING THE MICRO CHEMICAL PROCESS

Eiji Fujii, Koji Kawabata, Yoshiaki Nakazaki, Yuji Tanizawa, Akihiro Matsumoto, Yuki Shirosaki, Satoshi Hayakawa, Akiyoshi Osaka

ADVANCES IN BIOCERAMICS AND BIOTECHNOLOGIES 218 185 - + 2010

Language：English Publisher：AMER CERAMIC SOC

A micro-chemical process was applied to prepare nanometer-size hydroxyapatite (HA) particles with various shapes and sizes so as to provide high surface activities, where solutions of reagent-grade calcium nitrate tetrahydrate and diammonium hydrogen phosphate were introduced in a micro reactor. The particles were characterized by X-ray diffractometry, transmission electron microscopy, or inductively coupled plasma photometry. Particle size and shape were dependent on not only pH and concentration of the mixing solutions but also the flow rate. Dilute solutions containing 3 mM Ca(II) and 5 mM P(V) yielded spherical HA particles, whose average particle size increased from about 3 nm to 40 nm as the flow rate increased from 0.3 to 3 ml.min(-1), where pH and the temperature of the reaction system were respectively maintained at 10 and at 40 degrees C. Concentrated solutions with 50 mM Ca(II) and 30 mM P(V) yielded rectangular plate-like HA particles, 300 am long and 50 nm wide, when pH was kept at 8, while agglomerations of smaller HA particles of about 20-50 am were obtained when pH was kept at 10.

チタン系インプラントの表面改質—酸化チタン層への紫外線照射による生体親和性の向上

早川聡, 尾坂明義, 城﨑由紀

チタン 58 ( 2 ) 54 - 56 2010

105 GRAPE^<[○!R]> Technology : Spatial design and thermal treatment provide titanium with osteocompatibility

SUGINO Atsushi, DOI Kenji, KURAMOTO Koichi, TSURU Kanji, OHTSUKI Chikara, HAYAKAWA Satoshi, SHIROSAKI Yuki, OSAKA Akiyoshi

59 9 - 10 2010

In vitro cytocompatibility of injectable chitosan-silicate hydrogel

Yuki Shirosaki, Masashi Hirai, Satoshi Hayakawa, Maria A. Lopes, José D. Santos, Akiyoshi Osaka

Archives of Bio Ceramics Research 10 14 - 17 2010

Effect of UV-irradiation environment on induction time for apatite nucleation on TiO2 layer

Keita Uetsuki, Shinsuke Nakai, Yuki Shirosaki, Satoshi Hayakawa, Akiyoshi Osaka

Archives of Bio Ceramics Research 10 50 - 53 2010

リン酸エステル系機能性モノマーによる歯質接着界面の形成メカニズムの解明

吉原久美子, 早川聡, 長岡紀幸, 吉田靖弘, 鈴木一臣, 皆木省吾

歯科材料・器械 28 ( 2 ) 51 - 51 2009.3

医用金属チタンの生体親和性の制御

早川聡, 城﨑由紀, 尾坂明義

未来材料（株）エヌ・ティー・エス 9 ( 5 ) 38 - 44 2009

Viscoelastic Property of collagen gels with aligned fibril structure

Y. LiN, Hirota, M.Okuda, S.Chen, M.Tagaya, Y.Shirosaki, S.Hayakawa, A.Osaka, N.Hanagata, T. Ikoma

Bioceramics 22 661 - 664 2009

A NMR Investigation of Borate Incorporation in Apatitic Biomaterials

S. Barheine, S. Hayakawa, A. Osaka, C. Jaeger

BIOCERAMICS 21 396-398 205 - 208 2009

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

The incorporation of ions in the lattice of hydroxyapatite alters significantly its structure. Particularly, if anions such as trigonal borate units are accommodated in the lattice severe distortions must occur around the substitution site because of different geometric shape, electric charge and anion size. Solid-state NMR has been used to investigate this problem in detail for a hydroxyapatite sample synthesized by high temperature solid state reaction. The results clearly verify the existence of network distortions. Indeed, only about 1/3 of the total phosphate content forms crystalline hydroxyapatite (also found in XRD) whereas the residual amount is contained in two different phosphate sites with 31 p chemical shifts of 5.5 ppm and 2.3 ppm, but broad resonances lines suggesting disorder. Furthermore, a novel proton signal at -0.6 ppm was found which is directly associated with the borate incorporation. No specific correlation of the two structurally different berate units with the two phosphate groups is found.

DOI： 10.4028/0-87849-353-0.205

Effect of Si(IV) released from chitosan-silicate hybrids on proliferation and differentiation of MG63 osteoblastic cells

Y. Shirosaki, K. Tsuru, S. Hayakawa, Y. NakamuraI, R. Gibson, A. Osaka

Bioceramics 22 217 - 220 2009

A Novel Method of Preparing a Nano-meter Rod Array of Hydroxyapatite Crystals

S. HayakawaY. LiY, ShirosakiA, OsakaE, FujiiK. Kawabata

Bioceramics 22 89 - 92 2009

Apatite-forming ability on spatial design enhanced by autoclaving

Yoko Nakao, Atsushi Sugino, Kanji Tsuru, Keita Uetsuki, Yuki Shirosaki, Satoshi Hayakawa, Akiyoshi Osaka

Archives of Bio Ceramics Research 9 387 - 390 2009

ULTRAVIOLET IRRADIATION HAD LIMITED EFFECTS ON ENHANCING IN VITRO APATITE FORMATION ON SOL-GEL DERIVED TITANIA FILMS Reviewed

Akiyoshi Osaka, Tetsuya Shozui, Kanji Tsuru, Satoshi Hayakawa

ADVANCES IN BIOCERAMICS AND POROUS CERAMICS 29 ( 7 ) 199 - 210 2009

Language：English Publisher：AMER CERAMIC SOC

As UV irradiation on titania causes several effects, such as decomposing organic substances and attaining super-hydrophilic surfaces. the present study explored the UV irradiation effects on apatite deposition on titania gel films (anatase) that were developed on a few substrates: pure titanium (Ti), stainless-steel (SUS316L), alumina (Al(2)O(3)) and glass slide (GS). Those substrates were dip-coated with a precursor sot (Ti(OC(2)H(5))(4) : C(2)H(5)OH : H(2)O : HNO(3) = 1 : 50 : 2 : 0.2) and heated at 500 degrees C for 10 min before irradiated with UV light (365 nm, 170 mW/cm(2)) in air for 1 h. They were subsequently soaked in simulated body fluid (SBF. Kokubo solution) and their in vitro apatite formation was evaluated by X-ray diffractometry and scanning electron micrograph. It was found that the UV irradiation enhanced apatite formation on the titania gel film on Ti and SUS by shortening the induction time. However, least effects were found for the titania gel films on Al(2)O(3) and GS as they did not deposit apatite within 7 days, even with the UV irradiation. These results indicated that UV irradiation had limited effects to enhance in vitro apatite formation on the titania films, i.e., it depended on the substrates.

PREPARATION AND BIOMINERALIZATION OF SILICA-BASED ORGANIC-INORGANIC HYBRID HOLLOW NANOPARTICLES FOR BONE TISSUE GENERATION Reviewed

Song Chen, Akiyoshi Osaka, Kanji Tsuru, Satoshi Hayakawa

ADVANCES IN BIOCERAMICS AND POROUS CERAMICS 29 ( 7 ) 19 - 26 2009

Language：English Publisher：AMER CERAMIC SOC

Novel bioactive silica-based organic-inorganic hollow hybrid particles involving Ca(2+) ions for stimulating and inducing bone generation were prepared via a templating synthesis route. The solid hybrid nanoparticles were first derived from the core-silica particles and natural polymer shell layers that were composed of chitosan and calcium alginate. They were then soaked in a concentrated NaOH solution and subjected to controlled dissolution of the core-silica, which led to yielding the hollow hybrid particles. The resultant particles were spherical in shape, with the porous surface. The polymer shells suppressed the dissolution behavior of the core-silica, and thus a partially void structure was formed inside the hybrid particles. An Energy Dispersion Spectroscopic analysis indicated that the polymer shells retained much silica and offered a matrix to maintain the spherical shape of the partially hollow particles. When soaked in the Kokubo's simulated body fluid (SBF), the hollow particles deposited apatite crystals within one week, that is, they exhibited strong bioactivity. In contrast, it took one month or longer for the apatite to be deposited on the naked silica particles without the polymer shell coatings layers. Thus, Ca in the hollow particles significantly accelerated apatite formation. Therefore, the present organic-inorganic hollow particles could be a promising candidate for bone regeneration drug or factor carriers.

