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Sample records for calcium phosphate coatings

  1. Dissolution kinetics of calcium phosphate coatings.

    Science.gov (United States)

    Burke, E M; Lucas, L C

    1998-01-01

    Plasma spray and high velocity oxy-fuel (HVOF) techniques produce coatings with varying composition and amounts of amorphous and crystalline phases. For coatings containing greater amorphous phases, a higher release of calcium ions is evident when samples are placed in Hank's calcium-free balanced salt solutions. Calcium is released from the amorphous phases in the coating, a conclusion that is supported by x-ray powder diffraction (XRD) results. Ion beam sputtering and RF magnetron sputtering under lower energy conditions produce amorphous coatings that will dissolve in a very short time period. When heat treated, crystalline phases are produced in the coatings. Heat-treated coatings are significantly more stable than the amorphous coatings. The dissolution rates of both amorphous and crystalline coatings produced by RF magnetron sputtering have been measured under constant solution conditions at pH 6.50. No reprecipitation is possible under these conditions. The amorphous coating dissolved at a significantly higher rate than the heat-treated coating. Reprecipitation of calcium phosphate onto amorphous coatings is possible in a physiological pH solution. Under these conditions, the dissolution rate of the amorphous coating is four times slower than at the pH 6.50 conditions. PMID:10196809

  2. A review paper on biomimetic calcium phosphate coatings

    OpenAIRE

    Lin, X.; De Groot,, P.A.J.; Wang, D.; Hu, Q; Wismeijer, D.; Liu, Y

    2015-01-01

    Biomimetic calcium phosphate coatings have been developed for bone regeneration and repair because of their biocompatibility, osteoconductivity, and easy preparation. They can be rendered osteoinductive by incorporating an osteogenic agent, such as bone morphogenetic protein 2 (BMP-2), into the crystalline lattice work in physiological situations. The biomimetic calcium phosphate coating enables a controlled, slow and local release of BMP-2 when it undergoes cell mediated coating degradation ...

  3. Investigation of calcium phosphate coatings for biomedical applications

    International Nuclear Information System (INIS)

    Calcium phosphate is the main constituent of our bone and tooth minerals. The use of this bioactive material for coating implant such as artificial joint prosthesis, therefore, can promote biological fixation and enhance biocompatibility. Our initial work has been focused on the evaluation of experimental conditions of coating preparation and the effects of post-deposition calcium phosphate coatings on stainless steel substrates. The coating layers were produced by the precipitation technique and coatings were carried out in sol-gel by the dipping method. For comparison purposes a wet method was used to obtain a fine calcium phosphate ceramic powder for fabrication of microcrystal suspension used as a coating material. Scanning electron microscopy (SEM), energy dispersive microanalysis (EDS), energy dispersive x-ray fluorescence (EDXRF) and x-ray diffraction (XRD) were used to characterise the morphology, chemical composition and structure of the coatings. The results showed that the dip coating of stainless steel substrates using viscous solutions lead to the formation of porous calcium phosphate layers. These results suggested that fabrication of bioactive calcium phosphate coatings using this route offers significant advantages over the currently used methods due to considerably lower temperature process involved and may produce better result for substrates with complex shapes

  4. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    Energy Technology Data Exchange (ETDEWEB)

    Yang Liang; Habibovic, Pamela; Van Blitterswijk, Clemens A [Department of Tissue Regeneration, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Hedhammar, My; Johansson, Jan [Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, the Biomedical Centre, Box 575, 751 23 Uppsala (Sweden); Blom, Tobias; Leifer, Klaus [Department of Engineering Sciences, Uppsala University, Box 534, S-751 21 Uppsala (Sweden)

    2010-08-01

    Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently, artificial spider silk, with mechanical and structural characteristics similar to those of native spider silk, has been produced from recombinant minispidroins. In the present study, supersaturated simulated body fluid was used to deposit calcium phosphate coatings on recombinant spider silk fibres. The mineralization process was followed in time using scanning electron microscopy equipped with an energy dispersive x-ray (EDX) detector and Raman spectroscope. Focused ion beam technology was used to produce a cross section of a coated fibre, which was further analysed by EDX. Preliminary in vitro experiments using a culture of bone marrow-derived human mesenchymal stem cells (hMSCs) on coated fibres were also performed. This study showed that recombinant spider silk fibres were successfully coated with a homogeneous and thick crystalline calcium phosphate layer. In the course of the mineralization process from modified simulated body fluid, sodium chloride crystals were first deposited on the silk surface, followed by the deposition of a calcium phosphate layer. The coated silk fibres supported the attachment and growth of hMSCs.

  5. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    International Nuclear Information System (INIS)

    Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently, artificial spider silk, with mechanical and structural characteristics similar to those of native spider silk, has been produced from recombinant minispidroins. In the present study, supersaturated simulated body fluid was used to deposit calcium phosphate coatings on recombinant spider silk fibres. The mineralization process was followed in time using scanning electron microscopy equipped with an energy dispersive x-ray (EDX) detector and Raman spectroscope. Focused ion beam technology was used to produce a cross section of a coated fibre, which was further analysed by EDX. Preliminary in vitro experiments using a culture of bone marrow-derived human mesenchymal stem cells (hMSCs) on coated fibres were also performed. This study showed that recombinant spider silk fibres were successfully coated with a homogeneous and thick crystalline calcium phosphate layer. In the course of the mineralization process from modified simulated body fluid, sodium chloride crystals were first deposited on the silk surface, followed by the deposition of a calcium phosphate layer. The coated silk fibres supported the attachment and growth of hMSCs.

  6. The influence of Sr content in calcium phosphate coatings

    International Nuclear Information System (INIS)

    In this study calcium phosphate coatings with different amounts of strontium (Sr) were prepared using a biomineralization method. The incorporation of Sr changed the composition and morphology of coatings from plate-like to sphere-like morphology. Dissolution testing indicated that the solubility of the coatings increased with increased Sr concentration. Evaluation of extracts (with Sr concentrations ranging from 0 to 2.37 μg/mL) from the HA, 0.06Sr, 0.6Sr, and 1.2Sr coatings during in vitro cell cultures showed that Sr incorporation into coatings significantly enhanced the ALP activity in comparison to cells treated with control and HA eluted media. These findings show that calcium phosphate coatings could promote osteogenic differentiation even in a low amount of strontium. - Highlights: • Calcium phosphate coating doping with low Sr contents was prepared via a biomineralization process. • The solubility of the coatings increased with increased Sr concentration. • Present findings show the potential that Sr has on promoting osteogenic differentiation even in a low amount

  7. The influence of Sr content in calcium phosphate coatings

    Energy Technology Data Exchange (ETDEWEB)

    Lindahl, Carl [Department of Biomaterials, Institute for Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg (Sweden); BIOMATCELL, VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg (Sweden); Pujari-Palmer, Shiuli; Hoess, Andreas; Ott, Marjam [Applied Materials Science, Department of Engineering Sciences, Uppsala University, Uppsala (Sweden); Engqvist, Håkan [BIOMATCELL, VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg (Sweden); Applied Materials Science, Department of Engineering Sciences, Uppsala University, Uppsala (Sweden); Xia, Wei, E-mail: wei.xia@angstrom.uu.se [BIOMATCELL, VINN Excellence Center of Biomaterials and Cell Therapy, Gothenburg (Sweden); Applied Materials Science, Department of Engineering Sciences, Uppsala University, Uppsala (Sweden)

    2015-08-01

    In this study calcium phosphate coatings with different amounts of strontium (Sr) were prepared using a biomineralization method. The incorporation of Sr changed the composition and morphology of coatings from plate-like to sphere-like morphology. Dissolution testing indicated that the solubility of the coatings increased with increased Sr concentration. Evaluation of extracts (with Sr concentrations ranging from 0 to 2.37 μg/mL) from the HA, 0.06Sr, 0.6Sr, and 1.2Sr coatings during in vitro cell cultures showed that Sr incorporation into coatings significantly enhanced the ALP activity in comparison to cells treated with control and HA eluted media. These findings show that calcium phosphate coatings could promote osteogenic differentiation even in a low amount of strontium. - Highlights: • Calcium phosphate coating doping with low Sr contents was prepared via a biomineralization process. • The solubility of the coatings increased with increased Sr concentration. • Present findings show the potential that Sr has on promoting osteogenic differentiation even in a low amount.

  8. Mechanical properties of porous, electrosprayed calcium phosphate coatings

    NARCIS (Netherlands)

    Leeuwenburgh, S.C.G.; Wolke, J.G.C.; Lommen, L.; Pooters, T.; Schoonman, J.; Jansen, J.A.

    2006-01-01

    Mechanical properties of calcium phosphate coatings (CaP), deposited using the electrostatic spray deposition (ESD) technique, have been characterized using a range of analytical techniques, including tensile testing (ASTM C633), fatigue testing (ASTM E855), and scratch testing using blunt and sharp

  9. Bioactivity of calcium phosphate bioceramic coating fabricated by laser cladding

    Science.gov (United States)

    Zhu, Yizhi; Liu, Qibin; Xu, Peng; Li, Long; Jiang, Haibing; Bai, Yang

    2016-05-01

    There were always strong expectations for suitable biomaterials used for bone regeneration. In this study, to improve the biocompatiblity of titanium alloy, calcium phosphate bioceramic coating was obtained by laser cladding technology. The microstructure, phases, bioactivity, cell differentiation, morphology and resorption lacunae were investigated by optical microscope (OM), x-ray diffraction (XRD), methyl thiazolyl tetrazolium (MTT) assay, tartrate-resistant acid phosphatase (TRAP) staining and scanning electronic microscope (SEM), respectively. The results show that bioceramic coating consists of three layers, which are a substrate, an alloyed layer and a ceramic layer. Bioactive phases of β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) were found in ceramic coating. Osteoclast precursors have excellent proliferation on the bioceramic surface. The bioceramics coating could be digested by osteoclasts, which led to the resorption lacunae formed on its surface. It revealed that the gradient bioceramic coating has an excellent bioactivity.

  10. Coating of calcium phosphate on biometallic materials by electrophoretic deposition

    Institute of Scientific and Technical Information of China (English)

    ZHANG Er-lin; YANG Ke

    2005-01-01

    Although biometallic materials have been used as bone implant materials for a long time, they are still detected as foreign bodies by human immune system. Calcium phosphate coating, especially hydroxyapatite(HA)coating attracts special attention due to its good biocompatibility. Being one of the effective methods used to deposit HA coating onto the metallic implant, the electrophoretic deposition(EPD) was reviewed in detail, including the process of EPD, the advantages and disadvantages, the important processing factors and the microstructure and mechanical properties of the coating. Research results on the processing and the coating show potential application of EPD process to the biomedical materials surface modification. In addition, the nanoparticulate HA coating as a new trend in HA coating was also introduced.

  11. Effects of protein incorporation on calcium phosphate coating

    OpenAIRE

    Leonor, I. B.; C.M. Alves; Azevedo, Helena S.; Reis, R.L.

    2009-01-01

    The incorporation of proteins into calcium phosphate (Ca–P) coatings is expected to alter their properties. The aim of this work is, therefore, to study the effect of protein concentration on the formation of Ca–P film. A biodegradable blend of corn starch/ethylene vinyl alcohol (SEVA-C) was used as substrate and bioactive glass (45S5 Bioglass®) was used as a nucleating agent. Bovine serum albumin (BSA) and α-amylase were added, separately, at a concentration of 0.5, 1, and 5 mg/mLto simulate...

  12. Mixed zirconia calcium phosphate coatings for dental implants: Tailoring coating stability and bioactivity potential

    International Nuclear Information System (INIS)

    Enhanced coating stability and adhesion are essential for long-term success of orthopedic and dental implants. In this study, the effect of coating composition on mechanical, physico-chemical and biological properties of coated zirconia specimens is investigated. Zirconia discs and dental screw implants are coated using the wet powder spraying (WPS) technique. The coatings are obtained by mixing yttria-stabilized zirconia (TZ) and hydroxyapatite (HA) in various ratios while a pure HA coating served as reference material. Scanning electron microscopy (SEM) and optical profilometer analysis confirm a similar coating morphology and roughness for all studied coatings, whereas the coating stability can be tailored with composition and is probed by insertion and dissections experiments in bovine bone with coated zirconia screw implants. An increasing content of calcium phosphate (CP) resulted in a decrease of mechanical and chemical stability, while the bioactivity increased in simulated body fluid (SBF). In vitro experiments with human osteoblast cells (HOB) revealed that the cells grew well on all samples but are affected by dissolution behavior of the studied coatings. This work demonstrates the overall good mechanical strength, the excellent interfacial bonding and the bioactivity potential of coatings with higher TZ contents, which provide a highly interesting coating for dental implants. - Highlights: • Different ratios of zirconia (TZ) and calcium phosphate (CP) were deposited on zirconia substrates. • Enhancement of TZ content in mixed coatings increased coating stability. • Enhancement of CP content in mixed coatings increased bioactivity. • All tested coating compositions were non-toxic

  13. Mixed zirconia calcium phosphate coatings for dental implants: Tailoring coating stability and bioactivity potential

    Energy Technology Data Exchange (ETDEWEB)

    Pardun, Karoline [University of Bremen, Advanced Ceramics, Am Biologischen Garten 2, 28359 Bremen (Germany); Treccani, Laura, E-mail: treccani@uni-bremen.de [University of Bremen, Advanced Ceramics, Am Biologischen Garten 2, 28359 Bremen (Germany); Volkmann, Eike [University of Bremen, Advanced Ceramics, Am Biologischen Garten 2, 28359 Bremen (Germany); Streckbein, Philipp [University Hospital, Justus-Liebig-University Giessen, Department of Cranio-Maxillo-Facial Surgery, Klinikstrasse 33, 35385 Giessen (Germany); Heiss, Christian [University Hospital of Giessen-Marburg, Department of Trauma Surgery, Rudolf-Buchheim-Strasse 7, 35385 Giessen, Germany, (Germany); Laboratory of Experimental Surgery, Kerkraderstrasse 9, 35392 Giessen (Germany); Destri, Giovanni Li; Marletta, Giovanni [Laboratory for Molecular Surfaces and Nanotechnology (LAMSUN), Department of Chemistry, University of Catania and CSGI, Viale A. Doria 6, 95125 Catania (Italy); Rezwan, Kurosch [University of Bremen, Advanced Ceramics, Am Biologischen Garten 2, 28359 Bremen (Germany)

    2015-03-01

    Enhanced coating stability and adhesion are essential for long-term success of orthopedic and dental implants. In this study, the effect of coating composition on mechanical, physico-chemical and biological properties of coated zirconia specimens is investigated. Zirconia discs and dental screw implants are coated using the wet powder spraying (WPS) technique. The coatings are obtained by mixing yttria-stabilized zirconia (TZ) and hydroxyapatite (HA) in various ratios while a pure HA coating served as reference material. Scanning electron microscopy (SEM) and optical profilometer analysis confirm a similar coating morphology and roughness for all studied coatings, whereas the coating stability can be tailored with composition and is probed by insertion and dissections experiments in bovine bone with coated zirconia screw implants. An increasing content of calcium phosphate (CP) resulted in a decrease of mechanical and chemical stability, while the bioactivity increased in simulated body fluid (SBF). In vitro experiments with human osteoblast cells (HOB) revealed that the cells grew well on all samples but are affected by dissolution behavior of the studied coatings. This work demonstrates the overall good mechanical strength, the excellent interfacial bonding and the bioactivity potential of coatings with higher TZ contents, which provide a highly interesting coating for dental implants. - Highlights: • Different ratios of zirconia (TZ) and calcium phosphate (CP) were deposited on zirconia substrates. • Enhancement of TZ content in mixed coatings increased coating stability. • Enhancement of CP content in mixed coatings increased bioactivity. • All tested coating compositions were non-toxic.

  14. A new evaporation-based method for the preparation of biomimetic calcium phosphate coatings on metals

    International Nuclear Information System (INIS)

    This study reports a new method to prepare biomimetic calcium phosphate coatings on titanium, stainless steel, CoCrMo, and tantalum. The method does not require surface etching, high supersaturation, or tight control of solution conditions. Metallic samples were dipped into a supersaturated calcium phosphate solution, withdrawn, and left to dry at room temperature. Calcium phosphate crystallites formed on and completely covered the surfaces by repeating the dip-and-dry treatment. The crystallite-covered surfaces readily grew to calcium phosphate coatings when immersed in the supersaturated solution. The mechanism of the treatment was suggested to be an evaporation-induced surface crystallization process.

  15. A safer disposal of hazardous phosphate coating sludge by formation of an amorphous calcium phosphate matrix.

    Science.gov (United States)

    Navarro-Blasco, I; Duran, A; Pérez-Nicolás, M; Fernández, J M; Sirera, R; Alvarez, J I

    2015-08-15

    Phosphate coating hazardous wastes originated from the automotive industry were efficiently encapsulated by an acid-base reaction between phosphates present in the sludge and calcium aluminate cement, yielding very inert and stable monolithic blocks of amorphous calcium phosphate (ACP). Two different compositions of industrial sludge were characterized and loaded in ratios ranging from 10 to 50 wt.%. Setting times and compressive strengths were recorded to establish the feasibility of this method to achieve a good handling and a safe landfilling of these samples. Short solidification periods were found and leaching tests showed an excellent retention for toxic metals (Zn, Ni, Cu, Cr and Mn) and for organic matter. Retentions over 99.9% for Zn and Mn were observed even for loadings as high as 50 wt.% of the wastes. The formation of ACP phase of low porosity and high stability accounted for the effective immobilization of the hazardous components of the wastes. PMID:26024992

  16. Bioactive calcium phosphate coating formed on micro-arc oxidized magnesium by chemical deposition

    Energy Technology Data Exchange (ETDEWEB)

    Liu, G.Y. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Hu, J., E-mail: hujin@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Ding, Z.K.; Wang, C. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2011-01-01

    In order to improve the bioactivity of the micro-arc oxidized magnesium, a calcium phosphate coating was formed on the surface of micro-arc oxidized magnesium using a chemical method. The microstructures of the substrate and the calcium phosphate coating before and after the simulated body fluids (SBF) incubation were characterized by X-ray diffraction, Fourier-transformed infrared spectroscopy and scanning electron microscopy. The results showed that the calcified coating was composed of calcium deficient hydroxyapatite (HA) and dicalcium phosphate dihydrate (DCPD). After SBF incubation, some new apatite formation on the calcified coating surface from SBF could be found. The corrosion behaviours of the samples in SBF were also investigated by potentiodynamic polarization curves and immersion tests. The results showed that calcium phosphate coating increased the corrosion potential, and decreased the hydrogen gas release.

  17. Preparation and bioactivity of micro-arc oxidized calcium phosphate coatings

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Y.K. [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Ji' nan, Shandong 250061 (China); School of Materials Science and Engineering, Shandong University, Ji' nan, Shandong 250061 (China); Chen, C.Z., E-mail: czchen@sdu.edu.cn [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Ji' nan, Shandong 250061 (China); School of Materials Science and Engineering, Shandong University, Ji' nan, Shandong 250061 (China); Wang, D.G.; Lin, Z.Q. [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Ji' nan, Shandong 250061 (China); School of Materials Science and Engineering, Shandong University, Ji' nan, Shandong 250061 (China)

    2013-09-16

    Calcium phosphate (CaP) coatings were prepared on ZK60 magnesium alloy by micro-arc oxidation (MAO) in electrolyte containing calcium acetate monohydrate (CH{sub 3}COO){sub 2}Ca·H{sub 2}O) and disodium hydrogen phosphate dodecahydrate (Na{sub 2}HPO{sub 4}·12H{sub 2}O). Scanning electron microscope (SEM), energy-dispersive X-ray spectrometry (EDX) and X-ray diffractometer (XRD) were employed to characterize the microstructure, elemental distribution and phase composition of the CaP coatings respectively. Simulated body fluid (SBF) immersion test was used to evaluate the coating degradability and bioactivity. After 30 days of SBF immersion, the CaP coatings effectively reduce the degradation rate. The surfaces of CaP coatings are covered by a new layer formed of numerous needle-like, spherical and columned calcium phosphates. SEM, EDX and XRD results suggest that these calcium phosphates are bioactive calcium phosphate phases such as hydroxyapatite (Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}, HA) and calcium pyrophosphates (Ca{sub 2}P{sub 2}O{sub 7}, CPP). The formation of these calcium phosphates indicates that the CaP coatings have bioactivity. - Highlights: • Bioactive CaP coatings are successfully formed on ZK60 magnesium alloy. • CaP coatings consist of MgO, MgF{sub 2}, CaO, CaF{sub 2} and Ca{sub 3}(PO{sub 4}){sub 2}. • Needle-like, spherical and columned calcium phosphates formed in SBF. • CaP coatings exhibit bioactivity and low corrosion rate.

  18. RBS and XPS analyses of the composite calcium phosphate coatings for biomedical applications

    International Nuclear Information System (INIS)

    The calcium phosphate coatings on metallic implants are widely used for biomedical applications. The calcium phosphate coatings require mechanical strength, strong adhesion to the metallic implants, chemical stability and low dissolution into the human body fluid for stable functioning in the corrosive environment of the human body. In this study, a novel approach for improving the calcium phosphate coatings is utilized by adding trace metallic element into the coatings. We focused on teeth enamel, which is the hardest calcium phosphate tissue in the human body. Zn concentration increases exponentially from the interior to the surface of the enamel. As the Zn concentration increases, so the local hardness increases. Our previous studies suggest that Zn has influence on the hardness and other properties of enamel, calcium phosphate tissue. Calcium phosphate coatings doped with Zn was fabricated and characterized. The atomic composition and chemical state were investigated by using Rutherford backscattering spectroscopy (RBS) and X-ray photoelectron spectrometer (XPS), respectively. Scratch test was also carried out for measuring the adhesion of the coatings

  19. Microanalyses of the hydroxyl—poly—calcium sodium phosphate coatings produced by ion beam assisted deposition

    Institute of Scientific and Technical Information of China (English)

    LIUZhong-Yang; WANGChang-Xing; 等

    2002-01-01

    Thin calcium phosphate catings on titanium alloy substrates were prepared by Ar+ ion beam assisted deposition(IBAD) from hydroxyl-poly-calcium sodium phosphate(HPPA) target.The coatings were analyzed by XRD,FTIR,XPS,These analyses revealed that the as-deposited films were amorphous or no apparent crystallinity.No distinct absorption band of the hydroxyl group was observed in FTIR spectra of the coatings but new absorption bands were presented for CO3-2,The calcium to phosphorous ratio of these catings in different IBAD conditions varied from 0.46 to 3.36.

  20. Lipid-coated nano-calcium-phosphate (LNCP) for gene delivery

    OpenAIRE

    Zhou, Chenguang; Yu, Bo; Yang, Xiaojuan; Huo, Tianyao; Lee, L. James; Barth, Rolf F; Lee, Robert J.

    2010-01-01

    While calcium-phosphate has been used to deliver plasmid DNA (pDNA) for decades, the method is typically characterized by low and irreproducible transfection efficiency relative to the other non-viral approaches, such as liposomes and polymers. Here we report a novel gene transfer vector comprising lipid-coated nano-calcium-phosphate (LNCP) that provides consistently efficient and satisfactory pDNA delivery. It is based on core-shell nanoparticles comprising a calcium-phosphate core and a cat...

  1. A novel biodegradable nicotinic acid/calcium phosphate composite coating on Mg–3Zn alloy

    International Nuclear Information System (INIS)

    A novel biodegradable composite coating is prepared to reduce the biodegradation rate of Mg–3Zn alloy. The Mg–3Zn substrate is first immersed into 0.02 mol L−1 nicotinic acid (NA) solution, named as vitamin B3, to obtain a pretreatment film, and then the electrodeposition of calcium phosphate coating with ultrasonic agitation is carried out on the NA pretreatment film to obtain a NA/calcium phosphate composite coating. Surface morphology is observed by scanning electron microscopy (SEM). Chemical composition is determined by X-ray diffraction (XRD) and EDX. Protection property of the coatings is evaluated by electrochemical tests. The biodegradable behavior is investigated by immersion tests. The results indicate that a thin but compact bottom layer can be obtained by NA pretreatment. The electrodeposition calcium phosphate coating consists of many flake particles and ultrasonic agitation can greatly improve the compactness of the coating. The composite coating is biodegradable and can reduce the biodegradation rate of Mg alloys in stimulated body fluid (SBF) for twenty times. The biodegradation process of the composite coating can be attributed to the gradual dissolution of the flake particles into chippings. - Highlights: ► NA/calcium phosphate composite coating is prepared to protect Mg–3Zn alloy implant. ► Nicotinic acid (vitamin B3) is available to obtain a protective bottom film. ► Ultrasonic agitation greatly improves the compactness of calcium phosphate coating. ► The composite coating can reduce the biodegradation rate of Mg–3Zn twenty times. ► The composite coating is biodegraded by the dissolution of flakes into chippings.

  2. A novel biodegradable nicotinic acid/calcium phosphate composite coating on Mg-3Zn alloy

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yingwei, E-mail: ywsong@imr.ac.cn; Shan, Dayong; Han, En-Hou

    2013-01-01

    A novel biodegradable composite coating is prepared to reduce the biodegradation rate of Mg-3Zn alloy. The Mg-3Zn substrate is first immersed into 0.02 mol L{sup -1} nicotinic acid (NA) solution, named as vitamin B{sub 3}, to obtain a pretreatment film, and then the electrodeposition of calcium phosphate coating with ultrasonic agitation is carried out on the NA pretreatment film to obtain a NA/calcium phosphate composite coating. Surface morphology is observed by scanning electron microscopy (SEM). Chemical composition is determined by X-ray diffraction (XRD) and EDX. Protection property of the coatings is evaluated by electrochemical tests. The biodegradable behavior is investigated by immersion tests. The results indicate that a thin but compact bottom layer can be obtained by NA pretreatment. The electrodeposition calcium phosphate coating consists of many flake particles and ultrasonic agitation can greatly improve the compactness of the coating. The composite coating is biodegradable and can reduce the biodegradation rate of Mg alloys in stimulated body fluid (SBF) for twenty times. The biodegradation process of the composite coating can be attributed to the gradual dissolution of the flake particles into chippings. - Highlights: Black-Right-Pointing-Pointer NA/calcium phosphate composite coating is prepared to protect Mg-3Zn alloy implant. Black-Right-Pointing-Pointer Nicotinic acid (vitamin B{sub 3}) is available to obtain a protective bottom film. Black-Right-Pointing-Pointer Ultrasonic agitation greatly improves the compactness of calcium phosphate coating. Black-Right-Pointing-Pointer The composite coating can reduce the biodegradation rate of Mg-3Zn twenty times. Black-Right-Pointing-Pointer The composite coating is biodegraded by the dissolution of flakes into chippings.

  3. Novel sol–gel derived calcium phosphate coatings on Mg4Y alloy

    International Nuclear Information System (INIS)

    Calcium phosphates (CaPs) and silicon containing calcium phosphates (Si-CaPs) coatings on a biodegradable magnesium yttrium alloy (Mg4Y) were prepared by a sol–gel technique to improve the bioactivity of the alloy surface. The experimental results show that thick porous coatings comprised of nano-sized calcium phosphate particles can be prepared by heating the as dip coated substrates at 450 °C. The in vitro degradation results show that the coatings do not alter the degradation kinetics of the substrates significantly and the release of magnesium and yttrium ions at initial time points was very similar for both the coated and bare substrates. The cyto-compatibility studies using MC3T3-E1 osteoblasts show that the coated substrates were more bioactive than the uncoated substrates as the cells begin to grow and form a matrix on the coated substrates more easily than on the bare metal. These preliminary results collectively show the potential of use of sol–gel derived calcium phosphate coatings on magnesium based degradable scaffolds to improve their surface bioactivity.

  4. Dense and porous titanium substrates with a biomimetic calcium phosphate coating

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, A.A., E-mail: aantunesr@yahoo.com.br [Powder Technology Laboratory, Materials Processing and Characterization Division, National Institute of Technology, No. 82 Venezuela Avenue, Room 602, 20081-312 Rio de Janeiro, RJ (Brazil); Balestra, R.M. [Powder Technology Laboratory, Materials Processing and Characterization Division, National Institute of Technology, No. 82 Venezuela Avenue, Room 602, 20081-312 Rio de Janeiro, RJ (Brazil); Rocha, M.N. [Metallurgical and Materials Engineering Program, COPPE, Federal University of Rio de Janeiro, P.O. Box 68505, 21941-972 Rio de Janeiro, RJ (Brazil); Peripolli, S.B. [Materials Metrology Division, National Institute of Metrology, Normalization and Quality, No. 50 Nossa Senhora das Gracas Street, Building 3, 25250-020 Duque de Caxias, RJ (Brazil); Andrade, M.C. [Polytechnic Institute of Rio de Janeiro, Rio de Janeiro State University, s/n, Alberto Rangel Street, 28630-050 Nova Friburgo, RJ (Brazil); Pereira, L.C. [Metallurgical and Materials Engineering Program, COPPE, Federal University of Rio de Janeiro, P.O. Box 68505, 21941-972 Rio de Janeiro, RJ (Brazil); Oliveira, M.V. [Powder Technology Laboratory, Materials Processing and Characterization Division, National Institute of Technology, No. 82 Venezuela Avenue, Room 602, 20081-312 Rio de Janeiro, RJ (Brazil)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer A biomimetic coating method with simplified solution is proposed. Black-Right-Pointing-Pointer Titanium substrates are submitted to chemical and heat treatments. Black-Right-Pointing-Pointer Titanium substrates are coated with biocompatible calcium phosphate phases. Black-Right-Pointing-Pointer The simplified solution shows potential to be applied as a coating technique. - Abstract: The present work studied a biomimetic method using a simplified solution (SS) with calcium and phosphorus ions for coating titanium substrates, in order to improve their bioactivity. Commercially pure titanium dense sheet, microporous and macroporous titanium samples, both produced by powder metallurgy, were treated in NaOH solution followed by heat-treating and immersed in SS for 7, 14 or 21 days. The samples characterization was performed by quantitative metallographic analysis, confocal scanning optical microscopy, scanning electron microscopy, energy dispersive spectroscopy and low angle X-ray diffraction. The results showed coatings with calcium phosphate precipitation in all samples, with globular or plate-like morphology, typical of hydroxyapatite and octacalcium phosphate, respectively, indicating that the solution (SS) has potential for coating titanium substrates. In addition, the different surfaces of substrates had an effect on the formed calcium phosphate phase and thickness of coatings, depending on the substrate type and imersion time in the simplified solution.

  5. Calcium phosphate coating on magnesium alloy by biomimetic method :Investigation of morphology ,composition and formation process

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Magnesium alloy has similar mechanical properties with natural bone and can degrade via corrosion in the electrolytic environment of the human body.Calcium phosphate has been proven to possess bioactivity and bone inductivity.In order to integrate both advantages,calcium phosphate coating was fabricated on magnesium alloy by a biomimetic method.Supersaturated calcification solutions (SCSs) with different Ca/P ratio and C1- concentration were used as mimetic solutions.The morphology,composition and formation process of the coating were studied with scanning electron microscopy (SEM),energy dispersive spectrometer (EDS),Fourier transformed infrared spectroscopy (FTIR) and X-ray diffraction (XRD).The results show that a uniform calcium phosphate coating was observed on magnesium alloy,the properties of which could be adjusted by the SCSs with different Ca/P ratio.The formation process of the coating was explored by immersing magnesium alloy in SCSs with different Cl- concentration which could adjust the hydrogen production.According to SEM results,the hydrogen bubbles were associated with the formation of grass-like and flower-like coating morphologies.In conclusion,the biomimetic method was effective to form calcium phosphate coating on magnesium alloy and the morphology and composition of the coating could be accommodated by the Ca/P ratio and Cl- concentration in SCSs.

  6. The formation of calcium phosphate coatings by pulse laser deposition on the surface of polymeric ferroelectric

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Calcium phosphate coatings were obtained on ferroelectric polymer materials surface by using PLD method. • Obtained coatings have well-developed surface. • Depending on sputtering target composition it is possible to obtain crystalline or amorphous coating. • Formation of coating does not change the crystal structure of the ferroelectric polymer material. - Abstract: This work analyses the properties of calcium phosphate coatings obtained by pulsed laser deposition on the surface of the ferroelectric polymer material. Atomic force and scanning electron microscopy studies demonstrate that, regardless of the type of sputtering target, the calcium phosphate coatings have a multiscale rough surface that is potentially capable of promoting the attachment and proliferation of osteoblasts. This developed surface of the coatings is due to its formation mainly from a liquid phase. The chemical and crystalline composition of the coatings depends on the type of sputtering target used. It was shown that, regardless of the type of sputtering target, the crystalline structure of the ferroelectric polymer material does not change. Cell viability and adhesion studies of mesenchymal stromal cells on the coatings were conducted using flow cytometry and fluorescent microscopy. These studies indicated that the produced coatings are non-toxic

  7. The formation of calcium phosphate coatings by pulse laser deposition on the surface of polymeric ferroelectric

    Energy Technology Data Exchange (ETDEWEB)

    Bolbasov, E.N. [Tomsk Polytechnic University, 30 Lenin Avenue, Tomsk 634050 (Russian Federation); Lapin, I.N.; Svetlichnyi, V.A. [Tomsk State University, 36 Lenin Avenue, Tomsk 634050 (Russian Federation); Lenivtseva, Y.D. [Tomsk Polytechnic University, 30 Lenin Avenue, Tomsk 634050 (Russian Federation); Malashicheva, A. [Federal Almazov Medical Research Centre, 2 Akkuratova St., St. Petersburg 197341 (Russian Federation); St. Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg 199034 (Russian Federation); ITMO University, Institute of translational Medicine, St. Petersburg (Russian Federation); Malashichev, Y. [St. Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg 199034 (Russian Federation); Golovkin, A.S. [Federal Almazov Medical Research Centre, 2 Akkuratova St., St. Petersburg 197341 (Russian Federation); Anissimov, Y.G. [Griffith University, School of Natural Sciences, Engineering Dr., Southport, QLD 4222 (Australia); Tverdokhlebov, S.I., E-mail: tverd@tpu.ru [Tomsk Polytechnic University, 30 Lenin Avenue, Tomsk 634050 (Russian Federation)

    2015-09-15

    Graphical abstract: - Highlights: • Calcium phosphate coatings were obtained on ferroelectric polymer materials surface by using PLD method. • Obtained coatings have well-developed surface. • Depending on sputtering target composition it is possible to obtain crystalline or amorphous coating. • Formation of coating does not change the crystal structure of the ferroelectric polymer material. - Abstract: This work analyses the properties of calcium phosphate coatings obtained by pulsed laser deposition on the surface of the ferroelectric polymer material. Atomic force and scanning electron microscopy studies demonstrate that, regardless of the type of sputtering target, the calcium phosphate coatings have a multiscale rough surface that is potentially capable of promoting the attachment and proliferation of osteoblasts. This developed surface of the coatings is due to its formation mainly from a liquid phase. The chemical and crystalline composition of the coatings depends on the type of sputtering target used. It was shown that, regardless of the type of sputtering target, the crystalline structure of the ferroelectric polymer material does not change. Cell viability and adhesion studies of mesenchymal stromal cells on the coatings were conducted using flow cytometry and fluorescent microscopy. These studies indicated that the produced coatings are non-toxic.

