I had a chance to visit Kohama Island in Okinawa this March, where a beautiful coral reef expanded continuously near the sea shore. It is well known that coral is composed of inorganic calcium carbonate (Aragonite). We can find red and blue coral in addition to a popular white coral. I don’t know how they are colored. We admire the surprising colorful nature. Shells are also composed with calcium carbonate and keep a number of shapes and colors as well.
{"title":"A FUN SURVEY OF THE MYSTERY OF APATITES","authors":"M. Okazaki","doi":"10.3363/PRB.26.16","DOIUrl":"https://doi.org/10.3363/PRB.26.16","url":null,"abstract":"I had a chance to visit Kohama Island in Okinawa this March, where a beautiful coral reef expanded continuously near the sea shore. It is well known that coral is composed of inorganic calcium carbonate (Aragonite). We can find red and blue coral in addition to a popular white coral. I don’t know how they are colored. We admire the surprising colorful nature. Shells are also composed with calcium carbonate and keep a number of shapes and colors as well.","PeriodicalId":20022,"journal":{"name":"Phosphorus Research Bulletin","volume":"54 1","pages":"16-17"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74999552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Toshiisa Konishi, Shuhei Takahashi, Minori Mizumoto, M. Honda, K. Oribe, M. Aizawa
In order to enhance the handling ability and mechanical properties of chelate-setting β-tricalcium phosphate (β-TCP) cement, various polysaccharides, such as sodium alginate, sodium dextran sulfate, sodium chondroitin sulfate, and chitosan (Chito GL and W10), were added to mixing solutions for cement preparation. When mixing solutions containing the above additives were used, the handling ability of all the cement pastes was improved compared with the case of pure water without polysaccharide. Among the examined cement specimens, the cement with the highest compressive strength (17.4 MPa) was obtained using Chito W10. Although the viability of cells co-cultured with cements fabricated using additives was less than that of the control and water on the first day, the number of cells increased until the fifth day. The addition of chitosan (Chito W10) into the mixing solution is promising in the fabrication of chelate-setting β-TCP cement with enhanced handling ability and mechanical properties. (Received January 28, 2012; Accepted February 9, 2012)
{"title":"EFFECT OF THE ADDITION OF VARIOUS POLYSACCHARIDES ON THE MATERIAL PROPERTIES AND CYTOTOXICITY OF CHELATE-SETTING β-TRICALCIUM PHOSPHATE CEMENT","authors":"Toshiisa Konishi, Shuhei Takahashi, Minori Mizumoto, M. Honda, K. Oribe, M. Aizawa","doi":"10.3363/PRB.26.59","DOIUrl":"https://doi.org/10.3363/PRB.26.59","url":null,"abstract":"In order to enhance the handling ability and mechanical properties of chelate-setting β-tricalcium phosphate (β-TCP) cement, various polysaccharides, such as sodium alginate, sodium dextran sulfate, sodium chondroitin sulfate, and chitosan (Chito GL and W10), were added to mixing solutions for cement preparation. When mixing solutions containing the above additives were used, the handling ability of all the cement pastes was improved compared with the case of pure water without polysaccharide. Among the examined cement specimens, the cement with the highest compressive strength (17.4 MPa) was obtained using Chito W10. Although the viability of cells co-cultured with cements fabricated using additives was less than that of the control and water on the first day, the number of cells increased until the fifth day. The addition of chitosan (Chito W10) into the mixing solution is promising in the fabrication of chelate-setting β-TCP cement with enhanced handling ability and mechanical properties. (Received January 28, 2012; Accepted February 9, 2012)","PeriodicalId":20022,"journal":{"name":"Phosphorus Research Bulletin","volume":"5 1","pages":"59-64"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75961235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: Fe(III)-treated hydroxyapatites, HAP-300-Fe and HAP-400-Fe, were prepared from hydroxyapatites, HAP-300 (stoichiometric type) and HAP-400 (Ca-deficient type), respectively, and applied to photo-Fenton reaction of dyes as heterogeneous catalysts in comparison with other Fe catalysts such as Fe 2 O 3 , FePO 4 •2H 2 O, and FeOOH. Among the Fe catalysts, HAP-400-Fe revealed the highest consumption and mineralization in photo-Fenton reaction of alizarin red S (ARS), and also indicated good catalytic activity to other dyes, alizarin, neutral red, methyl red, methyl orange (MO), Congo red, and indigo carmine. Generation of hydroxyl radical •OH as an oxidation species from H 2 O 2 was observed in the all Fe catalysts by an indirect method using N, N-dimethylamino-4-nitrosoaniline, which is exclusively sensitive to •OH. In order to elucidate catalysis mechanism of Fe catalysts, kinetic investigation based on Michaelis-Menten theory was conducted in the reaction of ARS and MO. As a result, HAP-400-Fe indicated high ability of bearing many dye molecules but low degradative catalysis ability to H 2 O 2 , compared with Fe 2 O 3 . However, judging from high mineralization ability as well as repeating availability (5 times), HAP-400-Fe is considered as an excellent heterogeneous catalyst for photo-Fenton reaction.