Nerve regeneration guided by chitosan hybrid membranes

Yuki Shirosaki, Maria A. Lopes, José D. Santos, Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka, Ana C. Maurício, Stefano Geuna

Archives of Bio Ceramics Research 9 147 - 150 2009

GRAPE® technology improves apatite-formation on thermally derived titania layer

Atsushi Sugino, Keita Uetsuki, Yuki Shirosaki, Satoshi Hayakawa, Kanji Tsuru, Chikara Ohtsuki, Akiyoshi Osaka

Archives of Bio Ceramics Research 9 175 - 178 2009

Preparation of chitosan hybrid membranes inducing osteodifferentiation

城崎由紀, 盛林洋史, 中村有里, 都留寛治, 早川聡, 尾坂明義

キチン・キトサン研究 15 ( 2 ) 2009

Study of biomaterials by solid-state NMR: HAp layer on active bioglass

F. Pourpoint, C. Bonhomme, C. Gervais, G. Gasqueres, A. J. Salinas, S. Hayakawa, A. Osaka

8th World Biomaterials Congress 2008 2 865 2008.12

Preparation, characterization and biological assessment of bioactive and mesoporous silica nanoparticle coatings for bone regeneration

Song Chen, Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka

A Global Road Map for Ceramic Materials and Technologies: Forecasting the Future of Ceramics, International Ceramic Federation - 2nd International Congress on Ceramics, ICC 2008, Final Programme 2008.12

Bioactive porous silica particle coatings were fabricated on the stainless steel substrates as bone repairing implants to enhance the apatite deposition. The particles were prepared from tetraethoxysilane (TEOS) and cetyltrimethylammonium bromide (CTAB) via the sol-gel method and then calcined at 600°C for 2 h to produce the porous structure. Subsequently, the clean substrates were sequentially soaked in the chitosan, silica and calcium alginate solutions to obtain the chitosan/silica/calcium alginate coatings via the charged layer-by-layer deposition technique. The treated substrates deposited bioactive apatite when soaked in the Kokubo's simulated body fluid (SBF) and exhibited bioactivity. Thus, such bioactive porous silica coatings are applicable to the reservoirs for storing and releasing the bone factors.

Preparation of silica-natural polymer hybrid nanoparticles for clinical applications

Song Chen, Kanji Tsuru, Satoshi Hayakawa, Lei Ren, Qiqing Zhang, Akiyoshi Osaka

8th World Biomaterials Congress 2008 1 338 2008.12

Structure of substituted hydroxyapatite: The solid state nmr (nuclear magnetic resonance) point of view.

C. Bonhomme, F. Babonneau, C. Gervais, F. Pourpoint, G. Gasqueres, S. Hayakawa, A. Osaka

8th World Biomaterials Congress 2008 2 920 2008.12

We have shown that the combination of advanced solid state NMR experiments [7] and ab initio calculations of NMR parameters can lead to a novel description of substituted HAp structures. In the case of silicate substitution, the anions located within the structure are unambiguously characterized by selective 1H → 29Si CP transfer and 31P → 29Si experiments can edit the 29Si MAS spectra in terms of 31P/29Si dipolar interaction. 2D heteronuclear interactions will be performed in a near future. In the case of carbonate substituted HAp, the study of the 1H → 13C dynamics allowed to fully characterize the various 13C sites. By combining NMR calculations starting from DFT models and experiments, distributions of A-, B- and A/B sites were clearly characterized.

Formation of nano- and micrometer-scale hydroxyapatite rod array structure on ca-containing glass

Satoshi Hayakawa, Hiroshi Kazama, Kanji Tsuru, Akiyoshi Osaka, Eiji Fujii, Koji Kawabata

8th World Biomaterials Congress 2008 1 134 2008.12

Solid state NMR highlights local structures of OXO-anions in hydroxyapatite lattice

A. Osaka, S. Hayakawa, K. Tsuru, T. Kanaya, E. Fujii, K. Kawabata, G. Gasqueres, C. Bonhomme, F. Babonneau, C. Jäger

A Global Road Map for Ceramic Materials and Technologies: Forecasting the Future of Ceramics, International Ceramic Federation - 2nd International Congress on Ceramics, ICC 2008, Final Programme 2008.12

Carbonate- and Si-involving hydroxyapatite (C-HA, Si-HA) as well as hydroxyapatite (HAp) was prepared through wet chemical processes. Magic angle Spinning (MAS) NMR spectroscopy was applied together with Cross-Polarization (CP) techniques to study chemical environments around the guest oxo-anions. C-HA involved at least four carbonate sites, but the one for ∼168 ppm was left unassigned. In Si-HA, only Q0 (SiO44-) replaced the phosphate ion site but other Si atoms were polymerized and present on the surface or in the grain boundary of the Si-HA particles. The 31P MAS and CP-MAS spectra indicated the absence of HPO42- in the lattice, and suggested the presence of an amorphous phosphate phase on the particle surface.

Si-eluting gelatin -silicate hybrid scaffolds inspired by bioactive glasses

K. Tsuru, Z. Robertson, B. Annaz, I. R. Gibson, S. M. Best, Y. Shirosaki, S. Hayakawa, A. Osaka

8th World Biomaterials Congress 2008 1 305 2008.12

Spatial design of titanium implant intended to enhance osteoconductivity

TSURU K., SUGINO A., HAYAKAWA S., OHTSUKI C., ISHIKAWA K., OSAKA A.

Journal of the Japanese Society for Dental Materials and Devices 27 ( 5 ) 341 - 341 2008.9

Gap effect on the heterogeneous nucleation of apatite on thermally oxidized titanium substrate

Atsushi Sugino, Keita Jetsuki, Kanji Tsuru, Satoshi Hayakawa, Chikara Ohtsuki, Akiyoshi Osaka

BIOCERAMICS, VOL 20, PTS 1 AND 2 361-363 621 - + 2008

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Apatite formation on the surface of materials in body environment is an essential condition to show osteoconduction after implantation in bony defects. This study reports the novel technique for providing the apatite-forming ability to titanium metals by only controlling the spatial gap and thermal oxidation. Two pieces of titanium thermally oxidized at 400 degrees C were set together like Wetter with varied mouth opening. They showed the formation of apatite on both facing surface after exposure to a simulated body fluid (SBF) proposed by Kokubo and his colleagues, when the gap was less than approximately 600 mu m. Moreover, specimens with micro-grooves of 500 mu m in depth and 200-1000 mu m in width was able to form apatite in SBF with in 7 days, after they were thermally oxidized at 400 degrees C. These results indicated that the titanium metals were provided with apatite-forming ability, i.e. osteoconduction, due to controlled gap with thermally oxidized surface. Hence, we conclude that bioactive titanium substrate showing osteoconduction can be produced by designed machining followed by thermal oxidation at an appropriate temperature.

Cell proliferation and tissue compatibility of organic-inorganic hybrid materials

Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka

Key Engineering Materials 377 167 - 180 2008

Language：English

Sol-gel preparation of few organic-inorganic hybrids have been reviewed briefly as well as their behaviors under contact with blood plasma using a simulated body fluid (SBF) of the Kokubo recipe mimicking plasma. The starting resources of the hybrids included not only such silanes as poly(dimethylsiloxane) (PDMS), 3-glycidoxypropyltrimethoxysilane (GPTMS), tetraethoxysilane (TEOS), and titanium tetra-isopropoxide, but gelatin and chitosan. Apatite deposition in SBF was examined for the solid hybrids or membranes, and cell compatibility was assessed on proliferating osteoblastic cells (MC3T3E1, MG63). In addition, 3-dimensional interconnected pore structure was established for those hybrids, for which the possibility for scaffold and bioreactor applications was examined in terms of cell proliferation of human hepatocytes or keratinocytes. Gelatin-GPTMS and PDMS-TEOS scaffolds were implanted in brain defects to see no inflammation. Nerve cell tissue regeneration was observed, which was enhanced by the impregnation of growth factors, like bFGF and VEGF. With observing those empirical data, the silane based organic-inorganic hybrids have been considered very promising for tissue regeneration scaffolds. © 2008 Trans Tech Publications.

DOI： 10.4028/0-87849-395-6.167

The microstructure of bioceramics and its analysis

Satoshi Hayakawa, Kanji Tsuru, Akiyoshi Osaka

Bioceramics and their Clinical Applications 53 - 77 2008

Hybrid chitosan membranes tested in sheep for guided tissue regeneration

P. P. Cortez, Y. Shirosaki, C. M. Botelho, M. J. Simoes, F. Gartner, R. M. Gil da Costa, K. Tsuru, S. Hayakawa, A. Osaka, M. A. Lopes, J. D. Santos, A. C. Mauricio

BIOCERAMICS, VOL 20, PTS 1 AND 2 361-363 1265 - + 2008

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Previous in vitro studies confirmed an improved cytocompatibility of chitosan-silicate hybrid membranes over chitosan membranes. The main goal of this study was to assess the in vivo histocompatibility of both membranes through subcutaneous implantations at different time periods.. I week, 1, 2 and 3 months, using a sheep model. Chitosan membranes elicited an exuberant inflammatory response and were consequently rejected. The hybrid chitosan membranes were not rejected and the degree of inflammatory response decreased gradually until the third month of implantation. Histological evaluation also showed that these membranes can be resorbed in vivo. This study demonstrates that the incorporation of silicate into the chitosan solution improves its histocompatibility, indicating that the hybrid chitosan-silicate membranes are suitable candidates to be used in clinical applications.

