Faculty Profiles - HAYAKAWA Satoshi

Papers - HAYAKAWA Satoshi

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Microstructure evolution in Stober-type silica nanoparticles and their in vitro apatite deposition Reviewed

Song Chen, Akiyoshi Osaka, Satoshi Hayakawa, Kanji Tsuru, Eiji Fujii, Koji Kawabata

JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY 48 ( 3 ) 322 - 335 2008.12

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

Prepared via Stober-type sol-gel routes were three types of silica particles of < 1 mu m in size: pure silica, Ca-involving silica, and chitosan/alginate-coated silica with a polymershell-silica core structure. Calcium ions were impregnated in the organic layers of the polymer-coated silica particle. The sol-gel procedure was applied to tetraethoxysilane dissolved in an ethanol/water mixture, while Ca-silica was derived from CaCl(2)-containing ethanol/water solutions. Scanning and transmission electron micrograph analyses indicated that those silica particles consisted of similar to 10 nm primary particles, the Ca-silica particles (similar to 500 nm) were larger than the Ca-free ones (similar to 200 nm) and that their size increased with the Ca concentration in the precursor solutions. From (1)H- and (29)Si- magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectra and (29)Si cross-polarization NMR spectra, the mechanism of primary particle agglomeration and degradation of the secondary particles in saline were discussed in terms of the content of H(2)O molecules and > Si-OH as well as hydrogen bonding interactions among them. In addition, the Ca-silica and core-shell silica deposited apatite in Kokubo's simulated body fluid. Thus, the present Ca-silica and polymer-coated silica particles were suggested to be applicable to injectable bone fillers for bone generation.

DOI： 10.1007/s10971-008-1823-z

Novel One-pot Sol-Gel Preparation of Amino-functionalized Silica Nanoparticles Reviewed

Song Chen, Akiyoshi Osaka, Satoshi Hayakawa, Kanji Tsuru, Eiji Fujii, Koji Kawabata

CHEMISTRY LETTERS 37 ( 11 ) 1170 - 1171 2008.11

Language：English Publishing type：Research paper (scientific journal) Publisher：CHEMICAL SOC JAPAN

Amino-functionalized silica nanoparticles smaller than 200 nm in diameter were directly prepared from precursor mixtures of tetraethoxysilane and aminopropyltriethoxysilane in ethanol/water solutions via a novel one-pot sol-gel procedure.

DOI： 10.1246/cl.2008.1170

Bilirubin adsorption property of sol-gel-derived titania particles for blood purification therapy Reviewed

Takuji Asano, Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka

ACTA BIOMATERIALIA 4 ( 4 ) 1067 - 1072 2008.7

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

Titania (anatase) gel powders were prepared by peptizing commercially available titania sols and heating them at temperatures up to 700 degrees C, as candidates for bilirubin adsorbents for blood purification therapy. Those titania particles were in contact with a protein solution containing bilirubin and bovine serum albumin that mimics the blood of bilirubinemia patients. The amount of free or direct bilirubin in the solution insignificant. Indirect bilirubin or a bilirubin complex with albumin was adsorbed on the anatase powders, the primary particle size of which was as large as or larger than the size of an albumin molecule. The surface charge and surface charge density were only minor factors in controlling the indirect bilirubin adsorption. The present results indicated that the size of primary particles and hydrophobicity were significant for the sol-derived anatase in terms of bilirubin adsorption, and both were controllable by the heating temperature and the time period. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.actbio.2008.02.024

Novel fabrication of nano-rod array structures on titanium and in vitro cell responses Reviewed

Yongxing Liu, Weihui Chen, Yunzhi Yang, Joo L. Ong, Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka

JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE 19 ( 7 ) 2735 - 2741 2008.7

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

Nano-scale rod arrays of titania were fabricated on titanium surface by a glass phase topotaxy growth (GPT) method, which was featured by an interfacial reaction between sodium tetraborate coating and the preheated metallic titanium at elevated temperature. The samples were characterized by thin-film X-ray diffraction (XRD), scanning electron microscope (SEM), profilometer and contact angle measurement. Thin-film XRD analysis indicated that the nano-rod arrays were composed of pure rutile titania phase. SEM images showed that these rutile rods were 100-200 nm wide and 1-2 mu m long. The nano-rod arrays had significantly higher average roughness (P < 0.05) and greater hydrophilicity (P < 0.05) compared to the control. Human embryonic palatal mesenchymal (HEPM) cells were grown to evaluate in vitro cell responses to the nano-rod array structures in terms of cell attachment and proliferation. An equivalent high attachment rate of 94% was observed after 4-h incubation, but a lower proliferation rate was observed on the nano-rod array after 12-day culture compared to the control (P < 0.05).