  8. Fabrication and characterization of graded calcium phosphate coatings produced by ion beam sputtering/mixing deposition

    International Nuclear Information System (INIS)

    Ion beam sputtering/mixing deposition was used to produce thin calcium phosphate coatings on titanium substrate from the hydroxyapatite target. It was found that as-deposited coatings were amorphous. No distinct absorption band of the hydroxyl group was observed in FTIR spectra of the coatings but new absorption bands were present for CO32-, which was brought about during the deposition process. Scanning electron microscopy revealed that the deposited coatings had a uniform and dense structure. The calcium to phosphorous ratio of these coatings varied between 2.0 and 8.0. Analyses of XPS data revealed that the coating could be divided into four distinctive zones, and a graded structure was achieved in the as-received coating. Scratch tests showed that the coatings adhered well to the substrate

  9. A brief review of calcium phosphate conversion coating on magnesium and its alloys

    Science.gov (United States)

    Zaludin, Mohd Amin Farhan; Jamal, Zul Azhar Zahid; Jamaludin, Shamsul Baharin; Derman, Mohd Nazree

    2016-07-01

    Recent developments have shown that magnesium is a promising candidate to be used as a biomaterial. Owing to its light weight, biocompatibility and compressive strength comparable with natural bones makes magnesium as an excellent choice for biomaterial. However, high reactivity and low corrosion resistance properties have restricted the application of magnesium as biomaterials. At the moment, several strategies have been developed to solve this problem. Surface modification of magnesium is one of the popular solutions to solve the problem. Among many techniques developed in the surface modification, conversion coating method is one of the simple and effective techniques. From various types of conversion coating, calcium phosphate-based conversion coating is the most suitable for biomedical fields. This paper reviews some studies on calcium phosphate coating on Mg and its alloys via chemical conversion method and discusses some factors determining the coating performance.

  10. In vitro degradation of electrodeposited calcium phosphate coatings by osteoclast-like cells

    International Nuclear Information System (INIS)

    The aim of this study is to investigate the in vitro degradation of electrolytically deposited calcium phosphate coatings in the presence of osteoclast-like cells. Titanium alloy plates electrolytically coated with calcium phosphate with or without chitosan were incubated with RAW264.7 cells for 14 days. The TRAP activity was measured and the cell attachment and proliferation capacity were analyzed. The calcium ion concentrations in the culture medium before and after incubation were calculated. Both coatings were observed with scanning electron microscopy and characterized through an x-ray diffractometer and Fourier transform infrared spectrum. The RAW264.7 cells differentiated into TRAP-positive osteoclast-like cells on both coatings after 7 days. Although presenting different cell attachment pattern, the RAW264.7 cells demonstrated the similar TRAP activity and proliferation capacity. It was found that the calcium ion concentrations in the medium decreased at the beginning, but increased after 11 and 14 days. The chitosan containing coatings had higher Ca2+ concentration in the medium compared to that without chitosan. Besides, the incubation of coatings with cells induced higher calcium ion concentrations than those without cells at day 11 and day 14. Despite the structural changes of dissolution pits and osteoclastic resorption lacunae present on both coatings, the x-ray diffractometer and Fourier transform infrared spectrum showed few alternations in their chemical compositions. Both electrodeposited calcium phosphate coatings can be resorbed by osteoclast-like RAW264.7 cells and dissolved in the culture medium in vitro. The degradation brings little change to the chemical compositions of both coatings. (paper)

  11. A construction of novel iron-foam-based calcium phosphate/chitosan coating biodegradable scaffold material.

    Science.gov (United States)

    Wen, Zhaohui; Zhang, Liming; Chen, Chao; Liu, Yibo; Wu, Changjun; Dai, Changsong

    2013-04-01

    Slow corrosion rate and poor bioactivity restrict iron-based implants in biomedical application. In this study, we design a new iron-foam-based calcium phosphate/chitosan coating biodegradable composites offering a priority mechanical and bioactive property for bone tissue engineering through electrophoretic deposition (EPD) followed by a conversion process into a phosphate buffer solution (PBS). Tensile test results showed that the mechanical property of iron foam could be regulated through altering the construction of polyurethane foam. The priority coatings were deposited from 40% nano hydroxyapatite (nHA)/ethanol suspension mixed with 60% nHA/chitosan-acetic acid aqueous solution. In vitro immersion test showed that oxidation-iron foam as the matrix decreased the amount of iron implanted and had not influence on the bioactivity of this implant, obviously. So, this method could also be a promising method for the preparation of a new calcium phosphate/chitosan coating on foam construction. PMID:23827538

  12. Pulsed electrodeposition for the synthesis of strontium-substituted calcium phosphate coatings with improved dissolution properties.

    Science.gov (United States)

    Drevet, Richard; Benhayoune, Hicham

    2013-10-01

    Strontium-substituted calcium phosphate coatings are synthesized by pulsed electrodeposition on titanium alloy (Ti6Al4V) substrates. Experimental conditions of the process are optimized in order to obtain a coating with a 5% atomic substitution of calcium by strontium which corresponds to the best observations on the osteoblast cells activity and on the osteoclast cells proliferation. The physical and chemical characterizations of the obtained coating are carried out by scanning electron microscopy associated to energy dispersive X-ray spectroscopy (EDXS) for X-ray microanalysis and the structural characterization of the coating is carried out by X-ray diffraction. The in vitro dissolution/precipitation properties of the coated substrates are investigated by immersion into Dulbecco's Modified Eagle Medium (DMEM) from 1h to 14 days. The calcium, phosphorus and strontium concentrations variations in the biological liquid are assessed by Induced Coupled Plasma - Atomic Emission Spectroscopy for each immersion time. The results show that under specific experimental conditions, the electrodeposition process is suitable to synthesize strontium-substituted calcium phosphate coatings. Moreover, the addition of hydrogen peroxide (H2O2) into the electrolytic solution used in the process allows us to observe a control of the strontium release during the immersion of the prosthetic materials into DMEM. PMID:23910341

  13. Analytical and mechanical testing of high velocity oxy-fuel thermal sprayed and plasma sprayed calcium phosphate coatings.

    Science.gov (United States)

    Haman, J D; Chittur, K K; Crawmer, D E; Lucas, L C

    1999-01-01

    Plasma spraying (PS) is the most frequently used coating technique for implants; however, in other industries a cheaper, more efficient process, high-velocity oxy-fuel thermal spraying (HVOF), is in use. This process provides higher purity, denser, more adherent coatings than plasma spraying. The primary objective of this work was to determine if the use of HVOF could improve the mechanical properties of calcium phosphate coatings. Previous studies have shown that HVOF calcium phosphate coatings are more crystalline than plasma sprayed coatings. In addition, because the coatings are exposed to more complex loading profiles in vivo than standard ASTM tensile tests provide, a secondary objective of this study was to determine the applicability of four-point bend testing for these coatings. Coatings produced by HVOF and PS were analyzed by profilometry, diffuse reflectance Fourier transform infrared spectroscopy, X-ray diffraction, four-point bend, and ASTM C633 tensile testing. HVOF coatings were found to have lower amorphous calcium phosphate content, higher roughness values, and lower ASTM C633 bond strengths than PS coatings; however, both coatings had similar crystal unit cell sizes, phases present (including hydroxyapatite, beta-tricalcium phosphate, and tetracalcium phosphate), and four-point bend bond strengths. Thus, the chemical, structural, and mechanical results of this study, in general, indicate that the use of HVOF to produce calcium phosphate coatings is equivalent to those produced by plasma spraying. PMID:10556851

  14. Investigation of duty cycle effect on corrosion properties of electrodeposited calcium phosphate coatings.

    Science.gov (United States)

    Azem, Funda Ak; Delice, Tulay Koc; Ungan, Guler; Cakir, Ahmet

    2016-11-01

    The bioceramic calcium phosphate (CaP) is frequently used for improving bone fixation in titanium medical implants and thus increasing lifetime of the implant. It is known that the application of CaP coatings on metallic implant devices offers the possibility of combining the strength of the metals and the bioactivity of the ceramic materials. Many different techniques are available for producing CaP coatings. Electrochemical deposition method is widely used because of its ease of operation parameters, low temperature requirement, reproducibility and suitability for coating complex structures. This technique allows obtaining CaP coatings which promote bone in growth during the first healing period leading to permanent fixation. Electrochemical pulse technique is an alternative to calcium phosphate deposition techniques usually employed to cover orthopedic or dental titanium implant surfaces. Additionally, pulse electrodeposition technique can produce more uniform and denser CaP coatings on metallic implants. In this study, CaP based coatings were produced by electrochemical pulse technique on Ti6Al4V substrates. The resulting CaP deposits were investigated by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Corrosion properties of the CaP coatings were also investigated. The results showed that various duty cycle ranges have remarkably effect on morphology, crystallinity and corrosion properties of the produced CaP coatings. PMID:27524068

  15. Effects of calcium phosphate composition in sputter coatings on in vitro and in vivo performance.

    Science.gov (United States)

    Urquia Edreira, Eva R; Wolke, Joop G C; Aldosari, Abdullah AlFarraj; Al-Johany, Sulieman S; Anil, Sukumaran; Jansen, John A; van den Beucken, Jeroen J J P

    2015-01-01

    Calcium phosphate (CaP) ceramic coatings have been used to enhance the biocompatibility and osteoconductive properties of metallic implants. The chemical composition of these ceramic coatings is an important parameter, which can influence the final bone performance of the implant. In this study, the effect of phase composition of CaP-sputtered coatings was investigated on in vitro dissolution behavior and in vivo bone response. Coatings were prepared by a radio frequency (RF) magnetron sputtering technique; three types of CaP target materials were used to obtain coatings with different stoichiometry and calcium to phosphate ratios (hydroxyapatite (HA), α-tricalciumphosphate (α-TCP), and tetracalciumphosphate (TTCP)) were compared with non-coated titanium controls. The applied ceramic coatings were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and inductively coupled plasma optical emission spectroscopy. The in vitro dissolution/precipitation of the CaP coatings was evaluated using immersion tests in simulated body fluid (SBF). To mimic the in vivo situation, identical CaP coatings were also evaluated in a femoral condyle rabbit model. TCPH and TTCPH showed morphological changes during 4-week immersion in SBF. The results of bone implant contact (BIC) and peri-implant bone volume (BV) showed a similar response for all experimental coatings. An apparent increase in tartrate resistant acid phosphatase (TRAP) positive staining was observed in the peri-implant region with decreasing coating stability. In conclusion, the experimental groups showed different coating properties when tested in vitro and an apparent increase in bone remodeling with increasing coating dissolution in vivo. PMID:24659523

  16. Effect of power and type of substrate on calcium-phosphate coating morphology and microhardness

    Energy Technology Data Exchange (ETDEWEB)

    Kulyashova, Ksenia, E-mail: kseniya@ispms.tsc.ru; Glushko, Yurii, E-mail: glushko@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Sharkeev, Yurii, E-mail: sharkeev@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Sainova, Aizhan, E-mail: aizhan-sainova@mail.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation)

    2015-10-27

    As known, the influence of the different sputtering process parameters and type of substrate on structure of the deposited coating is important to identify, because these parameters are significantly affected on structure of coating. The studies of the morphology and microhardness of calcium-phosphate (CaP) coatings formed and obtained on the surface of titanium, zirconium, titanium and niobium alloy for different values of the power of radio frequency discharge are presented. The increase in the radio frequency (rf) magnetron discharge leads to the formation of a larger grain structure of the coating. The critical depths of indentation for coatings determining the value of their microhardness have been estimated. Mechanical properties of the composite material on the basis of the bioinert substrate metal and CaP coatings are superior to the properties of the separate components that make up this composite material.

  17. Effect of power and type of substrate on calcium-phosphate coating morphology and microhardness

    International Nuclear Information System (INIS)

    As known, the influence of the different sputtering process parameters and type of substrate on structure of the deposited coating is important to identify, because these parameters are significantly affected on structure of coating. The studies of the morphology and microhardness of calcium-phosphate (CaP) coatings formed and obtained on the surface of titanium, zirconium, titanium and niobium alloy for different values of the power of radio frequency discharge are presented. The increase in the radio frequency (rf) magnetron discharge leads to the formation of a larger grain structure of the coating. The critical depths of indentation for coatings determining the value of their microhardness have been estimated. Mechanical properties of the composite material on the basis of the bioinert substrate metal and CaP coatings are superior to the properties of the separate components that make up this composite material

  18. Effect of power and type of substrate on calcium-phosphate coating morphology and microhardness

    Science.gov (United States)

    Kulyashova, Ksenia; Sharkeev, Yurii; Glushko, Yurii; Sainova, Aizhan

    2015-10-01

    As known, the influence of the different sputtering process parameters and type of substrate on structure of the deposited coating is important to identify, because these parameters are significantly affected on structure of coating. The studies of the morphology and microhardness of calcium-phosphate (CaP) coatings formed and obtained on the surface of titanium, zirconium, titanium and niobium alloy for different values of the power of radio frequency discharge are presented. The increase in the radio frequency (rf) magnetron discharge leads to the formation of a larger grain structure of the coating. The critical depths of indentation for coatings determining the value of their microhardness have been estimated. Mechanical properties of the composite material on the basis of the bioinert substrate metal and CaP coatings are superior to the properties of the separate components that make up this composite material.

  19. Characterization of calcium phosphate coating and zinc incorporation on the porous alumina scaffolds

    Directory of Open Access Journals (Sweden)

    Hermes de Souza Costa

    2007-03-01

    Full Text Available Bone ingrowth requires materials with the existence of open and interconnected pores with diameters larger than 150 µm for proper circulation of nutrients. Such materials must possess enough mechanical strength to avoid failure whilst offering a bioactive surface for bone regeneration. We have developed porous ceramic alumina scaffold with compressive strength that achieves 3.3 MPa by replication method by using the network structure of cellular polymer foam. However, the biocompatibility of ceramics based on Al2O3 requires further improvement so that it could have strong bonding to natural bone tissue. To address this problem of the interface between alumina and bone, we have developed a novel calcium phosphate with Zn2+ (CaP-Zn coating onto porous alumina ceramic scaffold by impregnating with calcium phosphate/poly(vinyl alcohol slurry. The tri-dimensional alumina scaffold coated with CaP-Zn was extensively characterized by SEM, EDS and FTIR.

  20. Effect of Microstructural Evolution on Wettability of Laser Coated Calcium Phosphate on Titanium Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kurella, Anil K [ORNL; Hu, Michael Z. [ORNL; Dahotre, Narendra B [ORNL

    2008-01-01

    Surface engineering of synthetic implant materials provides an exciting opportunity to mimic natural biomaterials. Surface that are bioactive and textured at multi scale have the potential for easier osseointegration. Ti alloy surfaces known for their biocompatibility are coated with bioactive Calcium Phosphate using a laser source at multiple processing speeds. The resulting surface has multiscale morphology and multi-phase chemical nature. Faster processing speeds showed improved wettability to water along with higher degree of crystallinity in the phases present.

  1. Next-generation resorbable polymer scaffolds with surface-precipitated calcium phosphate coatings

    OpenAIRE

    Kim, Jinku; Magno, Maria Hanshella R.; Ortiz, Ophir; McBride, Sean; Darr, Aniq; Kohn, Joachim; Hollinger, Jeffrey O.

    2015-01-01

    Next-generation synthetic bone graft therapies will most likely be composed of resorbable polymers in combination with bioactive components. In this article, we continue our exploration of E1001(1k), a tyrosine-derived polycarbonate, as an orthopedic implant material. Specifically, we use E1001(1k), which is degradable, nontoxic, and osteoconductive, to fabricate porous bone regeneration scaffolds that were enhanced by two different types of calcium phosphate (CP) coatings: in one case, pure ...

  2. Calcium Phosphate Biomaterials: An Update

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Current calcium phosphate (CaP) biomaterials for bone repair, substitution, augmentation and regeneration include hydroxyapatite ( HA ) from synthetic or biologic origin, beta-tricalcium phosphate ( β-TCP ) , biphasic calcium phosphate (BCP), and are available as granules, porous blocks, components of composites (CaP/polymer) cements, and as coatings on orthopedic and dental implants. Experimental calcium phosphate biomaterials include CO3- and F-substituted apatites, Mg-and Zn-substituted β-TCP, calcium phosphate glasses. This paper is a brief review of the different types of CaP biomaterials and their properties such as bioactivity, osteoconductivity, osteoinductivity.

  3. Biomimetic coating of calcium phosphate on biometallic materials

    Institute of Scientific and Technical Information of China (English)

    ZHANG Er-lin; YANG Ke

    2005-01-01

    The biomimetic coating process in comparison with other processes is reviewed. This processing shows advantages in the surface bio-modification, such as low cost and flexible processing, wide range of apatite composition and thickness, non-line-of-sight characteristic and possibility to coat polymers and porous implants. The bio-mimetic apatite coating is made up of larger number of globules with size of 1-5μm. Each globule is a group of numerous flakes with a size range of 100-200nm to 30μm in length and 0.1-1μm in thickness. In-vitro and in-vivo studies show that the biomimetic apatite coating can promote an early and strong bonding to bone or promote the bone in-growth into the porous structure, which will be beneficial to the cementless stable fixation of orthopaedic implants. Recently developed co-precipitation of a kind of protein molecules into the HA coating shows much promising.

  4. In vitro behavior of HVOF sprayed calcium phosphate splats and coatings.

    Science.gov (United States)

    Khor, K A; Li, H; Cheang, P; Boey, S Y

    2003-02-01

    Hydroxyapatite (HA) coatings and splats deposited by high velocity oxy-fuel (HVOF) spray technique was investigated in vitro. HA coatings prepared from two different HA powder size range (30+/-5 and 50 +/-5 microm) were immersed in a simulated body fluid with various incubation periods of maximum 6 weeks. The dissolution/precipitation behavior was studied and the degradation of HA coatings caused by in vitro ageing was demonstrated by measuring the changes in flexural modulus through a 3-point bend test. It was found that the dissolution and precipitation behavior of the coatings was significantly dependent upon the incipient coating phase composition and the precipitation of bone-like hydroxyapatite on the coating's surface was found to be directly related to the dissolution process. Higher dissolution rates of tricalcium phosphate, tetracalcium phosphate and amorphous calcium phosphate relative to HA, resulted in accelerated precipitation. Furthermore, analysis of coatings' surface morphology demonstrated that advanced precipitation invariably occurred at regions where dissolution took place. Results showed that the changes in flexural modulus of investigated HA coatings accompanying different incubation duration was not systematic but was found to be dependent upon changes of coating structure and other factors brought about by in vitro ageing. In vitro investigation of individual HA splats collected from different HA particle sizes revealed, after 3 days ageing, that the rate ratio of precipitation to dissolution was directly determined by the local phase composition, and this phenomenon could be effectively used to explain the behavior of thermally sprayed HA coatings in vitro. It implied that the precipitation was strongly dependent on the first molecule attachment. To achieve rapid precipitation in vitro, partial molten state of HA particles during HVOF coating deposition was recommended. PMID:12485791

  5. Laser engineered multilayer coating of biphasic calcium phosphate/titanium nanocomposite on metal substrates.

    Science.gov (United States)

    Zhang, Martin Yi; Ye, Chang; Erasquin, Uriel Joseph; Huynh, Toan; Cai, Chengzhi; Cheng, Gary J

    2011-02-01

    In this work, laser coating of biphasic calcium phosphate/titanium (BCP/Ti) nanocomposite on Ti-6Al-4 V substrates was developed. A continuous wave neodymium-doped yttrium aluminium garnet (Nd:YAG) laser was used to form a robust multilayer of BCP/Ti nanocomposite starting from hydroxyapatite and titanium nanoparticles. In this process, low power coating is realized because of the strong laser-nanoparticle interaction and good sinterability of nanosized titanium. To guide the optimization of laser processing conditions for the coating process, a multiphysics model coupling electromagnetic module with heat transfer module was developed. This model was validated by laser coating experiments. Important features of the coated samples, including microstructures, chemical compositions, and interfacial bonding strength, were characterized. We found that a multilayer of BCP, consisting of 72% hydroxyapatite (HA) and 28% beta-tricalcium phosphate (β-TCP), and titanium nanocomposite was formed on Ti-6Al-4 V substrates. Significantly, the coating/substrate interfacial bonding strength was found to be two times higher than that of the commercial plasma sprayed coatings. Preliminary cell culture studies showed that the resultant BCP/Ti nanocomposite coating supported the adhesion and proliferation of osteoblast-like UMR-106 cells. PMID:21207950

  6. A study of strontium doped calcium phosphate coatings on AZ31

    International Nuclear Information System (INIS)

    Calcium phosphate (CaP) coatings have been studied to tailor the uncontrolled non-uniform corrosion of Mg based alloys while simultaneously enhancing bioactivity. The use of immersion techniques to deposit CaP coatings is attractive due to the ability of the approach to coat complex structures. In the current study, AZ31 substrates were subjected to various pretreatment conditions prior to depositing Sr2+ doped and undoped CaP coatings. It was hypothesized that the bioactivity and corrosion protection of CaP coatings could be improved by doping with Sr2+. Heat treatment to elevated temperatures resulted in the diffusion of alloying elements, Mg and Zn, into the pretreated layer. Sr2+ doped and undoped CaP coatings formed on the pretreated substrates consisted of biphasic mixtures of β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA). Electrochemical corrosion experiments indicated that the extent of Sr2+ doping and pretreatment both influenced the corrosion protection. Cytotoxicity was evaluated with MC3T3-E1 mouse preosteoblasts and human mesenchymal stem cells (hMSCs). For both cell types, proliferation decreased upon increasing the Sr2+ concentration. However, both osteogenic gene and protein expression significantly increased upon increasing Sr2+ concentration. These results suggest that Sr2+ doped coatings are capable of promoting osteogenic differentiation on degradable Mg alloys, while also enhancing corrosion protection, in comparison to undoped CaP coatings

  7. Preparation of calcium phosphate coating on pure titanium substrate by electrodeposition method

    Institute of Scientific and Technical Information of China (English)

    赵中伟; 张刚; 李洪桂

    2004-01-01

    The influences of pH value, electrolyte temperature and loading time on depositing calcium phosphate coating on pure titanium substrate by electrodeposition process were investigated. The process was carried out with an electrochemical work-station supplying a direct current power at potential of -0.8V (vs SCE). The electrolyte consists of 7 mmol·L-1 CaCl2·2H2O, 3 mmol·L-1 Ca(H2PO4)2·H2O and 2.5% H2O2. NaOH and HCl solutions were used to adjust pH value. The deposited samples were characterized by X-ray diffraction and scanning electron microscope. The comparison of the deposits obtained at lower and higher pH values demonstrates that the crystallization process at the interface is favoured by high pH value. With temperature increasing, the deposited hydroxyapatite is occasionally of plate-like shape, and the width and the length of the deposited calcium phosphates at 65 ℃ are larger than those at 55 ℃. Therefore, it is confirmed that the morphology and microstructure of electrochemically deposited calcium phosphates can be regulated. Additionally, the coating formed in electrolyte with H2O2 additive is homogeneous and the evolution of H2 bubble can be eliminated.

  8. Calcium phosphate coating containing silver shows high antibacterial activity and low cytotoxicity and inhibits bacterial adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Ando, Yoshiki, E-mail: andoy@jmmc.jp [Division of Microbiology, Department of Pathology and Microbiology, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501 (Japan); Research Department, Japan Medical Materials Corporation, Uemura Nissei Bldg.9F 3-3-31 Miyahara, Yodogawa-ku, Osaka 532-0003 (Japan); Miyamoto, Hiroshi [Division of Microbiology, Department of Pathology and Microbiology, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501 (Japan); Noda, Iwao; Sakurai, Nobuko [Research Department, Japan Medical Materials Corporation, Uemura Nissei Bldg.9F 3-3-31 Miyahara, Yodogawa-ku, Osaka 532-0003 (Japan); Akiyama, Tomonori [Division of Microbiology, Department of Pathology and Microbiology, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501 (Japan); Yonekura, Yutaka; Shimazaki, Takafumi; Miyazaki, Masaki; Mawatari, Masaaki; Hotokebuchi, Takao [Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501 (Japan)

    2010-01-01

    Surgical site infection is one of the serious complications of orthopedic implants. In order to reduce the incidence of implant-associated infections, we developed a novel coating technology of calcium phosphate (CP) containing silver (Ag), designated Ag-CP coating, using a thermal spraying technique. In this study, we evaluated the antibacterial efficacy and biological safety of this coating. In vitro antibacterial activity tests showed that the growths of Escherichia coli, Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) are completely suppressed on Ag-CP coating. In vitro bacterial adherence tests revealed that the number of adherent bacteria on the surface of this coating is significantly less (p < 0.02) than that on the surface of the CP coating. Moreover, the Ag-CP coating completely inhibits MRSA adhesion [<10 colony-forming units (CFU)] when 10{sup 2} CFU MRSA is inoculated. On the other hand, V79 Chinese hamster lung cells were found to grow on the Ag-CP coating as well as on the CP coating in a cytotoxicity test. These results indicate that the Ag-CP coating on the surface of orthopedic implants exhibits antibacterial activity and inhibits bacterial adhesion without cytotoxicity.

  9. Monolithic calcium phosphate/poly(lactic acid) composite versus calcium phosphate-coated poly(lactic acid) for support of osteogenic differentiation of human mesenchymal stromal cells

    OpenAIRE

    Tahmasebi Birgani, Zeinab; van Blitterswijk, Clemens A; Habibovic, Pamela

    2016-01-01

    Calcium phosphates (CaPs), extensively used synthetic bone graft substitutes, are often combined with other materials with the aim to overcome issues related to poor mechanical properties of most CaP ceramics. Thin ceramic coatings on metallic implants and polymer-ceramic composites are examples of such hybrid materials. Both the properties of the CaP used and the method of incorporation into a hybrid structure are determinant for the bioactivity of the final construct. In the present study, ...

  10. Biomimetic calcium phosphate coating of additively manufactured porous CoCr implants

    Science.gov (United States)

    Lindahl, Carl; Xia, Wei; Engqvist, Håkan; Snis, Anders; Lausmaa, Jukka; Palmquist, Anders

    2015-10-01

    The aim of this work was to study the feasibility to use a biomimetic method to prepare biomimetic hydroxyapatite (HA) coatings on CoCr substrates with short soaking times and to characterize the properties of such coatings. A second objective was to investigate if the coatings could be applied to porous CoCr implants manufactured by electron beam melting (EBM). The coating was prepared by immersing the pretreated CoCr substrates and EBM implants into the phosphate-buffered solution with Ca2+ in sealed plastic bottles, kept at 60 °C for 3 days. The formed coating was partially crystalline, slightly calcium deficient and composed of plate-like crystallites forming roundish flowers in the size range of 300-500 nm. Cross-section imaging showed a thickness of 300-500 nm. In addition, dissolution tests in Tris-HCl up to 28 days showed that a substantial amount of the coating had dissolved, however, undergoing only minor morphological changes. A uniform coating was formed within the porous network of the additive manufactured implants having similar thickness and morphology as for the flat samples. In conclusion, the present coating procedure allows coatings to be formed on CoCr and could be used for complex shaped, porous implants made by additive manufacturing.

  11. Bioactivity and corrosion properties of gelatin-containing and strontium-doped calcium phosphate composite coating

    Science.gov (United States)

    Huang, Yong; Yan, Yajing; Pang, Xiaofeng; Ding, Qiongqiong; Han, Shuguang

    2013-10-01

    To improve coating corrosion resistance and bioactivity, strontium (Sr) and gelatin (GLT) were simultaneously incorporated in calcium phosphate (Ca-P) to form Sr-Ca-P/GLT composite coating on titanium (Ti) by electrodeposition. The surface morphology, chemical composition, phase identification, bond strength, corrosion resistance, and cytocompatibility of the films were studied. Results revealed that the Sr-Ca-P/GLT layer was rough and inhomogeneous, with floral-like crystals or flake agglomerate morphology. The Sr-Ca-P crystals were Sr-doped apatite (hydroxyapatite and brushite), and Sr2+ ions and GLT were homogeneously distributed in the Ca-P coating. The thickness of the composite coating was almost 10 μm without delamination and/or cracking at the interface. The bond strength of the composite coating was 5.6 ± 1.8 MPa. The Sr-Ca-P/GLT coated Ti had lower corrosion rates than bare Ti, suggesting a protective character of the composite coating. Osteoblast cellular tests demonstrated that the Sr-Ca-P/GLT composite coating better enhanced the in vitro biocompatibility of Ti than Ca-P coating.

  12. Bioactivity and corrosion properties of gelatin-containing and strontium-doped calcium phosphate composite coating

    International Nuclear Information System (INIS)

    To improve coating corrosion resistance and bioactivity, strontium (Sr) and gelatin (GLT) were simultaneously incorporated in calcium phosphate (Ca–P) to form Sr–Ca–P/GLT composite coating on titanium (Ti) by electrodeposition. The surface morphology, chemical composition, phase identification, bond strength, corrosion resistance, and cytocompatibility of the films were studied. Results revealed that the Sr–Ca–P/GLT layer was rough and inhomogeneous, with floral-like crystals or flake agglomerate morphology. The Sr–Ca–P crystals were Sr-doped apatite (hydroxyapatite and brushite), and Sr2+ ions and GLT were homogeneously distributed in the Ca–P coating. The thickness of the composite coating was almost 10 μm without delamination and/or cracking at the interface. The bond strength of the composite coating was 5.6 ± 1.8 MPa. The Sr–Ca–P/GLT coated Ti had lower corrosion rates than bare Ti, suggesting a protective character of the composite coating. Osteoblast cellular tests demonstrated that the Sr–Ca–P/GLT composite coating better enhanced the in vitro biocompatibility of Ti than Ca–P coating.

  13. Calcium phosphate coating containing silver shows high antibacterial activity and low cytotoxicity and inhibits bacterial adhesion

    International Nuclear Information System (INIS)

    Surgical site infection is one of the serious complications of orthopedic implants. In order to reduce the incidence of implant-associated infections, we developed a novel coating technology of calcium phosphate (CP) containing silver (Ag), designated Ag-CP coating, using a thermal spraying technique. In this study, we evaluated the antibacterial efficacy and biological safety of this coating. In vitro antibacterial activity tests showed that the growths of Escherichia coli, Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) are completely suppressed on Ag-CP coating. In vitro bacterial adherence tests revealed that the number of adherent bacteria on the surface of this coating is significantly less (p 2 CFU MRSA is inoculated. On the other hand, V79 Chinese hamster lung cells were found to grow on the Ag-CP coating as well as on the CP coating in a cytotoxicity test. These results indicate that the Ag-CP coating on the surface of orthopedic implants exhibits antibacterial activity and inhibits bacterial adhesion without cytotoxicity.

  14. Influence of precursor solution parameters on chemical properties of calcium phosphate coatings prepared using Electrostatic Spray Deposition (ESD).

    NARCIS (Netherlands)

    Leeuwenburgh, S.C.G.; Wolke, J.G.C.; Schoonman, J.; Jansen, J.A.

    2004-01-01

    A novel coating technique, referred to as Electrostatic Spray Deposition (ESD), was used to deposit calcium phosphate (CaP) coatings with a variety of chemical properties. The relationship between the composition of the precursor solutions and the crystal and molecular structure of the deposited coa

  15. Biological influence of Ca/P ratio on calcium phosphate coatings by sol-gel processing.

    Science.gov (United States)

    Catauro, M; Papale, F; Sapio, L; Naviglio, S

    2016-08-01

    The objective of this work has been to develop low temperature sol-gel glass coatings to modify the substrate surface and to evaluate their bioactivity and biocompatibility. Glasses, based on SiO2·CaO·P2O5, were synthesized by the sol-gel technique using tetraethyl orthosilicate, calcium nitrate tetrahydrate and triethyl phosphate as precursors of SiO2, CaO and P2O5, respectively. Those materials, still in the sol phase, have been used to coat substrates by means of the dip-coating technique. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) has been used for characterize coatings and a microstructural analysis has been obtained using scanning electron microscopy (SEM). The potential applications of the coatings in the biomedical field were evaluated by bioactivity and biocompatibility tests. The coated substrate was immersed in simulated body fluid (SBF) for 21days and the hydroxyapatite deposition on its surface was subsequently evaluated via SEM-EDXS analysis, as an index of bone-bonding capability. In order to study the cell behavior and response to our silica based materials, prepared via the sol-gel method, with various Ca/P ratio and coating substrate, we have used the human osteoblast-like U2OS cell line. PMID:27157742

  16. The porosity and roughness of electrodeposited calcium phosphate coatings in simulated body fluid

    Directory of Open Access Journals (Sweden)

    Đošić Marija S.

    2015-01-01

    Full Text Available Calcium phosphate coatings were electrochemically deposited on titanium from the aqueous solution of Ca(NO32 and NH4H2PO4 with the current density of 10 mA cm-2 for deposition time of 15 min. The obtained brushite coatings, (CaHPO4·2H2O, were converted to hydroxyapatite (HA by soaking in simulated body fluid (SBF for 2, 7 and 14 days. The brushite and hydroxyapatite coatings were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM and atomic force microscopy (AFM. It was shown that the increase in soaking time increases the porosity, roughness and crystallite domain size of HA coatings and decreases the unit cell parameters and unit cell volume, while does not affect the HA mean pore area. The calcium and phosphorus ions concentrations in SBF were determined by atomic absorption spectroscopy (AAS and UV-Vis spectroscopy, respectively and the mechanism of HA growth based on dissolution-precipitation was proposed. [Projekat Ministarstva nauke Republike Srbije, br. III 45019, br. III 45015 i br. OI 72004

  17. Effects of phosphates on microstructure and bioactivity of micro-arc oxidized calcium phosphate coatings on Mg-Zn-Zr magnesium alloy.