Biodegradable chitosan-silicate porous hybrids for drug delivery

Y. Shirosaki, K. Tsuru, S. Hayakawa, A. Osaka

BIOCERAMICS, VOL 20, PTS 1 AND 2 361-363 1219 - + 2008

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Porous chitosan-silicate hybrids were prepared by freeze-drying the precursor sol solutions synthesized from chitosan and 3-glycidoxypropyltrimethoxysilane (GPTMS). Degradability of and the release of cytochrome C in to phosphate buffer saline solution (PBS) were examined as a function of the GPTMS content. The hybrids were less degradable with larger GPTMS contents, and the cytochrome C release profile was so controllable as to give either burst release or slow one due to the GPTMS content. Thus, the present porous chitosan-silicate hybrids were considered applicable to drug delivery systems.

Sol-gel synthesis and in vitro cell compatibility analysis of silicate-containing biodegradable hybrid gels

K. Tsuru, Z. Robertson, B. Annaz, I. R. Gibson, S. M. Best, Y. Shirosaki, S. Hayakawa, A. Osaka

BIOCERAMICS, VOL 20, PTS 1 AND 2 361-363 447 - + 2008

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Novel hybrid gels in the system gelatin-GPTMS-TEOS were prepared via a sol-gel route, and their ability to release Si(IV) was examined using MG63 osteoblast-like cell culture. The amount of Si released and the release rate were controllable by changing the mixing ratio of GPTMS and TEOS. In addition, the hybrids had biocompatible surfaces. It is expected that the hybrids will be utilized for the investigation of the effect of Si on cell differentiation and tissue regeneration.

Preparation and characterization of boron-containing hydroxyapatite

Satoshi Hayakawa, Akihito Sakai, Kanji Tsuru, Akiyoshi Osaka, Eiji Fujii, Koji Kawabata, Christian Jaeger

BIOCERAMICS, VOL 20, PTS 1 AND 2 361-363 191 - + 2008

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Boron-containing hydroxyapatite (BHAp) particles were synthesized by the wet chemical processing method and subsequent thermal treatment at the temperature ranging from 700-1200 degrees C, and examined the effect of boron introduction on the microstructure of BHAp. The local structure around boron and phosphorus in the BHAp was analyzed by solid-state magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. The heat-treatment above 700 degrees C induced the thermal decomposition of HAp to beta-TCP and then the chemical reaction between HAp and B(OH)3 was induced above 900 degrees C, resulting in the formation of boron-substituted HAp particles accompanied by the formation of beta-TCP and its transformation to alpha-TCP above 1200 degrees C.

生体用結晶化ガラス

尾坂明義, 早川聡, 都留, 寛治, 城﨑由紀

セラミックス 43 ( 12 ) 1055 - 1061 2008

Structure and in vitro solubility of silicon-substituted hydroxyapatite

Tomoko Kanaya, Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka, Eiji Fujii, Koji Kawabata, Georgiana Gasqueresc, Christian Bonhornme, Florence Babonneau

BIOCERAMICS, VOL 20, PTS 1 AND 2 361-363 63 - + 2008

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Hydroxyapatite (HAp) and Si-containing hydroxyapatite (SiHAp) particles were of synthesized by a wet chemical method. Local structures around Si, P and H in the hydroxyapatites were analyzed by solid-state magic-angle spinning nuclear magnetic resonance spectroscopy. In vitro solubility of those SiHAp particles was evaluated by soaking them in acetic acid/acetate buffer IF solution (pH=4.0) at 36.5 degrees C. As the Si content increased, the in vitro solubility of the SiHAp particles increased, while their crystallite size changed little.

Synthesis and characterization of Mg-containing nano-apatite

Satoshi Hayakawa, Akiyoshi Osaka, Kanji Tsuru, Eiji Fujiid, Kouji Kawabata, Kanae Ando, Christian Bonhomme, Florence Babonneau

BIOCERAMICS, VOL 20, PTS 1 AND 2 361-363 47 - + 2008

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Nano-crystalline Mg-containing hydroxyapatite (Mg.HAp) were prepared by a wet chemical method, for which selective adsorption of proteins was examined, taking bovine serum albumin (BSA) and a pathogenic protein beta(2)-microglobulin (beta(2)-MG) as the model proteins. Increase in the Mg content led to smaller crystallites and larger specific surface area (SA) of Mg.HAps as well as zeta potential, while the amount both of BSA and beta(2)-MG adsorption on Mg.HAp particles. It is thus concluded that the adsorption of BSA and beta(2)-MG on Mg.HAp was associated with surface charges.

Enhanced in vitro apatite-forming ability of sol-gel derived titania films by ultraviolet irradiation

T. Shozui, K. Tsuru, S. Hayakawa, A. Osaka

BIOCERAMICS, VOL 20, PTS 1 AND 2 361-363 601 - 604 2008

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Ultraviolet (UV) light was irradiated in air for 1 h on titania (anatase) films sol-gel derived on Ti, stainless steel, alumina, and glass slide substrates, coded as C5Ti, C5SUS, C5Al(2)O(3) and C5GS, respectively. They were then soaked in a simulated body fluid (SBF, Kokubo solution) and their apatite-forming ability (bioactivity) was evaluated. UV light irradiated C5SUS deposited bone-like apatite within 7 days whereas C5SUS did not within 7 days. Moreover, the apatite was deposited faster on UV light irradiated C5Ti than on C5Ti without UV light irradiation, whereas UV light irradiated C5GS, C5Al(2)O(3) and C5GS did not apatite within 7 days. Therefore, the ultraviolet light irradiation was confirmed to enhance in vitro apatite-forming ability of the sol-gel derived titania films on various substrates, but the effect depended on substrates.

UV irradiation enhanced in vitro apatite-forming ability of the sol-gel derived titania on Ti, SUS, alumina, and Na-Ca glass substrates

Tetsuya Shozui, Kanji Tsuru, Satoshi Hayakawa, Yuki Shirosaki, Akiyoshi Osaka

Archieves of Bio Ceramics Research 8 85 - 88 2008

Solid state NMR characterization of nano-crystalline hydroxy-carbonate apatite using 1H-31P-13C triple resonance experiments

Florence Babonneau, Christian Bonhomme, Satoshi Hayakawa, Akiyoshi Osaka

Materials Research Society Symposium Proceedings 984 39 - 44 2007.12

The local structure around hydrogen atoms, phosphate ions and carbonate ions in nano-crystalline nonstoichiometric hydroxy-carbonate apatite was investigated in this study. The use of C enriched precursors allowed to perform 1D and 2D CP MAS HETCOR (HETeronuclear CORrelation) experiments with 13C as a target spin. 2D triple resonance experiments involving the 1H/13C/31P spins were also performed. All these experiments led to the partial editing of the corresponding projection spectra and revealed fine structural details for the corresponding material. At least four 13C peaks, corresponding to carbonate ions in A-sites (OH) and B-sites (PO43-) were evidenced. © 2007 Materials Research Society.

Apatite deposition in simulated body fluid on rutile and anatase type titania derived from hydrolysis of titaniumoxysulfate

Sulphuric acid and industry. 60 ( 3 ) 44 - 50 2007.3

Medical Applications of Hybrid Materials

Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka

Hybrid Materials: Synthesis, Characterization, and Applications 301 - 335 2007.2

より豊かな生活に貢献する医療技術に関する研究歯周炎と人工歯根周囲炎に罹患した歯周組織再生のための局所的遺伝子・細胞治療用人工素材の開発

高柴正悟, 鈴木一臣, 尾坂明義, 早川聡, 明貝文夫

医科学応用研究財団研究報告 24 74 - 79 2007.2

Language：Japanese Publisher：(公財)鈴木謙三記念医科学応用研究財団

臨床応用可能な歯周組織再生のための人工素材を開発するため、新規の歯周組織再生素材を開発し、その組織再生誘導能をin vitroおよびin vivoの実験系で検証し、抗菌物質の適応によって口腔内の細菌感染のコントロールを評価した。MC3T3-E1細胞の増殖能は、CAの濃度依存的に有意に抑制された。低濃度のヒドロキシアパタイト(HA)および歯科用骨補填材ボーンジェクト(BJ)は細胞を刺激しない場合と比較して、有意に細胞増殖活性を亢進し、高濃度のHAおよびBJの添加によって細胞増殖活性の程度に有意な変化はなかった。SDラットの口蓋骨欠損部にCAを填人した後、2週間経過したラット口蓋骨欠損部の新生骨形成量は、BJを填入した群と比較して明らかに増加傾向を示した。hb42を唾液腺に遺伝子導入したラットの口腔内細菌量は、対照ラットと比較して有意に減少した。