{"title":"Erratum: PHOTO-FENTON REACTION OF DYES WITH Fe(III)-TREATED HYDROXYAPATITES AS HETEROGENEOUS CATALYSTS IN WATER","authors":"T. Moriguchi, S. Nakagawa","doi":"10.3363/PRB.26.117","DOIUrl":"https://doi.org/10.3363/PRB.26.117","url":null,"abstract":": Fe(III)-treated hydroxyapatites, HAP-300-Fe and HAP-400-Fe, were prepared from hydroxyapatites, HAP-300 (stoichiometric type) and HAP-400 (Ca-deficient type), respectively, and applied to photo-Fenton reaction of dyes as heterogeneous catalysts in comparison with other Fe catalysts such as Fe 2 O 3 , FePO 4 •2H 2 O, and FeOOH. Among the Fe catalysts, HAP-400-Fe revealed the highest consumption and mineralization in photo-Fenton reaction of alizarin red S (ARS), and also indicated good catalytic activity to other dyes, alizarin, neutral red, methyl red, methyl orange (MO), Congo red, and indigo carmine. Generation of hydroxyl radical •OH as an oxidation species from H 2 O 2 was observed in the all Fe catalysts by an indirect method using N, N-dimethylamino-4-nitrosoaniline, which is exclusively sensitive to •OH. In order to elucidate catalysis mechanism of Fe catalysts, kinetic investigation based on Michaelis-Menten theory was conducted in the reaction of ARS and MO. As a result, HAP-400-Fe indicated high ability of bearing many dye molecules but low degradative catalysis ability to H 2 O 2 , compared with Fe 2 O 3 . However, judging from high mineralization ability as well as repeating availability (5 times), HAP-400-Fe is considered as an excellent heterogeneous catalyst for photo-Fenton reaction.","PeriodicalId":20022,"journal":{"name":"Phosphorus Research Bulletin","volume":"17 1","pages":"117-130"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82999580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rikako Miyamoto, Asuka Ozawa, Takeshi Yamada, H. Shibata, Katsumi Yoshida, Osamu Yamanuro, K. Hashimoto
Manganese (II) ions were substituted for Ca ions at the Ca(4) and Ca(5) sites located in the A column of the β-tricalcium phosphate (β-TCP) crystal structure, and effects of additions of Mn ions on proliferation and differentiation of osteoblasts were examined using mouse MC3T3-E1 osteoblast-like cells. The X-ray diffraction patterns of β-TCP doped with manganese (II) ions (Mn-β-TCP) indicated the formation of β-TCP solid solution to 13.64 mol%. MC3T3-E1 cells attached on Mn-β-TCP well proliferated compare to those on β-TCP. In particular, Mn-β-TCP doped with 3 mol% showed the most excellent cell proliferation and the highest ALP activity level. We consider that the new bone formation may be promoted by dissolution of calcium ions and manganese ions from Mn--TCP. The present Mn-β-TCP is expected as an implant biomaterial with enhanced bioactivity. (Received May 31, 2012; Accepted June 12, 2012)
{"title":"PROLIFERATION AND DIFFERENTIATION OF OSTEOBLAST-LIKE CELLS ON β-TRICALCIUM PHOSPHATE DOPED WITH MANGANESE (II) IONS","authors":"Rikako Miyamoto, Asuka Ozawa, Takeshi Yamada, H. Shibata, Katsumi Yoshida, Osamu Yamanuro, K. Hashimoto","doi":"10.3363/PRB.26.87","DOIUrl":"https://doi.org/10.3363/PRB.26.87","url":null,"abstract":"Manganese (II) ions were substituted for Ca ions at the Ca(4) and Ca(5) sites located in the A column of the β-tricalcium phosphate (β-TCP) crystal structure, and effects of additions of Mn ions on proliferation and differentiation of osteoblasts were examined using mouse MC3T3-E1 osteoblast-like cells. The X-ray diffraction patterns of β-TCP doped with manganese (II) ions (Mn-β-TCP) indicated the formation of β-TCP solid solution to 13.64 mol%. MC3T3-E1 cells attached on Mn-β-TCP well proliferated compare to those on β-TCP. In particular, Mn-β-TCP doped with 3 mol% showed the most excellent cell proliferation and the highest ALP activity level. We consider that the new bone formation may be promoted by dissolution of calcium ions and manganese ions from Mn--TCP. The present Mn-β-TCP is expected as an implant biomaterial with enhanced bioactivity. (Received May 31, 2012; Accepted June 12, 2012)","PeriodicalId":20022,"journal":{"name":"Phosphorus Research Bulletin","volume":"76 1","pages":"87-90"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72689061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"PREPARATION AND