    Science.gov (United States)

    Pan, Y K; Chen, C Z; Wang, D G; Zhao, T G

    2013-09-01

    Calcium phosphate (CaP) coatings were prepared on Mg-Zn-Zr magnesium alloy by micro-arc oxidation (MAO) in electrolyte containing calcium acetate monohydrate (CH3COO)2Ca·H2O) and different phosphates (i.e. disodium hydrogen phosphate dodecahydrate (Na2HPO4·12H2O), sodium phosphate (Na3PO4·H2O) and sodium hexametaphosphate((NaPO3)6)). Scanning electron microscope (SEM), energy-dispersive X-ray spectrometry (EDS) and X-ray diffractometer (XRD) were employed to characterize the microstructure, elemental distribution and phase composition of the CaP coatings. Simulated body fluid (SBF) immersion test was used to evaluate the coating bioactivity and degradability. Systemic toxicity test was used to evaluate the coating biocompatibility. Fluoride ion selective electrode (ISE) was used to measure F(-) ions concentration during 30 days SBF immersion. The CaP coatings effectively reduced the corrosion rate and the surfaces of CaP coatings were covered by a new layer formed of numerous needle-like and scale-like apatites. The formation of these calcium phosphate apatites indicates that the coatings have excellent bioactivity. The coatings formed in (NaPO3)6-containging electrolyte exhibit thicker thickness, higher adhesive strength, slower degradation rate, better apatite-inducing ability and biocompatibility. PMID:23603036

  18. Calcium phosphate glass-ceramics for bioactive coating on a β-titanium alloy

    International Nuclear Information System (INIS)

    The formation of a porous coating is the decisive feature for the bio-compatibility of silica-free calcium phosphate glass ceramics on alloy surfaces like the β-Ti structured Ti-29Nb-13Ta-4.6Zr used in this work. The ceramic composition is highly important: 50CaO-40P2O5-7Na2O-3TiO2 glass powder produces a pore-free coating unable to bind hydroxyapatite, whereas 60CaO-30P2O5-7Na2O-3TiO2 glass incorporates pores from which a crystalline hydroxyapatite phase can grow over the surface from simulated body fluid (see Figure). (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  19. Preliminary research on a novel bioactive silicon doped calcium phosphate coating on AZ31 magnesium alloy via electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Xun [Department of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Institute of Metal Research, Chinese Academy of Science, Shenyang 110016 (China); Wan, Peng, E-mail: pwan@imr.ac.cn [Institute of Metal Research, Chinese Academy of Science, Shenyang 110016 (China); Tan, LiLi [Institute of Metal Research, Chinese Academy of Science, Shenyang 110016 (China); Fan, XinMin [Department of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Yang, Ke [Institute of Metal Research, Chinese Academy of Science, Shenyang 110016 (China)

    2014-03-01

    A silicon doped calcium phosphate coating was obtained successfully on AZ31 alloy substrate via pulse electrodeposition. A novel dual-layer structure was observed with a porous lamellar-like and outer block-like apatite layer. In vitro immersion tests were adopted in simulated body fluid within 28 days of immersion. Slow degradation rate obtained from weight loss was observed for the Si-doped Ca–P coating, which was also consistent with the results of electrochemical experiments showing an enhanced corrosion resistance for the coating. Further formation of an apatite-like layer on the surface after immersion proved better integrity and biomineralization performance of the coating. Biological characterization was carried out for viability, proliferation and differentiation of MG63 osteoblast-like cells. The coating showed a good cell growth and an enhanced cell proliferation. Moreover, an increased activity of osteogenic marker ALP was found. All the results demonstrated that the Si-doped calcium phosphate was perspective to be used as a coating for magnesium alloy implants to control the degradation rate and enhance the bioactivity, which would facilitate the rapidity of bone tissue repair. - Highlights: • A Si-doped calcium phosphate coating was achieved via pulse ED on AZ31 alloy. • The coating was composed of a porous lamellar-like layer and outer block-like apatite. • The coating showed slow degradation rate and better biomineralization property. • The coating improved cell proliferation and activity of osteogenic marker ALP.

  20. Preliminary research on a novel bioactive silicon doped calcium phosphate coating on AZ31 magnesium alloy via electrodeposition

    International Nuclear Information System (INIS)

    A silicon doped calcium phosphate coating was obtained successfully on AZ31 alloy substrate via pulse electrodeposition. A novel dual-layer structure was observed with a porous lamellar-like and outer block-like apatite layer. In vitro immersion tests were adopted in simulated body fluid within 28 days of immersion. Slow degradation rate obtained from weight loss was observed for the Si-doped Ca–P coating, which was also consistent with the results of electrochemical experiments showing an enhanced corrosion resistance for the coating. Further formation of an apatite-like layer on the surface after immersion proved better integrity and biomineralization performance of the coating. Biological characterization was carried out for viability, proliferation and differentiation of MG63 osteoblast-like cells. The coating showed a good cell growth and an enhanced cell proliferation. Moreover, an increased activity of osteogenic marker ALP was found. All the results demonstrated that the Si-doped calcium phosphate was perspective to be used as a coating for magnesium alloy implants to control the degradation rate and enhance the bioactivity, which would facilitate the rapidity of bone tissue repair. - Highlights: • A Si-doped calcium phosphate coating was achieved via pulse ED on AZ31 alloy. • The coating was composed of a porous lamellar-like layer and outer block-like apatite. • The coating showed slow degradation rate and better biomineralization property. • The coating improved cell proliferation and activity of osteogenic marker ALP

  1. Phase evolution in calcium phosphate coatings obtained by in situ laser cladding

    International Nuclear Information System (INIS)

    Calcium phosphate coating was fabricated by in situ laser cladding using mixed powders of CaCO3 and CaHPO4, which presented a complex phase constitution since the reactions between CaCO3 and CaHPO4 would produce not only hydroxyapatite (HA) in the coating, but also other phases, such as Ca4(PO4)2O (TTCP) and α-Ca3(PO4)2 (α-TCP). In order to realize the control of the phase constitution, the effects of the Ca/P molar ratio of mixed powders, laser power, scanning velocity and heat treatment on the phase constitution of the coatings were investigated through X-ray diffraction analysis. It is found that the variation of the Ca/P molar ratio of the mixed powders, laser power and scanning velocity can adjust, to a certain extent, the proportion of HA, α-TCP, and TTCP in the coating. However, the α-TCP and TTCP cannot be eliminated from the coating due to the intrinsic high cooling rate of the laser melt pool during laser cladding. By suitable post heat treatment, the TTCP and α-TCP in the coating can be partially or completely transformed into HA. Therefore, HA coating or coatings with desirable proportion of HA, α-TCP and TTCP can be obtained by in situ laser cladding plus post heat treatment. - Highlights: ► The phase constitution varies with the Ca/P molar ratio of the mixed powders of CaCO3 and CaHPO4. ► High laser powder and scanning velocity are disadvantages for the synthesis of HA. ► Heat treatment with furnace cooling can make α-TCP and TTCP transform into HA.

  2. Delivery of fluorophores by calcium phosphate-coated nanoliposomes and interaction with Staphylococcus aureus biofilms.

    Science.gov (United States)

    Rivero Berti, Ignacio; Dell' Arciprete, María Laura; Dittler, María Laura; Miñan, Alejandro; Fernández Lorenzo de Mele, Mónica; Gonzalez, Mónica

    2016-06-01

    The delivery capacity and mechanical stability of calcium phosphate (CaP) coated 1,2-dioleoyl-sn-glycero-3-phosphate (DOPA) liposomes free and adsorbed on bacterial surface was investigated introducing either acridine orange (AO) or 5,10,15,20-Tetrakis(1-methyl-4-pyridinio)porphyrin (TMP) in the aqueous core of the liposomes. The obtained nanomaterials were thoroughly characterized by electron and optical microscopy and by fluorescence techniques. Distribution of the AO and TMP molecules between the aqueous liposomes core and the outer solution was demonstrated by the band shifts and broadening of the excitation-emission matrices and the modified Stern-Volmer model for fluorescence quenching. In aqueous suspensions, c.a. 40% of AO was released to the outer solution while only a small percentage of TMP was observed to reach the outer liposome surface. The nanoliposomes adhesion capacity and the leaking of fluorophore molecules to Staphylococcus aureus (S. aureus) biofilms were further evaluated. A close interaction between liposomes and S. aureus biofilm was evidenced by TEM and SEM imaging. Epifluorescence experiments demonstrated that CaP-coated liposomes have good biofilm staining capability after two hours incubation of the biofilms with the liposomes, thus supporting an important release of the fluorophores when in contact with the biofilm. Altogether, the obtained results strongly suggest that CaP-coated liposomes are capable of activating drug release when in presence of S. aureus biofilms and smears. The studies herein presented, indicate that CaP-coated liposomes are potential vehicles for the selective delivery of drugs to S. aureus biofilms, as is the case of the singlet oxygen photosensitizer TMP, a well known photodynamic antibacterial agent. PMID:26954088

  3. Antimicrobial peptides on calcium phosphate-coated titanium for the prevention of implant-associated infections

    DEFF Research Database (Denmark)

    Kazemzadeh-Narbat, Mehdi; Kindrachuk, Jason; Duan, Ke;

    2010-01-01

    ) bacteria with 106-fold reductions of both bacterial strains within 30 min as assessed by measuring colony-forming units (CFU). Repeated CFU assays on the same CaP-Tet213 specimen demonstrated retention of antimicrobial activity by the CaP-Tet213 surfaces through four test cycles. The susceptibility of......Prevention of implant-associated infections has been one of the main challenges in orthopaedic surgery. This challenge is further complicated by the concern over the development of antibiotic resistance as a result of using traditional antibiotics for infection prophylaxis. The objective of this...... study was to develop a technique that enables the loading and local delivery of a unique group of cationic antimicrobial peptides (AMP) through implant surfaces. A thin layer of micro-porous calcium phosphate (CaP) coating was processed by electrolytic deposition onto the surface of titanium as the drug...

  4. Isolation and characterization of biogenic calcium carbonate/phosphate from oral bacteria and their adhesion studies on YSZ-coated titanium substrate for dental implant application

    Indian Academy of Sciences (India)

    GOBI SARAVANAN KALIARAJ; KAMALAN KIRUBAHARAN; G PRADHABAN; P KUPPUSAMI; VINITA VISHWAKARMA

    2016-04-01

    Biogenic calcium carbonate/phosphate were isolated and characterized from oral bacteria (CPOB). The crystalline nature and morphology of calcium carbonate/phosphate were characterized by X-ray diffraction (XRD)and field emission scanning electron microscopy (FESEM), respectively. XRD analysis revealed the cubic phase of YSZ coating as well as biogenic calcium carbonate (rhombohedral) and calcium phosphate oxide (hexagonal) wasobserved from CPOB. FESEM confirmed the extracellular synthesis of calcium compounds. Bacterial adhesion result reveals that YSZ coating drastically reduce bacterial invasion than titanium substrate.

  5. Effect of nano-hydroxyapatite coating on the osteoinductivity of porous biphasic calcium phosphate ceramics

    Science.gov (United States)

    2014-01-01

    Background Porous biphasic calcium phosphate (BCP) ceramics exhibit good biocompatibility and bone conduction but are not inherently osteoinductive. To overcome this disadvantage, we coated conventional porous BCP ceramics with nano-hydroxyapatite (nHA). nHA was chosen as a coating material due to its high osteoinductive potential. Methods We used a hydrothermal deposition method to coat conventional porous BCP ceramics with nHA and assessed the effects of the coating on the physical and mechanical properties of the underlying BCP. Next, its effects on mesenchymal stem cell (MSC) attachment, proliferation, viability, and osteogenic differentiation were investigated. Results nHA formed a deposited layer on the BCP surface, and synthesized nHA had a rod-like shape with lengths ranging from ~50–200 nm and diameters from ~15–30 mm. The nHA coating did not significantly affect the density, porosity, flexural strength, or compressive strength of the underlying BCP (P > 0.1). Scanning electron microscopy showed MSC attachment to the scaffolds, with a healthy morphology and anchorage to nHA crystals via cytoplasmic processes. The densities of MSCs attached on BCP and nHA-coated BCP scaffolds were 62 ± 26 cells/mm2 and 63 ± 27 cells/mm2 (P > 0.1), respectively, after 1 day and 415 ± 62 cells/mm2 and 541 ± 35 cells/mm2 (P < 0.05) respectively, after 14 days. According to an MTT assay, MSC viability was higher on nHA-coated BCP scaffolds than on BCP scaffolds (P < 0.05). In addition, MSCs on nHA-coated BCP scaffolds produced more alkaline phosphatase, collagen type I, and osteocalcin than MSCs on BCP scaffolds (P < 0.05). Conclusions Our results demonstrate that BCP scaffolds coated with nHA were more conducive for MSC adhesion, proliferation, and osteogenic differentiation than conventional, uncoated BCP scaffolds, indicating that nHA coating can enhance the osteoinductive potential of BCP ceramics, making this material more

  6. Synthesis of calcium hydrogen phosphate and hydroxyapatite coating on SS316 substrate through pulsed electrodeposition.

    Science.gov (United States)

    Chakraborty, Rajib; Sengupta, Srijan; Saha, Partha; Das, Karabi; Das, Siddhartha

    2016-12-01

    The orthopaedic implants for human body are generally made of different biomaterials like stainless steels or Ti based alloys. However, it has been found that from surface properties point of view, none of these materials is attractive for fast tissue or cell growth on the surface of implant. This is one of the most important criteria to assure quick bonding between implant and body tissues vis-à-vis minimum recovery time for the patient. Keeping in view of the above facts, this work involves the pulsed electro-deposition coating of biocompatible hydroxyapatite and its group compounds from a diluted bath of calcium and phosphate salt at various current densities over the biomaterial sheet of SS316. SEM study confirms different morphologies of the coatings at different current densities. Characterization techniques like X-ray diffraction, SEM with EDX and FTIR have been used to confirm the phase and percentage quantity of hydroxyapatite compound in the depositions. This coating can serve as a medium for faster tissue growth over the metallic implants. PMID:27612782

  7. Microstructure, corrosion properties and bio-compatibility of calcium zinc phosphate coating on pure iron for biomedical application.

    Science.gov (United States)

    Chen, Haiyan; Zhang, Erlin; Yang, Ke

    2014-01-01

    In order to improve the biocompatibility and the corrosion resistance in the initial stage of implantation, a phosphate (CaZn2(PO4)2·2H2O) coating was obtained on the surface of pure iron by a chemical reaction method. The anti-corrosion property, the blood compatibility and the cell toxicity of the coated pure iron specimens were investigated. The coating was composed of some fine phosphate crystals and the surface of coating was flat and dense enough. The electrochemical data indicated that the corrosion resistance of the coated pure iron was improved with the increase of phosphating time. When the specimen was phosphated for 30min, the corrosion resistance (Rp) increased to 8006 Ω. Compared with that of the naked pure iron, the anti-hemolysis property and cell compatibility of the coated specimen was improved significantly, while the anti-coagulant property became slightly worse due to the existence of element calcium. It was thought that phosphating treatment might be an effective method to improve the biocompatibility of pure iron for biomedical application. PMID:24268250

  8. Calcium phosphate/porous silicon biocomposites prepared by cyclic deposition methods: Spin coating vs electrochemical activation

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Montelongo, J., E-mail: jacobo.hernandez@uam.es [Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Gallach, D.; Naveas, N.; Torres-Costa, V. [Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Climent-Font, A. [Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Centro de Microanálisis de Materiales (CMAM), Universidad Autónoma de Madrid, Madrid 28049 (Spain); García-Ruiz, J.P. [Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, Madrid 28049 (Spain); Manso-Silvan, M. [Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain)

    2014-01-01

    Porous silicon (PSi) provides an excellent platform for bioengineering applications due to its biocompatibility, biodegradability, and bioresorbability. However, to promote its application as bone engineering scaffold, deposition of calcium phosphate (CaP) ceramics in its hydroxyapatite (HAP) phase is in progress. In that sense, this work focuses on the synthesis of CaP/PSi composites by means of two different techniques for CaP deposition on PSi: Cyclic Spin Coating (CSC) and Cyclic Electrochemical Activation (CEA). Both techniques CSC and CEA consisted on alternate Ca and P deposition steps on PSi. Each technique produced specific morphologies and CaP phases using the same independent Ca and P stem-solutions at neutral pH and at room temperature. The brushite (BRU) phase was favored with the CSC technique and the hydroxyapatite (HAP) phase was better synthesized using the CEA technique. Analyses by elastic backscattering spectroscopy (EBS) on CaP/PSi structures synthesized by CEA supported that, by controlling the CEA parameters, an HAP coating with the required Ca/P atomic ratio of 1.67 can be promoted. Biocompatibility was evaluated by bone-derived progenitor cells, which grew onto CaP/PSi prepared by CSC technique with a long-shaped actin cytoskeleton. The density of adhered cells was higher on CaP/PSi prepared by CEA, where cells presented a normal morphological appearance and active mitosis. These results can be used for the design and optimization of CaP/PSi composites with enhanced biocompatibility for bone-tissue engineering. - Highlights: • Proposed cyclic methods produce specific morphologies and CaP phases in biocomposites. • The brushite phase is favored in the biocomposite produced by Cyclic Spin Coating. • The hydroxyapatite phase is favored in the biocomposite produced by Cyclic Electrochemical Activation. • The Ca/P atomic ratio of hydroxyapatite was validated by elastic backscattering spectroscopy. • Cells grown showed morphological and

  9. Calcium phosphate/porous silicon biocomposites prepared by cyclic deposition methods: Spin coating vs electrochemical activation

    International Nuclear Information System (INIS)

    Porous silicon (PSi) provides an excellent platform for bioengineering applications due to its biocompatibility, biodegradability, and bioresorbability. However, to promote its application as bone engineering scaffold, deposition of calcium phosphate (CaP) ceramics in its hydroxyapatite (HAP) phase is in progress. In that sense, this work focuses on the synthesis of CaP/PSi composites by means of two different techniques for CaP deposition on PSi: Cyclic Spin Coating (CSC) and Cyclic Electrochemical Activation (CEA). Both techniques CSC and CEA consisted on alternate Ca and P deposition steps on PSi. Each technique produced specific morphologies and CaP phases using the same independent Ca and P stem-solutions at neutral pH and at room temperature. The brushite (BRU) phase was favored with the CSC technique and the hydroxyapatite (HAP) phase was better synthesized using the CEA technique. Analyses by elastic backscattering spectroscopy (EBS) on CaP/PSi structures synthesized by CEA supported that, by controlling the CEA parameters, an HAP coating with the required Ca/P atomic ratio of 1.67 can be promoted. Biocompatibility was evaluated by bone-derived progenitor cells, which grew onto CaP/PSi prepared by CSC technique with a long-shaped actin cytoskeleton. The density of adhered cells was higher on CaP/PSi prepared by CEA, where cells presented a normal morphological appearance and active mitosis. These results can be used for the design and optimization of CaP/PSi composites with enhanced biocompatibility for bone-tissue engineering. - Highlights: • Proposed cyclic methods produce specific morphologies and CaP phases in biocomposites. • The brushite phase is favored in the biocomposite produced by Cyclic Spin Coating. • The hydroxyapatite phase is favored in the biocomposite produced by Cyclic Electrochemical Activation. • The Ca/P atomic ratio of hydroxyapatite was validated by elastic backscattering spectroscopy. • Cells grown showed morphological and

  10. Monolithic calcium phosphate/poly(lactic acid) composite versus calcium phosphate-coated poly(lactic acid) for support of osteogenic differentiation of human mesenchymal stromal cells.

    Science.gov (United States)

    Tahmasebi Birgani, Zeinab; van Blitterswijk, Clemens A; Habibovic, Pamela

    2016-03-01

    Calcium phosphates (CaPs), extensively used synthetic bone graft substitutes, are often combined with other materials with the aim to overcome issues related to poor mechanical properties of most CaP ceramics. Thin ceramic coatings on metallic implants and polymer-ceramic composites are examples of such hybrid materials. Both the properties of the CaP used and the method of incorporation into a hybrid structure are determinant for the bioactivity of the final construct. In the present study, a monolithic composite comprising nano-sized CaP and poly(lactic acid) (PLA) and a CaP-coated PLA were comparatively investigated for their ability to support proliferation and osteogenic differentiation of bone marrow-derived human mesenchymal stromal cells (hMSCs). Both, the PLA/CaP composite, produced using physical mixing and extrusion and CaP-coated PLA, resulting from a biomimetic coating process at near-physiological conditions, supported proliferation of hMSCs with highest rates at PLA/CaP composite. Enzymatic alkaline phosphatase activity as well as the mRNA expression of bone morphogenetic protein-2, osteopontin and osteocalcin were higher on the composite and coated polymer as compared to the PLA control, while no significant differences were observed between the two methods of combining CaP and PLA. The results of this study confirmed the importance of CaP in osteogenic differentiation while the exact properties and the method of incorporation into the hybrid material played a less prominent role. PMID:26787486

  11. Next-generation resorbable polymer scaffolds with surface-precipitated calcium phosphate coatings.

    Science.gov (United States)

    Kim, Jinku; Magno, Maria Hanshella R; Ortiz, Ophir; McBride, Sean; Darr, Aniq; Kohn, Joachim; Hollinger, Jeffrey O

    2015-03-01

    Next-generation synthetic bone graft therapies will most likely be composed of resorbable polymers in combination with bioactive components. In this article, we continue our exploration of E1001(1k), a tyrosine-derived polycarbonate, as an orthopedic implant material. Specifically, we use E1001(1k), which is degradable, nontoxic, and osteoconductive, to fabricate porous bone regeneration scaffolds that were enhanced by two different types of calcium phosphate (CP) coatings: in one case, pure dicalcium phosphate dihydrate was precipitated on the scaffold surface and throughout its porous structure (E1001(1k) + CP). In the other case, bone matrix minerals (BMM) such as zinc, manganese and fluoride were co-precipitated within the dicalcium phosphate dihydrate coating (E1001(1k) + BMM). These scaffold compositions were compared against each other and against ChronOS (Synthes USA, West Chester, PA, USA), a clinically used bone graft substitute (BGS), which served as the positive control in our experimental design. This BGS is composed of poly(lactide co-ε-caprolactone) and beta-tricalcium phosphate. We used the established rabbit calvaria critical-sized defect model to determine bone regeneration within the defect for each of the three scaffold compositions. New bone formation was determined after 2, 4, 6, 8 and 12 weeks by micro-computerized tomography (μCT) and histology. The experimental tyrosine-derived polycarbonate, enhanced with dicalcium phosphate dihydrate, E1001(1k) + CP, supported significant bone formation within the defects and was superior to the same scaffold containing a mix of BMM, E1001(1k) + BMM. The comparison with the commercially available BGS was complicated by the large variability in bone formation observed for the laboratory preparations of E1001(1k) scaffolds. At all time points, there was a trend for E1001(1k) + CP to be superior to the commercial BGS. However, only at the 6-week time point did this trend reach statistical significance

  12. Evaluation of human polymorphonuclear behavior on textured titanium and calcium-phosphate coated surfaces

    International Nuclear Information System (INIS)

    Few studies have evaluated the effects of titanium (Ti) surface modifications on polymorphonuclear neutrophils (PMNs). Human PMNs' viability and release of key mediators—such as IL1β, IL6, TNFα, IL12, IL10, IL4, TGFβ1, IL8, IP-10, and Mig—were evaluated on three different Ti surface treatments: (1) machined Ti; (2) alumina-blasted and acid-etched Ti (AB/AE); and (3) calcium phosphate coating of 300–500 nm by ion beam onto the AB/AE Ti surface (CaP). A polystyrene surface was used as a negative control. The PMNs were purified from whole human blood and cultured for 6 h. Cell viability was determined by flow cytometry, and the supernatant was evaluated to determine the levels of cytokines and chemokines. Results showed that the percentage of viable cells was significantly lower on the CaP surface compared to the control (p < 0.05) relative to the other groups. No differences in the levels of IL8, MIG, and IP10 were detected between groups. Significantly higher levels of IL1β (p = 0.046) and TNFα (p = 0.016) were detected for the CaP surfaces compared to AB/AE surface only. The levels of IL4, IL10, and TGFβ1 secreted from the PMNs in the CaP group were significantly lower than in the control and machined groups (p < 0.05) that were statistically comparable to AB/AE. Overall, the addition of a thin CaP coating to the AB/AE Ti surface influenced the secretion profile of pro-inflammatory cytokines due to the higher release of pro-inflammatory cytokines (IL1β and TNFα) on these surfaces. (paper)

  13. Preliminary research on a novel bioactive silicon doped calcium phosphate coating on AZ31 magnesium alloy via electrodeposition.

    Science.gov (United States)

    Qiu, Xun; Wan, Peng; Tan, Lili; Fan, Xinmin; Yang, Ke

    2014-03-01

    A silicon doped calcium phosphate coating was obtained successfully on AZ31 alloy substrate via pulse electrodeposition. A novel dual-layer structure was observed with a porous lamellar-like and outer block-like apatite layer. In vitro immersion tests were adopted in simulated body fluid within 28 days of immersion. Slow degradation rate obtained from weight loss was observed for the Si-doped Ca-P coating, which was also consistent with the results of electrochemical experiments showing an enhanced corrosion resistance for the coating. Further formation of an apatite-like layer on the surface after immersion proved better integrity and biomineralization performance of the coating. Biological characterization was carried out for viability, proliferation and differentiation of MG63 osteoblast-like cells. The coating showed a good cell growth and an enhanced cell proliferation. Moreover, an increased activity of osteogenic marker ALP was found. All the results demonstrated that the Si-doped calcium phosphate was perspective to be used as a coating for magnesium alloy implants to control the degradation rate and enhance the bioactivity, which would facilitate the rapidity of bone tissue repair. PMID:24433888

  14. Electrolytic deposition of calcium phosphate/chitosan coating on titanium alloy: Growth kinetics and influence of current density, acetic acid, and chitosan

    NARCIS (Netherlands)

    Wang, Jiawei; Apeldoorn, van Aart; Groot, de Klaas

    2006-01-01

    Electrolytically deposited calcium phosphate/chitosan coating demonstrated good bone marrow stromal cell attachment. The aim of this study was to understand the coating's growth kinetics as well as the effects of current density, acetic acid, and chitosan on the coating's formation. The scanning ele

  15. Radio frequency magnetron sputtering deposition of calcium phosphate coatings: The effect of resputtering on the coating composition

    International Nuclear Information System (INIS)

    Radio frequency magnetron plasma sputtering deposition is a fairly complex deposition method. Deposition of the film is influenced by the energetic bombardment of several species, like energetic electrons, neutrals, ions from the sputtering target and the plasma, and ultraviolet light. In this work we study the origin and the degree of (preferential) resputtering of species from a calcium phosphate ceramic film during the deposition process. We found that negatively charged oxygen is mostly responsible for the resputtering phenomena that occur. The degree of resputtering was determined by comparing the amount of material deposited behind and at the position of an aperture, which was positioned between the sputtering target and the substrate. The degree of resputtering can be derived, because the material behind the aperture is almost completely protected from bombardment by negatively charged oxygen. We found that at low Ar pressure, more than half of the material deposited is resputtered, preferentially P. Resputtering of the coating decreases with an increase in Ar pressure. An explanation for this may be that more negatively charged, energetic oxygen is ejected from the target at low Ar pressure, while at high Ar pressure more neutral, less energetic, oxygen is ejected. The former gives a higher resputtering rate

  16. Blood compatibility of zinc-calcium phosphate conversion coating on Mg-1.33Li-0.6Ca alloy

    Science.gov (United States)

    Zou, Yu-Hong; Zeng, Rong-Chang; Wang, Qing-Zhao; Liu, Li-Jun; Xu, Qian-Qian; Wang, Chuang; Liu, Zhi-Wei

    2016-06-01

    Magnesium alloys as a new class of biomaterials possess biodegradability and biocompatibility in comparison with currently used metal implants. However, their rapid corrosion rates are necessary to be manipulated by appropriate coatings. In this paper, a new attempt was used to develop a zinc-calcium phosphate (Zn-Ca-P) conversion coating on Mg-1.33Li-0.6Ca alloys to increase the biocompatibility and improve the corrosion resistance. In vitro blood biocompatibility of the alloy with and without the Zn-Ca-P coating was investigated to determine its suitability as a degradable medical biomaterial. Blood biocompatibility was assessed from the hemolysis test, the dynamic cruor time test, blood cell count and SEM observation of the platelet adhesion to membrane surface. The results showed that the Zn-Ca-P coating on Mg-1.33Li-0.6Ca alloys had good blood compatibility, which is in accordance with the requirements for medical biomaterials.

  17. Blood compatibility of zinc-calcium phosphate conversion coating on Mg-1.33Li-0.6Ca alloy

    Science.gov (United States)

    Zou, Yu-Hong; Zeng, Rong-Chang; Wang, Qing-Zhao; Liu, Li-Jun; Xu, Qian-Qian; Wang, Chuang; Liu, Zhi-Wei

    2016-09-01

    Magnesium alloys as a new class of biomaterials possess biodegradability and biocompatibility in comparison with currently used metal implants. However, their rapid corrosion rates are necessary to be manipulated by appropriate coatings. In this paper, a new attempt was used to develop a zinc-calcium phosphate (Zn-Ca-P) conversion coating on Mg-1.33Li-0.6Ca alloys to increase the biocompatibility and improve the corrosion resistance. In vitro blood biocompatibility of the alloy with and without the Zn-Ca-P coating was investigated to determine its suitability as a degradable medical biomaterial. Blood biocompatibility was assessed from the hemolysis test, the dynamic cruor time test, blood cell count and SEM observation of the platelet adhesion to membrane surface. The results showed that the Zn-Ca-P coating on Mg-1.33Li-0.6Ca alloys had good blood compatibility, which is in accordance with the requirements for medical biomaterials.

  18. Study on the bonding strength between calcium phosphate/chitosan composite coatings and a Mg alloy substrate

    International Nuclear Information System (INIS)

    Highlights: ► Calcium phosphate/chitosan composite coatings on the MAO-AZ91D alloy were prepared. ► The bonding force between the coating and the magnesium alloy was optimized. ► The composite coating slowed down the corrosion rate of magnesium alloy in m-SBF. - Abstract: In order to improve the bonding strength between calcium phosphate/chitosan composite coatings and a micro-arc oxidized (MAO)-AZ91D Mg alloy, different influencing parameters were investigated in the process of electrophoretic deposition (EPD) followed by conversion in a phosphate buffer solution (PBS). Surface morphology and phase constituents of the as-prepared materials were investigated by using X-ray diffractometer (XRD), Fourier-transformed infrared spectrophotometer (FTIR), Raman spectrometer, scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS), and a thermo gravimetric and differential thermal analyzer (TG–DTA). Scratch tests were carried out to study the bonding properties between the coatings and the substrates. In vitro immersion tests were conducted to determine the corrosion behaviors of samples with and without deposit layers through electrochemical experiments. In the EPD process, the acetic acid content in the electrophoresis suspension and the electrophoretic voltage played important roles in improving the bonding properties, while the contents of chitosan (CS) and nano-hydroxyapatite (nHA, Ca10(PO4)6(OH)2) in the suspension had less significant influences on the mechanical bonding strength. It was observed that the coatings showed the excellent bonding property when an electrophoretic voltage was in a range of 40–110 V with other reagent amounts as follows: acetic acid: 4.5 vol.%, CS ≤ 0.25 g, nHA ≤ 2.0 g in 200 ml of a CS–acetic acid aqueous solution and nHA ≤ 2.5 g in 300 ml of absolute ethanol. The morphology of the composite coating obtained under the above optimal condition had a flake-like crystal structure. The EPD in the n

  19. Application of Calcium Phosphate Materials in Dentistry

    Directory of Open Access Journals (Sweden)

    Jabr S. Al-Sanabani

    2013-01-01

    Full Text Available Calcium phosphate materials are similar to bone in composition and in having bioactive and osteoconductive properties. Calcium phosphate materials in different forms, as cements, composites, and coatings, are used in many medical and dental applications. This paper reviews the applications of these materials in dentistry. It presents a brief history, dental applications, and methods for improving their mechanical properties. Notable research is highlighted regarding (1 application of calcium phosphate into various fields in dentistry; (2 improving mechanical properties of calcium phosphate; (3 biomimetic process and functionally graded materials. This paper deals with most common types of the calcium phosphate materials such as hydroxyapatite and tricalcium phosphate which are currently used in dental and medical fields.

  20. Combined Effect of a Microporous Layer and Type I Collagen Coating on a Biphasic Calcium Phosphate Scaffold for Bone Tissue Engineering

    OpenAIRE

    Mun-Hwan Lee; Changkook You; Kyo-Han Kim

    2015-01-01

    In this study, type I collagen was coated onto unmodified and modified microporous biphasic calcium phosphate (BCP) scaffolds. Surface characterization using a scanning electron microscope (SEM) and a surface goniometer confirmed the modification of the BCP coating. The quantity of the collagen coating was investigated using Sirius Red staining, and quantitative assessment of the collagen coating showed no significant differences between the two groups. MG63 cells were used to evaluate cell p...

  1. Data for accelerated degradation of calcium phosphate surface-coated polycaprolactone and polycaprolactone/bioactive glass composite scaffolds

    OpenAIRE

    Poh, Patrina S.P.; Hutmacher, Dietmar W.; Holzapfel, Boris M; Solanki, Anu K.; Woodruff, Maria A.

    2016-01-01

    Polycaprolactone (PCL)-based composite scaffolds containing 50 wt% of 45S5 bioactive glass (45S5) or strontium-substituted bioactive glass (SrBG) particles were fabricated into scaffolds using melt-extrusion based additive manufacturing technique. Additionally, the PCL scaffolds were surface coated with a layer of calcium phosphate (CaP). For a comparison of the scaffold degradation, the scaffolds were then subjected to in vitro accelerated degradation by immersion in 5 M sodium hydroxide (Na...

  2. NiTi shape memory alloys coated with calcium phosphate by plasma-spraying. Chemical and biological properties

    Energy Technology Data Exchange (ETDEWEB)

    Prymak, O.; Epple, M. [Institute of Inorganic Chemistry, University of Duisburg-Essen, D-45117 Essen (Germany); Bogdansk, D.; Esenwein, S.A.; Koeller, M. [Department of Surgery, BG Kliniken Bergmannsheil - Universitaetsklinik, Buerkle-de-la-Camp-Platz 1, D-44780 Bochum (Germany)

    2004-05-01

    Plates of superelastic nickel-titanium shape memory alloy (NiTi) were coated with calcium phosphate (hydroxyapatite) by high-temperature plasma-spraying. The porous layer of about 100 {mu}m thickness showed a good adhesion to the metallic substrate that withstood bending of the plate but detached upon cutting the plate. The biocompatibility was tested by cultivation of blood cells (whole blood and isolated granulocytes [a subpopulation of blood leukocytes]). As substrates, pure NiTi, plasma-spray-coated NiTi and calcium phosphate-coated NiTi prepared by a dip-coating process were used. The adhesion of whole blood cells to all materials was not significantly different. In contrast, isolated granulocytes showed an increased adhesion to both calcium phosphate-coated NiTi samples. However, compared to non-coated NiTi or dip-coated NiTi, the number of dead granulocytes adherent to plasma-sprayed surfaces was significantly increased for isolated granulocytes (p<0.01). (Abstract Copyright [2004], Wiley Periodicals, Inc.) [German] Bleche aus superelastischer Nickel-Titan-Legierung (NiTi) wurden durch Hochtemperatur-Plasmaspritzen mit Calciumphosphat (Hydroxylapatit) beschichtet. Die Haftung der ca. 100 {mu}m starken poroesen Schicht auf der metallischen Unterlage ist so gut, dass das Blech gebogen werden kann. Das Schneiden des Bleches fuehrte allerdings zur Abloesung der Schicht. Die Biokompatibilitaet der beschichteten Bleche wurde im Zellkulturexperiment mit Blutzellen (Vollblut und isolierte Granulozyten, [eine Subpopulation von Blutleukozyten]) untersucht. Zum Vergleich wurden reines NiTi und Calciumphosphat-beschichtetes NiTi (hergestellt durch einen Tauchprozess) ebenfalls in der Zellkultur untersucht. Die Adhaerenz der Vollblutzellen an die Materialien war nicht signifikant unterschiedlich. Im Gegensatz dazu zeigten isolierte Granulozyten eine hoehere Adhaesion auf beiden Calciumphosphat-beschichteten NiTi-Proben. Die Anzahl von toten Granulozyten war auf

  3. Using scratch testing to measure the adhesion strength of calcium phosphate coatings applied to poly(carbonate urethane) substrates.