異分野融合のためのバイオマテリアルの基礎PART3 分析：セラミックバイオマテリアルのキャラクタリゼーション

早川聡, 都留寛治, 尾坂明義

バイオマテリアル－生体材料 25 ( 6 ) 383 - 392 2007

HYDROXYAPATITE HYBRIDIZED WITH METAL OXIDES FOR BIOMEDICAL APPLICATIONS

Akiyoshi Osaka, Eiji Fujii, Koji Kawabata, Hideyuki Yoshimatsu, Satoshi Hayakawa, Kanji Tsuru, Christian Bonhomme, Florence Babonneau

ADVANCES IN BIOCERAMICS AND BIOCOMPOSITES II 27 ( 6 ) 39 - + 2007

Language：English Publisher：AMER CERAMIC SOC

Zn-substituted apatites with homogeneous Zn distribution in the particles (Zn center dot HAp) and those with graded distribution (Zn/HAp) were prepared via a conventional wet chemical synthesis and soaking the Zn-free apatite particles in zinc nitrate solutions X-ray photoelectron spectra of the apatites confirmed such Zn distribution Physical and chemical properties such as particle size, specific surface area, or zeta-potential and were correlated to adsorption of beta(2)-microglobulin (beta(2)-MG) and bovine serum albumin (BSA) Adsorption of beta(2)-MG on both apatites increased with the Zn content, whereas more beta(2)-MG was adsorbed on Zn/HAp than on Zn center dot HAp The amount of BSA adsorbed on Zn center dot HAp reached a maximum at about 1 5%, while it remained constant for Zn/HAp From the results It was suggested that Zn-substituted sites had better affinity against beta(2)-MG and favored beta(2)-MG adsorption Surface charge on the particles was one of the factors to explain the suppressed adsorption of BSA by both apatites

In vitro apatite-forming ability of titania fims depends on their substrates

T. Shozui, K. Tsuru, S. Hayakawa, A. Osaka

BIOCERAMICS, VOL 19, PTS 1 AND 2 330-332 633 - + 2007

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Titania films were coated by means of sol-gel method on various substrates such as titanium, titanium alloy, silicon wafer, stain less-stee 1, alumina, and glass slide where they coded as C5Ti, C5Ti6Al4V, C5Si, C5SUS, C5Al(2)O(3) and C5GS, respectively. Their in vilro apatite-forming ability was examined with the Kokubo's simulated body fluid (SBF; pH 7.4, 36.5 degrees C). C5Ti, C5Ti6Al4V and C5Si deposited apatite particles on their surface within 7 days, whereas, C5SUS, C5Al(2)O(3) and C5GS did not. These results implied that the in vitro apatite-forming ability of the titania films indirectly depended on the chemical or physical properties of the Substrates.

Bonelike apatite formation on synthetic organic polymers and fiber coated with titania

Jin-Fang Liu, Satoshi Hayakawa, Kanji Tsuru, J. Z. Jiang, Akiyoshi Osaka

BIOCERAMICS, VOL 19, PTS 1 AND 2 330-332 679 - + 2007

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Rutile films were deposited on polyethylene terephatalate (PET), polytetrafluoroethylene (PTFE), Silicone, poly6-caprolactam (Nylon6), polyhexamethylene adipamide (Nylon6,6) and Nylon fiber substrates using 0.03 M TiOSO4 and 0.03 M H2O2 aqueous solution at 80 degrees C for 24 h. The rutile films exhibited excellent in vitro bioactivity as they induced apatite deposition in a simulated body fluid (SBF).

Cell proliferation on Titania layer with in vitro apatite forming ability

S. Yabe, K. Tsuru, S. Hayakawa, A. Osaka, Y. Yoshida, K. Suzuki, T. Kuboki

BIOCERAMICS, VOL 19, PTS 1 AND 2 330-332 131 - + 2007

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Titania layer was fabricated on the titanium substrates with chemical treatment with 20ml or 40ml of hydrogen peroxide solution and subsequent heat treatment at 400 degrees C, coded as CHT20 and CHT40, respectively. CHT20 spontaneously deposited apatite on the surface in a simulated body fluid (SBF), while CHT40 did not. TF-XRD patterns showed that the diffraction intensity of anatase of CHT20 was higher than that of CHT40. It was suggested that the thicker titania layer indicated in vitro apatite forming ability. The cell proliferation of CHT20 and CHT40 were lower than NT and HT. Since the surface of titania layers became hydrophobic after autoclaving, we can suppose that the cell proliferation on CHT20 and CHT40 were lower than NT and HT due to their surface hydrophobicity.

Preparation of hydroxyapatite/titania double layer coating on poly-l-lactide due to hydrolysis of titanium tetrachloride

Jin-Fang Liu, Satoshi Hayakawa, Kanji Tsuru, Jian-zhong Jiang, Akiyoshi Osaka

BIOCERAMICS, VOL 19, PTS 1 AND 2 330-332 687 - + 2007

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Rutile films were deposited on poly-l-lactide (PLLA) substrates using 0.5 M titanium tetrachloride aqueous solution at 40 degrees C for 72 h. The rutile films exhibited excellent in vitro bioactivity as they induced apatite deposition in a simulated body fluid (SBF) within 3 days, This simple treatment provided an effective route to synthesize bioactive and biodegradable scaffolds.

生命機能と材料－生命機能マテリアル／生命現象マテリアル生体セラミックスの骨組織結合性発現機序とこれに基づく医用材料設計

尾坂明義, 早川聡, 都留寛治

マテリアルインテグレーション 20 ( 11 ) 2 - 7 2007

Microstructure and biomolecule adsorption property of hydroxyapatite modified with biologically active inorganic ions

Materials integration 20 ( 11 ) 78 - 83 2007

Preparation of porous organically-modified silicate hybrids cell culture matrix

K. Tsuru, S. Hayakawa, Y. Shirosaki, T. Okayama, K. Kataoka, N-H. Huh, A. Osaka

BIOCERAMICS, VOL 19, PTS 1 AND 2 330-332 1177 - + 2007

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Porous & rubbery organic-inorganic hybrids were synthesized from tetraethoxysilane (TEOS) and polydimethylsiloxane(PDMS) through a sol-gel route using sieved sucruse granules as a porogen. The porous hybrids with a high content of PDMS behaved like polymer sponge. The porosity was over 90% irrespective of the hybrid composition and the pore diameter ranged from 100 to 500 mu m. In the three-dimensional cell culture, mammalien cells were well cultured in the porous hybrids. The present results indicate that the hybrids may be a promising scaffold for developing such functional culture methods.

異分野融合のためのバイオマテリアルの基礎PART3 導入：セラミックバイオマテリアルの特色

尾坂明義, 早川聡, 都留寛治

バイオマテリアル－生体材料 25 ( 6 ) 366 - 373 2007

Direct deposition of a rutile layer on polymer substrates to induce bioactivity in vitro

JM Wu, M Wang, S Hayakawa, K Tsuru, A Osaka

BIOCERAMICS 18, PTS 1 AND 2 309-311 419 - 422 2006

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Rutile films were deposited on polytetrafluoroethylene (PTFE) substrates using 1.5 M titanium tetrachloride aqueous solution at 60 degrees C. The rutile films exhibited excellent in vitro bioactivity as they induced apatite deposition in a simulated body fluid (SBF) within 2 days. Chlorine incorporated in the rutile films did not inhibit apatite deposition.

Characterization of sol-gel derived titania films on titanium and biomimetic apatite-formation

T Shozui, K Tsuru, S Hayakawa, A Osaka

BIOCERAMICS 18, PTS 1 AND 2 309-311 717 - 720 2006

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Titania films with various thickness (about 100 nm to 300 nm) were prepared on titanium substrate by means of sol- gel method. Their surface energy was derived and in vitro apatite-forming ability was studied. The thickness of titania films of the sample coded C1, C3 and C5 was 98 nm, 204 nm, and 302 nm, respectively. Titania films of C5 showed smoother and more hydrophilic. The surface free energy of C5 was the highest of all. In vitro apatite-forming ability showed the titania films of C5,only. It was thus suggested that the titania films with more hydrophilic and higher surface free energy favored apatite-formation than those with smaller surface free energy.

Selective protein adsorption property and structure of nano-crystalline hydroxy-carbonate apatite

S Hayakawa, K Ohnishi, K Tsuru, A Osaka, E Fujii, K Kawabata, F Babonneau, C Bonhomme

BIOCERAMICS 18, PTS 1 AND 2 309-311 503 - 506 2006

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

The selective protein adsorption property and the local structure around carbonate ions of nanocrystalline hydroxy-carbonate apatite were examined in this study. Considerable change in the selectivity in the adsorption of BSA and beta(2)-MG was observed due to the incorporation of the carbonate ions in hydroxyapatite lattice. Since the protein adsorption property seems to be related to the surface charge density of hydroxyapatite due to the carbonation, the chemical states of the incorporated carbonate ions were examined by the C-31 CP-MAS NMR spectroscopy. At least four peaks assignable to carbonate ions in A-site(OH-) and B-site(PO43-) were observed in C-13 CP-MAS NMR spectrum. Thus, we must take into consideration that the surface charge distribution and the decrement of polar groups such as OH- groups due to the distribution of carbonate ions in both A- and B-sites of the hydroxyapatite lattice are particularly favorable for beta(2)-MG adsorption rather than for BSA adsorption.