APATITE-FORMING ABILITY OF CaSO4-PHOSPHATE GLASS COMPOSITES","authors":"Naoya Yoshida, Takayo Shirai, T. Okura","doi":"10.3363/PRB.26.95","DOIUrl":"https://doi.org/10.3363/PRB.26.95","url":null,"abstract":"","PeriodicalId":20022,"journal":{"name":"Phosphorus Research Bulletin","volume":"47 1","pages":"95-100"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86519181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: Iron phosphate was prepared from iron nitrate and phosphoric acid with sodium dodecyl-sulfate at various stirring hours. The chemical composition of the obtained samples was estimated from ICP and XRD measurements. Particle shape and size distribution were observed by SEM images and laser diffraction / scattering methods. Further, the catalytic activity was studied with the decomposition of the complex between hormaldehyde and acetylacetone. Samples heated at 600ºC indicated XRD peaks of FePO 4 . Iron phosphates heated at 200 and 400ºC works as a catalyst.
{"title":"PREPARATION AND ACIDIC PROPERTIES OF IRON PHOSPHATES WITH SODIUM DODECYL-SULFATE","authors":"H. Onoda, T. Sakumura","doi":"10.3363/PRB.27.28","DOIUrl":"https://doi.org/10.3363/PRB.27.28","url":null,"abstract":": Iron phosphate was prepared from iron nitrate and phosphoric acid with sodium dodecyl-sulfate at various stirring hours. The chemical composition of the obtained samples was estimated from ICP and XRD measurements. Particle shape and size distribution were observed by SEM images and laser diffraction / scattering methods. Further, the catalytic activity was studied with the decomposition of the complex between hormaldehyde and acetylacetone. Samples heated at 600ºC indicated XRD peaks of FePO 4 . Iron phosphates heated at 200 and 400ºC works as a catalyst.","PeriodicalId":20022,"journal":{"name":"Phosphorus Research Bulletin","volume":"45 1","pages":"28-32"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85342149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Ganmoto, M. Honda, Toshiisa Konishi, Minori Mizumoto, H. Matsunari, Yasuhiro Takeuchi, H. Nagashima, M. Aizawa
We have successfully synthesized single-crystal apatite fibers (AF) by a homogeneous precipitation method with urea. The AF has a higher solubility than isotropic HAp powders. Thus, using the AF, we developed apatite-fiber scaffolds (AFSs) that enables three-dimensionally cell culture and induces differentiation into osteoblasts. Recently, we have successfully enhanced mechanical properties of the AFSs using carbon beads (CB) with a diameter of 150 m and 20 m, together with uniaxial pressing of the green compacts. In this study, we fabricated the AFSs with enhanced mechanical property (AFS700(50-50)), and then implanted them into tibia of pig to evaluate a biocompatibility to a hard tissue. The porosity of the resulting and compressive strength of typical AFS700(50-50) were 93.5% and 128 kPa, respectively. The AFS700(50-50) had a number of micro pores, macro-pores and interconnected pores. In the histological observation after 13 weeks implantation, newly-formed bone and cells were invaded into pores of the AFS700(50-50), and the scaffolds were incorporated into a cycle of bone remodeling. The AFS700(50-50) was also observed to be replaced with autologous tissue. The present scaffold may be expected as a high performance scaffold for bone regeneration. (Received May 8, 2012; Accepted May 16, 2012)
{"title":"IN VIVO BIOCOMPATIBILITY OF APATITE-FIBER SCAFFOLD WITH ENHANCED MECHANICAL PROPERTY USING PIG MODEL BY IMPLANTING INTO TIBIA","authors":"T. Ganmoto, M. Honda, Toshiisa Konishi, Minori Mizumoto, H. Matsunari, Yasuhiro Takeuchi, H. Nagashima, M. Aizawa","doi":"10.3363/PRB.26.1","DOIUrl":"https://doi.org/10.3363/PRB.26.1","url":null,"abstract":"We have successfully synthesized single-crystal apatite fibers (AF) by a homogeneous precipitation method with urea. The AF has a higher solubility than isotropic HAp powders. Thus, using the AF, we developed apatite-fiber scaffolds (AFSs) that enables three-dimensionally cell culture and induces differentiation into osteoblasts. Recently, we have successfully enhanced mechanical properties of the AFSs using carbon beads (CB) with a diameter of 150 m and 20 m, together with uniaxial pressing of the green