    Science.gov (United States)

    Barnes, Dunstan; Johnson, Scott; Snell, Robert; Best, Serena

    2012-02-01

    Bioactive coatings are applied to components of modern orthopædic implants to improve the host tissue response to the implants. Such coatings cannot be applied to polymeric implants by high-temperature techniques, because the use of high temperatures may critically degrade the polymer substrate. Regardless of the coating technique that is used, the coating must be sufficiently well adhered to the underlying substrate to provide any practical benefit. This paper investigates the use of scratch testing to measure the adhesion strength of calcium phosphate (CaP) coatings that were applied to a poly(carbonate urethane) (PCU) substrate by an aqueous process at temperatures of 19, 28, 37, and 50 °C. This work represents the first time that scratch testing analysis has been used to study CaP coatings deposited by an aqueous, low-temperature process on to a polymer substrate. Scratch testing was shown to be a useful technique for obtaining comparative, rather than absolute, values of adhesion strength for hard coatings formed on a compliant substrate. Generally, the coating temperature was not found to influence the CaP-PCU adhesion strength. Although CaP coatings formed at 19 °C exhibited considerably lower adhesion strengths than CaP coatings formed at 28, 37, and 50 °C, this finding was attributable to the inconsistency of CaP coatings formed on the PCU substrates at 19 °C. The coating-substrate adhesion strength was measured for CaP coatings of four different coating ages (0, 1, 2, and 3 years). CaP coatings that were aged for 0, 1, or 2 years exhibited similar coating-substrate adhesion strengths to each other. In contrast, CaP coatings that were aged for 3 years demonstrated considerably lower coating-substrate adhesion strengths. The observed reduction in adhesion strength with age was thought to be attributable to suspected "drying out" of the CaP coatings. PMID:22301182

  4. In vitro corrosion investigations of plasma-sprayed hydroxyapatite and hydroxyapatite–calcium phosphate coatings on 316L SS

    Indian Academy of Sciences (India)

    Gurpreet Singh; Hazoor Singh; Buta Singh Sidhu

    2014-10-01

    The present paper discusses various issues associated with biological corrosion of uncoated and plasma-sprayed hydroxyapatite (HA)-coated 316L SS and studies the effect of contents of calcium phosphate (CaP) on corrosion behaviour of hydroxyapatite (HA) coatings in simulated body fluid (Ringer’s solution). Three types of coatings, i.e. HA + 20 wt% CaP (type 1), HA + 10 wt% CaP (type 2), HA (type 3), were laid on 316L SS using plasma-spraying technique. Structural characterization techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) were used to investigate the crystallinity, microstructure and morphology of the coatings. Electrochemical potentiodynamic tests were performed to determine the corrosion resistance of uncoated and all the three coatings. After the electrochemical corrosion testing, the samples were examined by XRD, SEM and EDX. The electrochemical study showed a significant improvement in the corrosion resistance after HA coating and corrosion resistance of type 3 coating was found maximum.

  5. Comparison of calcium phosphate coatings formed on femtosecond laser-induced and sand-blasted titanium

    Science.gov (United States)

    Liang, C. Y.; Yang, X. J.; Wei, Q.; Cui, Z. D.

    2008-11-01

    High energy femtosecond laser process was employed to create regular surface patterning on titanium while sand blasting treatment made a coarse surface. Both laser-induced titanium and blasted titanium could promote the formation of calcium phosphate compounds after the acid and alkali treatment, but little crystallized hydroxyapatite was grown on the laser-induced titanium in 1.5SBF only for 6 h, whereas Ca 4P 6O 19 was formed on the sand-blasted titanium. The femtosecond laser process together with common acid and alkali treatment might provide potential choice to enhance the biocompatibility of titanium and its alloys.

  6. Preparation and in vitro evaluation of a biomimetic nanoscale calcium phosphate coating on a polyethylene terephthalate artificial ligament

    Science.gov (United States)

    CHEN, CHEN; LI, HONG; GUO, CHANGAN; CHEN, SHIYI

    2016-01-01

    In the present study, a polyethylene terephthalate (PET) artificial ligament was coated with an organic layer-by-layer (LBL) self-assembled template of chitosan and hyaluronic acid, and then incubated in a calcium phosphate (CaP) solution to prepare a biomimetic CaP coating. The surface characterization of the ligament was examined using scanning electron microscopy, atomic force microscopy and energy-dispersive X-ray spectroscopy. The effects of CaP coatings on the osteogenic activity of MC3T3 E1 mouse osteoblastic cells were investigated by evaluating their attachment, proliferation and the relative expression levels of alkaline phosphatase. The results revealed that the organic LBL template on the PET artificial ligament was effective for CaP apatite formation. Following incubation for 72 h, numerous nanoscale CaP apatites were deposited on the PET ligament fibers. In addition, the results of the in vitro culture of MC3T3-E1 mouse osteoblastic cells demonstrated that the CaP coating had a good biocompatibility for cell proliferation and adhesion, and the CaP-coated group had a significantly higher alkaline phosphatase activity compared with the uncoated control group after seven days of cell culture. Collectively, these results demonstrated that the biomimetic nanoscale CaP-coated PET artificial ligaments have potential in bone-tissue engineering. PMID:27347053

  7. Electrochemical and morphological investigation of silver and zinc modified calcium phosphate bioceramic coatings on metallic implant materials.

    Science.gov (United States)

    Furko, M; Jiang, Y; Wilkins, T A; Balázsi, C

    2016-05-01

    In our research nanostructured silver and zinc doped calcium-phosphate (CaP) bioceramic coatings were prepared on commonly used orthopaedic implant materials (Ti6Al4V). The deposition process was carried out by the pulse current technique at 70°C from electrolyte containing the appropriate amount of Ca(NO3)2 and NH4H2PO4 components. During the electrochemical deposition Ag(+) and Zn(2+) ions were introduced into the solution. The electrochemical behaviour and corrosion rate of the bioceramic coatings were investigated by potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS) measurements in conventional Ringer's solution in a three electrode open cell. The coating came into contact with the electrolyte and corrosion occurred during immersion. In order to achieve antimicrobial properties, it is important to maintain a continuous release of silver ions into physiological media, while the bioactive CaP layer enhances the biocompatibility properties of the layer by fostering the bone cell growth. The role of Zn(2+) is to shorten wound healing time. Morphology and composition of coatings were studied by Scanning Electron Microscopy, Transmission Electron Microscopy and Energy-dispersive X-ray spectroscopy. Differential thermal analyses (DTA) were performed to determine the thermal stability of the pure and modified CaP bioceramic coatings while the structure and phases of the layers were characterized by X-ray diffraction (XRD) measurements. PMID:26952421

  8. Data for accelerated degradation of calcium phosphate surface-coated polycaprolactone and polycaprolactone/bioactive glass composite scaffolds.

    Science.gov (United States)

    Poh, Patrina S P; Hutmacher, Dietmar W; Holzapfel, Boris M; Solanki, Anu K; Woodruff, Maria A

    2016-06-01

    Polycaprolactone (PCL)-based composite scaffolds containing 50 wt% of 45S5 bioactive glass (45S5) or strontium-substituted bioactive glass (SrBG) particles were fabricated into scaffolds using melt-extrusion based additive manufacturing technique. Additionally, the PCL scaffolds were surface coated with a layer of calcium phosphate (CaP). For a comparison of the scaffold degradation, the scaffolds were then subjected to in vitro accelerated degradation by immersion in 5 M sodium hydroxide (NaOH) solution for up to 7 days. The scaffold׳s morphology was observed by means of SEM imaging and scaffold mass loss was recorded over the experimental period. PMID:27081669

  9. Calcium phosphate/chitosan composite coating: Effect of different concentrations of Mg{sup 2+} in the m-SBF on its bioactivity

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jie [School of Chemistry Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Pharmacy College, Jiamusi University, Jiamusi 154007 (China); Dai, Changsong, E-mail: changsd@hit.edu.cn [School of Chemistry Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Wei, Jie [School of Chemistry Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); School of Chemistry and Bioengineering, Suzhou Science Technology University, Suzhou 215009 (China); Wen, Zhaohui, E-mail: wenzhaohui1968@163.com [Department of neuro intern, First Affiliated Hospital of Harbin Medical University, Harbin 150001 (China); Zhang, Shujuan; Lin, Lemin [Department of neuro intern, First Affiliated Hospital of Harbin Medical University, Harbin 150001 (China)

    2013-09-01

    The purpose of this study was to investigate the effect of different concentration of Mg{sup 2+} in a modified simulated body fluid (m-SBF) on the bioactivity of calcium phosphate/chitosan composite coating. Calcium phosphate/chitosan composite coating was prepared on graphite substrate via electrophoretic deposition (EPD) followed by conversion in a phosphate buffer solution (PBS). The obtained samples were soaked in the m-SBF containing different concentration of Mg{sup 2+} for different times. And then, the composite coatings were assessed using X-ray diffractometer (XRD), Fourier-transformed infrared spectroscopy (FTIR), Raman spectra, and scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS). The soaking solution was evaluated by inductively coupled plasma optical emission spectrometer (ICP-OES) test. The analytical results showed that hydroxyapatite (HA) and bone-like apatite (HCA) grew on the surface of calcium phosphate/chitosan composite coating after incubation in different m-SBF. With Mg{sup 2+} concentration in m-SBF increased from 1× Mg to 10× Mg, HA in the composite coating first presented a dissolving process and then a precipitating one slowly, while HCA presented a growing trend, continuously. The increasing of Mg{sup 2+} concentration in the m-SBF inhibited the total growing process of HA and HCA as a whole. The structure of the composite coating changed from spherical into irregular morphology with the concentration of Mg{sup 2+} increasing from 1× Mg to 10× Mg. Over all, with the Mg{sup 2+} concentration increasing, the bioactivity of calcium phosphate/chitosan composite coating tended to decrease.

  10. Calcium phosphate/chitosan composite coating: Effect of different concentrations of Mg2+ in the m-SBF on its bioactivity

    International Nuclear Information System (INIS)

    The purpose of this study was to investigate the effect of different concentration of Mg2+ in a modified simulated body fluid (m-SBF) on the bioactivity of calcium phosphate/chitosan composite coating. Calcium phosphate/chitosan composite coating was prepared on graphite substrate via electrophoretic deposition (EPD) followed by conversion in a phosphate buffer solution (PBS). The obtained samples were soaked in the m-SBF containing different concentration of Mg2+ for different times. And then, the composite coatings were assessed using X-ray diffractometer (XRD), Fourier-transformed infrared spectroscopy (FTIR), Raman spectra, and scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS). The soaking solution was evaluated by inductively coupled plasma optical emission spectrometer (ICP-OES) test. The analytical results showed that hydroxyapatite (HA) and bone-like apatite (HCA) grew on the surface of calcium phosphate/chitosan composite coating after incubation in different m-SBF. With Mg2+ concentration in m-SBF increased from 1× Mg to 10× Mg, HA in the composite coating first presented a dissolving process and then a precipitating one slowly, while HCA presented a growing trend, continuously. The increasing of Mg2+ concentration in the m-SBF inhibited the total growing process of HA and HCA as a whole. The structure of the composite coating changed from spherical into irregular morphology with the concentration of Mg2+ increasing from 1× Mg to 10× Mg. Over all, with the Mg2+ concentration increasing, the bioactivity of calcium phosphate/chitosan composite coating tended to decrease.

  11. Incorporation of proteins and enzymes at different stages of the preparation of calcium phosphate coatings on a degradable substrate by a biomimetic methodology

    OpenAIRE

    Azevedo, Helena S.; Leonor, I. B.; C.M. Alves; Reis, R.L.

    2005-01-01

    In this work, the possibility of incorporating proteins into calcium phosphate (Ca-P) coatings, prepared on the surface of starch polymeric biomaterials by means of a biomimetic route, was investigated. The morphology, chemical composition and crystallinity of Ca-P coatings was assessed and related to the incorporation of the studied biomolecules. For that, bovine serum albumin (BSA) and aamylase were added in concentrations of 1 mg/ml to simulated body fluid (SBF) solutions, being both ad...

  12. Enhanced healing of rabbit segmental radius defects with surface-coated calcium phosphate cement/bone morphogenetic protein-2 scaffolds

    International Nuclear Information System (INIS)

    Large osseous defects remain a difficult clinical problem in orthopedic surgery owing to the limited effective therapeutic options, and bone morphogenetic protein-2 (BMP-2) is useful for its potent osteoinductive properties in bone regeneration. Here we build a strategy to achieve prolonged duration time and help inducting new bone formation by using water-soluble polymers as a protective film. In this study, calcium phosphate cement (CPC) scaffolds were prepared as the matrix and combined with sodium carboxymethyl cellulose (CMC-Na), hydroxypropylmethyl cellulose (HPMC), and polyvinyl alcohol (PVA) respectively to protect from the digestion of rhBMP-2. After being implanted in the mouse thigh muscles, the surface-modified composite scaffolds evidently induced ectopic bone formation. In addition, we further evaluated the in vivo effects of surface-modified scaffolds in a rabbit radius critical defect by radiography, three dimensional micro-computed tomographic (μCT) imaging, synchrotron radiation-based micro-computed tomographic (SRμCT) imaging, histological analysis, and biomechanical measurement. The HPMC-modified CPC scaffold was regarded as the best combination for segmental bone regeneration in rabbit radius. - Highlights: • A simple surface-coating method was used to fabricate composite scaffolds. • Growth factor was protected from rapid depletion via superficial coating. • Significant promotion of bone regeneration was achieved. • HPMC-modification displayed optimal effect of bone regeneration

  13. Enhanced healing of rabbit segmental radius defects with surface-coated calcium phosphate cement/bone morphogenetic protein-2 scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yi; Hou, Juan; Yin, ManLi [Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Wang, Jing, E-mail: biomatwj@163.com [Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Liu, ChangSheng, E-mail: csliu@sh163.net [Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); The State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237 (China); Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China)

    2014-11-01

    Large osseous defects remain a difficult clinical problem in orthopedic surgery owing to the limited effective therapeutic options, and bone morphogenetic protein-2 (BMP-2) is useful for its potent osteoinductive properties in bone regeneration. Here we build a strategy to achieve prolonged duration time and help inducting new bone formation by using water-soluble polymers as a protective film. In this study, calcium phosphate cement (CPC) scaffolds were prepared as the matrix and combined with sodium carboxymethyl cellulose (CMC-Na), hydroxypropylmethyl cellulose (HPMC), and polyvinyl alcohol (PVA) respectively to protect from the digestion of rhBMP-2. After being implanted in the mouse thigh muscles, the surface-modified composite scaffolds evidently induced ectopic bone formation. In addition, we further evaluated the in vivo effects of surface-modified scaffolds in a rabbit radius critical defect by radiography, three dimensional micro-computed tomographic (μCT) imaging, synchrotron radiation-based micro-computed tomographic (SRμCT) imaging, histological analysis, and biomechanical measurement. The HPMC-modified CPC scaffold was regarded as the best combination for segmental bone regeneration in rabbit radius. - Highlights: • A simple surface-coating method was used to fabricate composite scaffolds. • Growth factor was protected from rapid depletion via superficial coating. • Significant promotion of bone regeneration was achieved. • HPMC-modification displayed optimal effect of bone regeneration.

  14. Processing-microstructure-property relations in HVOF sprayed calcium phosphate based bioceramic coatings.

    Science.gov (United States)

    Khor, K A; Li, H; Cheang, P

    2003-06-01

    Hydroxyapatite (HA) based bioceramic coatings were deposited onto titanium alloy substrates using the high velocity oxy-fuel (HVOF) spray technique. This study aimed to reveal the relations among processing parameters, microstructure, and properties of the bioceramic coatings. The processing conditions were altered through changing the starting HA powder size, content of bioinert ceramic additives or composite powder preparation techniques. Coating structure was characterized through scanning electron microscopy (SEM) and transmission electron microscopy (TEM); and the mechanical properties, Young's modulus and fracture toughness, of the coatings were evaluated through indentation techniques. Results demonstrated dominant influence of the melt state of HA powders on the phase composition of resultant coatings, and it was found that the HVOF HA coatings possess competitive mechanical properties. Furthermore, addition of titania or zirconia, as secondary phase in HA, showed promising effect on improving the mechanical properties of the HVOF HA-based coatings. Chemical reactions between HA and titania; and, HA and zirconia during coating deposition were revealed and characterized. Incorporation modes of the additives into HA and their reinforcing mechanisms were elucidated. The relationship among the processing, microstructure, and mechanical properties of the HVOF sprayed bioceramic coatings was summarily examined. PMID:12699659

  15. Combined Effect of a Microporous Layer and Type I Collagen Coating on a Biphasic Calcium Phosphate Scaffold for Bone Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Mun-Hwan Lee

    2015-03-01

    Full Text Available In this study, type I collagen was coated onto unmodified and modified microporous biphasic calcium phosphate (BCP scaffolds. Surface characterization using a scanning electron microscope (SEM and a surface goniometer confirmed the modification of the BCP coating. The quantity of the collagen coating was investigated using Sirius Red staining, and quantitative assessment of the collagen coating showed no significant differences between the two groups. MG63 cells were used to evaluate cell proliferation and ALP activity on the modified BCP scaffolds. The modified microporous surfaces showed low contact angles and large surface areas, which enhanced cell spreading and proliferation. Coating of the BCP scaffolds with type I collagen led to enhanced cell-material interactions and improved MG63 functions, such as spreading, proliferation, and differentiation. The micropore/collagen-coated scaffold showed the highest rate of cell response. These results indicate that a combination of micropores and collagen enhances cellular function on bioengineered bone allograft tissue.

  16. Physicochemical Characterization and In Vivo Evaluation of Amorphous and Partially Crystalline Calcium Phosphate Coatings Fabricated on Ti-6Al-4V Implants by the Plasma Spray Method

    OpenAIRE

    Bonfante, Estevam A.; Lukasz Witek; Nick Tovar; Marcelo Suzuki; Charles Marin; Rodrigo Granato; Paulo G. Coelho

    2012-01-01

    Objective. To characterize the topographic and chemical properties of 2 bioceramic coated plateau root form implant surfaces and evaluate their histomorphometric differences at 6 and 12 weeks in vivo. Methods. Plasma sprayed hydroxyapatite (PSHA) and amorphous calcium phosphate (ACP) surfaces were characterized by scanning electron microscopy (SEM), interferometry (IFM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). Implants were placed in the radius epiphysis,...

  17. Protein coated microcrystals formulated with model antigens and modified with calcium phosphate exhibit enhanced phagocytosis and immunogenicity.

    Science.gov (United States)

    Jones, Sarah; Asokanathan, Catpagavalli; Kmiec, Dorota; Irvine, June; Fleck, Roland; Xing, Dorothy; Moore, Barry; Parton, Roger; Coote, John

    2014-07-16

    Protein-coated microcrystals (PCMCs) were investigated as potential vaccine formulations for a range of model antigens. Presentation of antigens as PCMCs increased the antigen-specific IgG responses for all antigens tested, compared to soluble antigens. When compared to conventional aluminium-adjuvanted formulations, PCMCs modified with calcium phosphate (CaP) showed enhanced antigen-specific IgG responses and a decreased antigen-specific IgG1:IgG2a ratio, indicating the induction of a more balanced Th1/Th2 response. The rate of antigen release from CaP PCMCs, in vitro, decreased strongly with increasing CaP loading but their immunogenicity in vivo was not significantly different, suggesting the adjuvanticity was not due to a depot effect. Notably, it was found that CaP modification enhanced the phagocytosis of fluorescent antigen-PCMC particles by J774.2 murine monocyte/macrophage cells compared to soluble antigen or soluble PCMCs. Thus, CaP PCMCs may provide an alternative to conventional aluminium-based acellular vaccines to provide a more balanced Th1/Th2 immune response. PMID:24120484

  18. Rapid prototyped porous titanium coated with calcium phosphate as a scaffold for bone tissue engineering.

    NARCIS (Netherlands)

    Lopez-Heredia, M.A.; Sohier, J.; Gaillard, C.; Quillard, S.; Dorget, M.; Layrolle, P.

    2008-01-01

    High strength porous scaffolds and mesenchymal stem cells are required for bone tissue engineering applications. Porous titanium scaffolds (TiS) with a regular array of interconnected pores of 1000 microm in diameter and a porosity of 50% were produced using a rapid prototyping technique. A calcium

  19. Effects of calcium phosphate coating to SLA surface implants by the ion-beam-assisted deposition method on self-contained coronal defect healing in dogs

    International Nuclear Information System (INIS)

    The aim of this study was to evaluate the healing of self-contained coronal defects on a sand-blasted, large-grit, acid-etched (SLA) surface implant, which had a calcium phosphate (CaP) coating applied by ion-beam-assisted deposition (IBAD). We also evaluated the effect of heating the coating to different temperatures. The CaP-coated SLA implants exhibited a slightly larger bone healing capacity in the self-contained coronal defect than SLA implants, indicating that combining SLA surface implants and a CaP coating by the IBAD method had synergistic effects on bone healing. There was no difference in the healing capacity between 350 deg. C and 450 deg. C heat treatment of the coating layer.

  20. Effects of calcium phosphate coating to SLA surface implants by the ion-beam-assisted deposition method on self-contained coronal defect healing in dogs

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Heun-Joo; Song, Ji-Eun; Um, Yoo-Jung; Chae, Gyung Joon; Jung, Ui-Won; Kim, Chang-Sung; Choi, Seong-Ho [Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, 134 Shinchon-Dong, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Chung, Sung-Min [Dentium Co., Seoul (Korea, Republic of); Lee, In-Seop, E-mail: shchoi726@yuhs.a [Institute of Physics and Applied Physics, Atomic-scale Surface Science Research Center, Yonsei University, Seoul (Korea, Republic of)

    2009-08-15

    The aim of this study was to evaluate the healing of self-contained coronal defects on a sand-blasted, large-grit, acid-etched (SLA) surface implant, which had a calcium phosphate (CaP) coating applied by ion-beam-assisted deposition (IBAD). We also evaluated the effect of heating the coating to different temperatures. The CaP-coated SLA implants exhibited a slightly larger bone healing capacity in the self-contained coronal defect than SLA implants, indicating that combining SLA surface implants and a CaP coating by the IBAD method had synergistic effects on bone healing. There was no difference in the healing capacity between 350 deg. C and 450 deg. C heat treatment of the coating layer.

  1. A novel auto-catalytic deposition methodology to produce calcium-phosphate coatings on polymeric biomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Leonor, I.B.; Reis, R.L. [Universidade do Minho, Braga (Portugal). Dept. of Polymer Engineering

    2001-07-01

    The aim of this research is to develop a new methodology to obtain bioactive coatings on bioinert and biodegradable polymers that are not intrinsically bioactive. In this study three types of materials were used as substrates: (i) high molecular weight polyethylene (HMWPE) and two different types of biodegradable starch based blends (ii) starch/ethylene vinyl alcohol blends, SEVA-C and (iii) starch/cellulose acetate blends, SCA, both from Novamont, Italy. These materials were obtained by injection moulding. Two types of baths were studied to produce the novel proposed auto-catalytic Ca-P, coatings: (i) alkaline and (ii) acid bath. The obtained results indicated that it was possible to coat the materials surfaces with Ca-P layer with only 60 min of immersion in both types of auto-catalytic solutions. These new methodologies allow for the production of an adherent bioactive film on the polymeric surfaces. Furthermore, it was possible observe the clear bioactive nature of the Ca-P coatings after different immersion periods in a simulated body fluid (SBF). (orig.)

  2. Research on the corrosion resistance and formation of double-layer calcium phosphate coating on AZ31 obtained at varied temperatures

    International Nuclear Information System (INIS)

    In this study, the effect of varied processing temperatures on the corrosion resistance and formation of dual-layer calcium phosphate coating on AZ31 was investigated. The microstructure, phase and morphology were characterized by a scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffractometer (XRD), respectively. The in vitro degradation behavior of coated AZ31 samples were evaluated by electrochemical and immersion tests in simulated body fluid. The results showed that the varied processing temperatures responded to different microstructure, phase and morphology; and a dual-layer coating was formed during the deposition process at 70 °C. Meanwhile the higher processing temperature induced a faster coating formation rate and greater surface coverage. The in vitro degradation tests in simulated body fluid indicated that the corrosion rates of AZ31 alloy were effectively decreased with increasing processing temperature, which was attributed to the denser protective coating. The formation mechanism of dual-layer coating influenced by deposition temperature was proposed. - Highlights: • Double-layer Ca–P coating was successfully fabricated on AZ31 alloy by chemical deposition. • Effect of processing temperatures on coating formation and performance was studied. • The coating obtained at 70 °C showed better corrosion resistance by electrochemical and immersion tests. • The formation mechanism of dual-layer coating influenced by deposition temperature was proposed

  3. Biomimetic Route to Calcium Phosphate Coated Polymeric Nanoparticles: Influence of Different Functional Groups and pH

    OpenAIRE

    Schoeller, Katrin; Ethirajan, Anitha; Zeller, Anke; Landfester, Katharina

    2011-01-01

    The controlled synthesis of organic-inorganic hybrid particles with selective morphology using polymeric nanoparticles as templates offers an effective biomimetic route to design composite materials with interesting properties for various potential applications. In this study, the formation of hybrid particles via the bio-inspired mineralization of calcium phosphate (CaP) on the surface of different surface-functionalized polymeric nanoparticles is reported. The versatile miniemulsion polymer...

  4. Calcium phosphate in catheter encrustation.

    Science.gov (United States)

    Cox, A J; Harries, J E; Hukins, D W; Kennedy, A P; Sutton, T M

    1987-02-01

    Encrusted catheters from nine female patients were the source of samples of deposits which were examined by X-ray diffraction, atomic absorption spectroscopy, infra-red spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy. In eight samples the only crystalline phase which could be clearly distinguished by X-ray diffraction was ammonium magnesium orthophosphate hexahydrate, NH4MgPO4 X 6H2O, which occurs naturally as the mineral struvite. However, atomic absorption spectroscopy revealed an appreciable concentration of calcium in all samples. Calcium phosphates have previously been detected in catheter deposits. Infra-red and EXAFS spectra were consistent with the calcium phosphate being present as a poorly crystalline hydroxyapatite. Thus the deposits appear to consist of a mixture of crystalline struvite and a form of hydroxyapatite which is not fully crystalline. PMID:3030487

  5. 21 CFR 582.1217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium phosphate. 582.1217 Section 582.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  6. 21 CFR 182.1217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium phosphate. 182.1217 Section 182.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  7. 21 CFR 582.5217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium phosphate. 582.5217 Section 582.5217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  8. Physicochemical Characterization and In Vivo Evaluation of Amorphous and Partially Crystalline Calcium Phosphate Coatings Fabricated on Ti-6Al-4V Implants by the Plasma Spray Method

    Directory of Open Access Journals (Sweden)

    Estevam A. Bonfante

    2012-01-01

    Full Text Available Objective. To characterize the topographic and chemical properties of 2 bioceramic coated plateau root form implant surfaces and evaluate their histomorphometric differences at 6 and 12 weeks in vivo. Methods. Plasma sprayed hydroxyapatite (PSHA and amorphous calcium phosphate (ACP surfaces were characterized by scanning electron microscopy (SEM, interferometry (IFM, X-ray diffraction (XRD, and Fourier transform infrared spectroscopy (FT-IR. Implants were placed in the radius epiphysis, and the right limb of dogs provided implants that remained for 6 weeks, and the left limb provided implants that remained 12 weeks in vivo. Thin sections were prepared for bone-to-implant contact (BIC and bone-area-fraction occupancy (BAFO measurements (evaluated by Friedman analysis <0.05. Results. Significantly, higher Sa (<0.03 and Sq (<0.02 were observed for ACP relative to PSHA. Chemical analysis revealed significantly higher HA, calcium phosphate, and calcium pyrophosphate for the PSHA surface. BIC and BAFO measurements showed no differences between surfaces. Lamellar bone formation in close contact with implant surfaces and within the healing chambers was observed for both groups. Conclusion. Given topographical and chemical differences between PSHA and ACP surfaces, bone morphology and histomorphometric evaluated parameters showed that both surfaces were osseoconductive in plateau root form implants.

  9. Enhanced bone forming ability of SLA-treated Ti coated with a calcium phosphate thin film formed by e-beam evaporation

    International Nuclear Information System (INIS)

    With an electron-beam evaporation process, a calcium phosphate (Ca-P) thin film of ∼500 nm thick was deposited on sand blasted with large grits and acid etched (SLA) Ti without changing the typical morphology of the SLA surface. Dissolution behavior was investigated by measuring the amount of dissolved phosphate ions with ion chromatography after immersing the SLA Ti sample coated with a Ca-P film in 1 ml de-ionized water maintained at 37 0C for different periods of soaking time, and the surface morphology was observed with field emission scanning electron microscopy. The amount of phosphate ions increased quickly right after immersion but began to decrease after 2 days of immersion by redeposition with Ca ions as apatite, and the amount of biomimetic apatite increased with the extended soaking time. The Saos-2 cell was more attached on the coated surface, and the in vivo evaluation was that the Ca-P deposited SLA implant greatly improved the new bone formation ability.

  10. Enhanced bone forming ability of SLA-treated Ti coated with a calcium phosphate thin film formed by e-beam evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyeongil [Restorative Dentistry, School of Dental Medicine, University at Buffalo, NY 14214 (United States); Choi, Seong-Ho [Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, Seoul 120-752 (Korea, Republic of); Chung, Sung-Min; Li, Long-Hao [Dentium Clinic Implantium Institute, Seoul 135-879 (Korea, Republic of); Lee, In-Seop, E-mail: inseop@yonsei.ac.k [Atomic-Scale Surface Science Research Center, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2010-08-01

    With an electron-beam evaporation process, a calcium phosphate (Ca-P) thin film of {approx}500 nm thick was deposited on sand blasted with large grits and acid etched (SLA) Ti without changing the typical morphology of the SLA surface. Dissolution behavior was investigated by measuring the amount of dissolved phosphate ions with ion chromatography after immersing the SLA Ti sample coated with a Ca-P film in 1 ml de-ionized water maintained at 37 {sup 0}C for different periods of soaking time, and the surface morphology was observed with field emission scanning electron microscopy. The amount of phosphate ions increased quickly right after immersion but began to decrease after 2 days of immersion by redeposition with Ca ions as apatite, and the amount of biomimetic apatite increased with the extended soaking time. The Saos-2 cell was more attached on the coated surface, and the in vivo evaluation was that the Ca-P deposited SLA implant greatly improved the new bone formation ability.

  11. Fabrication and characterization of nano-HA-45S5 bioglass composite coatings on calcium-phosphate containing micro-arc oxidized CP-Ti substrates

    Energy Technology Data Exchange (ETDEWEB)

    Farnoush, Hamidreza, E-mail: farnoush@aut.ac.ir [Department of Metallurgy and Materials Engineering, Faculty of Engineering, University of Kashan, P.O. Box 87317-51167, Kashan (Iran, Islamic Republic of); Muhaffel, Faiz; Cimenoglu, Huseyin [Department of Metallurgical and Materials Engineering, Istanbul Technical University, 34469 Maslak, Istanbul (Turkey)

    2015-01-01

    Highlights: • Introducing a calcium-containing titanium oxide interlayer by MAO on CP-Ti. • EPD was utilized for HA and HA-BG coatings on MAO CP-Ti substrates. • Highest bonding strength was obtained for HA-BG/MAO 360 Ti sample. • Enhancement of corrosion resistance for HA-BG/MAO 360 Ti sample in SBF. - Abstract: In the present study, micro-arc oxidation (MAO) was carried out on commercially pure titanium (CP-Ti) to fabricate porous titanium oxide coatings containing calcium phosphates (CaP) at different applied voltages of 300, 330 and 360 V for 5 min. Subsequently, nano-hydroxyapatite (HA) and HA-45S5 bioglass (BG) composite were effectively coated on micro-arc oxidized substrate by electrophoretic deposition (EPD) at a constant voltage of 30 V for 120 s. The phase, structural agents, microstructure and composition of MAO interlayer and subsequent EPD coatings were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy, respectively. Thermal stability of the as-deposited coatings was analyzed by simultaneous differential scanning calorimetry and thermal gravimetery. The pull-off adhesion tests showed the highest bonding strength was obtained for HA-BG coating on micro-oxidized sample at 360 V. The results of potentiodynamic polarization and impedance spectroscopic measurements in simulated body fluid solution depicted that the combination of MAO treatment at 360 V and EPD of HA-BG composite could effectively increase the corrosion resistance of CP-Ti substrates.

  12. Fabrication and characterization of nano-HA-45S5 bioglass composite coatings on calcium-phosphate containing micro-arc oxidized CP-Ti substrates

    International Nuclear Information System (INIS)

    Highlights: • Introducing a calcium-containing titanium oxide interlayer by MAO on CP-Ti. • EPD was utilized for HA and HA-BG coatings on MAO CP-Ti substrates. • Highest bonding strength was obtained for HA-BG/MAO 360 Ti sample. • Enhancement of corrosion resistance for HA-BG/MAO 360 Ti sample in SBF. - Abstract: In the present study, micro-arc oxidation (MAO) was carried out on commercially pure titanium (CP-Ti) to fabricate porous titanium oxide coatings containing calcium phosphates (CaP) at different applied voltages of 300, 330 and 360 V for 5 min. Subsequently, nano-hydroxyapatite (HA) and HA-45S5 bioglass (BG) composite were effectively coated on micro-arc oxidized substrate by electrophoretic deposition (EPD) at a constant voltage of 30 V for 120 s. The phase, structural agents, microstructure and composition of MAO interlayer and subsequent EPD coatings were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy, respectively. Thermal stability of the as-deposited coatings was analyzed by simultaneous differential scanning calorimetry and thermal gravimetery. The pull-off adhesion tests showed the highest bonding strength was obtained for HA-BG coating on micro-oxidized sample at 360 V. The results of potentiodynamic polarization and impedance spectroscopic measurements in simulated body fluid solution depicted that the combination of MAO treatment at 360 V and EPD of HA-BG composite could effectively increase the corrosion resistance of CP-Ti substrates

  13. Biphasic calcium phosphate in periapical surgery

    OpenAIRE

    Suneelkumar, Chinni; Datta, Krithika; Manali R Srinivasan; Kumar, Sampath T

    2008-01-01

    Calcium phosphate ceramics like hydroxyapatite and β -tricalcium phosphate (β -TCP) possess mineral composition that closely resembles that of the bone. They can be good bone substitutes due to their excellent biocompatibility. Biphasic calcium phosphate is a bone substitute which is a mixture of hydroxyapatite and β -tricalcium phosphate in fixed ratios. Studies have demonstrated the osteoconductive potential of this composition. This paper highlights the clinical use of biphasic calcium pho...