DOI： 10.1007/s10856-008-3396-3

Gelatin-siloxane hybrid scaffolds with vascular endothelial growth factor induces brain tissue regeneration Reviewed

Hanzhe Zhang, Tatsushi Kamiya, Takeshi Hayashi, Kanji Tsuru, Kentaro Deguchi, Violeta Lukic, Atsushi Tsuchiya, Toru Yamashita, Satoshi Hayakawa, Yoshio Ikeda, Akiyoshi Osaka, Koji Abe

CURRENT NEUROVASCULAR RESEARCH 5 ( 2 ) 112 - 117 2008.5

Language：English Publishing type：Research paper (scientific journal) Publisher：BENTHAM SCIENCE PUBL LTD

In the brain after infarction or trauma, the tissue becomes pannecrotic and forms a cavity. In such situation, a scaffold is necessary to produce new tissue. In this study, we implanted a new porous gelatin-siloxane hybrid derived from gelatin and 3-(glycidoxypropyl) trimethoxysilane (gelatin-GPTMS) scaffolds into a brain defect, and investigated whether it makes a new brain tissue. In addition, vascular endothelial growth factor ( VEGF) was added on gelatin-GPTMS scaffolds and its effect on tissue regeneration was examined. At 30 days after the implantation, the marginal territory of the scaffolds became occupied by newly formed tissue. Immunohistochemical analysis revealed that the new tissue was constituted by endothelial, astroglial and microglial cells, some of which were labeled for bromodeoxyuridine (BrdU). Addition of VEGF promoted numbers of these cells. Thus, combination of gelatin-GPTMS scaffolds and VEGF is preferable for brain regeneration.

DOI： 10.2174/156720208784310204

Revisiting silicate substituted hydroxyapatite by solid-state NMR Reviewed

G. Gasqueres, C. Bonhomme, J. Maquet, F. Babonneau, S. Hayakawa, T. Kanaya, A. Osaka

MAGNETIC RESONANCE IN CHEMISTRY 46 ( 4 ) 342 - 346 2008.4

Language：English Publishing type：Research paper (scientific journal) Publisher：JOHN WILEY & SONS LTD

Silicon-substituted hydroxyapatite (Si-HAp) has shown promising properties such as high-bone remodeling around implants. So far, the techniques used for the structural characterization of the Si-HAp have given indirect evidence of the presence of silicon inside the structure (by X-ray and neutron diffraction). In this paper, we focus on Si-HAp derivatives obtained by a precipitation method (widely described in the literature). We demonstrate here by solid-state NMR spectroscopy that only a fraction of the silicon atoms are incorporated into the HAp lattice in the form of Q(0) (SiO44-) species, for 4.6 wt% Si-HAp. A large amount of silicate units are located outside the HAp structure and correspond to silica-gel units. All results were established through Si-29 MAS, H-1 -> Si-29 CP MAS and T1 rho(H-1) edited H-1 -> Si-29 CP MAS experiments. This last pulse scheme acted as a powerful editing sequence, leading to unambiguous spectroscopic conclusions, concerning the location of the SiO44- moieties. Copyright (C) 2008 John Wiley & Sons, Ltd.

DOI： 10.1002/mrc.2109

Modification of Ti implant surface for cell proliferation and cell alignment Reviewed

Jia Ming Zhao, Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka

JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A 84A ( 4 ) 988 - 993 2008.3

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-LISS

Surface properties of implants are the keys for ensuring their long-lasting anchorage to the tissue. This study aims to develop a novel implant surface microstructure with high biocompatibility and ability of guided tissue formation. By a photolithography method, gold (Au) grids (1 X 1 mm(2) square lattices, 10 pm in grid-line width) were deposited on titanium substrates. They were oxidized with H2O2 solution to yield titania (anatase) layer, and the Au grid formed channels due to larger molar volume of anatase than Ti. L-Cysteine and type I collagen were then immobilized on them to yield the target substrates, CHT-Au-cys-col. Apatite deposited within 3 days when they were soaked in Kokubo's simulated body fluid, regardless of the protein coating, but not on the bottom of the Au channel. Osteoblast-like MC3T3-E1 cells were cultured on the CHT-Au-cys-col substrates, showing that (1) the cysteine-collagen coating promoted cell attachment and proliferation, and (2) the Au channels were filled with the cells which were aligned along the channel direction and were connected to the neighboring cells as well as attached to the channel wall with cytoplasmic extensions. The results thus ensured filopodial guidance for the substrates. (C) 2007 Wiley Periodicals, Inc.