compacts. In this study, we fabricated the AFSs with enhanced mechanical property (AFS700(50-50)), and then implanted them into tibia of pig to evaluate a biocompatibility to a hard tissue. The porosity of the resulting and compressive strength of typical AFS700(50-50) were 93.5% and 128 kPa, respectively. The AFS700(50-50) had a number of micro pores, macro-pores and interconnected pores. In the histological observation after 13 weeks implantation, newly-formed bone and cells were invaded into pores of the AFS700(50-50), and the scaffolds were incorporated into a cycle of bone remodeling. The AFS700(50-50) was also observed to be replaced with autologous tissue. The present scaffold may be expected as a high performance scaffold for bone regeneration. (Received May 8, 2012; Accepted May 16, 2012)","PeriodicalId":20022,"journal":{"name":"Phosphorus Research Bulletin","volume":"26 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84158812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: Morphological control of hydroxyapatite (HAp) is very difficult because this compound has very low solubility. However, CaCO 3 , a calcium salt with the same insolubility, dissolves easily in solutions containing CO 2 . Therefore, HAp was easily dissolved by CO 2 blowing into the HAp suspension. The dissolution amount was 200 times that found without CO 2 blowing. Thus, a high-concentration HAp solution could be prepared through the simple process of CO 2 blowing. Moreover, flower-like HAp particles were deposited by outgassing the dissolved CO 2 in the HAp solution under heating.
{"title":"PREPARATION OF HIGH-CONCENTRATION HYDROXYAPATITE SOLUTION BY CARBON DIOXIDE BLOWING FOR MORPHOLOGICAL CONTROL OF HYDROXYAPATITE","authors":"T. Toyama, H. Nakajima, Y. Kojima, N. Nishimiya","doi":"10.3363/PRB.26.91","DOIUrl":"https://doi.org/10.3363/PRB.26.91","url":null,"abstract":": Morphological control of hydroxyapatite (HAp) is very difficult because this compound has very low solubility. However, CaCO 3 , a calcium salt with the same insolubility, dissolves easily in solutions containing CO 2 . Therefore, HAp was easily dissolved by CO 2 blowing into the HAp suspension. The dissolution amount was 200 times that found without CO 2 blowing. Thus, a high-concentration HAp solution could be prepared through the simple process of CO 2 blowing. Moreover, flower-like HAp particles were deposited by outgassing the dissolved CO 2 in the HAp solution under heating.","PeriodicalId":20022,"journal":{"name":"Phosphorus Research Bulletin","volume":"233 1","pages":"91-94"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74507880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Miho Nakamura, Masahiro Inuzuka, K. Hashimoto, A. Nagai, K. Yamashita
Yttria-stabilized zirconia is currently used as an orthopedic and dental material, because of its excellent mechanical properties. In this study, we have improved the bioactivity of yttria-stabilized zirconia by a combination of electrical polarization and chemical treatment. The phase transformation from tetragonal to monoclinic ZrO2 after alkaline treatment was inhibited on positively charged yttria-stabilized zirconia surfaces compared with negatively charged and conventional surfaces. During polarization, some oxide ions move from the positively charged surface to the negatively charged surface, leading to an increase in oxygen vacancies on the positive surface and hence greater formation of Zr-OH when this surface was exposed to alkaline solution. The bioactivity was assessed by immersing the samples in simulated body fluid and evaluating the growth of apatite on the surfaces. The combination of polarization and alkaline treatment increased the bioactivity in vitro. (Received January 11, 2012; Accepted February 3, 2012) INTRODUCTION Since the late 1960s, yttria-stabilized zirconia (YSZ), especially 3 mol% Y2O3-doped zirconia, has been shown to be a biomaterial with excellent mechanical properties, and YSZ ceramics are currently used as ball heads in artificial hip joints and post-crowns in dental applications [1-2]. YSZ is however bioinert, meaning that no direct bonding of YSZ to natural bones occurs in vivo. In the present study, we have addressed this shortcoming by employing chemical