  14. Fabrication and characterization of nano-HA-45S5 bioglass composite coatings on calcium-phosphate containing micro-arc oxidized CP-Ti substrates

    Science.gov (United States)

    Farnoush, Hamidreza; Muhaffel, Faiz; Cimenoglu, Huseyin

    2015-01-01

    In the present study, micro-arc oxidation (MAO) was carried out on commercially pure titanium (CP-Ti) to fabricate porous titanium oxide coatings containing calcium phosphates (CaP) at different applied voltages of 300, 330 and 360 V for 5 min. Subsequently, nano-hydroxyapatite (HA) and HA-45S5 bioglass (BG) composite were effectively coated on micro-arc oxidized substrate by electrophoretic deposition (EPD) at a constant voltage of 30 V for 120 s. The phase, structural agents, microstructure and composition of MAO interlayer and subsequent EPD coatings were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy, respectively. Thermal stability of the as-deposited coatings was analyzed by simultaneous differential scanning calorimetry and thermal gravimetery. The pull-off adhesion tests showed the highest bonding strength was obtained for HA-BG coating on micro-oxidized sample at 360 V. The results of potentiodynamic polarization and impedance spectroscopic measurements in simulated body fluid solution depicted that the combination of MAO treatment at 360 V and EPD of HA-BG composite could effectively increase the corrosion resistance of CP-Ti substrates.

  15. Characterization of calcium phosphate coatings doped with Mg, deposited by pulsed laser deposition technique using ArF excimer laser.

    Science.gov (United States)

    Mróz, W; Jedyński, M; Prokopiuk, A; Slósarczyk, A; Paszkiewicz, Z

    2009-01-01

    Calcium phosphate layers were deposited on Ti6Al4V substrates with TiN buffer layers by use of pulsed laser deposition method. With this technique three pressed pellets consisted of tricalcium phosphate (TCP, Ca(3)(PO(4))(2)), hydroxyapatite (HA, Ca(10)(PO(4))(6)(OH)(2)) and hydroxyapatite-doped with magnesium (HA with 4% of Mg and trace amount of (Ca,Mg)(3)(PO(4))(2)) were ablated using ArF excimer laser (lambda=193 nm). The using of different targets enabled to determine the influence of target composition on the nature of deposited layers. The obtained deposits were characterized by means of Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction method (XRD). The obtained Fourier spectras revealed differences in terms of intensity of spectral bands of different layers. The analysis from XRD showed that Mg-doped HA layer has crystalline structure and TCP and HA layers composition is characterized by amorphous nature. PMID:18407507

  16. Glycochenodeoxycholic acid inhibits calcium phosphate precipitation in vitro by preventing the transformation of amorphous calcium phosphate to calcium hydroxyapatite.

    OpenAIRE

    Qiu, S M; Wen, G.; Hirakawa, N; Soloway, R D; Hong, N K; Crowther, R S

    1991-01-01

    Calcium hydroxyapatite can be a significant component of black pigment gallstones. Diverse molecules that bind calcium phosphate inhibit hydroxyapatite precipitation. Because glycine-conjugated bile acids, but not their taurine counterparts, bind calcium phosphate, we studied whether glycochenodeoxycholic acid inhibits calcium hydroxyapatite formation. Glycochenodeoxycholic acid (2 mM) totally inhibited transformation of amorphous calcium phosphate microprecipitates to macroscopic crystalline...

  17. 21 CFR 182.8217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium phosphate. 182.8217 Section 182.8217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic). (b) Conditions of use. This...

  18. Poly(lactide-co-glycolide acid)/biphasic calcium phosphate composite coating on a porous scaffold to deliver simvastatin for bone tissue engineering.

    Science.gov (United States)

    Sadiasa, Alexander; Kim, Min Sung; Lee, Byong Taek

    2013-09-01

    In this study, simvastatin (SIM) drug incorporated poly(D,L-lactic-co-glycolide) (PLGA)/biphasic calcium phosphate (BCP) composite material (SPB) was coated on the BCP/ZrO2 (SPB-BCP/ZrO2) scaffold to enhance the mechanical and bioactive properties of the BCP/ZrO2 scaffold for bone engineering applications. The composite coating was prepared by combining different ratios of PLGA and BCP (1:2, 1:1, 2:1). After completion of the coating process, the compressive strength of the scaffolds was shown to increase with an increase in PLGA concentration from 8.5 ± 0.52 MPa for the SPB1-BCP/ZrO2 (1:2) to 11 ± 0.65 MPa for SPB3-BCP/ZrO2 (2:1) scaffolds when PLGA concentration was increased. Furthermore, the increase of PLGA in the coating composition corresponds to a decrease in porosity, degradation rate and weight loss of the scaffolds after 4 weeks. SIM release study demonstrated sustained release of the drug for the three kinds of scaffolds with improved biocompatibility. The increase of PLGA concentration also resulted in a lower release rate of SIM. Thus, the lower release rate of SIM brought upon by the increase of PLGA concentration further enhanced the performance of the scaffold in vitro making it a promising approach in the field of bone tissue regeneration. PMID:23815378

  19. Calcium phosphate fibers coated with collagen: In vivo evaluation of the effects on bone repair.

    Science.gov (United States)

    Ueno, Fabio Roberto; Kido, Hueliton Wilian; Granito, Renata Neves; Gabbai-Armelin, Paulo Roberto; Magri, Angela Maria Paiva; Fernandes, Kelly Rosseti; da Silva, Antonio Carlos; Braga, Francisco José Correa; Renno, Ana Claudia Muniz

    2016-08-12

    The aim of this study was to assess the characteristics of the CaP/Col composites, in powder and fiber form, via scanning electron microscopy (SEM), pH and calcium release evaluation after immersion in SBF and to evaluate the performance of these materials on the bone repair process in a tibial bone defect model. For this, four different formulations (CaP powder - CaPp, CaP powder with collagen - CaPp/Col, CaP fibers - CaPf and CaP fibers with collagen - CaPf/Col) were developed. SEM images indicated that both material forms were successfully coated with collagen and that CaPp and CaPf presented HCA precursor crystals on their surface. Although presenting different forms, FTIR analysis indicated that CaPp and CaPf maintained the characteristic peaks for this class of material. Additionally, the calcium assay study demonstrated a higher Ca uptake for CaPp compared to CaPf for up to 5 days. Furthermore, pH measurements revealed that the collagen coating prevented the acidification of the medium, leading to higher pH values for CaPp/Col and CaPf/Col. The histological analysis showed that CaPf/Col demonstrated a higher amount of newly formed bone in the region of the defect and a reduced presence of material. In summary, the results indicated that the fibrous CaP enriched with the organic part (collagen) glassy scaffold presented good degradability and bone-forming properties and also supported Runx2 and RANKL expression. These results show that the present CaP/Col fibrous composite may be used as a bone graft for inducing bone repair. PMID:27567780

  20. Aqueous deposition of calcium phosphates and silicate substituted calcium phosphates on magnesium alloys

    International Nuclear Information System (INIS)

    Attempts were made to deposit homogeneous films of calcium phosphates (CaPs) on two magnesium alloy systems, AZ31 and Mg–4Y, through an aqueous phosphating bath method. The deposition of silicate substituted CaPs by this aqueous method was also explored as silicate substitution is believed to increase the bioactivity of CaPs. The effect of doped and undoped coatings on the in vitro degradation and bioactivity of both alloy systems was studied. FTIR and EDX confirmed the deposition of Ca, P, and Si on both alloys and the coatings appeared to consist primarily biphasic mixtures of hydroxyapatite and β-TCP. These largely inhomogeneous coatings, as observed by SEM, were not shown to have any significant effect on maintaining the physiological pH of the culture medium in comparison to the uncoated samples, as the pH remained approximately in the 8.4–8.7 range. Interestingly, despite similar pH profiles between the coated and uncoated samples, CaP coatings affected the degradation of both alloys. These doped and undoped calcium phosphate coatings were observed to decrease the degradation of AZ31 whereas they increased the degradation of Mg–4Y. In vitro studies on cell attachment using MC3T3-E1 mouse osteoblasts showed that between the uncoated alloys, Mg–4Y appeared to be the more biocompatible of the two. Silicate substituted CaP coatings were observed to increase the cell attachment on AZ31 compared to bare and undoped CaPs coated samples, but did not have as great of an effect on increasing cell attachment on Mg–4Y.

  1. Analysis of bone formation on porous and calcium phosphate-coated acetabular cups: a randomised clinical [18F]fluoride PET study.

    Science.gov (United States)

    Ullmark, Gösta; Sörensen, Jens; Nilsson, Olle

    2012-01-01

    We present a study using Fluoride-Positron Emission Tomography (F-PET/CT) to analyse new bone formation in periacetabular bone adjacent to press fit cups following THA. In 16 THA (8 patients) with bilateral hip osteoarthritis simultaneous bilateral total hip arthroplasty (THA) was performed, employing electrochemically applied calcium phosphate coated (HA) cups or porous-coated (PC) cups allocated at random to compare the two sides. A reference group of 13 individuals with a normal healthy hip was used to determine 'normal' bone metabolism. [18F]fluoride -PET/CT was used to analyze bone formation adjacent to the cups 1 week, 4 months and 12 months after surgery. Clinical and radiographic evaluation was performed preoperatively, postoperatively and at 2 years. Bone forming activity had a mean of 5.71, 4.69 and 3.47 SUV around the HA- and 5.04, 4.80 and 3.50 SUV around the PC-cups at 1 week, 4 months and 12 months respectively. Normal bone metabolism was 3.68 SUV. After 1 year activity had declined to normal levels for both groups. The clinical results were good in all cases. HA coating resulted in higher uptake indicating higher bone forming activity after 1 week. F-PET/CT is a valuable tool to analyse bone formation and secondary stabilisation of an acetabular cup. PMID:22547382

  2. Osteogenecity of octacalcium phosphate coatings applied on porous metal implants

    NARCIS (Netherlands)

    Barrere, Florence; Valk, van der Chantal M.; Dalmeijer, Remco A.J.; Meijer, Gert; Blitterswijk, van Clemens A.; Groot, de Klaas; Layrolle, Pierre

    2003-01-01

    The biomimetic route allows the homogeneous deposition of calcium phosphate (Ca-P) coatings on porous implants by immersion in simulated physiologic solution. In addition, various Ca-P phases, such as octacalcium phosphate (OCP) or bone-like carbonated apatite (BCA), which are stable only at low tem

  3. Substitution of calcium by strontium within selected calcium phosphates

    Science.gov (United States)

    Rokita, E.; Hermes, C.; Nolting, H.-F.; Ryczek, J.

    1993-06-01

    Sr incorporation in the molecules of amorphous calcium phosphate, apatitic tricalcium phosphate, hydroxyapatite, octacalcium phosphate and dicalcium phosphate dihydrate was investigated. The concentration of Sr ranged from 225 to 1010 μ g / g, i.e. it overlapped with the physiological range of Sr concentrations in human bone. The leading experimental technique was extended X-ray absorption fine structure (EXAFS) at the Sr K edge. Results of these studies demonstrated the following: (1) Sr incorporation in the calcium phosphates is compound-dependent, (2) the coordination of incorporated Sr atoms in the Ca-P molecules is similar to that of Ca atoms, but interatomic distances are ≈0.015 nm larger, (3) in apatitic tricalcium phosphate, hydroxyapatite and octacalcium phosphate lattices Sr atoms may occupy selected Ca sites, which was not the case for dicalcium phosphate dihydrate, (4) in the apatite lattice Sr atoms are coordinated by 6 PO 4 tetrahedrals and (5) EXAFS spectra at the K edge of the incorporated Sr may be used to distinguish the structures of amorphous calcium phosphate, dicalcium phosphate dihydrate as well as apatite and its derivatives (apatitic tricalcium phosphate, octacalcium phosphate).

  4. Properties of heat-treated calcium phosphate coatings deposited by high-velocity oxy-fuel (HVOF) spray.

    Science.gov (United States)

    Li, H; Khor, K A; Cheang, P

    2002-05-01

    The influence of crystallization, upon heat treatment, on the properties of high-velocity oxy-fuel (HVOF) sprayed hydroxyapatite (HA) coatings was investigated. The characterization of the HA coating was performed by X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). Differential Scanning Calorimeter (DSC) was employed to determine the crystallization temperature of the amorphous phase in an as-sprayed HA coating. The study demonstrated the effect of crystallization on the coating properties by considering the changes in materials chemistry, crystallinity level, and mechanical performance. Results showed that complete crystallization of the amorphous phase occurred at approximately 700 degrees C and the crystallization temperature was dependent on sample heating rate in the DSC test. The changes of ion groups were detected by FTIR, before and after the phase transformation. The crystallization of the coating after annealing at 750 degrees C resulted in a significant increase of the coatings' adhesive strength and shear strength, which attained maximum values 34 +/- 3 and 14.1 -/+ 0.8 MPa, respectively. Young's modulus increased from 21 +/- 1 to 25 +/- 2 GPa. Microhardness measurements confirmed the changes in coating properties. It is also found that the transformation from the amorphous phase has crystalline HA as the only resultant phase detected by XRD. PMID:11962650

  5. Preparation and Properties of Biphasic Calcium Phosphate Scaffolds Multiply Coated with HA/PLLA Nanocomposites for Bone Tissue Engineering Applications

    Directory of Open Access Journals (Sweden)

    Lei Nie

    2012-01-01

    Full Text Available A well-developed BCP scaffolds coated with multilayer of HA/PLLA nanocomposites with interconnectivity, high porosity, and moderate compressive strength as well as good biocompatibility were fabricated for bone tissue engineering. After being multiply coated with HA/PLLA nanocomposites, the scaffolds maintained the BCP framework structure, and the porous network structure of scaffolds remained unchanged; however, the compressive strength was increased with the increase of coating layer number of HA/PLLA nanocomposites. The prepared scaffolds showed lower variation of pH values in SBF solution, and an increase of coating layer number led to the decrease of the biodegradation rate at different days. Moreover, the multilayer coating scaffolds had good cytocompatibility, showing no negative effects on cells growth and proliferation. Furthermore, the bone-like apatite layer was built obviously in the interface of scaffold after 21 days after implantation in SD rat muscle. In conclusion, the BCP scaffold coated with multilayer of HA/PLLA nanocomposites could be a candidate as an excellent substitute for damaged or defect bone in bone tissue engineering.

  6. 125 MeV Si9+ ion irradiation of calcium phosphate thin film coated by rf-magnetron sputtering technique

    International Nuclear Information System (INIS)

    Titanium substrate was coated with hydroxyapatite by radiofrequency magnetron sputtering (rf-magnetron sputtering) technique and subjected to swift heavy ion (SHI) irradiation of 125 MeV with Si9+ at fluences of 1 x 1010, 1 x 1011 and 1 x 1012 ions/cm2. The glancing incidence X-ray diffraction (GIXRD) analysis confirmed the HAp phase of the irradiated film. There was a considerable decrease in crystallinity and particle size after irradiation. In addition, DRS-UV reflectance spectra revealed a decrease in optical band gap (Eg) from 5.2 to 4.6 eV. Wettability of biocompatible materials plays an important role in biological cells proliferation for tissue engineering, drug delivery, gene transfer and bone growth. HAp thin films irradiated with 1 x 1011 ions/cm2 fluence showed significant increase in wettability. While the SHI irradiated samples exhibited enhanced bioactivity, there was no significant variation in cell viability. Surface roughness, pores and average particle size were analyzed by atomic force microscopy (AFM).

  7. Kinetics of strontium sorption in calcium phosphate

    International Nuclear Information System (INIS)

    Kinetics of strontium sorption by highly dispersed solids: tricalcium phosphate (Ca3(PO4)2, TCP) and hydroxyapatite (Ca5(PO4)3)H, HAP) were investigated. Analysis of sorption data was made taking into consideration composition and morphology of ultra micro particles. Conclusion is that the isomorphous strontium impurity is structurally sensitive element for calcium phosphate. It was determined that the beginning of strontium desorption corresponds to the beginning of transformation of the TCP - HAP (author)

  8. Synthesis and characterization of porous calcium phosphate

    International Nuclear Information System (INIS)

    The porous calcium phosphate was prepared by the continuous precipitation method using Ca(NO3)2.4H2O and NH4H2PO4 salts. The synthesized material was structurally and superficially characterized using the XRD, BET, IR TGA and SEM techniques. The obtained inorganic material was identified as calcium phosphate that presents a great specific area for what can be efficiently used as adsorbent material for adsorption studies in the radioactive wastes treatment present in aqueous solution. (Author)

  9. Solid state NMR study calcium phosphate ceramics

    International Nuclear Information System (INIS)

    High-resolution 31P and 1H NMR spectra at 40 and 121 MHz 31P and 300 MHz 1H of synthetic and biological samples of calcium phosphates have been obtained by magic angle spinning (MAS) at spinning speeds up to 6.5 kHz, and high power proton decoupling. The samples include crystalline hydroxyapatite, a deficient hydroxyapatite characterized by a Ca/P atomic ratio of 1.5, a poorly crystallized hydroxyapatite, monetite, brushite, octacalcium phosphate, β-tricalcium phosphate and rabbit femoral bone. The interactions between nuclei in unlike structures and the mobility of acid protons are discussed. (author). 11 refs.; 2 figs.; 1 tab

  10. Thermal stability of phosphate coatings on steel

    Directory of Open Access Journals (Sweden)

    P. Pokorny

    2015-07-01

    Full Text Available The work was validated thermal stability of zinc, manganese and tri-cations phosphate coatings on steel, made from commercial phosphating bath type Pragofos. Thermogravimetric data dehydration of scholzite, phosphophylite and hureaulite coatings in the temperature range 160 °C – 400 °C define the conditions for applying paints with higher firing temperature or thermal spraying ceramic coatings.

  11. Thermal stability of phosphated coatings on steels

    Czech Academy of Sciences Publication Activity Database

    Brožek, Vlastimil; Pokorný, P.; Szelag, P.; Cinert, Jakub

    Zagreb: Croatian Metallurgical Society (CMS), 2014 - (Mamuzić, I.). s. 405 ISBN N. [International Symposium of Croatian Metallurgical Society SHMD 2014/11./. 22.06.2014-26.06.2014, Šibenik] Institutional support: RVO:61389021 Keywords : steel phosphating * phosphate coatings * plasma spraying * ceramic coatings * corrosion resistance * bond strength of coatings Subject RIV: CA - Inorganic Chemistry

  12. Three-dimensionally Perforated Calcium Phosphate Ceramics

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Porous calcium phosphate ceramics were produced by compression molding using a special mold followed by sintering. The porous calcium phosphate ceramics have three-dimensional and penetrated open pores380-400μm in diameter spaced at intervals of 200μm. The layers of the linear penetration pores alternately lay perpendicular to pore direction. The porosity was 59%-65% . The Ca/P molar ratios of the porous calcium phosphate ceramics range from 1.5 to 1.85. A binder containing methyl cellulose was most effective for preparing the powder compact among vinyl acetate, polyvinyl alcohol, starch, stearic acid, methyl cellulose and their mixtures. Stainless steel, polystyrene, nylon and bamboo were used as the long columnar male dies for the penetrated open pores. When polystyrene, nylon and bamboo were used as the long columnar male dies, the dies were burned out during the sintering process. Using stainless steel as the male dies with the removal of the dies before heat treatment resulted in a higher level of densification of the calcium phosphate ceramic.

  13. The stability mechanisms of an injectable calcium phosphate ceramic suspension.

    OpenAIRE

    Fatimi, Ahmed; Tassin, Jean-François; Axelos, Monique; Weiss, Pierre

    2010-01-01

    Calcium phosphate ceramics are widely used as bone substitutes in dentistry and orthopedic applications. For minimally invasive surgery an injectable calcium phosphate ceramic suspension (ICPCS) was developed. It consists in a biopolymer (hydroxypropylmethylcellulose: HPMC) as matrix and bioactive calcium phosphate ceramics (biphasic calcium phosphate: BCP) as fillers. The stability of the suspension is essential to this generation of "ready to use" injectable biomaterial. But, during storage...

  14. Promotion of osteogenic differentiation of stem cells and increase of bone-bonding ability in vivo using urease-treated titanium coated with calcium phosphate and gelatin

    International Nuclear Information System (INIS)

    Because of its excellent biocompatibility and low allergenicity, titanium has been widely used for bone replacement and tissue engineering. To produce a desirable composite with enhanced bone response and mechanical strength, in this study bioactive calcium phosphate (CaP) and gelatin composites were coated onto titanium (Ti) via a novel urease technique. The cellular responses to the CaP/gelatin/Ti (CaP/gel/Ti) and bone bonding ability were evaluated with proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) on CaP/gel/Ti and CaP/Ti in vitro. The results showed that the optical density values, alkaline phosphatase expression and genes expression of MSCs on CaP/gel/Ti were similar to those on CaP/Ti, yet significantly higher than those on pure Ti (p < 0.05). CaP/gel/Ti and CaP/Ti rods (2 mm in diameter, 10 mm in length) were also implanted into femoral shaft of rabbits and pure Ti rods served as control (n = 10). Histological examination, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) measurements were performed at 4 and 8 weeks after the operation. The histological and SEM observations demonstrated clearly that more new bone formed on the surface of CaP/gel/Ti than in the other two groups at each time point. The CaP/gel/Ti bonded to the surrounding bone directly with no intervening soft tissue layer. An interfacial layer, containing Ti, Ca and P, was found to form at the interface between bone and the implant on all three groups by EDS analysis. However, the content of Ca, P in the surface of CaP/gel/Ti implants was more than in the other two groups at each time point. The CaP/gel/Ti modified by the urease method was not only beneficial for MSCs proliferation and osteogenic differentiation, but also favorable for bone bonding ability on Ti implants in vivo, suggesting that Ti functionalized with CaP and gelatin might have a great potential in clinical joint replacement or dental implants. (paper)

  15. Promotion of osteogenic differentiation of stem cells and increase of bone-bonding ability in vivo using urease-treated titanium coated with calcium phosphate and gelatin

    Science.gov (United States)

    Huang, Zhong-Ming; Qi, Yi-Ying; Du, Shao-Hua; Feng, Gang; Unuma, Hidero; Yan, Wei-Qi

    2013-10-01

    Because of its excellent biocompatibility and low allergenicity, titanium has been widely used for bone replacement and tissue engineering. To produce a desirable composite with enhanced bone response and mechanical strength, in this study bioactive calcium phosphate (CaP) and gelatin composites were coated onto titanium (Ti) via a novel urease technique. The cellular responses to the CaP/gelatin/Ti (CaP/gel/Ti) and bone bonding ability were evaluated with proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) on CaP/gel/Ti and CaP/Ti in vitro. The results showed that the optical density values, alkaline phosphatase expression and genes expression of MSCs on CaP/gel/Ti were similar to those on CaP/Ti, yet significantly higher than those on pure Ti (p < 0.05). CaP/gel/Ti and CaP/Ti rods (2 mm in diameter, 10 mm in length) were also implanted into femoral shaft of rabbits and pure Ti rods served as control (n = 10). Histological examination, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) measurements were performed at 4 and 8 weeks after the operation. The histological and SEM observations demonstrated clearly that more new bone formed on the surface of CaP/gel/Ti than in the other two groups at each time point. The CaP/gel/Ti bonded to the surrounding bone directly with no intervening soft tissue layer. An interfacial layer, containing Ti, Ca and P, was found to form at the interface between bone and the implant on all three groups by EDS analysis. However, the content of Ca, P in the surface of CaP/gel/Ti implants was more than in the other two groups at each time point. The CaP/gel/Ti modified by the urease method was not only beneficial for MSCs proliferation and osteogenic differentiation, but also favorable for bone bonding ability on Ti implants in vivo, suggesting that Ti functionalized with CaP and gelatin might have a great potential in clinical joint replacement or dental implants.

  16. 21 CFR 182.6215 - Monobasic calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Monobasic calcium phosphate. 182.6215 Section 182.6215 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....6215 Monobasic calcium phosphate. (a) Product. Monobasic calcium phosphate. (b) Conditions of use....

  17. 21 CFR 582.6215 - Monobasic calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Monobasic calcium phosphate. 582.6215 Section 582.6215 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....6215 Monobasic calcium phosphate. (a) Product. Monobasic calcium phosphate. (b) Conditions of use....

  18. Calcium phosphate ceramics in drug delivery

    Science.gov (United States)

    Bose, Susmita; Tarafder, Solaiman; Edgington, Joe; Bandyopadhyay, Amit

    2011-04-01

    Calcium phosphate (CaP) particulates, cements and scaffolds have attracted significant interest as drug delivery vehicles. CaP systems, including both hydroxyapaptite and tricalcium phosphates, possess variable stoichiometry, functionality and dissolution properties which make them suitable for cellular delivery. Their chemical similarity to bone and thus biocompatibility, as well as variable surface charge density contribute to their controlled release properties. Among specific research areas, nanoparticle size, morphology, surface area due to porosity, and chemistry controlled release kinetics are the most active. This article discusses CaP systems in their particulate, cements, and scaffold forms for drug, protein, and growth factor delivery toward orthopedic and dental applications.

  19. Electrodeposition of dicalcium phosphate dihydrate coatings on stainless steel substrates

    Indian Academy of Sciences (India)

    Belavalli E Prasad; P Vishnu Kamath

    2013-06-01

    Cathodic reduction of an aqueous solution containing dissolved calcium and phosphate ions results in the deposition of micrometer thick CaHPO4.2H2O (dicalcium phosphate dihydrate) coatings on stainless steel substrates. The coating obtained at a low deposition current (8 mA cm-2) comprises lath-like crystallites oriented along 020. The 020 crystal planes are non-polar and have a low surface energy. At a high deposition current (12 mA cm-2), platelets oriented along 12$\\bar{1}$ are deposited. CaHPO4.2H2O is an important precursor to the nucleation of hydroxyapatite, the inorganic component of bones. Differently oriented CaHPO4.2H2Ocoatings transform to hydroxyapatite with different kinetics, the transformation being more facile when the coating is oriented along 12$\\bar{1}$. These observations have implications for the development of electrodeposited biocompatible coatings for metal endoprostheses for medical applications.

  20. Calcium phosphate cements properties with polymers addition

    International Nuclear Information System (INIS)

    Calcium phosphate cements (CPC) have attracted great interest to use in orthopedics and dentistry as replacements for damaged parts of the skeletal system, showing good biocompatibility and osseointegration, allowing its use as bone graft. Several studies have shown that the addition of polymer additives have a strong influence on the cement properties. The low mechanical strength is the main obstacle to greater use of CPC as an implant material. The objective of this study was to evaluate properties of a cement based on α-tricalcium phosphate (α-TCP), added polymers. PVA (10%, 8%, 6%), sodium alginate (2%) and polyacrylate ammonia (3%), all in weight, were added to the synthesized α-TCP powder. The samples were molded and evaluated for density, porosity in vitro test (Simulated Body Fluid), crystalline phases and mechanical strength. The results show increased the mechanical properties of the cement when added these polymers

  1. Thermal stability of phosphate coatings on steel

    Czech Academy of Sciences Publication Activity Database

    Pokorný, P.; Szelag, P.; Novák, M.; Mastný, L.; Brožek, Vlastimil

    2015-01-01

    Roč. 54, č. 3 (2015), s. 489-492. ISSN 0543-5846 Institutional support: RVO:61389021 Keywords : Steel * phosphates * coatings * structure Subject RIV: CA - Inorganic Chemistry Impact factor: 0.959, year: 2014

  2. Characterization of a silver-incorporated calcium phosphate film by RBS and its antimicrobial effects

    International Nuclear Information System (INIS)

    A thin calcium phosphate film was synthesized on both commercially pure Ti and Si wafers by electron beam evaporation of hydroxyapatite as an evaporant with simultaneous Ar ion beam bombardments. Silver was introduced into an ion-beam-assisted deposition of a calcium phosphate thin film for antimicrobial effect. The amount of incorporated silver ions was controlled by immersing calcium-phosphate-coated samples in different AgNO3 concentrations, and Rutherford backscattering spectrometry (RBS) was employed to measure the amounts of substituted silver. The higher concentration of silver in the calcium phosphate film was more effective in reducing the bacteria of Escherichia coli ATCC 8739 and Streptococcus mutans OMZ 65 on contact with respect to controls

  3. Characterization of a silver-incorporated calcium phosphate film by RBS and its antimicrobial effects

    Energy Technology Data Exchange (ETDEWEB)

    Han, I-H [Institute of Physics and Applied Physics, and Atomic-Scale Surface Science Research Center, Yonsei University, Seou1 120-749 (Korea, Republic of); Lee, I-S [Institute of Physics and Applied Physics, and Atomic-Scale Surface Science Research Center, Yonsei University, Seou1 120-749 (Korea, Republic of); Song, J-H [Advanced Analysis Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Lee, M-H [Department of Medical Engineering, Yonsei University, Seoul 120-752 (Korea, Republic of); Park, J-C [Department of Medical Engineering, Yonsei University, Seoul 120-752 (Korea, Republic of); Lee, G-H [Korea Institute of Machinery and Materials, Chang-Won 641-010 (Korea, Republic of); Sun, X-D [Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Chung, S-M [Implantium Research Center, Seoul 135-879 (Korea, Republic of)

    2007-09-15

    A thin calcium phosphate film was synthesized on both commercially pure Ti and Si wafers by electron beam evaporation of hydroxyapatite as an evaporant with simultaneous Ar ion beam bombardments. Silver was introduced into an ion-beam-assisted deposition of a calcium phosphate thin film for antimicrobial effect. The amount of incorporated silver ions was controlled by immersing calcium-phosphate-coated samples in different AgNO{sub 3} concentrations, and Rutherford backscattering spectrometry (RBS) was employed to measure the amounts of substituted silver. The higher concentration of silver in the calcium phosphate film was more effective in reducing the bacteria of Escherichia coli ATCC 8739 and Streptococcus mutans OMZ 65 on contact with respect to controls.

  4. Seed selections for crystallization of calcium phosphate for phosphorus recovery

    Institute of Scientific and Technical Information of China (English)

    SONG Yong-hui; Dietfried DONNERT; Ute BERG; Peter G. WEIDLER; Rolf NUEESCH

    2007-01-01

    Seed induces and promotes the crystallization of calcium phosphate, and acts as carrier of the recovered phosphorus (P). In order to select suitable seed for P recovery from wastewater, three seeds including Apatite (AP), Juraperle (JP) and phosphate-modified Juraperle (M-JP) were tested and compared. Batch and fixed-bed column experiments of seeded crystallization of calcium phosphate were undertaken by using synthetic wastewater with 10 mg/L P phosphate. It shows that AP has bad enduring property in the crystallization process, while JP has better performance for multiple uses, and M-JP is a hopeful seed for P recovery by crystallization of calcium phosphate.

  5. Fabrications of zinc-releasing biocement combining zinc calcium phosphate to calcium phosphate cement.

    Science.gov (United States)

    Horiuchi, Shinya; Hiasa, Masahiro; Yasue, Akihiro; Sekine, Kazumitsu; Hamada, Kenichi; Asaoka, Kenzo; Tanaka, Eiji

    2014-01-01

    Recently, zinc-releasing bioceramics have been the focus of much attention owing to their bone-forming ability. Thus, some types of zinc-containing calcium phosphate (e.g., zinc-doped tricalcium phosphate and zinc-substituted hydroxyapatite) are examined and their osteoblastic cell responses determined. In this investigation, we studied the effects of zinc calcium phosphate (ZCP) derived from zinc phosphate incorporated into calcium phosphate cement (CPC) in terms of its setting reaction and MC3T3-E1 osteoblast-like cell responses. Compositional analysis by powder X-ray diffraction analysis revealed that HAP crystals were precipitated in the CPC containing 10 or 30wt% ZCP after successfully hardening. However, the crystal growth observed by scanning electron microscopy was delayed in the presence of additional ZCP. These findings indicate that the additional zinc inhibits crystal growth and the conversion of CPC to the HAP crystals. The proliferation of the cells and alkaline phosphatase (ALP) activity were enhanced when 10wt% ZCP was added to CPC. Taken together, ZCP added CPC at an appropriate fraction has a potent promotional effect on bone substitute biomaterials. PMID:24090874

  6. Calcium phosphate mineralization is widely applied in crustacean mandibles

    OpenAIRE

    Shmuel Bentov; Aflalo, Eliahu D.; Jenny Tynyakov; Lilah Glazer; Amir Sagi

    2016-01-01

    Crustaceans, like most mineralized invertebrates, adopted calcium carbonate mineralization for bulk skeleton reinforcement. Here, we show that a major part of the crustacean class Malacostraca (which includes lobsters, crayfishes, prawns and shrimps) shifted toward the formation of calcium phosphate as the main mineral at specified locations of the mandibular teeth. In these structures, calcium phosphate is not merely co-precipitated with the bulk calcium carbonate but rather creates speciali...

  7. Nano-porous calcium phosphate balls.

    Science.gov (United States)

    Kovach, Ildyko; Kosmella, Sabine; Prietzel, Claudia; Bagdahn, Christian; Koetz, Joachim

    2015-08-01

    By dropping a NaH2PO4·H2O precursor solution to a CaCl2 solution at 90°C under continuous stirring in presence of two biopolymers, i.e. gelatin (G) and chitosan (C), supramolecular calcium phosphate (CP) card house structures are formed. Light microscopic investigations in combination with scanning electron microscopy show that the GC-based flower-like structure is constructed from very thin CP platelets. Titration experiments indicate that H-bonding between both biopolymers is responsible for the synergistic effect in presence of both polymers. Gelatin-chitosan-water complexes play an important role with regard to supramolecular ordering. FTIR spectra in combination with powder X-ray diffraction show that after burning off all organic components (heating up >600°C) dicalcium and tricalcium phosphate crystallites are formed. From high resolution transmission electron microscopy (HR-TEM) it is obvious to conclude, that individual crystal platelets are dicalcium phosphates, which build up ball-like supramolecular structures. The results reveal that the GC guided crystal growth leads to nano-porous supramolecular structures, potentially attractive candidates for bone repair. PMID:26052107

  8. Osteogenecity of octacalcium phosphate coatings applied on porous metal implants.

    Science.gov (United States)

    Barrère, Florence; van der Valk, Chantal M; Dalmeijer, Remco A J; Meijer, Gert; van Blitterswijk, Clemens A; de Groot, Klaas; Layrolle, Pierre

    2003-09-15

    The biomimetic route allows the homogeneous deposition of calcium phosphate (Ca-P) coatings on porous implants by immersion in simulated physiologic solution. In addition, various Ca-P phases, such as octacalcium phosphate (OCP) or bone-like carbonated apatite (BCA), which are stable only at low temperatures, can be deposited. In this pilot study, experiments were designed with a twofold-purpose: (1) to investigate the osteoinduction of OCP-coated and noncoated porous tantalum cylinders and of dense titanium alloy cylinders (5 mm in diameter and 10 mm in length) in the back muscle of goats at 12 and 24 weeks (n = 4); and (2) to compare the osteogenic potentials of BCA-coated, OCP-coated, and bare porous tantalum cylinders in a gap of 1 mm created in the femoral condyle of a goat at 12 weeks (n = 2). In the goat muscle, after 12 weeks the OCP-coated porous cylinder had induced ectopic bone as well as bone within the cavity of the OCP-coated dense titanium cylinder. In the femoral condyle, bone did not fill the gap in any of the porous implants. In contrast with the two other groups, OCP-coated porous cylinders exhibited bone formation in the center of the implant. The nature of the Ca-P coating, via its microstructure, its dissolution rate, and its specific interactions with body fluids, may influence the osteogenecity of the Ca-P biomaterial. PMID:12926029

  9. Pathogenic Mineralization of Calcium Phosphate on Human Heart Valves

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    When calcium phosphate forms in soft tissues such as blood vessels and heart valves, it causes disease. The abnormal formation of calcium phosphate is called pathogenic mineralization or pathogenic calcification. Cases of rheumatic heart disease (RHD) always occur with fibrotic and calcified tissue of heart valve. In this article, samples taken from calcified human heart valves were studied. The characterization was performed by scanning electronic micrascope, X-ray Diffraction and transmission electron microscopy with selective diffraction patterns. It is found for the first time that calcium phosphate grains existing in the calcified human heart valves contain octacalcium phosphate (OCP).