DOI： 10.1002/jbm.a.31426

Surface topography designed to provide osteoconductivity to titanium after thermal oxidation Reviewed

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

MATERIALS TRANSACTIONS 49 ( 3 ) 428 - 434 2008.3

Language：English Publishing type：Research paper (scientific journal) Publisher：JAPAN INST METALS

Hydroxyapatite formation on the surface of materials in the body is an essential condition for demonstrating osteoconduction after implantation in bony defects. This paper reports a technique for providing hydroxyapatite formation properties to titanium metals by using specially designed surface topography followed by thermal oxidation. Two pieces of titanium thermally oxidized at 400 degrees C were set together in a V-shape with varied mouth opening. They showed the formation of hydroxyapatite on both facing surfaces after exposure to a simulated body fluid (SBF), when the gap height was approximately less than 600 mu m. Moreover, pure titanium specimens with macro-grooves less than 1000 pm in depth and 800 mu m in width were able to form hydroxyapatite deposits in SBF within 604.8 ks, after they were thermally oxidized at 400 degrees C for 3.6 ks. Hydroxyapatite also formed on the internal surfaces of macro-grooves made in Ti-15-Zr-4Ta-4Nb within 604.8 ks of soaking in SBF, after the sample was thermally oxidized at 500 degrees C for 3.6 ks, whereas it was not deposited on alloy made of Ti-6Al-4V extra low interstitial processed in the same way. These findings indicate that titanium and its alloys can be conferred with hydroxyapatite-forming ability, i.e. osteoconduction, within a controlled spatial gap and thermal oxidation. We conclude that bioactive titanium substrate showing osteoconduction can be produced by using a specially designed surface topography followed by thermal oxidation at an appropriate temperature.

DOI： 10.2320/matertrans.MBW200711

Synthesis and cytocompatibility of porous chitosan-silicate hybrids for tissue engineering scaffold application Reviewed

Yuki Shirosaki, Tomoyuki Okayama, Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka

CHEMICAL ENGINEERING JOURNAL 137 ( 1 ) 122 - 128 2008.3

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE SA

Chitosan-silicate hybrids with 3D porous structures were prepared with freeze-drying precursor solutions derived from chitosan and gamma-glycidoxypropyltrimethoxysilane (GPTMS). They were formed easily in any shape, such as sheets, pellets, disks, granules, and even roll-cakes. The pore size was strongly dependent on the freezing temperature: lower freezing temperature resulted smaller pores, about 110 mu m for the hybrids frozen at -20 degrees C, and about 50 mu m for those at -85 degrees C. The pore size was little dependent on the GPTMS content. In contrast, the GPTMS content affected porosity a littlie: similar to 80% for chitosan, and similar to 90% for the GPTMS-containing hybrids. Thus, their porous microstructure was controllable due to the freezing temperature and composition. MG63 osteoblastic cells were cultured up to 7 days on the porous hybrids. The cells adhered on the pore walls, proliferated, and migrated deep into the pore structure. It was thus concluded that the present chitosan-silicate hybrids were promising for tissue engineering scaffold applications. (C) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.cej.2007.10.012

Low density lipoprotein adsorption on sol-gel derived alumina for blood purification therapy Reviewed

Takuji Asano, Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka

BIO-MEDICAL MATERIALS AND ENGINEERING 18 ( 3 ) 161 - 170 2008

Language：English Publishing type：Research paper (scientific journal) Publisher：IOS PRESS

Among the clinical treatments of Familial Hyper cholesterolemia patients to reduce the concentration of low density lipoprotein (LDL), blood purification therapy is most suitable in which a blood-compatible adsorbent is employed. In the present study, alumina powders were prepared via a sol-gel route to develop a LDL-adsorbent Aluminum tri2-propoxide was hydrolyzed and subsequently calcined up to 1200 degrees C. Surface charge density and pore size distribution were measured, and the phases were identified. The alumina calcined above 400 degrees C had excellent blood compatibility in terms of endogenous clotting parameters, i.e., partial thromboplastin time: (PTT), prothrombin time: (PT), and the amount of fibrinogen: (Fib). The amount of LDL-adsorption (Delta W-LDL) increased with the calcining temperature, showing a good linear correlation to surface charge density. The 1200 degrees C sample consisted only of a-alumina, and was greatest in Delta W-LDL. All samples involved pores smaller than 20 nm but not the pores large enough to accommodate LDL molecules (20-25 nm). From those results, it was concluded for the present alumina particles that the surface charge density was the primary factor and that the chemical activity of a-alumina also contributed to the excellent LDL-adsorption for the 1200 degrees C sample, while entrapping LDL in the pores was not an active mechanism.