In vitro bioactivity of hydrogen peroxide modified titanium: Effects of surface morphology and film thickness

JM Wu, M Wang, S Hayakawa, K Tsuru, A Osaka

BIOCERAMICS 18, PTS 1 AND 2 309-311 407 - 410 2006

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Anatase films with various morphologies were formed on Ti surface through different approaches using hydrogen peroxide solutions. A porous anatase surface was found to favor apatite deposition in SBF, or in vitro bioactivity. Thicker films with wider crack gaps also showed enhanced in vitro bioactivity. However, the most predominant effect was the abundance of Ti-OH functional groups incorporated in the anatase films.

31P MAS-NMR studies of CaO-P2O5 glass ceramics

AG Dias, MA Lopes, K Tsuru, S Hayakawa, JD Santos, A Osaka

BIOCERAMICS 18, PTS 1 AND 2 309-311 301 - 304 2006

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

This work reports the structure of two glass ceramics prepared in the calcium phosphate system, MK5B and MT13B, using (31)p MAS-NMR technique. The results obtained showed that the network of MK5B consisted mainly of Q(1) and Q(2) groups. Besides these two groups, MT13B material also present Q(3) units. The Q(n) groups detected in both glass ceramics seem to be correlated to the crystalline phases present in their microstructure.

SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF NANOAPATITE CERAMICS POWDERS

K. Ando, S. Hayakawa, K. Tsuru, A. Osaka, E. Fujii, K. Kawabata, C. Bonhomme, F. Babonneau

Proceedings of The Sixth Asian BioCeramics Symposium 2006 2006

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF ORGANIC-INORGANIC HYBRIDS PREPARED FROM HEMA AND MPS

T. Uchino, C. Ohtsuki, K. Kikuta, M. Kamitakahara, M. Tanihara, S. Hayakawa, A. Osaka

Proceedings of The Sixth Asian BioCeramics Symposium 2006 2006

IN VITRO APATITE DEPOSITION ON MICRO-PATTERNED TITANIA LAYERS

A. Kaeriyama, K. Tsuru, S. Hayakawa, A. Osaka

Proceedings of The Sixth Asian BioCeramics Symposium 2006 2006

表面プラズモン共鳴のためのリン酸カルシウムおよび各種金属センサーの開発

吉田靖弘, 鈴木一臣, 尾坂明義, 早川聡, 石川邦夫, 岡崎正之, 平田伊佐雄

中谷電子計測技術振興財団年報 ( 20 ) 2006

無機-有機ナノハイブリッドの微細構造と細胞適合性 (特集セラミックスと細胞のナノインターフェイス制御)

都留寛治, 早川聡, 尾坂明義

バイオマテリアル 23 ( 5 ) 353 - 359 2005.9

Structure and Cytocompatibility of Chitosan-silicate Hybrids

TSURU K., SHIROSAKI Y., OKAYAMA T., HAYAKAWA S., OSAKA A.

11 ( 2 ) 112 - 113 2005.7

Conformational change of protein due to contact with bioceramic materials

S Nagai, K Tsuru, S Hayakawa, A Osaka

BIOCERAMICS, VOL 17 284-286 517 - 520 2005

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

The structural change of bovine serum albumin (BSA) was analyzed by means of ultraviolet (UV) and circular dichroism (CD) spectroscopy due to in contact with ceramics powders such as Al2O3, SiO2, TiO2, ZrO2, hydroxyapatite and beta-tricalcium phosphate. The absorbance of the UV spectra increased for the BSA solution in contact with TiO2, ZrO2 and Al2O3, that is, the BSA solution clouded. This indicated the aggregation of BSA after contact with those ceramics powders. The CD spectroscopy showed that the ordered secondary structure of BSA was diminished on contact with TiO2 and ZrO2. We discussed the protein adsorption property of ceramics on the basis of the magnitude of the interaction forces between proteins and the bioceramics.

Blood compatibility of organic-inorganic biomedical materials

A Osaka, T Yoshioka, T Yabuta, K Tsuru, S Hayakawa

BIOCERAMICS, VOL 17 284-286 713 - 716 2005

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Organic-inorganic hybrids involving Ti-O bonds were coated on stainless-steel (SUS316L) substrates. Tetraisopropoxide and titanium methacrylate triisopropoxide were employed as the major starting chemicals to provide TiO2-polydimethylsiloxane (PDMS) layers or organotitanium molecular thin layers, respectively. Fourier transform infrared spectra indicated that each layer contained Ti-O bonds in their structure. The obtained hybrid layers had little effects on the blood-clotting times such as active partial thromboplastin time and prothrombin time. In addition, the number of adhered platelet on the TiO2-PDMS layers depended on the composition, while the organotitanium molecular thin layers suppressed fibrinogen adsorption compared with coating-free SUS 316L substrate.

Deposition of bioactive titania layers under ambient conditions due to hydrolysis of titanium oxysulfate aqueous solutions

Fan Xiao, Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka

Archives of BioCeramics Research 2005

In vitro apatite formation on nano-crystalline titanium oxide layer grown at glass-coating/titanium interface

Satoshi Hayakawa, Yongxing Liu, Kanji Tsuru, Akiyoshi Osaka, Eiji Fujii, Kouji Kawabata

Archives of BioCeramics Research 2005

Nano-crystalline Titanium oxide layer grown at glass-coating/titanium interface for biomedical application,

Satoshi Hayakawa, Yongxing Liu, Kazuya Okamoto, Ayako Sekikawa, Kanji Tsuru, Akiyoshi Osaka

Proceedings of Third Balkan Conference on Glass Science and Technology, 15th Conference on Glass and Ceramics 2005

Surface characterization and corrosion behavior of NiTi alloy coated with nano-crystalline titanium oxide film

Miho Yamamoto, Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka, Eiji Fujii, Kouji Kawabata

Archives of BioCeramics Research 2005

In vitro protein release behavior of gelatin-silicate porous hybrids

Kanji Tsuru, Mitsuyuki Nagahara, Satoshi Hayakawa, Akiyoshi Osaka, Kerntaro Deguishi, Nam-ho Huh

Archives of BioCeramics Research 2005

Preparation of titanate nano-rod array on titanium substrates by novel microflux method

YX Liu, K Okamoto, S Hayakawa, K Tsuru, A Osaka

CERAMIC NANOMATERIALS AND NANOTECHNOLOGY III 159 193 - 199 2005

Language：English Publisher：AMER CERAMIC SOC

We proposed a new approach on preparing titania or titanate nano- or micro-rod arrays on metallic titanium (alpha-Ti) surfaces by coating a layer of sodium tetraborate or potassium metaborate on titanium substrates and subsequent thermal treatment. Thin-film X-ray diffraction analysis indicated that the sodium tetraborate gave rutile (TiO2: PDF# 21-1276) micro-rod array. The potassium metaborate, in contrast, yielded a potassium titanate (K2Ti6O13: PDF# 40-0403) nano-rod array. The rods in the arrays grew almost perpendicular to the substrate surface.

In vitro biodegradability of chitosan-organosiloxane hybrid membrane

K Tsuru, Y Shirosaki, S Hayakawa, A Osaka, MA Lopes, JD Santos, MH Fernandes

BIOCERAMICS, VOL 17 284-286 823 - 826 2005

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Chitosan-silicate hybrid membranes were prepared using gamma-glycidoxypropyltrimethoxysilane (GPSM) through a sol-gel process. The amino groups of chitosan chains were reacted with the epoxy groups of GPSM and GPSM have a function as the agent to cross-link the chitosan chains. The cross-linking degree of the hybrid membranes was determined by ninhydrin assay. Fourier-transform infrared (FT-IR) spectroscopy and Si-29 cross-polarization (CP) magic-angle spinning (MAS)-NMR spectroscopy were used to assess the structure of the hybrid membranes. The biodegradability of the hybrid membranes in phosphate-buffered saline solution or lysozyme solution was investigated as a function of the GPSM concentration.

ガラス研究機関訪問ガラス構造のコンセプトに触発されたハイブリッド医用材料の設計と創成

都留寛治, 早川聡, 尾坂明義

ニュ-ガラス 20 ( 4 ) 57 - 62 2005

Chemical interaction between hydroxyapatite and functional phosphoric acid ester monomers

FUKEGAWA D., YOSHIDA Y., SUZUKI K., HAYAKAWA S., OSAKA A., VAN MEERBEEK B.