  10. Preparation and Characterization of Porous Calcium Phosphate Bioceramics

    Institute of Scientific and Technical Information of China (English)

    Honglian Dai; Xinyu Wang; Yinchao Han; Xin Jiang; Shipu Li

    2011-01-01

    β-tricalcium phosphate (β-TCP) powder and Na2O-CaO-MgO-P2O5 glass binder were synthesized and mixed, and then the biodegradable porous calcium phosphate ceramics were successfully prepared by foaming and sintering at 850℃. The as-prepared ceramics possess a high porosity with partial three-dimension interconnected macro- and micro-pores. As in vitro experiment testified, the calcium phosphate ceramics (CPCs) has good degradability.

  11. Control of phase composition in hydroxyapatite/tetracalcium phosphate biphasic thin coatings for biomedical applications

    OpenAIRE

    Kim, H.; CAMATA, R. P.; Vohra, Y. K.; LACEFIELD, W. R.

    2005-01-01

    Biphasic calcium phosphates comprising well-controlled mixtures of nonresorbable hydroxyapatite and other resorbable calcium phosphate phases often exhibit a combination of enhanced bioactivity and mechanical stability that is difficult to achieve in single-phase materials. This makes these biphasic bioceramics promising substrate materials for applications in bone tissue regeneration and repair. In this paper we report the synthesis of highly crystalline, biphasic coatings of hydroxyapatite/...

  12. Biomimetic Nanocomposites of Calcium Phosphate and Self-Assembling Triblock and Pentablock Copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Drew Lenzen Enlow

    2006-08-09

    In an effort to mimic the growth of natural bone, self-assembling, micelle and gel-forming copolymers were used as a template for calcium phosphate precipitation. Because of the cationic characteristics imparted by PDEAEM end group additions to commercially available Pluronic{reg_sign} Fl27, a direct ionic attraction mechanism was utilized and a polymer-brushite nanocomposite spheres were produced. Brushite coated spherical micelles with diameters of {approx}40 nm, and agglomerates of these particles (on the order of 0.5 {mu}m) were obtained. Thickness and durability of the calcium phosphate coating, and the extent of agglomeration were studied. The coating has been shown to be robust enough to retain its integrity even below polymer critical micelle concentration and/or temperature. Calcium phosphate-polymer gel nanocomposites were also prepared. Gel samples appeared as a single phase network of agglomerated spherical micelles, and had a final calcium phosphate concentration of up to 15 wt%. Analysis with x-ray diffraction and NMR indicated a disordered brushite phase with the phosphate groups linking inorganic phase to the polymer.

  13. Phosphate coating on stainless steel 304 sensitized

    International Nuclear Information System (INIS)

    The stainless steel 304 can be sensitized when welding processes are applied, that causes the precipitation of chromium carbide in the grain limits, being promoted in this way the formation of galvanic cells and consequently the corrosion process. Using a phosphate coating is possible to retard the physiochemical damages that can to happen in the corrosion process. The stainless steel 304 substrate sensitized it is phosphate to base of Zn-Mn, in a immersion cell very hot. During the process was considered optimization values, for the characterization equipment of X-rays diffraction and scanning electron microscopy was used. The XRD technique confirmed the presence of the phases of manganese phosphate, zinc phosphate, as well as the phase of the stainless steel 304. When increasing the temperature from 60 to 90 C in the immersion process a homogeneous coating is obtained. (Author)

  14. Physical–chemical and biological behavior of an amorphous calcium phosphate thin film produced by RF-magnetron sputtering

    International Nuclear Information System (INIS)

    This work evaluates the thermal reactivity and the biological reactivity of an amorphous calcium phosphate thin film produced by radio frequency (RF) magnetron sputtering onto titanium substrates. The analyses showed that the sputtering conditions used in this work led to the deposition of an amorphous calcium phosphate. The thermal treatment of this amorphous coating in the presence of H2O and CO2 promoted the formation of a carbonated HA crystalline coating with the entrance of CO32− ions into the hydroxyl HA lattice. When immersed in culture medium, the amorphous and carbonated coatings exhibited a remarkable instability. The presence of proteins increased the dissolution process, which was confirmed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses. Moreover, the carbonated HA coating induced precipitation independently of the presence of proteins under dynamic conditions. Despite this surface instability, this reactive calcium phosphate significantly improved the cellular behavior. The cell proliferation was higher on the Ticp than on the calcium phosphate coatings, but the two coatings increased cellular spreading and stress fiber formation. In this sense, the presence of reactive calcium phosphate coatings can stimulate cellular behavior. - Highlights: ► Functionalization of Ti with reactive CaP thin film by RF-magnetron sputtering. ► De-hydroxylation facilitating the insertion of CO32− into the HA lattice. ► High surface reactivity in the presence of culture medium. ► Cell behavior improved by the presence of reactive films.

  15. Selective laser sintering of calcium phosphate materials for orthopedic implants

    Science.gov (United States)

    Lee, Goonhee

    control of micro and macro pore structure, to maximize bone healing and provide sufficient mechanical strength. It also permits the complete removal of the polymeric binders that are resided in the SLS process. In collaboration with the University of Texas Health Science Center at San Antonio and BioMedical Enterprises, Inc., porous implants based on anatomical geometry have been successfully implanted in rabbits and dogs. These histologic animal studies reveal excellent biocompatibility and show its great potential for commercial custom-fit implant manufacture. The second research effort involves fabrication of fully dense bone for application in dental restoration and load-bearing orthopedic functions. Calcium phosphate glass melts, proven to be biocompatible in the first effort, were cast into carbon molds. Processes were developed for preparing the molds. These carbon molds of anatomic shape can be prepared from either Computer Numerical Control (CNC) milling of slab stock or SLS processing of thermoset-coated graphite powder. The CNC milling method provides accurate dimension of the molds in a short period of time, however, the capable geometries are limited; generally two pieces of molds are required for complex shapes. The SLS method provides very complex shape green molds. However, they need to go through pyrolysis of thermoset binder to provide the high temperature capability reached at calcium phosphate melt temperatures (1100°C) and noticeable shrinkage was observed during pyrolysis. The cast glass was annealed to develop polycrystalline calcium phosphate. This process also exhibits great potential.

  16. Injectable bioactive calcium-magnesium phosphate cement for bone regeneration

    International Nuclear Information System (INIS)

    Novel injectable and degradable calcium-magnesium phosphate cement (CMPC) with rapid-setting characteristic was developed by the introduction of magnesium phosphate cement (MPC) into calcium phosphate cement (CPC). The calcium-magnesium phosphate cement prepared under the optimum P/L ratio exhibited good injectability and desired workability. It could set within 10 min at 37 0C in 100% relative humidity and the compressive strength could reach 47 MPa after setting for 48 h, indicating that the prepared cement has relatively high initial mechanical strength. The results of in vitro degradation experiments demonstrated the good degradability of the injectable CMPC, and its degradation rate occurred significantly faster than that of pure CPC in simulated body fluid (SBF) solution. It can be concluded that the novel injectable calcium-magnesium phosphate cement is highly promising for a wide variety of clinical applications, especially for the development of minimally invasive techniques.

  17. Characterization of calcium containing plasma electrolytic oxidation coatings on AM50 magnesium alloy

    International Nuclear Information System (INIS)

    An attempt was made to produce calcium containing plasma electrolytic oxidation (PEO) coatings on AM50 magnesium alloy using an alkaline electrolyte. This study was performed in three alkaline electrolytes containing calcium hydroxide and sodium phosphate with three different mass ratios viz., 1:2.5, 1:5 and 1:7.5. All the three coatings produced were found to contain Ca and P in appreciable amounts. The concentration of P was found to be higher in the coatings obtained in the electrolytes with higher concentration of phosphate ions. Even though all the three coatings were found to be constituted with magnesium oxide and magnesium phosphate phases, X-ray diffraction analyses revealed that the phase composition was influenced by the phosphate ion concentration/conductivity of the electrolyte. Further, the PEO coating obtained in the 1:7.5 ratio electrolyte was found to contain di-calcium phosphate (monetite) and calcium peroxide phases, which were absent in the other two coatings. Potentiodynamic polarization studies performed in 0.1 M NaCl solution showed that the coatings obtained from the 1:5 ratio electrolyte possessed a superior corrosion resistance, which is attributed to the combined effect of thickness, compactness and phase/chemical composition of this coating.

  18. Formation and properties of biocoatings based on wollastonite and calcium phosphates

    International Nuclear Information System (INIS)

    Wollastonite-calcium phosphate coatings were produced on titanium substrates by micro-arc oxidation method. There presented the study of influence of oxidation voltage, process duration and pulse duration on properties of the coatings such as thickness, surface morphology and surface roughness. The morphology and phase composition of the coatings were studied by scanning electron microscopy and X-ray diffraction methods. It was found that biocoatings with large amount of wollastonite particles were deposited under minimum oxidation voltage of 130–150 V. The structural elements with a spherical or plate-like shape were formed on the coating surface depending on micro-arc oxidation parameters

  19. Formation and properties of biocoatings based on wollastonite and calcium phosphates

    Energy Technology Data Exchange (ETDEWEB)

    Sedelnikova, M. B., E-mail: smb@ispms.tsc.ru; Sharkeev, Yu. P., E-mail: sharkeev@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Komarova, E. G., E-mail: katerina@ispms.tsc.ru; Tolkacheva, T. V., E-mail: tolkacheva@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation)

    2015-10-27

    Wollastonite-calcium phosphate coatings were produced on titanium substrates by micro-arc oxidation method. There presented the study of influence of oxidation voltage, process duration and pulse duration on properties of the coatings such as thickness, surface morphology and surface roughness. The morphology and phase composition of the coatings were studied by scanning electron microscopy and X-ray diffraction methods. It was found that biocoatings with large amount of wollastonite particles were deposited under minimum oxidation voltage of 130–150 V. The structural elements with a spherical or plate-like shape were formed on the coating surface depending on micro-arc oxidation parameters.

  20. Bioactivity and Surface Reactivity of RF-sputtered Calcium Phosphate Thin Films

    OpenAIRE

    Wal, Edwin van der

    2003-01-01

    Calcium phosphates (CaP) are known to be bioactive, i.e. able to bond to bone. This makes CaPs very suitable to be aplied as thin coatings on bone-implants. In this work we studied the physicochemical behaviour of CaP coatings applied with radio frequency (RF) magnetron sputtering, a deposition technique that can produce thin (~100 nm), homogeneous, and well-adhereing coatings. As-deposited CaP coatings are amorphous and can be crystallized by a heat-treatment of 30 minutes at 650C, resulting...

  1. Fibroblast and osteoblast adhesion and morphology on calcium phosphate surfaces

    Directory of Open Access Journals (Sweden)

    Baxter L. C.

    2002-09-01

    Full Text Available Implant loosening in bone fixation is an unresolved complication associated with internal fixation. It is generally accepted that this problem can be overcome by modifying the implant/bone interface for improved osseointegration. This is achieved, in part, by hydroxyapatite (HA or tricalcium phosphate coatings. Unfortunately, the benefits of these coatings are constrained by not only the generally low strength of their adhesion to the implant surface but also the limited cohesion within their layers. Anodic Plasma-chemical treatment (APC has been developed to incorporate electrolytes and produce coatings with various microtopographies and strong adhesion to implants. In this in vitro study fibroblast and osteoblast morphologies and adhesion to various substrates were evaluated using qualitative and quantitative methods. The substrates were Thermanox plastic and commercially pure titanium. The latter were surface-treated using several different methods: conventional anodisation, plasma spraying of HA and anodic plasma-chemical (APC treatment in an electrolyte solution containing either calcium and phosphate (APC-CaP or phosphoric acid (APC-P. Both osteoblasts and fibroblasts showed extensive cell spreading, total cell area and greatest amount of adhesion, with defined adhesion patterns on the Thermanox plastic, anodised titanium, and the two APC-CaP substrates. With fibroblasts, almost no cell spreading and very low adhesion, was observed in cells cultured on the APC-P and HA surfaces. The extent of cell spreading correlated with the area of focal adhesions as assessed by the amount of vinculin labelling. The Thermanox plastic, anodised titanium, and the two APC-CaP substrates were the most cytocompatible substrates with regard to this in vitro evaluation.

  2. Thermoluminescence in calcium phosphate doped with samarium

    International Nuclear Information System (INIS)

    Calcium phosphate is a main constitutional substance of human bones and teeth, and it seems worthwhile to investigate the thermoluminescence (TL) characteristics after X-ray irradiation at room temperature. It has been reported that there are two crystal modifications for the corresponding compounds, one rhombohedral and the other having a monoclinic lattice (α- and β-phase, respectively), and α-Ca3(PO4)2 is produced by heating the β-phase. However, it was rather difficult to get the former phase completely 100% from the latter only by heating. With the TL glow curves used for dosimetry it is generally required that a main isolated glow peak should be located at rather high-temperature regions, in order to avoid fading during the keeping of the irradiated materials at room temperature. It is the purpose of the present work to obtain a stable TL dosimeter peak by using β-Ca3(PO4)2, the raw material of which can be obtained directly from any chemical company. According to our preliminary experiments doping various activators into the β-Ca3(PO4)2, it was found that the addition of Sm2O3 into the raw material gives rise to a satisfactory result, and in this paper we describe the case in detail. (Author)

  3. The Antimicrobial Action of Silver Halides in Calcium Phosphate

    OpenAIRE

    Kalniņa, D; Gross, K; Onufrijevs, P.; Daukšta, E; Nikolajeva, V; Stankeviciute, Z; Kareiva, A.

    2015-01-01

    Silver halides represent a yet unexplored avenue for imparting antimicrobial activity to calcium phosphates. Negtively charged silver halide colloids (AgI, AgBr and AgCl) were added to synthesized amorphous calcium phosphate. Concurrent melting of silver halides and crystallization to carbonated apatite at 700 oC increased the silver halide surface area available to bacteria and formed a lower solubility apatite. The effect of the matrix solubility on antimicrobial response could ...

  4. Amorphous calcium phosphate composites with improved mechanical properties

    OpenAIRE

    O’Donnell, J.N.R.; Antonucci, J.M.; Skrtic, D.

    2006-01-01

    Hybridized zirconium amorphous calcium phosphate (ACP)-filled methacrylate composites make good calcium and phosphate releasing materials for anti-demineralizing/remineralizing applications with low mechanical demands. The objective of this study was to assess the effect of the particle size of the filler on the mechanical properties of these composites. Photo-curable resins were formulated from ethoxylated bisphenol A dimethacrylate, triethylene glycol dimethacrylate, 2-hydroxyethyl methacry...

  5. Calcium phosphate-based ceramic and composite materials for medicine

    International Nuclear Information System (INIS)

    The topical problems in chemistry and technology of materials based on calcium phosphates aimed at both the replacement of damaged bone tissue and its regeneration are discussed. Specific features of the synthesis of nanocrystalline powders and the fabrication of ceramic implants are described. Advances in the development of porous scaffolds from resorbable and osteoconductive calcium phosphates and of hybrid composites that form the basis of bone tissue engineering are considered.

  6. Influence of surface treatment of carbon fibers on electrochemical crystallization of calcium phosphate

    Institute of Scientific and Technical Information of China (English)

    TAO Ke; HUANG Su-ping; ZHOU Ke-chao

    2005-01-01

    Electrodeposition technique was used to coat calcium phosphate on carbon fiber which can be used to reinforce hydroxyapatite. The differences between fibers treated with and without nitric acid in electrodeposition were evaluated. The X-ray diffractometry results show that CaHPO4·2H2O is obtained as the kind of calcium phosphate coating on carbon fiber. The scanning electron microscopy photographs and deposit kinetic curve indicate that the influences of the functional group attained by nitric acid treatment, the crystal morphology and crystallization of the coating layers on the fiber with and without treatment rate are obviously different. The functional group, especially the acidic group, can act as nucleation centers of electrochemical crystallization.

  7. Effect of humic substances on the precipitation of calcium phosphate

    Institute of Scientific and Technical Information of China (English)

    SONG Yong-hui; Hermann H. HAHN; Erhard HOFFMANN; Peter G. WEIDLER

    2006-01-01

    For phosphorus (P) recovery from wastewater, the effect of humic substances (HS) on the precipitation of calcium phosphate was studied. Batch experiments of calcium phosphate precipitation were undertaken with synthetic water that contained 20 mg/L phosphate (as P) and 20 mg/L HS (as dissolved organic carbon, DOC) at a constant pH value in the range of 8.0-10.0. The concentration variations of phosphate, calcium (Ca) and HS were measured in the precipitation process; the crystalline state and compositions of the precipitates were analysed by powder X-ray diffraction (XRD) and chemical methods, respectively. It showed that at solution pH 8.0, the precipitation rate and removal efficiency of phosphate were greatly reduced by HS, but at solution pH ≥9.0,the effect of HS was very small. The Ca consumption for the precipitation of phosphate increased when HS was added; HS was also removed from solution with the precipitation of calcium phosphate. At solution pH 8.0 and HS concentrations ≤ 3.5 mg/L, and at pH ≥ 9.0 and HS concentrations ≤ 10 mg/L, the final precipitates were proved to be hydroxyapatite (HAP) by XRD. The increases of solution pH value and initial Ca/P ratio helped reduce the influence of HS on the precipitation of phosphate.

  8. In vitro and in vivo degradation of biomimetic octacalcium phosphate and carbonate apatite coatings on titanium implants

    NARCIS (Netherlands)

    Barrere, F.; Valk, van der C.M.; Dalmeijer, R.A.J.; Blitterswijk, van C.A.; Groot, de K.; Layrolle, P.

    2003-01-01

    Calcium phosphate (Ca-P) coatings have been applied onto titanium alloys prosthesis to combine the srength of metals with the bioactivity of Ca-P. It has been clearly shown in many publications that Ca-P coating accelerates bone formation around the implant. However, longevity of the Ca-P coating fo

  9. Cathodic phosphate coating containing nano zinc particles on magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A technology for preparation of a cathodic phosphate coating mainly containing nano metallic zinc particles and phosphate compounds on magnesium alloy was developed.The influence of cathodic current density on the microstructure of the cathodic phosphate coating Was investigated.The results show that the crystals of the coating are finer and the microstructures of the outer surface of the coatings are zigzag at the cathodic density of 0.2-0.5 A/dm2.The content of nano metallic zinc particles in the coating decreases with the increase of the thickness of the coatings and tends to be zero when the coating thickness is 4.14 μm.The cathodic phosphate coating was applied to be a transition coating for improving the adhesion between the paints and the magnesium alloys.The formation mechanism of the cathodic phosphate coating was investigated as well.

  10. Characterization of cement calcium phosphate for use dental

    International Nuclear Information System (INIS)

    Calcium phosphates are interesting biological and medical attention due to its occurrence in different animal species and humans. Ceramics based on calcium phosphate in the form of implants or porous particulate materials, have proven to be suitable replacements for bone tissue when they are only subjected to small mechanical stresses. Was obtained research laboratory DEMA/UFCG a calcium phosphate phase. The goal is to characterize the material by X-ray diffraction (XRD) in order to analyze what the phases and infrared spectroscopy (FTIR) to identify the absorption bands of the bonding characteristic. Was identified by XRD phase present in the sample is hydroxyapatite Ca/P 1.67. In infrared spectroscopy has absorption bands characteristic of the phosphate group at 1032 cm1 region. (author)

  11. Investigation of Wear Coefficient of Manganese Phosphate Coated Tool Steel

    OpenAIRE

    S. Ilaiyavel; Venkatesan, A.

    2013-01-01

    In recent years the properties of the coating in terms of wear resistance is of paramount importance in order to prevent the formation of severe damages. In this study, Wear coefficient of uncoated, Manganese Phosphate coated, Manganese Phosphate coated with oil lubricant, Heat treated Manganese Phosphate coated with oil lubricant on AISI D2 steels was investigated using Archard’s equation. The wear tests were performed in a pin on disk apparatus as per ASTM G-99 Standard. The volumetric wear...

  12. Effect of Calcium Ions on the Disintegration of Enteric-Coated Solid Dosage Forms.

    Science.gov (United States)

    Al-Gousous, Jozef; Langguth, Peter

    2016-02-01

    To investigate the effect of calcium ions on the disintegration of enteric-coated dosage forms, disintegration testing was performed on enteric-coated aspirin tablets in the presence and absence of calcium in the test media. The results show that the presence of calcium ions retards the disintegration of enteric-coated dosage forms. This finding, which has not been reported in scientific literature, sheds light on the importance of conducting well-designed detailed investigations into the potential of calcium from dietary sources, calcium supplements, antacids, and/or phosphate binders affecting the absorption of drugs formulated into enteric-coated dosage forms. Moreover, it shows the necessity to investigate the potential of the occurrence of additional nutrient-excipient interactions. PMID:26523769

  13. Calcium phosphate bioceramics prepared from wet chemically precipitated powders

    Directory of Open Access Journals (Sweden)

    Kristine Salma

    2010-03-01

    Full Text Available In this work calcium phosphates were synthesized by modified wet chemical precipitation route. Contrary to the conventional chemical precipitation route calcium hydroxide was homogenized with planetary mill. Milling calcium oxide and water in planetary ball mill as a first step of synthesis provides a highly dispersed calcium hydroxide suspension. The aim of this work was to study the influence of main processing parameters of wet chemical precipitation synthesis product and to control the morphology, phase and functional group composition and, consequently, thermal stability and microstructure of calcium phosphate bioceramics after thermal treatment. The results showed that it is possible to obtain calcium phosphates with different and reproducible phase compositions after thermal processing (hydroxyapatite [HAp], β-tricalcium phosphate [β-TCP] and HAp/β-TCP by modified wet-chemical precipitation route. The β-TCP phase content in sintered bioceramics samples is found to be highly dependent on the changes in technological parameters and it can be controlled with ending pH, synthesis temperature and thermal treatment. Pure, crystalline and highly thermally stable (up to 1300°C HAp bioceramics with homogenous grainy microstructure, grain size up to 200–250 nm and high open porosity can be successfully obtained by powder synthesized at elevated synthesis temperature of 70°C and stabilizing ending pH at 9.

  14. Corrosion resistance of phosphated steels with plasma sprayed ceramic coatings

    Czech Academy of Sciences Publication Activity Database

    Brožek, Vlastimil; Mastný, L.; Pokorný, P.

    Zagreb: Croatian Metallurgical Society (CMS), 2014 - (Mamuzić, I.). s. 401 ISBN N. [International Symposium of Croatian Metallurgical Society SHMD 2014/11./. 22.06.2014-26.06.2014, Šibenik] Institutional support: RVO:61389021 Keywords : steel phosphating * phosphate coatings * plasma spraying * ceramic coatings * corrosion resistance * bond strength of coatings Subject RIV: CA - Inorganic Chemistry

  15. Characterisation of calcium phosphate layers grown on polycaprolactone for tissue engineering purposes

    OpenAIRE

    Lebourg, M.; Antón, J. Suay; Ribelles, J.L. Gomez

    2010-01-01

    Abstract Composites fabricated by biomimetic mineral precipitation on polymeric substrates are of interest for tissue engineering. As biological properties of such mineral layers vary with slight changes in composition, a good physical characterization is necessary in order to study their biological activity. In this work polycaprolactone sheets were subjected to air plasma treatment followed by nucleation of calcium phosphate seeds to activate the growth of an apatite-like coating...

  16. Electrodeposition on nanofibrous polymer scaffolds: Rapid mineralization, tunable calcium phosphate composition and topography

    OpenAIRE

    He, Chuanglong; Xiao, Guiyong; Jin, Xiaobing; Sun, Chenghui; Ma, Peter X.

    2010-01-01

    We developed a straightforward, fast, and versatile technique to fabricate mineralized nanofibrous polymer scaffolds for bone regeneration in this work. Nanofibrous poly(l-lactic acid) scaffolds were fabricated using both electrospinning and phase separation techniques. An electrodeposition process was designed to deposit calcium phosphate on the nanofibrous scaffolds. Such scaffolds contain a high quality mineral coating on the fiber surface with tunable surface topography and chemical compo...

  17. Calcium-phosphate-osteopontin particles for caries control

    DEFF Research Database (Denmark)

    Schlafer, Sebastian; Birkedal, Henrik; Olsen, Jakob;

    2016-01-01

    Caries is caused by acid production in biofilms on dental surfaces. Preventing caries therefore involves control of microorganisms and/or the acid produced. Here, calcium-phosphate-osteopontin particles are presented as a new approach to caries control. The particles are made by co-precipitation ......Caries is caused by acid production in biofilms on dental surfaces. Preventing caries therefore involves control of microorganisms and/or the acid produced. Here, calcium-phosphate-osteopontin particles are presented as a new approach to caries control. The particles are made by co......, and the pH always remained above 5.5. Hence, calcium-phosphate-osteopontin particles show potential for applications in caries control....

  18. Casein Phosphopeptide- Amorphous Calcium Phosphate in Dentistry: A Literature Review

    OpenAIRE

    KESKİN, Arş. Gör. Dt. Gül; GÜLER, Yrd. Doç. Dr. Çiğdem

    2013-01-01

    Casein is a phosphoprotein in bovine milk and accounts for almost 80 percent of its total protein. Casein fosfopeptit (CPP) is produced as a result of decomposition of casein with trypsin enzyme using a selective deposition method. CPP can remarkably stabilize calcium phosphate in a state-forming CPPamorphous calcium phosphate (ACP) complex. CPPACP is located in topical gels, sugar-free chewing gum and mint dragees at the present day. In this paper, the effectiveness of CPP-ACP and usage in d...

  19. Calcium-phosphate-osteopontin particles for caries control

    DEFF Research Database (Denmark)

    Schlafer, Sebastian

    Oftentimes caries lesions develop in protected sites that are difficult to access by self-performed mechanical tooth cleaning. At present, there is a growing interest in chemical adjuncts to mechanical procedures of oral hygiene that aim at biofilm control rather than biofilm eradication. Calcium...... drops to 6 or below and release buffering phosphate ions that stabilize biofilm pH above the critical level for enamel dissolution. With that twofold approach, calcium-phosphate-osteopontin particles may make a relevant contribution to clinical caries control....

  20. Optimization of calcium phosphate fine ceramic powders preparation

    Science.gov (United States)

    Sezanova, K.; Tepavitcharova, S.; Rabadjieva, D.; Gergulova, R.; Ilieva, R.

    2013-12-01

    The effect of biomimetic synthesis method, reaction medium and further precursor treatments on the chemical and phase composition, crystal size and morphology of calcium phosphates was examined. Nanosized calcium phosphate precursors were biomimetically precipitated by the method of continuous precipitation in three types of reaction media at pH 8: (i) SBF as an inorganic electrolyte system; (ii) organic (glycerine) modified SBF (volume ratio of 1:1); (iii) polymer (10 g/l xanthan gum or 10 g/l guar gum) modified SBF (volume ratio of 1:1). After maturation (24 h) the samples were lyophilized, calcinated at 300°C for 3 hours, and washed with water, followed by new gelation, lyophilization and step-wise (200, 400, 600, 800, and 1000°C, each for 3 hours) sintering. The reaction medium influenced the chemical composition and particle size but not the morphology of the calcium phosphate powders. In all studied cases bi-phase calcium phosphate fine powders with well-shaped spherical grains, consisting of β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) with a Ca/P ratio of 1.3 - 1.6 were obtained. The SBF modifiers decreased the particle size of the product in the sequence guar gum ˜ xanthan gum < glycerin < SBF medium.

  1. Synthesis and characterization of zirconium-doped calcium phosphate biomaterial

    International Nuclear Information System (INIS)

    A new synthesis route for the production of calcium phosphate biomaterial was developed by using organic di-(2-ethylhexyl) phosphoric acid (DEHPA) mixed with calcium hydroxide slurry. Unlike the conventional involving chemical precipitation process this new method involves a sol-gel process. Another advantage of this method is the starting material DEHPA can form strong bonding with many elements including zirconium and rare earths. This makes it suitable to be used as drug delivery material especially those involving bone related disease. It also improves the biomaterial strength with the presence of zirconium oxide phase. From XRD analysis, the result shows the present of HA, α-TCP and β-TCP. The addition of different rare elements on to the calcium phosphate will varies the amount of these three phases. SEM analysis was also performed to study the morphology of the calcium phosphate material. The presence of the rare earths on to the calcium phosphate was established by using the EDS technique. (Author)

  2. Casein Phosphopeptide-Amorphous Calcium Phosphate Nanocomplexes: A Structural Model.

    Science.gov (United States)

    Cross, Keith J; Huq, N Laila; Reynolds, Eric C

    2016-08-01

    Tryptic digestion of the calcium-sensitive caseins yields casein phosphopeptides (CPP) that contain clusters of phosphorylated seryl residues. The CPP stabilize calcium and phosphate ions through the formation of complexes. The calcium phosphate in these complexes is biologically available for intestinal absorption and remineralization of subsurface lesions in tooth enamel. We have studied the structure of the complexes formed by the CPP with calcium phosphate using a variety of nuclear magnetic resonance (NMR) techniques. Translational diffusion measurements indicated that the β-CN(1-25)-ACP nanocomplex has a hydrodynamic radius of 1.526 ± 0.044 nm at pH 6.0, which increases to 1.923 ± 0.082 nm at pH 9.0. (1)H NMR spectra were well resolved, and (3)JH(N)-H(α) measurements ranged from a low of 5.5 Hz to a high of 8.1 Hz. Total correlation spectroscopy and nuclear Overhauser effect spectroscopy spectra were acquired and sequentially assigned. Experiments described in this paper have allowed the development of a structural model of the β-CN(1-25)-amorphous calcium phosphate nanocomplex. PMID:27434168

  3. Rickets induced by calcium or phosphate depletion.

    OpenAIRE

    Abugassa, S.; Svensson, O.

    1990-01-01

    We studied the effects of calciopenia and phosphopenia on longitudinal growth, skeletal mineralization, and development of rickets in young Sprague-Dawley rats. At an age of 21 days, two experimental groups were given diets containing 0.02% calcium or 0.02% phosphorus; otherwise the diets were nutritionally adequate. After 7, 14, and 21 days, five animals from each group were randomly chosen. The animals were anaesthetized and blood samples were drawn for analysis of calcium, phosphorus, and ...

  4. A facile approach to construct hybrid multi-shell calcium phosphate gene particles*

    OpenAIRE

    Xu, Zhi-xue; Zhang, Ran; Wang, You-xiang; Hu, Qiao-ling

    2010-01-01

    The calcium phosphate (CaP) particles have attracted much attention in gene therapy. How to construct stable gene particles was the determining factor. In this study, hybrid multi-shell CaP gene particles were successfully constructed. First, CaP nanoparticles served as a core and were coated with DNA for colloidal stabilization. The ξ-potential of DNA-coated CaP nanoparticles was −15 mV. Then polyethylenimine (PEI) was added and adsorbed outside of the DNA layer due to the electrostatic attr...

  5. Calcium and phosphate homeostasis: concerted interplay of new regulators.

    NARCIS (Netherlands)

    Renkema, K.Y.R.; Alexander, R.T.; Bindels, R.J.M.; Hoenderop, J.G.J.

    2008-01-01

    Calcium (Ca(2+)) and phosphate (P(i)) are essential to many vital physiological processes. Consequently the maintenance of Ca(2+) and P(i) homeostasis is essential to a healthy existence. This occurs through the concerted action of intestinal, renal, and skeletal regulatory mechanisms. Ca(2+) and P(

  6. Osteoinduction of calcium phosphate biomaterials in small animals

    International Nuclear Information System (INIS)

    Although osteoinduction mechanism of calcium phosphate (CP) ceramics is still unclear, several essential properties have been reported, such as chemical composition, pore size and porosity, etc. In this study, calcium phosphate powder (Ca3(PO4)2, CaP, group 1), biphasic calcium phosphate ceramic powder (BCP, group 2), and intact BCP rods (group 3) were implanted into leg muscles of mice and dorsal muscles of rabbits. One month and three months after implantation, samples were harvested for biological and histological analysis. New bone tissues were observed in 10/10 samples in group 1, 3/10 samples in group 2, and 9/10 samples in group 3 at 3rd month in mice, but not in rabbits. In vitro, human mesenchymal stem cells (hMSCs) were cultured with trace CaP and BCP powder, and osteogenic differentiation was observed at day 7. Our results suggested that chemical composition is the prerequisite in osteoinduction, and pore structure would contribute to more bone formation. - Highlights: ► Intrinsic osteoinduction of calcium phosphate biomaterials was observed implanted in muscles of mice. ► Biomaterials powder also has osteoinduction property. ► Osteogenic genes and protein could be detected by RT-PCR and Western blot in implanted biomaterials. ► Osteogenic phenomenon could be observed by electron microscopy. ► The chemical composition is the prerequisite in osteoinduction, and pore structure would contribute to more bone formation

  7. Amorphous calcium phosphate and its application in dentistry

    Directory of Open Access Journals (Sweden)

    Sun Wei-bin

    2011-07-01

    Full Text Available Abstract Amorphous Calcium Phosphate (ACP is an essential mineral phase formed in mineralized tissues and the first commercial product as artificial hydroxyapatite. ACP is unique among all forms of calcium phosphates in that it lacks long-range, periodic atomic scale order of crystalline calcium phosphates. The X-ray diffraction pattern is broad and diffuse with a maximum at 25 degree 2 theta, and no other different features compared with well-crystallized hydroxyapatite. Under electron microscopy, its morphological form is shown as small spheroidal particles in the scale of tenths nanometer. In aqueous media, ACP is easily transformed into crystalline phases such as octacalcium phosphate and apatite due to the growing of microcrystalline. It has been demonstrated that ACP has better osteoconductivity and biodegradability than tricalcium phosphate and hydroxyapatite in vivo. Moreover, it can increase alkaline phosphatase activities of mesoblasts, enhance cell proliferation and promote cell adhesion. The unique role of ACP during the formation of mineralized tissues makes it a promising candidate material for tissue repair and regeneration. ACP may also be a potential remineralizing agent in dental applications. Recently developed ACP-filled bioactive composites are believed to be effective anti-demineralizing/remineralizing agents for the preservation and repair of tooth structures. This review provides an overview of the development, structure, chemical composition, morphological characterization, phase transformation and biomedical application of ACP in dentistry.