DOI： 10.3233/BME-2008-0519

Enhancement of in vitro apatite-forming ability of thermally oxidized titanium surfaces by ultraviolet irradiation Reviewed

Tetsuya Shozui, Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka

Journal of the Ceramic Society of Japan 116 ( 1352 ) 530 - 535 2008

Language：English Publishing type：Research paper (scientific journal) Publisher：Ceramic Society of Japan

Ultraviolet (UV) light was irradiated in air for 1 h on titania (rutile) films prepared by thermal oxidation of titanium substrates from 300°C up to 800°C, coded as HT300UV, HT400UV, HT500UV, HT600UV, HT700UV, and HT800UV, respectively. All samples were then soaked in a simulated body fluid (SBF, Kokubo solution) and their in vitro apatite-forming ability was evaluated. It was found that bone-like apatite particles were deposited on HT500UV, HT600UV, and HT700UV within 7 d whereas that was not the case with others during the same period. Moreover, the apatite particles were deposited more on HT500UV than on the others. Therefore, the ultraviolet light irradiation enhanced the in vitro apatite-forming ability of the thermally oxidized titanium. ©2008 The Ceramic Society of Japan. All rights reserved.

DOI： 10.2109/jcersj2.116.530

空間デザインによるチタン系医用金属へのアパタイト形成能付与

都留寛治, 杉野篤史, 早川聡, 大槻主税, 尾坂明義

PHOSPHORUS LETTER 61 ( 61 ) 10 - 16 2008

Vascular endothelial growth factor promotes brain tissue regeneration with a novel biomaterial polydimethylsiloxane-tetraethoxysilane Reviewed

HanZhe Zhang, Takeshi Hayashi, Kanji Tsuru, Kentaro Deguchi, Mitsuyuki Nagahara, Satoshi Hayakawa, Makiko Nagai, Tatsushi Kamiya, Akiyoshi Osaka, Koji Abe

Journal of Cerebral Blood Flow and Metabolism Volume 1132 Issue 1 pp. 29-35. 2007.11

Background: Injury of the central nervous system (CNS) of mammals may cause irreparable damage due to the limited regeneration capacity of the tissue. In order for the CNS tissue to regenerate, to supply a scaffold for the newly produced cells to adhere is necessary. Application of biodegradable polymers such as collagen, gelatin, fibrin and alginates has been investigated for organ damage other than the CNS. In this context, we recently produced a novel biomaterial from polydimethylsiloxane (PDMS) and tetraethoxysilane (TEOS). We added the most potent angiogenic factor vascular endothelial growth factor (VEGF) and observed the difference in brain regenerative process in the PDMS-TEOS scaffold. Methods: Male Wistar rats of 12 weeks old were anesthetized and placed in a stereotaxic apparatus. A piece of bone over the right frontal cortex was excised, and 2 x 5 mm defect in the brain was made by cutting and aspiration. The defect was positioned from 1.0 mm anterior to 4.0 mm posterior of the bregma and 2.0 to 4.0 mm lateral to the midline. The depth of the lesion was 2.0 mm from the brain surface. The block of PDMS-TEOS scaffold, with or without VEGF, was placed into the lesion immediately after making the defect. The animals were sacrificed at 30 days after PDMS-TEOS scaffold implantation. For histological analysis of the newly formed tissue, the sections were stained with HE. In order to identify cell types in the newly formed tissue, we performed immunohistochemical analysis for glial fibrillary acidic protein (GFAP), an astrocyte marker, and N-acetylglucosamine oligomer (NAGO), an endothelial cells marker. In order to determine whether the cells in PDMS-TEOS scaffold were under mitosis, we carried out double fluorescent study for cell phenotype markers and Ki67. Result: The PDMS-TEOS scaffold remained at the implanted site for 30 days and kept the integrity of brain shape (Fig. A and B). HE staining showed that a small number of cells infiltrated into the PDMS-TEOS scaffold even without VEGF at 30 days after the implantation, but that addition of VEGF significantly increased the number of infiltrated cells NAGO staining showed only a few positive cells in the PDMS-TEOS scaffold without VEGF, but significant increase of endothelial cells with VEGF was confirmed. Immunohistochemical study for GFAP demonstrated that only a few astrocytes were found in the PDMS-TEOS scaffold without VEGF, which was again significantly increased with VEGF. Double staining with proliferation maker Ki67 demonstrated that VEGF significantly increased newly formed astrocytes and endotheial cells, indicating that addition of VEGF accelerated tissue restoration and angiogenesis. Conclusions: The present study showed that a new porous PDMS-TEOS is a good candidate biomaterial for brain tissue restoration. Endothelial as well as glial cells successfully infiltrated into this biomaterial. Addition of VEGF further promoted new tissue formation.