Journal of the Japanese Society for Dental Materials and Devices 24 P - 35 2005

ナノ結晶性酸化チタン層のin vitro生体活性に及ぼす無機イオン吸着の影響

松浦直子, 都留寛治, 早川聡, 尾坂明義, 吉田靖弘, 鈴木一臣, 窪木拓男

日本セラミックス協会秋季シンポジウム講演予稿集 18th 2005

Hydroxyapatite formation on and inside of cotton fibrilla with an oxysulfate solution

J. F. Liu, S. Hayakawa, K. Tsuru, A. Osaka

Transactions - 7th World Biomaterials Congress 977 2004.12

Protein adsorption properties of stainless-steel and titanium modified with alginic acid

T. Yoshioka, K. Tsuru, S. Hayakawa, A. Osaka

Transactions - 7th World Biomaterials Congress 1408 2004.12

The protein adsorption on the alginic acid layers covalently immobilized on stainless-steel and titanium was examined by Fourier transform infrared spectroscopy using a reflection adsorption method (FT-IRRAS). The relationship between platelet adhesion and protein adsorption was also investigated. The contact angle measurement and FT-IRRAS spectra confirmed the successful immobilization of γ-APS and alginic acid onto stainless-steel and titanium substrates. The result shows that less protein adsorption leads to blood-compatible surface on the alginic acid-immobilization.

In vitro cytocompatibility of osteoblastic cells cultured on chitosan-organosiloxane hybrid membrane

Y Shirosaki, K Tsuru, S Hayakawa, A Osaka, MA Lopes, JD Santos, MH Fernandes

BIOCERAMICS, VOL 16 254-2 857 - 860 2004

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Chitosan-silicate hybrids were synthesized using gamma-glycidoxypropyltrimethoxysilane (GPSM) as the agent to cross-link the chitosan chains. Fourier-transform infrared (FT-IR) spectroscopy was used to analyze the structures of the hybrids. The swelling ability and the cytocompatibility of the hybrids were investigated as a function of the GPSM concentration. The swelling of the hybrids was suppressed by addition of GPSM. MG63 human osteoblastic cells were cultured on the hybrids. The adhesion and proliferation of the MG63 cells cultured on the chitosan-GPSM hybrid surface were improved comparing to that on chitosan membrane, regardless the GPSM concentration.

Control of morphology of titania film with high apatite-forming ability derived from chemical treatments of titanium with hydrogen peroxide

S Kawasaki, K Tsuru, S Hayakawa, A Osaka

BIOCERAMICS, VOL 16 254-2 443 - 446 2004

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

We prepared titanium substrates with sub-micron scale pores and without sub-micron scale pores by means of chemical treatments with hydrogen peroxide and subsequent thermal treatments. Sub-micron scale pores were observed on the surface of the titanium substrate treated with 3 mass% H2O2 at 90degreesC for 1 h(H1) by scanning electron microscopy. On the other hand, the sub-micron scale pores were not observed on the substrate treated with 3mass% H2O2 at 90degreesC for 72 h(H72). The surface roughness, Ra of H1 and H72 substrates was 27 and 14 nm, respectively. Both substrates showed high in vitro apatite-forming ability in simulated body fluid (SBF of Kokubo's recipe). The apatite-forming ability of H72 substrate with low Ra value was higher than that of H1 with high Ra value.

Platelet adhesion on titania film prepared from interaction of Ni-Ti alloy with hydrogen peroxide solution

S Hayakawa, K Tsuru, A Osaka

BIOCERAMICS, VOL 16 254-2 865 - 868 2004

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Titania films were prepared from interaction of Ni-Ti shape memory alloy with hydrogen peroxide solution followed by heating at 400degreesC. The titania films consisted of crystalline phase of TiO2 (anatase). The in vitro platelet adhesion property of the titania films was examined. The titania films on Ni-Ti alloy substrates adhered less platelets than Ni-Ti alloy substrate without treatment. This indicates that the titania film can suppress the adhesion of platelet. The present chemical modification process with hydrogen peroxide solution is applicable to prevent the Ni-Ti shape memory alloy materials from platelet adhesion when in contact with blood.

特集I バイオとガラス医用金属材料の生体適合性制御

早川聡, 都留寛治, 尾坂明義

ニューガラス Vol.19 [3],pp.21-27 ( 3 ) 21 - 27 2004

Platelet adhesion on metal oxide layers

S Takemoto, T Yamamoto, K Tsuru, S Hayakawa, A Osaka

BIOCERAMICS, VOL 16 254-2 853 - 856 2004

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

This study was concerned with blood compatibility of titanium oxide layers on stainless steel. The titanium oxide layers were prepared through sol-gel process by dip-coating of tetraethyltitanate solution and heated at 500degreesC. The crystal phase, thickness and wettability of the oxide were characterized. The blood compatibility was evaluated in term of platelet adhesion using human platelet rich plasma. Consequently, with increase in the thickness of the titanium oxide layers, the number of platelet adhered on the stainless steel coated with titanium oxide layer decreased rapidly. When the thickness of titanium oxide layers on stainless steel grew more than 150 nm, the number of adherent platelets decreased less than 10% in comparison with that on non-coated stainless steel. The titanium oxide layers indicated to be more hydrophilic than non-coated stainless steel. In conclusion, the thicker and more hydrophilic titanium oxide layer on stainless steel appears to inhibit platelet adhesion.

Preparation of chitosan-silicate hybrid for bone formation

Yuki Shirosaki, Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka

53rd SPSJ Symposium on Macromolecules, Polymer Preprints 53 ( 2 ) 3698 - 3699 2004

Study of porous TEOS-PDMS hybrids for cell cultured matrix

Tsuru Kanji, Yabuta Takeshi, Hayakawa Satoshi, Osaka Akiyoshi, Kataoka Ken, Huh Nam-ho

Preprints of Annual Meeting of The Ceramic Society of Japan<br>Preprints of Fall Meeting of The Ceramic Society of Japan 2004 ( 0 ) 525 - 525 2004

Publisher：The Ceramic Society of Japan

取り扱いに耐えうる強度や加工性を有し，かつ良好な細胞適合性を有する多孔材料が創製できれば，組織工学的な細胞培養用マトリックスとして有用であり組織工学の発展に繋がる。本研究では， TEOS-PDMS型ナノハイブリッド多孔体を合成し，力学的特性，気孔率，孔径および細胞適合性を評価した。ハイブリッド体の歪み率は80%以上で高い柔軟性を持ち，手術用メス刃等を用いて容易に切断できる加工性を有していた。貫通気孔の割合は約85%で孔径は自由に制御できた。各種哺乳類細胞はハイブリッドに対して良好に接着・増殖している様子が観察された。以上より，本多孔体は細胞培養用担体として有用であると考えられる。

DOI： 10.14853/pcersj.2004S.0.525.0

In vitro biological reactivity of porous chitosan-organosiloxane hybrids

Yuki Shirosaki, Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka

The 20th International Congress on Glass 2004

化学ベクトルセラミックス〜培養細胞機能をコントロールする多孔質ゼラチン-シリケートハイブリッド

都留寛治, 早川聡, 尾坂明義

バイオマテリアル-生体材料- Vol.21, No.5, 389頁〜395頁 2003

Hydroxy carbonate apatite: Synthesis, blood compatibility and adsorption of specific pathogenic proteins

S Hayakawa, Y Kusudo, S Takemoto, K Tsuru, A Osaka, S Takashima

BIOCERAMICS: MATERIALS AND APPLICATIONS IV 147 111 - 119 2003

Language：English Publisher：AMER CERAMIC SOC

Hydroxy-carbonate apatite (CAp) compositions containing carbonate ions from 0 to 10.9 wt% were synthesized by a wet chemical method. Infrared analysis revealed that carbonate ions were substituted both PO43- and OH- sites. The introduction of CO32- ion into the hydroxyapatite lattice led to an increase in specific surface area and surface charge density. Blood clotting properties were not affected by the contact with CAp samples. The adsorption behavior of proteins was investigated by contacting CAp with model saline containing bovine serum albumin (BSA) and beta(2)-microglobulin (beta(2)-MG). The selectivity against beta(2)-MG increased with increase in the amount of carbonate ions. As surface charge density increased with increase in the amount of carbonate ions, surface charge density played an important role in selective adsorption of beta(2)-MG, but not a sole factor.

Blood compatibility of metal oxide layers on stainless-steel

K Tsuru, S Takemoto, T Yamamoto, S Hayakawa, A Osaka, S Takashima

POLYMER/METAL INTERFACES AND DEFECT MEDIATED PHENOMENA IN ORDERED POLYMERS 734 327 - 332 2003

Language：English Publisher：MATERIALS RESEARCH SOCIETY

We examined blood compatibility of titanium oxide layer on stainless-steel (SUS316L). The oxide layers with varied thickness were yielded on SUS316L plates by dip-coating of sol-gel solution starting from tetraethyltitanate. The blood compatibility was evaluated in term of platelet adhesion using platelet rich plasma. With increase in the thickness of the oxide layer, the number of adherent platelets decreased rapidly, reached minimum around 150nm. This indicated that the thickness of titanium oxide layer affected platelet adhesion.