treatments with the aim of increasing the bioactivity of YSZ. We have recently demonstrated that the ceramic hydroxyapatite (HA) [3] may be polarized via proton migration [4], and that the polarized surfaces of HA enhanced tissue regeneration of both hard [5] and soft [6] tissues in vivo. Additionally, the polarized HA also accelerated protein adsorption [7] and cell adhesion through improved wettability of water [8]. Thus electrical polarization can have excellent chemical, biological, and biomedical effects. Another serious problem with YSZ lies in its instability due to a tetragonal (t) to monoclinic (m) phase transformation at relatively low temperatures of (< 400C) in moist air or hot water [9]. These phenomena are usually termed low temperature degradation (LTD). Kobayashi et al. have reported that the annealing treatment of zirconia at 65-400C in water for a long time spontaneously gave rise to the transformation of tetragonal into monoclinic phase [10]. This t-m phase transformation in YSZ is reportedly accompanied by cracking on the surface due to the volume expansion of about 4-5% and degradation of mechanical strength, which can cause critical accidents in medical applications. It is crucial to inhibit the LTD of YSZ in medical and structural applications and also to understand the role of moisture in LTD. We observed that our polarization process successfully inhibited LTD in the chemical treatments of YSZ ceramics. This report details the bioa
{"title":"POLARIZED YTTRIA-STABILIZED ZIRCONIA IMPROVES DURABILITY FOR DEGRADATION AND APATITE FORMATION IN SIMULATED BODY FLUID","authors":"Miho Nakamura, Masahiro Inuzuka, K. Hashimoto, A. Nagai, K. Yamashita","doi":"10.3363/PRB.26.77","DOIUrl":"https://doi.org/10.3363/PRB.26.77","url":null,"abstract":"Yttria-stabilized zirconia is currently used as an orthopedic and dental material, because of its excellent mechanical properties. In this study, we have improved the bioactivity of yttria-stabilized zirconia by a combination of electrical polarization and chemical treatment. The phase transformation from tetragonal to monoclinic ZrO2 after alkaline treatment was inhibited on positively charged yttria-stabilized zirconia surfaces compared with negatively charged and conventional surfaces. During polarization, some oxide ions move from the positively charged surface to the negatively charged surface, leading to an increase in oxygen vacancies on the positive surface and hence greater formation of Zr-OH when this surface was exposed to alkaline solution. The bioactivity was assessed by immersing the samples in simulated body fluid and evaluating the growth of apatite on the surfaces. The combination of polarization and alkaline treatment increased the bioactivity in vitro. (Received January 11, 2012; Accepted February 3, 2012) INTRODUCTION Since the late 1960s, yttria-stabilized zirconia (YSZ), especially 3 mol% Y2O3-doped zirconia, has been shown to be a biomaterial with excellent mechanical properties, and YSZ ceramics are currently used as ball heads in artificial hip joints and post-crowns in dental applications [1-2]. YSZ is however bioinert, meaning that no direct bonding of YSZ to natural bones occurs in vivo. In the present study, we have addressed this shortcoming by employing chemical treatments with the aim of increasing the bioactivity of YSZ. We have recently demonstrated that the ceramic hydroxyapatite (HA) [3] may be polarized via proton migration [4], and that the polarized surfaces of HA enhanced tissue regeneration of both hard [5] and soft [6] tissues in vivo. Additionally, the polarized HA also accelerated protein adsorption [7] and cell adhesion through improved wettability of water [8]. Thus electrical polarization can have excellent chemical, biological, and biomedical effects. Another serious problem with YSZ lies in its instability due to a tetragonal (t) to monoclinic (m) phase transformation at relatively low temperatures of (< 400C) in moist air or hot water [9]. These phenomena are usually termed low temperature degradation (LTD). Kobayashi et al. have reported that the annealing treatment of zirconia at 65-400C in water for a long time spontaneously gave rise to the transformation of tetragonal into monoclinic phase [10]. This t-m