DOI： 10.1016/j.brainres.2006.09.117

Bilirubin adsorption using titanium oxide particles Reviewed

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

INTERNATIONAL JOURNAL OF ARTIFICIAL ORGANS 30 ( 8 ) 704 - 704 2007.8

Anatase/rutile dual layer deposition due to hydrolysis of titanium oxysulfate with hydrogen peroxide solution at low temperature Reviewed

Fan Xiao, Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka

JOURNAL OF MATERIALS SCIENCE 42 ( 15 ) 6339 - 6346 2007.8

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

Anatase/rutile dual layers were deposited on titanium and polyethylene substrates when they were soaked in TiOSO4/H2O2 solution and aged in hot water: The dense bottom layer predominantly consisted of rutile, while the upper layer consisted of loosely packed aggregation of anatase particles. The titania deposition was the results of compromise among three conflicting processes: (1) hydrolysis of TiOSO4 to yield either soluble titania-H2O2 complexes or titania, (2) dissolution of the titania layer under the presence of H2O2, and (3) corrosive reactions between titanium substrates and H2O2 to yield similar complexes or compounds. The dissolution-deposition equilibrium was found associated with pH of the sulfate solution and changed with soaking time. Thus, proper pH value and soaking time in the treating solution were the two key factors to control the formation of dense titania layers. The resulted titania layers were easily covered with fine apatite particles when soaked in a solution supersaturated with its component ions.

DOI： 10.1007/s10853-006-1220-3

Low-temperature deposition of rutile film on biomaterials substrates and its ability to induce apatite deposition in vitro Reviewed

Jin-Ming Wu, Jin-Fang Liu, Satoshi Hayakawa, Kanji Tsuru, Akiyoshi Osaka

JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE 18 ( 8 ) 1529 - 1536 2007.8

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

Low-temperature deposition of crystalline titania films on intrinsically bioinert materials to induce the bioactivity is of practical interest, not only because it meets the demand of providing organic biomaterials with bioactivity, which cannot tolerate high-temperature thermal treatments, but also because it reserves abundant Ti-OH groups facilitating the apatite deposition. In this paper, rutile films with thickness varied from 0.1 mu m to 1.7 mu m were deposited on commercially available pure titanium substrates from 1.5 M titanium tetrachloride aqueous solution kept at 60 degrees C for 3-60 h. The rutile films grew to give a preferred (101) crystalline plane in the X-ray diffraction pattern. After soaking in a simulated body fluid of the Kokubo solution (SBF) for 2 days, the rutile films with thickness over 0.6 mu m were covered with a layer of apatite. All the films with various thickness induced apatite deposition in SBF after soaking for 5 days. The bioinert polytetrafluoroethylene (PTFE) was also found to exhibit remarkable in vitro bioactivity as to induce apatite deposition from SBF within 2 days, after depositing the rutile film on the surface.

DOI： 10.1007/s10856-006-0115-9

Structural characterization and protein adsorption property of hydroxyapatite particles modified with zinc ions Reviewed

Satoshi Hayakawa, Kanae Ando, Kanji Tsuru, Akiyoshi Osaka, Eiji Fujii, Koji Kawabata, Christian Bonhomme, Florence Babonneau

JOURNAL OF THE AMERICAN CERAMIC SOCIETY 90 ( 2 ) 565 - 569 2007.2

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：BLACKWELL PUBLISHING

Zinc-containing hydroxyapatite particles (Zn/HAp) were prepared by an ion exchange reaction process involving hydroxyapatite (HAp) particles with aqueous solutions containing various amounts of zinc nitrate. The Zn2+ ion was partially substituted for the Ca2+ ion position in the HAp lattice, and hence, the obtained samples had changed little in crystallinity, particle size, and specific surface area. Adsorption of bovine serum albumin (BSA) and beta(2)-microglobulin (beta(2)-MG) in solutions containing both BSA and beta(2)-MG was examined. As the Zn2+ ion content in the apatites increased, the adsorbed amount of BSA was almost constant, whereas that of beta(2)-MG increased.