Cytocompatibility on silicone modified with organoalkoxysilane due to emulsion polymerization

Y Shirosaki, K Tsuru, S Hayakawa, A Osaka, S Takashima

BIOCERAMICS 15 240-2 687 - 690 2003

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

gamma-Methacryloxypropyltrimethoxysilane (gamma-MPS) molecules were grafted on silicone elastomer by emulsion polymerization. Fibroblast and osteoblastic cells were cultured to examine cytocompatibility of the grafted surface. A greater number of cells grew on the grafted silicone, even forming a cell layer, than on the original silicone. Moreover, the cultured cells were agglomerated on the latter though they adhered well. Thus the gamma-MPS grafting was concluded to improve cytocompatibility of silicone.

Blood compatibility of stainless-steel and titanium immobilized with alginic acid layers

T Yoshioka, K Tsuru, S Hayakawa, A Osaka

POLYMER/METAL INTERFACES AND DEFECT MEDIATED PHENOMENA IN ORDERED POLYMERS 734 333 - 338 2003

Language：English Publisher：MATERIALS RESEARCH SOCIETY

gamma-Aminopropyltriethoxysilane (,gamma-APS) was grafted on stainless-steel and titanium substrates, and subsequently alginic acid layer was immobilized on them. Their surfaces were characterized with X-ray photoelectron spectroscopy (XPS) and contact angle measurement. Blood compatibility of thus obtained substrates was evaluated in terms of both the number of the adhered platelets and blood clotting factors for plasma contacted with the substrates such as active partial thromboplastin time (PTT), prothrombin time (PT), and amount of fibrinogen (Fib). The steel and titanium substrates with alginic acid layer did not affect blood clotting factors. In vitro platelet adhesion assay indicated that those substrates adhered less number of platelets than non-treated substrates. Hence the alginic acid immobilization leads to blood compatible surfaces.

Biomimetic apatite deposition on titanium substrates treated with low concentrations of H2O2 solutions

K Shibata, K Tsuru, S Hayakawa, A Osaka

BIOCERAMICS 15 240-2 55 - 58 2003

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Titanium substrates were provided with ability of biomimetic apatite deposition in a simulated body fluid by means of chemical treatment and subsequent thermal treatment. Examined were the effects of the chemical treatment time, the concentration and pH conditions of the H2O2 solutions on formation of bioactive titania gel layer and in vitro bioactivity. The optimum process consist of 6 mass% H2O2 treatment at 60 degreesC for 3-6 h and subsequent thermal treatment at 400 degreesC for lh. Reactions between the titanium substrates and H2O2 involved titania gel formation and Ti (IV) dissolution. Each reaction rates well related with the concentration and pH of the H2O2 solutions.

Response to osteoblastic cells of bioactive organic-inorganic hybrid

Y Aburatani, T Uchida, Y Shirosaki, K Tsuru, S Hayakawa, A Osaka

BIOCERAMICS 15 240-2 683 - 686 2003

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Organically modified silicate gels were synthesized starting from ploy(dimethylsiloxane), tetraethoxysilane, calcium nitrate, and colloidal silica through sol-gel processing. In vitro apatite deposition on the colloidal silica containing hybrids in a simulated body fluid of the Kokubo recipe was confirmed, indicating they were bioactive. Cell proliferation for the hybrid gels with the colloidal silica was better than the colloidal silica free gels. The cells cultured for 7 days on the hybrid gels with colloidal silica expanded their pseudopodium and were well attached. In contrast, the cells were hardly observable on the colloidal silica free gels. Thus, the hybrids with colloidal silica are cytocompatible as well as bioactive.

Low-temperature deposition of bioactive crystalline titania films: Effects of tantalum

JM Wu, S Hayakawa, K Tsuru, A Osaka

BIOCERAMICS 15 240-2 533 - 536 2003

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Crystalline titania films (anatase and rutile) with excellent in vitro bioactivity were deposited through interactions of titanium and hydrogen peroxide solutions containing Ta(V) ions, under a low temperature of 80 degreesC. Ta(V) ions were found to favor both the low-temperature crystallization and the formation of rutile.

Deactivation of active oxygen species due to metals and their blood compatibility

S Takashima, T Yamamoto, K Tsuru, S Hayakawa, A Osaka

BIOCERAMICS 15 240-2 105 - 107 2003

Effects of Metals on Generation and Dismutation of Active Oxygen Species in Blood

Tomoya Ogawa, Kanji Tsuru, Satoshi Hayakawa, Seisuke Takashima, Akiyoshi Osaka

Archives of BioCeramics Research 2003

Bioactive titania gel derived from combined chemical and thermal treatments of titanium

S Hayakawa, K Shibata, K Tsuru, A Osaka

27TH INTERNATIONAL COCOA BEACH CONFERENCE ON ADVANCED CERAMICS AND COMPOSITES: A 24 ( 3 ) 227 - 232 2003

Language：English Publisher：AMER CERAMIC SOC

Bioactive titania gel was derived from chemical treatment of Ti substrate with dilute H2O2 solutions and subsequent thermal treatments. We examined the effects of the chemical treatment time and the concentration and pH of the H2O2 solutions on both formation of titania gel and in vitro deposition of apatite or bioactivity. The optimum treatments consisted of 6 mass% H2O2 treatment at 60 degreesC for 3-6 h and subsequent thermal treatment at 400 degreesC for 1 h. Reactions between the titanium substrates and H2O2 involved the oxidation of titanium, titania gel formation and Ti dissolution.

Low temperature synthesis of bioactive TiO2 thin film by two-step treatment

F Xiao, K Tsuru, S Hayakawa, A Osaka

BIOCERAMICS 15 240-2 537 - 540 2003

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Bioactive TiO2 films were deposited on Ti substrates by two-step treatment near room temperature. A well-crystalline TiO2 gel film was obtained on Ti by soaking in TiF4+ H2O2 Solution at 60degrees C for 24 h. Subsequent cathode polarization precipitated calcium hydroxide. Calcium carbonate appeared after samples soaking in a Kokubo simulated body fluid due to the reaction between calcium hydroxide and bicarbonate ions. Calcium hydroxide dissolved into SBF, supersaturated with calcium ions, favored apatite nucleation. Apatite thus deposited without heating the Ti substrates. This method was applicable to substrates other than Ti.

Effects of Organic Molecules in the Kokuboﾕs Simulated Body Fluid on Apatite Formation on Glass and Titanium Substrates

K. Tsuru, Y. Higashi, S. Hayakawa, A. Osaka

Proc. 2nd Asian BioCeramics Symposium(ABC2002), Korea 2002

Synthesis of carbonate-hydroxy apatite and selective adsorption activity against specific pathogenic substances

S Takashima, Y Kusudo, S Takemoto, K Tsura, S Hayakawa, A Osaka

BIOCERAMICS 14 218-2 175 - 178 2002

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Hydroxyapatite (HAP) and carbonate-hydroxy apatite (CAP5 and CAP15) were synthesized under the flow of N-2 containing 0%, 5%, or 15% CO2 by wet chemical method, and subsequently calcined at 105-700degreesC. Infrared analysis showed that carbonate ions substituted PO43- and OH- sites. The clotting characteristics for the fresh mixed plasma contacted with the samples indicated that CAP had better blood compatibility than HAP. The protein adsorption activity was evaluated by contacting with the model saline containing bovine serum albumin (BSA) and beta2-microgloburin (beta-MG). CAP15 calcined below 600degreesC adsorbed the lowest fraction of BSA (9%) whereas it adsorbed the highest fraction of beta(2)-MG (47%). It was concluded that the selective adsorption activity against beta(2)-MG was related to the carbonate ions incorporated in hydroxyapatite.

In vitro evaluation on bone-bonding of chemically modified titanium

JM Wu, S Hayakawa, K Tsuru, A Osaka, XX Wang

BIOCERAMICS 14 218-2 141 - 144 2002

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

Treatment with a hydrogen peroxide solution containing tantalum chloride followed by heating provided titanium with bioactivity where a titania gel layer derived on surface played the essential role. Effects of surface roughness and gel thickness on in vitro bioactivity were examined using the Kokubo solution. In vitro evaluation suggested enhanced interfacial bond strength between bone and Ti implants by obtaining thinner titania layer on rougher Ti surface.