  8. Magnetic properties study on Fe-doped calcium phosphate

    Science.gov (United States)

    Silva, C. C.; Vasconcelos, I. F.; Sombra, A. S. B.; Valente, M. A.

    2009-11-01

    Calcium phosphates are very important for applications in medicine due to their properties such as biocompatibility and bioactivity. In order to enhance these properties, substitution of calcium with other ions has been proposed. Partial substitution of calcium by different ions has been made in order to improve the properties of the calcium phosphates and also to allow new applications of apatite in medicine. In this work, hydroxyapatite [Ca10(PO4)6(OH)2—HAP] was prepared by high-energy dry milling (20 h) and mixed with iron oxide (5 wt.%). The mixture was calcinated at 900 °C for 5 h with a heating rate of 3 °C min-1 in an attempt to introduce iron oxide into the HAP structure. The sintered sample was characterized using x-ray diffraction (XRD) and magnetization. The 57Fe-Mössbauer spectra of the calcium phosphate oxides were also measured, revealing the presence of iron in three different phases: Ca2Fe2O5, Fe2O3 and hydroxyapatite.

  9. Formation of calcium phosphate mineral materialcontrolled by microemulsion

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In order to prepare calcium phosphate-based material with nano-structure and bioactivity, natural lecithin and n-tetradecane were used as the amphipile and the oil phase respectively, along with the water phase, to form a microemulsion template. Phosphate mineralization was induced and controlled by the microemulsion. The products, characterized by scanning electronic microscopy, infrared spectroscopy and X-ray diffraction analysis, are composed of lecithin and hydroxyapatite, and possess the nano-structure of sticks, balls and three-dimensional nets connected by tubes. These results show that the microemulsion can be used to control calcium phosphate mineralization for the preparation of biomimetic mineral materials with various nano-structures.

  10. An efficient calcium phosphate nanoparticle-based nonviral vector for gene delivery

    Directory of Open Access Journals (Sweden)

    Liu YC

    2011-04-01

    Full Text Available Yachun Liu1,2,*, Tao Wang1,*, Fangli He1,*, Qian Liu1,*, Dexi Zhang2, Shuanglin Xiang1, Shengpei Su2, Jian Zhang11Key Laboratory of Protein Chemistry and Developmental Biology, Ministry of Education of China, College of Life Sciences; 2Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research and Key Laboratory of Sustainable Resources Processing and Advanced Materials of Hunan Province, Ministry of Education of China, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, Hunan, China*These authors contributed equally to this workBackground: Smaller nanoparticles facilitate the delivery of DNA into cells through endocytosis and improve transfection efficiency. The aim of this study was to determine whether protamine sulfate-coated calcium phosphate (PS-CaP could stabilize particle size and enhance transfection efficiency.Methods: pEGFP-C1 green fluorescence protein was employed as an indicator of transfection efficiency. Atomic force microscopy was used to evaluate the morphology and the size of the particles, and an MTT assay was introduced to detect cell viability and inhibition. The classical calcium phosphate method was used as the control.Results: Atomic force microscopy images showed that the PS-CaP were much smaller than classical calcium phosphate particles. In 293 FT, HEK 293, and NIH 3T3 cells, the transfection efficiency of PS-CaP was higher than for the classical calcium phosphate particles. The difference in efficiencies implies that the smaller nanoparticles may promote the delivery of DNA into cells through endocytosis and could improve transfection efficiency. In addition, PS-CaP could be used to transfect HEK 293 cells after one week of storage at 4°C with a lesser extent of efficiency loss compared with classical calcium phosphate, indicating that protamine sulfate may increase the stability of calcium phosphate nanoparticles. The cell viability inhibition assay indicated that

  11. Influence of calcium on ceramide-1-phosphate monolayers.

    Science.gov (United States)

    Oliveira, Joana S L; Brezesinski, Gerald; Hill, Alexandra; Gericke, Arne

    2016-01-01

    Ceramide-1-phosphate (C1P) plays an important role in several biological processes, being identified as a key regulator of many protein functions. For instance, it acts as a mediator of inflammatory responses. The mediation of the inflammation process happens due to the interaction of C1P with the C2 domain of cPLA2α, an effector protein that needs the presence of submicromolar concentrations of calcium ions. The aim of this study was to determine the phase behaviour and structural properties of C1P in the presence and absence of millimolar quantities of calcium in a well-defined pH environment. For that purpose, we used monomolecular films of C1P at the soft air/liquid interface with calcium ions in the subphase. The pH was varied to change the protonation degree of the C1P head group. We used surface pressure versus molecular area isotherms coupled with other monolayer techniques as Brewster angle microscopy (BAM), infrared reflection-absorption spectroscopy (IRRAS) and grazing incidence X-ray diffraction (GIXD). The isotherms indicate that C1P monolayers are in a condensed state in the presence of calcium ions, regardless of the pH. At higher pH without calcium ions, the monolayer is in a liquid-expanded state due to repulsion between the negatively charged phosphate groups of the C1P molecules. When divalent calcium ions are added, they are able to bridge the highly charged phosphate groups, enhancing the regular arrangement of the head groups. Similar solidification of the monolayer structure can be seen in the presence of a 150 times larger concentration of monovalent sodium ions. Therefore, calcium ions have clearly a strong affinity for the phosphomonoester of C1P. PMID:26977381

  12. Osteogenesis-inducing calcium phosphate nanoparticle precursors applied to titanium surfaces

    International Nuclear Information System (INIS)

    This study investigated the effects of the morphology and physicochemical properties of calcium phosphate (CaP) nanoparticles on osteogenesis. Two types of CaP nanoparticles were compared, namely amorphous calcium phosphate (ACP) nano-spheres (diameter: 9–13 nm) and poorly crystalline apatite (PCA) nano-needles (30–50 nm × 2–4 nm) that closely resemble bone apatite. CaP particles were spin-coated onto titanium discs and implants; they were evaluated in cultured mouse calvarial osteoblasts, as well as after implantation in rabbit femurs. A significant dependence of CaP coatings was observed in osteoblast-related gene expression (Runx2, Col1a1 and Spp1). Specifically, the PCA group presented an up-regulation of the osteospecific genes, while the ACP group suppressed the Runx2 and Col1a1 expression when compared to blank titanium substrates. Both the ACP and PCA groups presented a more than three-fold increase of calcium deposition, as suggested by Alizarin red staining. The removal torque results implied a slight tendency in favour of the PCA group. Different forms of CaP nanostructures presented different biologic differences; the obtained information can be used to optimize surface coatings on biomaterials. (paper)

  13. Prediction of the Setting Properties of Calcium Phosphate Bone Cement

    Directory of Open Access Journals (Sweden)

    Seyed Mahmud Rabiee

    2012-01-01

    Full Text Available Setting properties of bone substitutes are improved using an injectable system. The injectable bone graft substitutes can be molded to the shape of the bone cavity and set in situ when injected. Such system is useful for surgical operation. The powder part of the injectable bone cement is included of β-tricalcium phosphate, calcium carbonate, and dicalcium phosphate and the liquid part contains poly ethylene glycol solution with different concentrations. In this way, prediction of the mechanical properties, setting times, and injectability helps to optimize the calcium phosphate bone cement properties. The objective of this study is development of three different adaptive neurofuzzy inference systems (ANFISs for estimation of compression strength, setting time, and injectability using the data generated based on experimental observations. The input parameters of models are polyethylene glycol percent and liquid/powder ratio. Comparison of the predicted values and measured data indicates that the ANFIS model has an acceptable performance to the estimation of calcium phosphate bone cement properties.

  14. Prediction of the setting properties of calcium phosphate bone cement.

    Science.gov (United States)

    Rabiee, Seyed Mahmud; Baseri, Hamid

    2012-01-01

    Setting properties of bone substitutes are improved using an injectable system. The injectable bone graft substitutes can be molded to the shape of the bone cavity and set in situ when injected. Such system is useful for surgical operation. The powder part of the injectable bone cement is included of β-tricalcium phosphate, calcium carbonate, and dicalcium phosphate and the liquid part contains poly ethylene glycol solution with different concentrations. In this way, prediction of the mechanical properties, setting times, and injectability helps to optimize the calcium phosphate bone cement properties. The objective of this study is development of three different adaptive neurofuzzy inference systems (ANFISs) for estimation of compression strength, setting time, and injectability using the data generated based on experimental observations. The input parameters of models are polyethylene glycol percent and liquid/powder ratio. Comparison of the predicted values and measured data indicates that the ANFIS model has an acceptable performance to the estimation of calcium phosphate bone cement properties. PMID:22919372

  15. The nucleation and growth of calcium phosphate crystals at protein and phosphatidylserine liposome surfaces.

    Science.gov (United States)

    Nancollas, G H; Tsortos, A; Zieba, A

    1996-01-01

    The kinetics of calcium phosphate crystal growth at the surfaces of proteins and phospholipids has been investigated using free drift and constant composition methods in supersaturated calcium phosphate solutions (relative supersaturations: with respect to hydroxyapatite, HAP, sigma HAP = 15.0, and with respect to octacalcium phosphate, OCP, sigma OCP = 1.9). Fibrinogen and collagen molecules adsorbed at hydrophobic surfaces as well as uncross-linked collagen fibrils induce ion binding and subsequent nucleation of calcium phosphate. The formation of OCP on phosphatidylserine vesicles introduced to highly supersaturated calcium phosphate solutions probably involves the interaction of the calcium ions with the ionized carboxylic groups of the phospholipid. PMID:9813627

  16. The role of polycarboxylic acids in calcium phosphate mineralization.

    Science.gov (United States)

    Tsortos, Achilles; Nancollas, George H

    2002-06-01

    The role of two polyelectrolytes, poly-L-glutamate and poly-L-aspartate, in the growth of calcium phosphate crystal phases, has been investigated at constant supersaturation. Both molecules are strong inhibitors of HAP growth when present in the solution phase but also act as hydroxyapatite and (octacalcium phosphate)-like crystal nucleators when adsorbed on germanium surfaces. The structure of the polymers in solution is presented and various adsorption models are analyzed. A "train-loop" structure of these long, flexible chain polymers on the crystal surface is consistent with all the adsorption (experimental and theoretical), inhibition, and electrophoretic mobility results. PMID:16290647

  17. Acid gelation of colloidal calcium phosphate-depleted preheated milk

    OpenAIRE

    Famelart, Marie-Hélène; Gauvin, Géraldine; Paquet, Denis; Brulé, Gérard

    2009-01-01

    Abstract – This study aimed at understanding the role of colloidal calcium phosphate (CCP) in acid gelation of milk. Milks were depleted in Calcium (Ca) by dialysis against milk permeate containing a cation-exchange resin. Dialysed milks were then heated (90 °C-10 min) and acidgelled at 42 °C with a yoghurt culture. Minerals, total and soluble protein contents, pH and optical density were measured in unheated and heated dialysed milk, together with diameters and ζ-potentials of particles. Dia...

  18. Mechanism of calcium phosphates precipitation in liquid crystals; Mecanisme de precipitation de phosphates de calcium dans des cristaux liquides

    Energy Technology Data Exchange (ETDEWEB)

    Prelot, B.; Zemb, T

    2004-04-01

    The possibility of using as a precursor an easily wet meso-porous powder would be a breakthrough in the preparation of nuclear waste storage ceramics. A concentrated solution containing ions to be stored would wet a dry powder and then, subjected to mild compression, lead to a micro-crystalline matrix of calcium phosphate at acceptable temperatures. Since no porous calcium phosphate different from calcined bone (patented) is described as porous precursor, we have compared the different synthesis routes towards meso-porous ceramics. First, we considered homogeneous precipitation of slats in water: using initially off-stoichiometry in reaction, micron-sized hydroxyapatite particles are produced with a specific surface up to 100 m{sup 2}/g. Then, we consider the classical route of precipitation of an hybrid material in the miscibility gap of a phase diagram, when an hexagonal liquid crystal is used a matrix for precipitation. The surfactant family consists in single chain surfactants containing phosphates as head-group to poison the growing surface of calcium phosphate nano-domains. Since the reaction is still too brutal, we considered using a cat-anionic precursor material of controllable surface charge. For certain concentrations and molar ratios, a new structure not yet described in surfactant precipitation literature is observed: since the periodicity is lower than twice the chain length, a disordered constant curvature monolayer (instead of the classical cylinder of twice chain length diameter) of surfactant is implied. Finally, we have investigated synthesis routes implying slow dissolution of pre-formed calcium phosphate in an already existing hexagonal matrix. For all these routes of synthesis, micro-structural determinations using SAXS, WARS and BET are performed, with a special attention to comparison of the precipitation material, the matrix obtained with all elements present, and also the material obtained after calcinations. (authors)

  19. Nanocrystalline biphasic resorbable calcium phosphate (HAp/β-TCP) thin film prepared by electron beam evaporation technique

    Energy Technology Data Exchange (ETDEWEB)

    Elayaraja, K.; Chandra, V. Sarath; Joshy, M.I. Ahymah; Suganthi, R.V. [Crystal Growth Centre, Anna University, Chennai 600025, Tamil Nadu (India); Asokan, K. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Kalkura, S. Narayana, E-mail: kalkura@yahoo.com [Crystal Growth Centre, Anna University, Chennai 600025, Tamil Nadu (India)

    2013-06-01

    Biphasic calcium phosphate (BCP) thin film having resorbable β-tricalcium phosphate (β-TCP) and non-resorbable hydroxyapatite (HAp) phases having enhanced bioactivity was synthesized by electron beam evaporation technique. Nanosized BCP was deposited as a layer (500 nm) on (0 0 1) silicon substrate by electron beam evaporation and crystalline phase of samples were found to improve on annealing at 700 °C. Uniform deposition of calcium phosphate on silicon substrate was verified from elemental mapping using scanning electron microscope (SEM-EDX). Annealing of the samples led to a decrease in surface roughness, hydrophobicity and dissolution of the coating layer. Amoxicillin loaded thin films exhibited significant bacterial resistance. In addition, BCP thin films did not exhibit any cytotoxicity. Antibiotics incorporated BCP coated implants might prevent the post-surgical infections and could promote bone-bonding of orthopedic devices.

  20. Nanocrystalline biphasic resorbable calcium phosphate (HAp/β-TCP) thin film prepared by electron beam evaporation technique

    International Nuclear Information System (INIS)

    Biphasic calcium phosphate (BCP) thin film having resorbable β-tricalcium phosphate (β-TCP) and non-resorbable hydroxyapatite (HAp) phases having enhanced bioactivity was synthesized by electron beam evaporation technique. Nanosized BCP was deposited as a layer (500 nm) on (0 0 1) silicon substrate by electron beam evaporation and crystalline phase of samples were found to improve on annealing at 700 °C. Uniform deposition of calcium phosphate on silicon substrate was verified from elemental mapping using scanning electron microscope (SEM-EDX). Annealing of the samples led to a decrease in surface roughness, hydrophobicity and dissolution of the coating layer. Amoxicillin loaded thin films exhibited significant bacterial resistance. In addition, BCP thin films did not exhibit any cytotoxicity. Antibiotics incorporated BCP coated implants might prevent the post-surgical infections and could promote bone-bonding of orthopedic devices.

  1. Improved Biocompatibility of Novel Biodegradable Scaffold Composed of Poly-L-lactic Acid and Amorphous Calcium Phosphate Nanoparticles in Porcine Coronary Artery

    OpenAIRE

    Dongsheng Gu; Gaoke Feng; Guanyang Kang; Xiaoxin Zheng; Yuying Bi; Shihang Wang; Jingyao Fan; Jinxi Xia; Zhimin Wang; Zhicheng Huo; Qun Wang; Tim Wu; Xuejun Jiang; Weiwang Gu; Jianmin Xiao

    2016-01-01

    Using poly-L-lactic acid for implantable biodegradable scaffold has potential biocompatibility issue due to its acidic degradation byproducts. We have previously reported that the addition of amorphous calcium phosphate improved poly-L-lactic acid coating biocompatibility. In the present study, poly-L-lactic acid and poly-L-lactic acid/amorphous calcium phosphate scaffolds were implanted in pig coronary arteries for 28 days. At the follow-up angiographic evaluation, no case of stent thrombosi...

  2. Aggregation of Calcium Phosphate and Oxalate Phases in the Formation of Renal Stones

    OpenAIRE

    Xie, Baoquan; Halter, Timothy J.; Borah, Ballav M.; Nancollas, George H.

    2014-01-01

    The majority of human kidney stones are comprised of multiple calcium oxalate monohydrate (COM) crystals encasing a calcium phosphate nucleus. The physiochemical mechanism of nephrolithiasis has not been well determined on the molecular level; this is crucial to the control and prevention of renal stone formation. This work investigates the role of phosphate ions on the formation of calcium oxalate stones; recent work has identified amorphous calcium phosphate (ACP) as a rapidly forming initi...

  3. Formation and thermal studies of calcium phosphate glasses

    International Nuclear Information System (INIS)

    Calcium Phosphate based glasses and glass ceramics are known for their bio- active nature. Thermal behaviour of three compositions of CaO-Na/sub 2/O-SiO/sub 2/-P/sub 2/O/sub 5/ glass system were studied. All glasses were clear and stable. Characteristic temperatures i.e. glass transition, glass softening temperature and liquids temperatures were determined by differential thermal analyzer and dilatometer. (author)

  4. Surgical Results of Lumbar Interbody Fusion Using Calcium Phosphate Cement

    OpenAIRE

    HIRASAWA, Motohiro; Mure, Hideo; Toi, Hiroyuki; Nagahiro, Shinji

    2014-01-01

    Clinical and radiological outcomes of lumbar interbody fusion using artificial fusion cages filled with calcium phosphate cements (CPCs) were retrospectively reviewed. Between 2002 and 2011, 25 patients underwent lumbar interbody fusion at Tokushima University Hospital, and 22 patients were enrolled in this study. Of these, 5 patients received autologous local bone grafts and 17 received CPC. Japan Orthopedic Association (JOA) score was used for clinical outcome assessments. Lumbar radiograph...

  5. Remineralization of Demineralized Enamel via Calcium Phosphate Nanocomposite

    OpenAIRE

    Weir, M.D.; Chow, L.C.; Xu, H.H.K.

    2012-01-01

    Secondary caries remains the main problem limiting the longevity of composite restorations. The objective of this study was to investigate the remineralization of demineralized human enamel in vitro via a nanocomposite containing nanoparticles of amorphous calcium phosphate (NACP). NACP were synthesized by a spray-drying technique and incorporated into a dental resin. First, caries-like subsurface enamel lesions were created via an acidic solution. Then, NACP nanocomposite or a commercial flu...

  6. Synthesis of hollow spherical calcium phosphate nanoparticles using polymeric nanotemplates

    International Nuclear Information System (INIS)

    Poly(methylmethacrylate)-block-poly(methacrylic acid) (PMMA-b-PMAA) copolymer was synthesized by an atom transfer radical polymerization (ATRP) technique. The block copolymer was employed as a template for the controlled precipitation of calcium phosphate from aqueous solution at different pH values. A Ca2+ ion selective electrode was used to study the interactions between Ca2+ ions and the polymer, which indicated a possible weak interaction between Ca2+ and un-ionized MAA segments at pH∼4.0 in addition to electrostatic interaction between Ca2+ and ionized MAA segments at higher pH. An interesting structure representing that of a superstructure consisting of hybrid nano-filaments was observed by the transmission electron microscope at pH∼4.0. The filaments originated from a core of similar size to primary polymer aggregates, suggesting that cooperative interactions at a local level between dissolving calcium phosphate clusters and disassembling polymer segments are responsible for the secondary growth process. A hollow spherical morphology was obtained at pH∼7.0 and 9.0. Such calcium phosphate/polymer monohybrids with complex morphologies are interesting and might be useful as novel drug delivery carriers, ceramics precursors, reinforcing fillers or biomedical implants

  7. Protein Adsorption of Calcium Phosphate Ceramics in vitro

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In order to provide valuable information for the design of new calcium phosphate bone repair materials, bone tissue engineering scaffold materials, and other clinical application, the interaction between calcium phosphate materials and proteins were investigated. The adsorption of the calcium phosphate ceramic to the protein was investigated by using FT- IR, XPS, SEM, and SDS- PAGE. As the results shown, the proteins were strongly adsorbed by the CPC, and a shift of the feature peak of the protein and also a chemical shift in the Ca2p and O1s bind energy of CPC was observed. This indicated that the acidic amino-group and alkaline amino- residue on the proteins' surface bonded to the Ca2 + in the β- TCP crystal by ionic bond and the proteins' alkaline amino groups to the oxygen in PO3-4 by hydrogen bond and electrostatic attraction. The adsorption mechanism of the protein in the CPC can be described as three ndsorption layers: irreversible chemical adsorption layer, physical adsorption layer and biomineralized adsorption layer.

  8. Characterization and biocompatibility of fluoridated biphasic calcium phosphate ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Z.L. [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China); Yu, H.Y. [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China)], E-mail: yhyang6812@tfol.com; Zeng, Q. [Institute for Nanobiomedical Technology and Membrane Biology, Sichuan University, Chengdu 610041 (China); He, H.W. [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China)

    2008-11-15

    Biphasic calcium phosphate ceramics (BCP) has been widely used in tooth and bone implants due to its excellent biocompatibility. Incorporation of fluorine ions in BCP has drawn much attention because of the beneficial role played by the fluorine ions in bone and tooth growth. The aim of this study was to obtain fluoridated biphasic calcium phosphate (FBCP) by immersing BCP into saturated ZnF{sub 2} solution with F{sup -} concentration of 3500 mg/l at different times. The phase and incorporation of fluoride into BCP were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). The biomineralization and influence of FBCP on osteoblastic behavior were evaluated and compared with that of biphasic calcium phosphate (BCP). The results exhibited that the phase evolution of the BCP was affected by the fluoride incorporation and the FBCP significantly improved the differentiation and proliferation of osteoblasts. These findings suggest that the FBCP would be very useful as a bone reconstructive material.

  9. Designing calcium phosphate-based bifunctional nanocapsules with bone-targeting properties

    Energy Technology Data Exchange (ETDEWEB)

    Khung, Yit-Lung; Bastari, Kelsen; Cho, Xing Ling; Yee, Wu Aik; Loo, Say Chye Joachim, E-mail: joachimloo@ntu.edu.sg [Nanyang Technological University, School of Materials Science and Engineering (Singapore)

    2012-06-15

    Using sodium dodecyl sulphate micelles as template, hollow-cored calcium phosphate nanocapsules were produced. The surfaces of the nanocapsule were subsequently silanised by a polyethylene glycol (PEG)-based silane with an N-hydroxysuccinimide ester end groups which permits for further attachment with bisphosphonates (BP). Characterisations of these nanocapsules were investigated using Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy, Fourier Transform Infra-Red Spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Dynamic Light Scattering. To further validate the bone-targeting potential, dentine discs were incubated with these functionalised nanocapsules. FESEM analysis showed that these surface-modified nanocapsules would bind strongly to dentine surfaces compared to non-functionalised nanocapsules. We envisage that respective components would give this construct a bifunctional attribute, whereby (1) the shell of the calcium phosphate nanocapsule would serve as biocompatible coating aiding in gradual osteoconduction, while (2) surface BP moieties, acting as targeting ligands, would provide the bone-targeting potential of these calcium phosphate nanocapsules.

  10. Calcium phosphate granulation in anaerobic treatment of black water: a new approach to phosphorus recovery

    NARCIS (Netherlands)

    Tervahauta, T.H.; Weijden, van der R.D.; Flemming, R.L.; Hernández, L.; Zeeman, G.; Buisman, C.J.N.

    2014-01-01

    Recovery of phosphorus from wastewater as calcium phosphate could diminish the need for mining of scarce phosphate rock resources. This study introduces a novel approach to phosphorus recovery by precipitation of calcium phosphate granules in anaerobic treatment of black water. The granules formed i

  11. Investigation of Wear Coefficient of Manganese Phosphate Coated Tool Steel

    Directory of Open Access Journals (Sweden)

    S. Ilaiyavel

    2013-03-01

    Full Text Available In recent years the properties of the coating in terms of wear resistance is of paramount importance in order to prevent the formation of severe damages. In this study, Wear coefficient of uncoated, Manganese Phosphate coated, Manganese Phosphate coated with oil lubricant, Heat treated Manganese Phosphate coated with oil lubricant on AISI D2 steels was investigated using Archard’s equation. The wear tests were performed in a pin on disk apparatus as per ASTM G-99 Standard. The volumetric wear loss and wear coefficient were evaluated through pin on disc test using a sliding velocity of 3.0 m/s under normal load of 40 N and controlled condition of temperature and humidity. Based on the results of the wear test, the Heat treated Manganese Phosphate with oil lubricant exhibited the lowest average wear coefficient and the lowest wear loss under 40 N load.

  12. Study of electrochemical phosphate conversion coating of metallic surfaces

    International Nuclear Information System (INIS)

    After an overview on phosphate conversion coating processes, on models of iron electrochemical dissolution, on the passivation phenomenon, and on the phosphate conversion coating treatment, this research thesis reports a detailed study of this last process. The author presents the experimental method, reports the study of this process and of passivation under constant polarization. He reports the use of various techniques and conditions: chrono-amperometry, chrono-potentiometry, cyclic volt-amperometry

  13. Calcium phosphates in Ca(2+)-fortified milk: phase identification and quantification by Raman spectroscopy.

    Science.gov (United States)

    Arifin, Martha; Swedlund, Peter J; Hemar, Yacine; McKinnon, Ian R

    2014-12-17

    Calcium phosphate nanoclusters (CPNs) are important for the structure, function, and nutrient density of many dairy products. Phosphorylated amino acids in caseins stabilize calcium phosphate as nanoclusters which are amorphous to X-ray diffraction and exist within casein micelles, and these CPNs play a key role in micelle stability. Addition of calcium to milk results in further calcium phosphate removal from the serum, and there is uncertainty about the nature of the material formed and its stability. In this work we investigate both the solution and colloidal phases in CaCl2 enriched bovine milk to identify, quantify, and determine the solubility of the calcium phosphate material formed in response to calcium addition to milk. The P-O stretching bands are quite distinct in the Raman spectra of the main synthetic calcium phosphate mineral phases, including the amorphous calcium phosphate phase. In response to adding between 5 and 40 mM CaCl2 to milk, the serum phosphate concentration decreased asymptotically from 7.5 ± 0.2 to 0.54 ± 0.05 mM. Using Raman spectroscopy with a combination of internal and external standards, it was possible to show that the calcium phosphate material formed after Ca(2+) addition to milk was the same as amorphous calcium phosphate nanoclusters present in the absence of added calcium. The use of an internal standard allowed a quantitative analysis of the spectra which demonstrated that the amorphous calcium phosphate formed accounted for all of the calcium and phosphate that was removed from solution in response to calcium addition. PMID:25414967

  14. Calcium-phosphate-osteopontin particles for caries control.

    Science.gov (United States)

    Schlafer, Sebastian; Birkedal, Henrik; Olsen, Jakob; Skovgaard, Jonas; Sutherland, Duncan S; Wejse, Peter L; Nyvad, Bente; Meyer, Rikke L

    2016-01-01

    Caries is caused by acid production in biofilms on dental surfaces. Preventing caries therefore involves control of microorganisms and/or the acid produced. Here, calcium-phosphate-osteopontin particles are presented as a new approach to caries control. The particles are made by co-precipitation and designed to bind to bacteria in biofilms, impede biofilm build-up without killing the microflora, and release phosphate ions to buffer bacterial acid production if the pH decreases below 6. Analysis of biofilm formation and pH in a five-species biofilm model for dental caries showed that treatment with particles or pure osteopontin led to less biofilm formation compared to untreated controls or biofilms treated with osteopontin-free particles. The anti-biofilm effect can thus be ascribed to osteopontin. The particles also led to a slower acidification of the biofilm after exposure to glucose, and the pH always remained above 5.5. Hence, calcium-phosphate-osteopontin particles show potential for applications in caries control. PMID:26923119

  15. Kinetics of dissolution of calcium phosphate (Ca-P bioceramics

    Directory of Open Access Journals (Sweden)

    Lukas Brazda

    2008-06-01

    Full Text Available Hydroxyapatite (HAp and β-tricalcium phosphate (β-TCP are widely used bioceramics for surgical or dental applications. This paper is dealing with dissolution kinetics of synthetically prepared β-TCP and four types of HAp granules. Two groups of HAp, treated at different temperatures, each of them with two different granule sizes, were tested. Three corrosive solutions with different pH and simulated body fluid (SBF were used for immersing of the samples. Changes in concentrations of calcium and phosphate ions, pH level and weight changes of the samples were observed. It was found that presence of TRIS buffer enhanced dissolution rate of the β-TCP approximately two times. When exposed to SBF solution, calcium phosphate (most probably hydroxyapatite precipitation predominates over β-TCP dissolution. Results from HAp samples dissolution showed some unexpected findings. Neither heat treatment nor HAp particle size made any major differences in dissolution rate of the same mass of each HAp sample.

  16. Accelerating calcium phosphate growth on NaOH-treated poly-(lactic- co-glycolic acid) by evaporation-induced surface crystallization

    Science.gov (United States)

    Duan, Ke; Tang, Allen; Wang, Rizhi

    2008-12-01

    Poly(lactic- co-glycolic acid) (PLGA) is a promising material for the regeneration of bone tissue, but its surface properties are not optimal for the application. Coating the surface of PLGA with a continuous layer of calcium phosphate is an effective approach to address the limitation. Current coating techniques for PLGA require immersion in supersaturated calcium phosphate solutions for days to weeks. In this study, we report a simple technique to accelerate the coating process to only 2 h immersion in supersaturated solutions. PLGA pellets were first treated with NaOH to increase their hydrophilicity. The NaOH-treated PLGA pellets were repeatedly dipped in a supersaturated calcium phosphate solution and dried in air. After 10 times of the dip-and-dry treatment, a layer of calcium phosphate crystallites uniformly covered the surfaces of the pellets. After the crystallite-covered pellets were immersed in the supersaturated solution for 2 h, about 5-μm thick continuous calcium phosphate coatings formed on the surfaces. The dip-and-dry technique was also applied on a variety of metals and porous structures. An evaporation-induced surface crystallization process was suggested as the mechanism for the dip-and-dry treatment.

  17. Characterization of the bone-like apatite precipitated on high velocity oxy-fuel (HVOF) sprayed calcium phosphate deposits.

    Science.gov (United States)

    Khor, K A; Li, H; Cheang, P

    2003-02-01

    Bone-like apatite was precipitated on the surface of thermal sprayed calcium phosphate coatings following in vitro incubation in a simulated body fluid. The coatings were initially deposited on titanium alloy substrates by the high velocity oxy-fuel (HVOF) spray technique. Structural characterization and mechanical evaluation of the precipitated apatite layer were conducted. Results showed that the precipitation rate was directly influenced by the local Ca(2+) concentration in the vicinity of the coating's surface and that preferential dissolution of certain phases was found to accelerate the precipitation of the bone-like apatite. The dense precipitates exhibited a competitive Young's modulus value of approximately 120GPa, which was obtained through nanoindentation. This compared favorably to the calcium phosphate matrix. Differences in microstructure at various locations within the layer resulted in altered Young's modulus and microhardness values. Precipitation mechanism investigation was carried out through a comparative experiment. Chemical analysis showed that the precipitation of bone-like apatite on the calcium phosphate coating was quite conceivably a partial diffusion-controlled process. PMID:12485795

  18. Evaluation of a porosity measurement method for wet calcium phosphate cements

    OpenAIRE

    Ajaxon, Ingrid; Maazouz, Yassine; Ginebra Molins, Maria Pau; Ohman, Caroline; Persson, Cecilia

    2015-01-01

    The porosity of a calcium phosphate cement is a key parameter as it affects several important properties of the cement. However, a successful, non-destructive porosity measurement method that does not include drying has not yet been reported for calcium phosphate cements. The aim of this study was to evaluate isopropanol solvent exchange as such a method. Two different types of calcium phosphate cements were used, one basic (hydroxyapatite) and one acidic (brushite). The cements were allowed ...

  19. Europium-doped amorphous calcium phosphate porous nanospheres: preparation and application as luminescent drug carriers

    OpenAIRE

    Zhang Kui-Hua; Mo Xiu-Mei; Chen Feng; Zhu Ying-Jie; Wu Jin; Wang Ke-Wei; Tang Qi-Li

    2011-01-01

    Abstract Calcium phosphate is the most important inorganic constituent of biological tissues, and synthetic calcium phosphate has been widely used as biomaterials. In this study, a facile method has been developed for the fabrication of amorphous calcium phosphate (ACP)/polylactide-block-monomethoxy(polyethyleneglycol) hybrid nanoparticles and ACP porous nanospheres. Europium-doping is performed to enable photoluminescence (PL) function of ACP porous nanospheres. A high specific surface area ...

  20. Preparation of Laminin-apatite-polymer Composites Using Metastable Calcium Phosphate Solutions

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A synthetic polymer with a laminin-apatite composite layer on its surface would be useful as a percutaneous device. The preparation of such a composite was attempted in the present study using poly ( ethylene terephthalate ) (PET) and polyethylene ( PE ) as the synthetic polymer. PET and PE plates and those pretreated with an oxygen plasma were alternately dipped in calcium and phosphate ion solutions, and then immersed in a metastable ealcium phosphate solution supplemented with laminin ( LCP solution ). The PET and PE plates pretreated with an oxygen plasma formed a uniform and continuous layer of a laminin- apatite composite on their surfaces. In contrast, the PET and PE plates that had not been pretreated with an oxygen plasma did not form a continuous layer of a laminin-apatite composite on their surfaces. The hydrophilic functional groups on the PET and PE surfaces introduced by the plasma treatment were responsible for the successful laminin-apatite composite coating.

  1. The Transformation of Calcium Phosphate Bioceramics in Vivo

    Institute of Scientific and Technical Information of China (English)

    DAI Hong-lian; CAO Xian-ying; LI Xiao-xi; YAN Yu-hua; LI Shi-pu

    2003-01-01

    To study the transformation process of calcium phosphate bioceramic in vivo,biodegradable porous β-tricalcium phosphate ceramics (β-TCP) were used in this experiment. The materials (φ5×8mm) were implanted in the tibia of rabbits. The β-TCP ceramics with bone tissue were retrieved and treated for histology, and then observed by using a scanning electron microscope (SEM) and an electron probe X-ray microanalyzer (EMPA) every month. The results show that β-TCP ceramics bond to bone directly,new bones are forming and maturing with materials continuous degrading,and the materials are nearly replaced by the formed bone finally.Parts of the materials were degraded,absorpted and recrystallized,the others dispersped on the cancellous bone and the Haversian lamella with an irregular arrangement incorporating in bone formation directly by remodeling structure.