DOI： 10.1111/j.1551-2916.2006.01396.x

Wet deposition of titania-apatite composite in cotton fibrils Reviewed

Satoshi Hayakawa, Jin-Fang Liu, Kanji Tsuru, Akiyoshi Osaka

JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY 40 ( 2-3 ) 253 - 258 2006.12

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

Titania consisting of rutile and anatase was precipitated on and inside of cotton fibrils when cotton was soaked in an aqueous solution of 30 mM TiOSO4 and 30 mM H2O2 kept at 80 degrees C for 24 h. As the resultant titania-cotton fibrils were soaked in a simulated body fluid (Kokubo solution), apatite was deposited on the fibrils to yield cotton-titania-apatite composites within 1 d. Thus, the present study provided a simple technique to prepare titania-apatite composites and coatings on organic materials at low temperature.

DOI： 10.1007/s10971-006-8759-y

Implantation of a new porous gelatin-siloxane hybrid into a brain lesion as a potential scaffold for tissue regeneration Reviewed

Kentaro Deguchi, Kanji Tsuru, Takeshi Hayashi, Mikiro Takaishi, Mitsuyuki Nagahara, Shoko Nagotani, Yoshihide Sehara, Guang Jin, HanZhe Zhang, Satoshi Hayakawa, Mikio Shoji, Masahiro Miyazaki, Akiyoshi Osaka, Nam-Ho Huh, Koji Abe

JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM 26 ( 10 ) 1263 - 1273 2006.10

Language：English Publishing type：Research paper (scientific journal) Publisher：NATURE PUBLISHING GROUP

For brain tissue regeneration, any scaffold for migrated or transplanted stem cells with supportive angiogenesis is important once necrotic brain tissue has formed a cavity after injury such as cerebral ischemia. In this study, a new porous gelatin-siloxane hybrid derived from the integration of gelatin and 3-(glycidoxypropyl) trimethoxysilane was implanted as a three-dimensional scaffold into a defect of the cerebral cortex. The porous hybrid implanted into the lesion remained at the same site for 60 days, kept integrity of the brain shape, and attached well to the surrounding brain tissues. Marginal cavities of the scaffolds were occupied by newly formed tissue in the brain, where newly produced vascular endothelial, astroglial, and microglial cells were found with bromodeoxyuridine double positivity, and the numbers of those cells were dose-dependently increased with the addition of basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF). Extension of dendrites was also found from the surrounding cerebral cortex to the newly formed tissue, especially with the addition of bFGF and EGF. The present study showed that a new porous gelatinsiloxane hybrid had biocompatibility after implantation into a lesion of the central nervous system, and thus provided a potential scaffold for cell migration, angiogenesis and dendrite elongation with dose-dependent effects of additive bFGF and EGF.

DOI： 10.1038/sj.jcbfm.9600275

Synthesis and structural characterization of silica-hybridized hydroxyapatite with gas adsorption capability Reviewed

Eiji Fujii, Koji Kawabata, Kanae Ando, Kanji Tsuru, Satoshi Hayakawa, Akiyoshi Osaka

JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 114 ( 1333 ) 769 - 773 2006.9

Language：English Publishing type：Research paper (scientific journal) Publisher：CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI

Silica-hybridized hydroxyapatite powder was prepared from a calcium hydroxide and phosphoric acid together with a tetra-n-butyl orthosilicate as the silica source in order to apply it as a gas adsorbent. According to the X-ray diffraction patterns, all peaks were assigned to the hydroxyapatite. No secondary phases, such as calcium hydroxide and silicon oxides, were observed. Moreover, the transmission electron microscope observations indicated that the crystallite size hardly changed by increasing the silicon oxide content. However, the adsorption areas of nitrogen, water and benzene were remarkably dependent on the silicon oxide content. In this paper, in order to explain the change in the adsorption areas, the lattice structure of the silica-hybridized hydroxyapatite is discussed based on the results obtained by the Si-29 and P-31 magic angle spinning-nuclear magnetic resonance spectroscopy (MAS-NMR).

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