phase transformation in YSZ is reportedly accompanied by cracking on the surface due to the volume expansion of about 4-5% and degradation of mechanical strength, which can cause critical accidents in medical applications. It is crucial to inhibit the LTD of YSZ in medical and structural applications and also to understand the role of moisture in LTD. We observed that our polarization process successfully inhibited LTD in the chemical treatments of YSZ ceramics. This report details the bioa","PeriodicalId":20022,"journal":{"name":"Phosphorus Research Bulletin","volume":"1 1","pages":"77-80"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74366976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effects of potassium peroxodisulfate (K2S2O8) on the formation of calcium phosphate particles produced by aging Ca(OH)2 and sodium triphosphate (sodium tripolyphosphate, Natpp: Na5P3O10) mixed solution at 100~160 C for 18 h were examined. Spherical and monodispersed particles were produced at low K2S2O8 concentration ([K2S2O8]) region ([K2S2O8]≤4 mM) and their size was increased by increase in [K2S2O8]. On the contrary, fine irregular particles were produced at [K2S2O8]≥6 mM. The monodispersed spherical particles produced at [K2S2O8]≤4 mM were amorphous, though small irregular particles produced at [K2S2O8]≥6 mM were poorly crystallized calcium pyrophosphates (-Ca2P2O7). The Ca/P atomic ratios of these samples were 0.79~0.90, fairly closed to the Ca/P atomic ratio of 1.0 for -Ca2P2O7. A high adsorption selectivity of H2O was observed on amorphous monodispersed spherical particles. On the other hand, the -Ca2P2O7 particles with small amounts of hydrated H2O produced at [K2S2O8]≥6 mM exhibited no selective adsorption of H2O. With increase in the aging temperature, small numbers of transparent balloon-like hollow spheres were obtained at 120~140C. However, the fraction of hollow spheres was less than 5%. Aging above 150C, no balloon-like hollow sphere was precipitated but finally calcium hydroxyapatite (Ca10(PO4)6(OH)2, Hap) particles with small rod-like shape could be precipitated. These Hap particles produced at 150 and 160 C did not exhibit selective adsorption of H2O. (Received July 9, 2012; Accepted July 30, 2012)
{"title":"PREPARATION AND CHARACTERIZATION OF CALCIUM PHOSPHATE PARTICLES FROM FORCED HYDROLYSIS OF Ca(OH)2-TRIPHOSPHATE-K2S2O8 MIXED SOLUTION","authors":"K. Kandori, N. Matsui","doi":"10.3363/PRB.27.37","DOIUrl":"https://doi.org/10.3363/PRB.27.37","url":null,"abstract":"The effects of potassium peroxodisulfate (K2S2O8) on the formation of calcium phosphate particles produced by aging Ca(OH)2 and sodium triphosphate (sodium tripolyphosphate, Natpp: Na5P3O10) mixed solution at 100~160 C for 18 h were examined. Spherical and monodispersed particles were produced at low K2S2O8 concentration ([K2S2O8]) region ([K2S2O8]≤4 mM) and their size was increased by increase in [K2S2O8]. On the contrary, fine irregular particles were produced at [K2S2O8]≥6 mM. The monodispersed spherical particles produced at [K2S2O8]≤4 mM were amorphous, though small irregular particles produced at [K2S2O8]≥6 mM were poorly crystallized calcium pyrophosphates (-Ca2P2O7). The Ca/P atomic ratios of these samples were 0.79~0.90, fairly closed to the Ca/P atomic ratio of 1.0 for -Ca2P2O7. A high adsorption selectivity of H2O was observed on amorphous monodispersed spherical particles. On the other hand, the -Ca2P2O7 particles with small amounts of hydrated H2O produced at [K2S2O8]≥6 mM exhibited no selective adsorption of H2O. With increase in the aging temperature, small numbers of transparent balloon-like hollow spheres were obtained at 120~140C. However, the fraction of hollow spheres was less than 5%. Aging above 150C, no balloon-like hollow sphere was precipitated but finally calcium hydroxyapatite (Ca10(PO4)6(OH)2, Hap) particles with small rod-like shape could be precipitated. These Hap particles produced at 150 and 160 C did not exhibit selective adsorption of H2O. (Received July 9, 2012; Accepted July 30, 2012)","PeriodicalId":20022,"journal":{"name":"Phosphorus Research Bulletin","volume":"345 1","pages":"37-44"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77684663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：