Heating effect on properties of organic-inorganic hybrids containing colloidal silica particles

Y Aburatani, K Tsuru, S Hayakawa, A Osaka

BIOCERAMICS 14 218-2 445 - 448 2002

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

The organic-inorganic hybrid gels were synthesized starting from poly (dimethylsiloxane)(PDMS), tetraethoxysilane (TEOS), colloidal silica and calcium nitrate (Ca(NO3)(2).4H(2)O) through sol-gel processing. The effects of heating on the mechanical properties and microstructure of the synthesized samples were investigated. The compressive strength of the synthesized samples increased by heating. The dynamic mechanical analysis of the synthesized samples showed increase of storage modulus and decrease of the loss factor, tandelta. It was suggested that the mobility of PDMS chain was restricted with the increase of PDMS-silica interaction by heating.

Blood Compatibility of Titanium Oxide Gels on Titanium Substrates

S. Takemoto, T, Yamamoto, K. Tsuru, S. Hayakawa, A. Osaka, S. Takashima

Proc.19th Korea-Japan Internatl. Seminar on Ceramics 2002

Apatite induction on titania due to combined chemical and thermal treatments of titanium

S Hayakawa, K Shibata, K Tsuru, A Osaka

BIOCERAMICS 14 218-2 71 - 74 2002

Language：English Publisher：TRANS TECH PUBLICATIONS LTD

We examined the effects of the thermal treatment temperature and Ta(V) species on in vitro apatite forming-ability of titania due to chemical treatment of titanium substrates. The formation of peroxo Ta(V) species (Ta(V)O-2) in the H2O2 solution at 60degreesC effectively promoted not only the decomposition and the elimination of the peroxo and hydroperoxide groups, such as Ti-OOH and Ta-OOH in the titania gel but also the decomposition of H2O2 Compared with the formation of peroxo Ti(rV) species (Ti(IV)O-2), resulting in enhanced ability of apatite deposition in spite of thermal treatment at the lower temperature such as 100degreesC. The combined chemical and thermal treatments were applicable for providing both pieces of Ti and Ti mesh with bioactivity.

Chitosan-organosiloxane hybrids for biomedical applications

YAMADA A

Abstract of the 3^<rd> Asian international Symposium on Biomaterials and Drug Delivery Systems, 2002 2002

Surface Characterization and Platelet Adhesion of Alginic Acid Layers on Glass Substrates

T. Yoshioka, K. Tsuru, S. Hayakawa, A. Osaka

Proc. 3rd Asian Internatl. Symposium on Biomaterials and Drug Delivery Systems 2002

Crystallization of Anatase from Amorphous Titania in Hot Water and In Vitro Biomineralzation

Jin-Ming WU, Satoshi HAYAKAWA, Kanji TSURU, Akiyoshi OSAKA

J.Ceram.Soc.Japan 110 ( 1278 ) 78 - 80 2002

Lab Tour : Department of Bioscience & Biotechnology, Faculty of Engineering, Okayama University

19 ( 6 ) 51 - 53 2001.12

Sol-Gel Derived Porous Gelatin-Siloxane Hybrids

K. Tsuru L. Ren, S. Hayakawa, A. Osaka

Internatl. Symposia on Materials Science for the 21st Century, Vol. B, Soc. Mater. Sci. Japan 2001

有機無機複合体の高機能性材料への応用

都留寛治, 早川聡, 尾坂明義

ケミカル・エンジニヤリング 46,No.10,25頁-31頁 ( 10 ) 769 - 775 2001

多孔質シリカゲルでのアパタイト形成

久保正明, 都留寛治, 早川聡, 尾坂明義

化学工業，特集：セラミックス生体材料の展望 52巻5号,372〜378 ( 5 ) 372 - 378 2001

In Vitro Apatite Formation on Titanium Treated with a Hydrogen Peroxide Solution

Koichi Shibata, Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka

Proceedings of 18th International Korea-Japan Seminar on Ceramics 2001

Synthesis of PDMS Based Porous Materials for Biomedical Applications

T. Yabuta E, P. Bescher J, D. Mackenzie, K. Tsuru, S. Hayakawa, A. Osaka

11th Internatl. Workshop on Glasses, Ceramics, Hybrids and Nanocomposites from Gels 2001

金属チタン表面の高生体活性化

川邊康宏, 都留寛治, 早川聡, 尾坂明義

化学工業，特集：セラミックス生体材料の展望 52巻5号,349〜353 ( 5 ) 349 - 353 2001

In Vitro Evaluation of the Osteoblast Response to Sol-Gel Derived Gelatin-Siloxane Hybrids

L. Ren, K. Tsuru, S. Hayakawa, A. Osaka

11th Internatl. Workshop on Glasses, Ceramics, Hybrids and Nanocomposites from Gels 2001

Bioactivity and Structure of Alkali Borosilicate Glasses

K. Tsuru, S. Hayakawa, C, Ohtsuki A. Osaka

Proc. XIX Internatl. Congress on Glass, Society of Glass Technology 2001

Structure of Divalent Metal Oxyfluorosilicate Glass

S. Hayakawa, A. Osaka

Proc. XIX Internatl. Congress on Glass, Society of Glass Technology 2001

Effects of Metal Ions in Simulated Body Fluids on Biomimetic Reactions of Materials

K. Tsuru, N. Azuma, M. Kubo, S. Hayakawa, A. Osaka

Internatl. Symposia on Materials Science for the 21st Century, Vol. B, Soc. Mater. Sci. Japan 2001

Improvement of Biocompatibility of Silicone Elastomer by Surface Modification

Shirosaki Yuki, Tsuru Kanji, Hayakawa Satoshi, Osaka Akiyoshi, Takashima Seisuke

Memoirs of the Faculty of Engineering, Okayama University 36 ( 1 ) 117 - 121 2001

In vitro apatite deposition and biodegradation of porous gelatin-silicate hybrids derived from sol-gel process

Lei Ren, Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka

Materials Research Society Symposium - Proceedings 628 2000.1

Ca(II) containing porous hybrids of gelatin and 3-(glycidoxypropyl) trimethoxysilane (GPSM) were prepared with sol-gel processing and freeze-drying techniques. The freezing temperature could control porosity and pore size of the hybrids. The biodegradation rate of the hybrids in a Tris buffer solution decreased with an increase in GPSM content. The bone-like apatite layer could form on the Ca(II) containing porous gelatin-silicate hybrids when they were soaked in a stimulated body fluid (SBF), hence they were applicable to be the bioactive scaffolds for bone tissue engineering.

Biomimetic Deposition of Calcium Phosphated in a Simulated Body Fluid

HAYAKAWA S, OSAKA A

J. Non-Cryst. Solids 263/264 409 - 415 2000

Mechanism of apatite formation on a sodium silicate glass in a simulated body fluid

S Hayakawa, K Tsuru, C Ohtsuki, A Osaka

JOURNAL OF THE AMERICAN CERAMIC SOCIETY 82 ( 8 ) 2155 - 2160 1999.8

Language：English Publisher：WILEY-BLACKWELL

Si-29 and P-31 magic-angle-spinning nuclear magnetic resonance (MAS-NMR) spectra were used to analyze 20Na(2)O . 80SiO(2) glass particles before and after soaking in a simulated body fluid (SBF; Kokubo solution, pH 7.4) for various periods (up to 14 d), The structure of the bulk glass and the glass surface, as well as the chemical states of the calcium phosphates adsorbed on the glass surface, were examined. The bulk glass before soaking in the SBF showed two Si-29 MAS-NMR resonances, at -100 and -110 ppm, which were attributable to Si(OSi)(3)ONa and Si(OSi)(4) units, respectively. A new -105 ppm peak, which was due to Si(OSi)(3)OH units, appeared after soaking in the SBF and grew as the soaking period increased, Thus, in the SBF, the glass network was degraded and hydrolyzed; that is, dissolution of the Na+ ions from the glass network and the formation of Si-O- groups occurred, After soaking for 1 d, a P-31 MAS-NMR IR resonance peak of orthophosphate (PO43-) ions that were deposited on the glass surface appeared at similar to 3.0 ppm and grew as the soaking period increased. The chemical shift shows that the local structural environment of phosphorus atoms and ions was very similar to that of hydroxyapatite or rabbit cortical bone. Inductively coupled plasma atomic emission spectroscopic analysis confirmed the adsorption of calcium phosphates on the glasses and the close relationship between the dissolution of the Naf ions and the precipitation of the calcium phosphates. It was concluded that the layer of hydrated silica gel, which was composed of Si(OSi)(3)O- units, provided the negatively charged sites that induced or promoted the precipitation of calcium phosphates, which led to apatite nucleation and crystallization.

Biomimetic Deposition of Calcium Phosphates on Oxides Soaked in a Simulated Body Fluid

S. Hayakawa, A. Osaka

Proc. 15th Univ. Conf. Glass Sci., ed. R. K. Brow, Univ. Missouri-Rolla, Paper M12 1999

Bioactivity of Nb(V)and Ta(V)-Doped Caclium Silicate Glasses(jointly worked)

Naoki Imayoshi, Satoshi Hayakawa, Chikara Ohtsuki, Akiyoshi Osaka

Memoirs of Fac. Eng. Okayama Univ 31 ( 2 ) 39-44 - 44 1997

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