  2. Initial deposition of calcium phosphate ceramic on polystyrene and polytetrafluoroethylene by rf magnetron sputtering deposition

    International Nuclear Information System (INIS)

    Calcium phosphate (CaP) coatings can be applied to improve the biological performance of polymeric medical implants. A strong interfacial bond between ceramic and polymer is required for clinical applications. Because the chemical structure of an interface plays an important role in the adhesion of a coating, we studied the formation of the interface between CaP and polystyrene (PS) and polytetrafluoroethylene (PTFE). The coating was deposited in a radio frequency (rf) magnetron sputtering deposition system. Prior to the deposition, some samples received an oxygen plasma pretreatment. We found that the two substrates show a strongly different reactivity towards CaP. On PS a phosphorus and oxygen enrichment is present at the interface. This is understood from POx complexes that are able to bind to the PS. The effects of the plasma pretreatment are overruled by the deposition process itself. On PTFE, a calcium enrichment and an absence of phosphorus is found at the interface. The former is the result of CaF2-like material being formed at the interface. The latter may be the result of phosphorus reacting with escaping fluorine to a PF3 molecule, which than escapes from the material as a gas molecule. We found that the final structure of the interface is mostly controlled by the bombardment of energetic particles escaping either from the plasma or from the sputtering target. The work described here can be used to understand and improve the adhesion of CaP coatings deposited on medical substrates

  3. Interactions of casein micelles with calcium phosphate particles.

    Science.gov (United States)

    Tercinier, Lucile; Ye, Aiqian; Anema, Skelte G; Singh, Anne; Singh, Harjinder

    2014-06-25

    Insoluble calcium phosphate particles, such as hydroxyapatite (HA), are often used in calcium-fortified milks as they are considered to be chemically unreactive. However, this study showed that there was an interaction between the casein micelles in milk and HA particles. The caseins in milk were shown to bind to the HA particles, with the relative proportions of bound β-casein, αS-casein, and κ-casein different from the proportions of the individual caseins present in milk. Transmission electron microscopy showed no evidence of intact casein micelles on the surface of the HA particles, which suggested that the casein micelles dissociated either before or during binding. The HA particles behaved as ion chelators, with the ability to bind the ions contained in the milk serum phase. Consequently, the depletion of the serum minerals disrupted the milk mineral equilibrium, resulting in dissociation of the casein micelles in milk. PMID:24896851

  4. Macrophage and osteoblast responses to biphasic calcium phosphate microparticles.

    Science.gov (United States)

    Fellah, Borhane Hakim; Delorme, Bruno; Sohier, Jérôme; Magne, David; Hardouin, Pierre; Layrolle, Pierre

    2010-06-15

    The aim of this work was to investigate in vitro the biological events leading to ectopic bone formation in contact with microporous biphasic calcium phosphate (BCP) ceramics. After implantation, microparticles may arise from their degradation and induce an inflammatory response involving macrophages. The secretion of pro-inflammatory cytokines may affect the differentiation of osteoblasts. Mouse macrophage-like (J774) and osteoblast-like (MC3T3-E1) cells were cultured in the presence of BCP microparticles of different sizes (response initiated by BCP microparticles may have both detrimental and beneficial effects on osteogenesis. PMID:20014296

  5. New developments in calcium phosphate bone cements: approaching spinal applications

    OpenAIRE

    Vlad, Maria Daniela

    2009-01-01

    La presente tesis doctoral (i.e., “New developments in calcium phosphate bone cements: approaching spinal applications”) aporta nuevos conocimientos en el campo de los cementos óseos de fosfato de calcio (CPBCs) en relación a su aplicación clínica en el campo de la cirugía vertebral mínimamente invasiva. La hipótesis central de esta investigación fue formulada en los siguientes términos: “Los cementos apatíticos pueden ser (si se optimizan) una alternativa mejor (debido a sus propiedades d...

  6. Mesoscale crystallization of calcium phosphate nanostructures in protein (casein) micelles

    Science.gov (United States)

    Thachepan, Surachai; Li, Mei; Mann, Stephen

    2010-11-01

    Aqueous micelles of the multi-protein calcium phosphate complex, casein, were treated at 60 °C and pH 7 over several months. Although partial dissociation of the micelles into 12 nm sized amorphous calcium phosphate (ACP)/protein nanoparticles occurred within a period of 14 days, crystallization of the ACP nanoclusters into bundles of hydroxyapatite (HAP) nanofilaments was not observed until after 12 weeks. The HAP nanofilaments were formed specifically within the partially disrupted protein micelles suggesting a micelle-mediated pathway of mesoscale crystallization. Similar experiments using ACP-containing synthetic micelles prepared from β-casein protein alone indicated that co-aligned bundles of HAP nanofilaments were produced within the protein micelle interior after 24 hours at temperatures as low as 35 °C. The presence of Mg2+ ions in the casein micelles, as well as a possible synergistic effect associated with the multi-protein nature of the native aggregates, could account for the marked inhibition in mesoscale crystallization observed in the casein micelles compared with the single-component β-casein constructs.Aqueous micelles of the multi-protein calcium phosphate complex, casein, were treated at 60 °C and pH 7 over several months. Although partial dissociation of the micelles into 12 nm sized amorphous calcium phosphate (ACP)/protein nanoparticles occurred within a period of 14 days, crystallization of the ACP nanoclusters into bundles of hydroxyapatite (HAP) nanofilaments was not observed until after 12 weeks. The HAP nanofilaments were formed specifically within the partially disrupted protein micelles suggesting a micelle-mediated pathway of mesoscale crystallization. Similar experiments using ACP-containing synthetic micelles prepared from β-casein protein alone indicated that co-aligned bundles of HAP nanofilaments were produced within the protein micelle interior after 24 hours at temperatures as low as 35 °C. The presence of Mg2+ ions in

  7. Physicochemical characterization of zinc-substituted calcium phosphates

    Indian Academy of Sciences (India)

    DOROTA WALCZYK; DAGMARA MALINA; MILENA KRÓL; KLAUDIA PLUTA; AGNIESZKA SOBCZAK-KUPIEC

    2016-04-01

    Biocompatible and bioactive calcium phosphates can make chemical bonds with living bones. Improvement of their biological and physicochemical properties can be achieved by doping with various ions that are presented in natural apatites of bones. These substitutions influence lattice parameters, structure and morphology of apatites. In recent times great attention has been devoted to zinc ions that are the second most abundant trace element present in bones. Zinc embedded into calcium phosphate may enhance the bone formation and in addition exhibits antifungal and antibacterial properties. Therefore, it is rational to form structures incorporated with this ion. In this paper the incorporation of the Zn ions into natural and synthetic calcium phosphates has been reported.Natural hydroxyapatites (HAs) applied in this study were derived mainly from pork bones whereas both brushite and synthetic were formed using wet chemical methods. Ambient temperature synthesis leads to the formation ofbrushite, whereas the process performed at elevated temperature gives HA. Subsequently, attained structures were modified with Zn ions by using in situ or sorption procedures. Phase composition and morphology of obtained materials were determined by means of X-ray diffractometry, Fourier transform infrared spectroscopy and scanning electron microscopy equipped with energy-dispersive spectroscopy. Introduced XRD patterns depict changes of the crystallinity of HA with the increase in the amount of embedded zinc ions. On the contrary, no changes of the crystallinity were observed for the brushite doped with Zn ions. Morphology of attained powders, visualized using scanningelectron microscopy exemplified structural changes between calcium phosphates conjugated with zinc ions. Many authors report that the addition of small amounts of Zn ions leads to loss of crystallinity and decrease of lattice parameters. Interestingly, upon addition of Zn ions to the natural and synthetic HAp by sorption

  8. Poly(ethylene imine)-controlled Calcium Phosphate mineralization

    OpenAIRE

    Shkilnyy, Andriy; Friedrich, Alwin; Tiersch, Brigitte; Schöne, Stefanie; Fechner, Mabya; Koetz, Joachim; Schläpfer, Carl-Wilhelm; Taubert, Andreas

    2008-01-01

    The current paper shows that poly(ethylene imine) (PEI) is an efficient template for the fabrication of spherical calcium phosphate (CaP)/polymer hybrid particles at pH values above 8. The polymer forms spherical entities, which contain one or a few CaP particles with diameters of ca. 6 nm. The samples contain up to 20 wt % polymer, which appears to be wrapped around the small CaP particles. The particles form via a mineralization-trapping pathway, where at the beginning of the precipitation ...

  9. Hemolysis effect and calcium-phosphate precipitation of heat-organic-film treated magnesium

    Institute of Scientific and Technical Information of China (English)

    GAO Jia-cheng; QIAO Li-ying; LI Long-chuan; WANG Yong

    2006-01-01

    A heat-organic-films process was employed to induce calcium-phosphate apatites formation on magnesium, consequently the corrosion resistance and hemolysis properties of magnesium were improved for biomedical applications. Firstly, magnesium samples were heat-treated at 773 K for 10 h; secondly, stearic acid films were coated on the surface of the heat-treated magnesium.Then the surface modified magnesium was soaked in simulated body fluid (SBF) to test its corrosion resistance. The results show that the heat treatment process allows magnesium to form a dense oxide layer with a thickness of around 20 μm, thereby the surface modified magnesium has higher corrosion resistance. After 24 h in SBF island apatite was deposited on magnesium. The unevenly precipitates were characterized by XRD and FTIR as the mixture of hydroxyapatite(HA) and octacalcium phosphate(OCP). The preliminary hemolysis experiment indicates that untreated magnesium has hemolytic effect (about 60%); whereas the heat-organic film treated samples has no hemolytic effect. The mechanism of fast nucleation and growth of calcium-phosphate apatites on surface modified magnesium in SBF was also discussed.

  10. Calcium phosphate nanoparticles-based systems for siRNA delivery.

    Science.gov (United States)

    Xu, Xiaochun; Li, Zehao; Zhao, Xueqin; Keen, Lawrence; Kong, Xiangdong

    2016-09-01

    Despite the enormous therapeutic potential of siRNA as a treatment strategy, the delivery is still a problem due to unfavorable biodistribution profiles and poor intracellular bioavailability. Calcium phosphate (CaP) co-precipitate has been used for nearly 40 years for in vitro transfection due to its non-toxic nature and simplicity of preparation. The surface charge of CaP will be tuned into positive by surface modification, which is important for siRNA loading and crossing cell membrane without enzymatic degradation. The new siRNA carrier system will also promote the siRNA escape from lysosome to achieve siRNA sustained delivery and high-efficiency silence. In this review, we focus on the current research activity in the development of CaP nanoparticles for siRNA delivery. These nanoparticles are mainly classified into lipid coated, polymer coated and various other types for discussion. PMID:27252888

  11. Conversion coatings prepared or treated with calcium hydroxide solutions

    Science.gov (United States)

    Minevski, Zoran (Inventor); Clarke, Eric (Inventor); Maxey, Jason (Inventor); Nelson, Carl (Inventor); Eylem, Cahit (Inventor)

    2002-01-01

    A conversion coating process that forms a stable and corrosion-resistant oxide layer on metal or metal oxide substrates or layers. Particularly, the conversion coating process involves contacting the metal or metal oxide substrate or layer with the aqueous calcium hydroxide solutions in order to convert the surface of the substrate to a stable metal oxide layer or coating. According to the present invention, the calcium hydroxide solution is prepared by removing carbon dioxide from water or an aqueous solution before introducing the calcium hydroxide. In this manner, formation of calcium carbonate particles is avoided and the porosity of the conversion coating produced by the calcium hydroxide solution is reduced to below about 1%.

  12. Structure and properties of gadolinium loaded calcium phosphate glasses

    International Nuclear Information System (INIS)

    The glass samples with composition xGd2O3–(50 − x)CaO–50P2O5 (0 ⩽ x ⩽ 9 mol%) were prepared by the conventional melt quench method. The structure and properties of gadolinium loaded in calcium phosphate glasses were investigated using XRD, SEM, DTA, IR and Raman spectroscopy. The XRD and SEM analysis for the samples show that the majority of samples are amorphous, and crystallization occurs when the content of Gd2O3 containing is up to 6 mol%. Two main crystalline phases, Ca2P2O7 and Gd3(P2O7)3, are embedded in an amorphous matrix. IR and Raman data indicate that glass structure consists of predominantly metaphosphate (Q2) units and the depolymerization of phosphate network with the addition of Gd2O3. Both the chemical durability and the glass transition temperature (Tg) are improved with the increase of Gd2O3, which suggests that the Gd acts a role of strengthening the cross-links between the phosphate chains of the glass

  13. On the development of an apatitic calcium phosphate bone cement

    Indian Academy of Sciences (India)

    Manoj Komath; H K Varma; R Sivakumar

    2000-04-01

    Development of an apatitic calcium phosphate bone cement is reported. 100 Particles of tetracalcium phosphate (TTCP) and dicalcium phosphate dihydrate (DCPD) were mixed in equimolar ratio to form the cement powder. The wetting medium used was distilled water with Na2HPO4 as accelerator to manipulate the setting time. The cement powder, on wetting with the medium, formed a workable putty. The setting times of the putty were measured using a Vicat type apparatus and the compressive strength was determined with a Universal Testing Machine. The nature of the precipitated cement was analyzed through X-ray diffraction (XRD), fourier transform infrared spectrometry (FTIR) and energy dispersive electron microprobe (EDAX). The results showed the phase to be apatitic with a calcium–to–phosphorous ratio close to that of hydroxyapatite. The microstructure analysis using scanning electron microscopy (SEM) showed hydroxyapatite nanocrystallite growth over particulate matrix surface. The structure has an apparent porosity of ∼ 52%. There were no appreciable dimensional or thermal changes during setting. The cement passed the in vitro toxicological screening (cytotoxicity and haemolysis) tests. Optimization of the cement was done by manipulating the accelerator concentration so that the setting time, hardening time and the compressive strength had clinically relevant values.

  14. The increasing of enamel calcium level after casein phosphopeptideamorphous calcium phosphate covering

    Directory of Open Access Journals (Sweden)

    Widyasri Prananingrum

    2012-06-01

    Full Text Available Background: Caries process is characterized by the presence of demineralization. Demineralization is caused by organic acids as a result of carbohydrate substrate fermentation. Remineralization is a natural repair process for non-cavitated lesions. Remineralization occurs if there are Ca2+ and PO43- ions in sufficient quantities. Casein-amorphous calcium phosphate phosphopeptide (CPP-ACP is a paste material containing milk protein (casein, that actually contains minerals, such as calcium and phosphate. The casein ability to stabilize calcium phosphate and enhance mineral solubility and bioavailability confers upon CPP potential to be biological delivery vehicles for calcium and phosphate. Purpose: The aim of this study was to determine the calcium levels in tooth enamel after being covered with CPP-ACP 2 times a day for 3, 14 and 28 days. Methods: Sample were bovine incisors of 3 year old cows divided into 4 groups, namely group I as control group, group II, III and IV as treatment groups covered with CPP-ACP 2 times a day. All of those teeth were then immersed in artificial saliva. Group II was immersed for 3 days, while group III was immersed for 14 days, and group IV was immersed for 28 days. One drop of CPP-ACP was used to cover the entire labial surface of teeth. The measurement of the calcium levels was then conducted by using titration method. All data were analyzed by One- Way ANOVA test with 5% degree of confidence. Results: The results showed significant difference of the calcium levels in tooth enamel of those groups after covered with CPP-ACP 2 times a day for 3, 14 and 28 days (p = 0.001. There is also significant difference of the calcium levels in tooth enamel of those treatment groups and the control group (p = 0.001. Conclusion: The calcium levels of tooth enamel are increased after covered with CPP-ACP 2 times a day for 3, 14 and 28 days.Latar belakang: Proses terjadinya karies gigi ditandai oleh adanya demineralisasi

  15. Effect of Fluoride, Casein Phosphopeptide–Amorphous Calcium Phosphate and Casein Phosphopeptide–Amorphous Calcium Phosphate Fluoride on Enamel Surface Microhardness After Microabrasion: An In Vitro Study

    OpenAIRE

    Ghazaleh Ahmadi Zenouz; Fariba Ezoji; Seyede Anese Enderami; Soraya Khafri

    2016-01-01

    Objectives: This study aimed to assess the effect of applying casein phosphopeptide–amorphous calcium phosphate (CPP-ACP) paste, casein phosphopeptide–amorphous calcium phosphate fluoride (CPP-ACPF) paste and sodium fluoride gel on surface microhardness of enamel after microabrasion.Materials and Methods: Thirty freshly extracted human premolars were selected. All samples were subjected to hardness indentations made with the Vickers hardness machine and the average value was recorded as the i...

  16. The flame photometric determination of calcium in phosphate, carbonate, and silicate rocks

    Science.gov (United States)

    Kramer, H.

    1957-01-01

    A flame photometric method of determining calcium in phosphate, carbonate, and silicate locks has been developed Aluminum and phosphate interference was overcome by the addition of a large excess of magnesium. The method is rapid and suitable for routine analysis Results obtained are within ?? 2% of the calcium oxide content. ?? 1957.

  17. Cytotoxicity, calcium release, and pH changes generated by novel calcium phosphate cement formulations.

    Science.gov (United States)

    Khashaba, Rania M; Lockwood, Petra E; Lewis, Jill B; Messer, Regina L; Chutkan, Norman B; Borke, James L

    2010-05-01

    Few published studies describe the biological properties of calcium phosphate cements (CPCs) for dental applications. We measured several biologically relevant properties of 3 CPCs over an extended (8 wk) interval. Monocalcium phosphate, calcium oxide, and synthetic hydroxyapatite were combined with either modified polyacrylic acid, light-activated modified polyalkenoic acid, or 35% w/w polymethyl vinyl ether maleic acid to obtain Types I, II, and III CPCs, respectively. Set cements were placed in direct contact with L929 fibroblasts for up to 8 weeks. Media Ca(+2) and pH were determined by atomic absorption spectroscopy and pH electrode respectively. Cell mitochondrial function was measured by MTT assay. Type I cements suppressed mitochondrial activity > 90% (vs. Teflon controls), but significantly (p 90% at all times. Type III cements elevated mitochondrial activity significantly after 7 wks. The pH profiles approached neutrality by 24 h, and all cements released calcium into the storage medium at all periods (24 h - 8 wk). We concluded that several types of cements had long-term biological profiles that show promise for dental applications. PMID:20235188

  18. Augmentation of Pedicle Screw Fixation with Calcium Phosphate Cement

    Institute of Scientific and Technical Information of China (English)

    YANG Shu-hua; FU De-hao; LI Jin; XU Wei-hua; YANG Cao; YE Zhe-wei; ZUO Xiao-yan

    2004-01-01

    To determine whether a biodegradable calcium phosphate cement(CPC) provides significant augmentation of pedicle screw fixation or not,an in vitro biomechanical study was carried out to evaluate the biomechanical effect of CPC in the restoration and augmentation of pedicle screw fixation.Axial pullout test and cyclic bending resistance test were employed in the experiment,and polymethylmethacrylate (PMMA) was chosen as control.The results demonstrate that the pullout strengths following CPC restoration and augmentation are 74% greater on an average than those of the control group,but less than those of PMMA restoration group and augmentation group respectively (increased by 126% versus control).In cyclic bending resistance test,the CPC augmented screws are found to withstand a greater number of cycles or greater loading with less displacement before loosening,but the augmentation effect of PMMA is greater than that of CPC.

  19. ANTICORROSION PROPERTIES OF ORGANIC COATINGS CONTAINING POLYPHENYLENEDIAMINE PHOSPHATE

    OpenAIRE

    Miroslav Kohl; Andréa Kalendová

    2015-01-01

    The present work was aimed at the synthesis of polyphenylenediamine, its description and determination of parameters whose knowledge is required for the formulation of organic coatings pigmented with this compound. Polyphenylenediamine phosphate was prepared by oxidation polymerization in acidic environment. Phosphoric acid was used as the doping acid. Based on the results, pigmented organic coatings containing polyphenylenediamine at volume concentrations of 0%, 0.5%, 1%, 3%; 5%, and 10% wer...

  20. Characterization of a calcium phosphate cement based on alpha-tricalcium phosphate obtained by wet precipitation process

    International Nuclear Information System (INIS)

    There are several systems of calcium phosphate cements being studied. Those based on alpha-tricalcium phosphate are of particular interest. After setting they produce calcium deficient hydroxyapatite similar to bone like hydroxyapatite. This work aims to obtain alpha-tricalcium phosphate powders by the wet precipitation process, using calcium nitrate and phosphoric acid as reagents. This powder was characterized by infrared spectroscopy, X-ray diffraction and particle size distribution. In order to prepare the calcium phosphate cement, the powder was mixed with an accelerator in an aqueous solution. The mechanical properties of the cement were assessed and it was evaluated by means of apparent density, X-ray diffraction and scanning electron microscopy. The described method produced crystalline alpha-tricalcium phosphate as the major phase. The calcium phosphate cement showed high values of compression strength (50 MPa). The soaking of the cement in a simulated body fluid (SBF) formed a layer of hydroxyapatite like crystals in the surface of the samples. (author)

  1. The thermophysical properties of calcium and barium zirconium phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Gregg, Daniel J., E-mail: daniel.gregg@ansto.gov.au; Karatchevtseva, Inna; Triani, Gerry; Lumpkin, Gregory R.; Vance, Eric R.

    2013-10-15

    The thermophysical and structural properties of calcium and barium zirconium phosphate ceramics (CZP and BZP) have been investigated for their potential candidacy as actinide hosts for inert matrix fuels (IMF) in nuclear reactors. These phosphate ceramics, which can accommodate minor actinides as well as the resulting fission products, are found to be thermally stable to 1600 °C in air, however they begin to decompose in an inert atmosphere above approximately 1400 °C. The heat capacity, thermal conductivity and bulk thermal-expansion were measured from room temperature up to 1200 °C. Structural changes in this temperature region as well as the anisotropic thermal-expansion behaviour were studied using high-temperature X-ray diffraction. A phase change from R-3 to R-3c was identified for Ba{sub 0.5}Zr{sub 2}(PO{sub 4}){sub 3} near 880 °C. The thermal conductivity for these ceramics at 1000 °C was found to be 1.0 W m{sup −1} K{sup −1}, a relatively low thermal conductivity that was increased to 5.0 W m{sup −1} K{sup −1} at 1000 °C for BZP:Ni (25:75 mass ratio) cermet composites.

  2. Calcium phosphate nanoparticles functionalized with a dimethacrylate monomer

    International Nuclear Information System (INIS)

    The synthesis of calcium phosphate nanoparticles may include modifying agents to tailor particle size, reduce agglomeration and add specific functionalities. This study describes the synthesis of dicalcium phosphate dihydrate (DCPD) nanoparticles functionalized with triethylene glycol dimethacrylate (TEGDMA), added to one of the reacting solutions, with the purpose of reducing agglomeration and improving the compatibility with vinyl-based resin matrices. The nanoparticles were characterized by X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FTIR), elemental analysis, thermogravimetric analysis (TGA), transmission electronic microscopy (TEM), dynamic light scattering (DLS), and surface area (BET). As controls, proprietary DCPD nanoparticles and nanoparticles synthesized without the addition of TEGDMA (“bare”) were subjected to the same analytical methods. XRD revealed a similar crystalline structure of the synthesized materials in comparison to the proprietary nanoparticles. The presence of a TEGDMA layer was confirmed by elemental analysis and TGA, corresponding to a mass fraction of 8.5%. FTIR analysis of the functionalized nanoparticles revealed the suppression of some absorbance bands found in the neat TEGDMA. A chemisorption mechanism between TEGDMA and the surface of primary particles by ion–dipole interaction involving TEGDMA oxyethylene, and also an interaction mechanism between the particle surface and terminal-CH3 groups are proposed. Functionalized nanoparticles showed 3 to 11 times higher surface area than the controls, in agreement with DLS data, indicating lower agglomeration. - Highlights: • Dicalcium phosphate (DCPD) nanoparticles were functionalized ab initio using TEGDMA. • Triethylene glycol dimethacrylate was chosen due to its polymerizable vinyl groups. • These nanoparticles would have a better interaction with dimethacrylate resins. • An ion–dipole chemisorption mechanism between DCPD and TEGDMA is described

  3. Silver-Doped Calcium Phosphate Bone Cements with Antibacterial Properties

    Science.gov (United States)

    Rau, J. V.; Fosca, M.; Graziani, V.; Egorov, A. A.; Zobkov, Yu. V.; Fedotov, A. Yu.; Ortenzi, M.; Caminiti, R.; Baranchikov, A. E.; Komlev, V. S.

    2016-01-01

    Calcium phosphate bone cements (CPCs) with antibacterial properties are demanded for clinical applications. In this study, we demonstrated the use of a relatively simple processing route based on preparation of silver-doped CPCs (CPCs-Ag) through the preparation of solid dispersed active powder phase. Real-time monitoring of structural transformations and kinetics of several CPCs-Ag formulations (Ag = 0 wt %, 0.6 wt % and 1.0 wt %) was performed by the Energy Dispersive X-ray Diffraction technique. The partial conversion of β-tricalcium phosphate (TCP) phase into the dicalcium phosphate dihydrate (DCPD) took place in all the investigated cement systems. In the pristine cement powders, Ag in its metallic form was found, whereas for CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, CaAg(PO3)3 was detected and Ag (met.) was no longer present. The CPC-Ag 0 wt % cement exhibited a compressive strength of 6.5 ± 1.0 MPa, whereas for the doped cements (CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt %) the reduced values of the compressive strength 4.0 ± 1.0 and 1.5 ± 1.0 MPa, respectively, were detected. Silver-ion release from CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, measured by the Atomic Emission Spectroscopy, corresponds to the average values of 25 µg/L and 43 µg/L, respectively, rising a plateau after 15 days. The results of the antibacterial test proved the inhibitory effect towards pathogenic Escherichia coli for both CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, better performances being observed for the cement with a higher Ag-content. PMID:27096874

  4. Investigating calcium polyphosphate addition to a conventional calcium phosphate cement for bone-interfacing applications

    Science.gov (United States)

    Krausher, Jennifer Lynn

    Calcium phosphate cements (CPCs) are of great interest in bone regeneration applications because of their biocompatibility and osteoconductivity, and as delivery vehicles for therapeutics; however, delivery applications have been limited by adverse interactions between therapeutics and the cement setting reaction. Amorphous calcium polyphosphate (CPP) yields a biodegradable material with a demonstrated drug delivery capacity following appropriate processing. The incorporation of drug-loaded CPP into a CPC is under consideration as a method of minimizing adverse interactions and extending drug release. This thesis represents the first investigation into the effects of CPP addition on the properties, setting and antibiotic release profile of a conventional apatitic calcium phosphate cement. As-made, gelled and vancomycin-loaded CPP particulate were added to the powder component of a conventional dicalcium phosphate/tetracalcium phosphate CPC. The setting behaviour, set properties and microstructure of the resulting CPP-CPCs were evaluated with setting time testing (Gilmore needle method), pH testing, mechanical testing, SEM imaging, XRD and FTIR analysis. In vitro degradation and elution behaviour were evaluated by monitoring calcium release (atomic absorbance spectroscopy), mechanical strength and vancomycin release (UV-visual spectrophotometry). CPP addition was found to increase the setting time, reduce the mechanical strength and inhibit the conversion of the CPC starting powders to the set apatitic phase. The most likely mechanism for the observed effect of CPP addition was the adsorption of polyphosphate chains on the particle surfaces, which would inhibit the dissolution of the starting powders and the conversion of apatite precursor phases to apatite, leading to reduced mechanical properties. The detrimental effects of CPP were reduced by limiting the CPP fraction to less than a few weight per cent and increasing the size of the CPP particulate. CPP

  5. Precipitation of calcium carbonate and calcium phosphate under diffusion controlled mixing

    Energy Technology Data Exchange (ETDEWEB)

    Tsigabu Gebrehiwet; James R. Henriksen; Luanjing Guo; Don T. Fox; Hai Huang; Lee Tu; Yoshiko Fujita; Robert W. Smith; George Redden

    2014-07-01

    Multi-component mineral precipitation in porous, subsurface environments is challenging to simulate or engineer when in situ reactant mixing is controlled by diffusion. In contrast to well-mixed systems, the conditions that favor mineral precipitation in porous media are distributed along chemical gradients, which evolve spatially due to concurrent mineral precipitation and modification of solute transport in the media. The resulting physical and chemical characteristics of a mixing/precipitation zone are a consequence of coupling between transport and chemical processes, and the distinctive properties of individual chemical systems. We examined the spatial distribution of precipitates formed in “double diffusion” columns for two chemical systems, calcium carbonate and calcium phosphate. Polyacrylamide hydrogel was used as a low permeability, high porosity medium to maximize diffusive mixing and minimize pressure- and density-driven flow between reactant solutions. In the calcium phosphate system, multiple, visually dense and narrow bands of precipitates were observed that were reminiscent of previously reported Liesegang patterns. In the calcium carbonate system, wider precipitation zones characterized by more sparse distributions of precipitates and a more open channel structure were observed. In both cases, formation of precipitates inhibited, but did not necessarily eliminate, continued transport and mixing of the reactants. A reactive transport model with fully implicit coupling between diffusion, chemical speciation and precipitation kinetics, but where explicit details of nucleation processes were neglected, was able to qualitatively simulate properties of the precipitation zones. The results help to illustrate how changes in the physical properties of a precipitation zone depend on coupling between diffusion-controlled reactant mixing and chemistry-specific details of precipitation kinetics.

  6. Bond strength of plasma sprayed ceramic coatings on phosphate steels

    Czech Academy of Sciences Publication Activity Database

    Pokorný, P.; Mastný, L.; Sýkora, V.; Pala, Zdeněk; Brožek, Vlastimil

    2015-01-01

    Roč. 54, č. 2 (2015), s. 411-414. ISSN 0543-5846 R&D Projects: GA ČR(CZ) GAP108/12/1872 Institutional support: RVO:61389021 Keywords : phosphating * plasma spraying * ceramic coatings * corrosion * bond strength Subject RIV: CA - Inorganic Chemistry Impact factor: 0.959, year: 2014

  7. Calcium phosphate granulation in anaerobic treatment of black water: a new approach to phosphorus recovery.

    Science.gov (United States)

    Tervahauta, Taina; van der Weijden, Renata D; Flemming, Roberta L; Hernández Leal, Lucía; Zeeman, Grietje; Buisman, Cees J N

    2014-01-01

    Recovery of phosphorus from wastewater as calcium phosphate could diminish the need for mining of scarce phosphate rock resources. This study introduces a novel approach to phosphorus recovery by precipitation of calcium phosphate granules in anaerobic treatment of black water. The granules formed in the Upflow Anaerobic Sludge Blanket (UASB) reactor at lab- and demonstration-scale were analyzed for chemical composition and mineralogy by Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES), Electron microprobe (EMP), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and micro X-ray Diffraction (XRD). The granules had a diameter of 1-2 mm, organic content of 33 wt%, and phosphorus content of 11-13 wt%. Three calcium phosphate phases were identified in the granules: hydroxyapatite, calcium phosphate hydrate and carbonated hydroxyapatite. Without any addition of chemicals, 7 gP/person/year can be recovered with the calcium phosphate granules, representing 2% of the incoming phosphorus in the UASB reactor. As the heavy metal content was lower compared to other phosphorus recovery products, phosphate rock and phosphorus fertilizer, the calcium phosphate granules could be considered as a new phosphorus product. PMID:24183558

  8. Effects of calcium-phosphate topography on osteoblast mechanobiology determined using a cytodetacher

    International Nuclear Information System (INIS)

    The Human fetal osteoblast (hFOB) cell morphology, adhesion force, and proliferation on a calcium-phosphate (Ca-P) micropattern surface were investigated and the mechanobiology was investigated by a cytodetachment test. Ca-P-coated groove patterns with 3.0-μm-deep grooves (C3), 4.5-μm-deep grooves (C4), and 5.5-μm-deep grooves (C5) were produced on silicon wafers using photolithography and wet etching techniques. The grooved substrates were coated with a 200-nm-thick layer of titanium (bond coat) and a 200-nm-thick layer of calcium phosphate (top coat) using a sputtering system. Smooth Ca-P-coated Si wafers were used as control surfaces. Analysis of the scanning electron microscopy observations shows that cells on the Ca-P micropattern showed spreading and elongation. The MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay indicated that C3 and C4 specimens had a significantly higher number of cells than did the control group after 5- and 15-day cultures. The cyto-compatibility of specimens was quantitatively evaluated using a cytodetacher, which directly measures the detachment shear force of an individual cell to the substrate. After 30-min culture, the cell adhesion forces were 38.4 nN for the smooth specimen, 140.8 nN for C3, 124.2 nN for C4, and 67.1 nN for C5. The results indicate that the cell adhesion force is influenced by cell shape and the Ca-P grooved patterns affect the cell shape and cytoskeletal structure, thus influence cell proliferation and cell adhesion force. The cytodetachment test with nanonewton resolution is a sensitive method for studying cell–biomaterial interaction. - Highlights: ► We fabricate different sizes of bioceramic groove surfaces which control the cell physiology. ► The mechanobiology was investigated by a cytodetachment test. ► The narrow size Ca-P micropatterns have better biocompatibility. ► The cytodetachment test with nanonewton resolution is a sensitive method for studying cell

  9. Effects of calcium-phosphate topography on osteoblast mechanobiology determined using a cytodetacher

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shih-Ping [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Yang, Chyun-Yu [Department of Orthopedics, National Cheng Kung University, Tainan 701, Taiwan (China); Lee, Tzer-Min, E-mail: tmlee@mail.ncku.edu.tw [Institute of Oral Medicine, National Cheng Kung University, Tainan 701, Taiwan (China); Lui, Truan-Sheng [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China)

    2012-02-01

    The Human fetal osteoblast (hFOB) cell morphology, adhesion force, and proliferation on a calcium-phosphate (Ca-P) micropattern surface were investigated and the mechanobiology was investigated by a cytodetachment test. Ca-P-coated groove patterns with 3.0-{mu}m-deep grooves (C3), 4.5-{mu}m-deep grooves (C4), and 5.5-{mu}m-deep grooves (C5) were produced on silicon wafers using photolithography and wet etching techniques. The grooved substrates were coated with a 200-nm-thick layer of titanium (bond coat) and a 200-nm-thick layer of calcium phosphate (top coat) using a sputtering system. Smooth Ca-P-coated Si wafers were used as control surfaces. Analysis of the scanning electron microscopy observations shows that cells on the Ca-P micropattern showed spreading and elongation. The MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay indicated that C3 and C4 specimens had a significantly higher number of cells than did the control group after 5- and 15-day cultures. The cyto-compatibility of specimens was quantitatively evaluated using a cytodetacher, which directly measures the detachment shear force of an individual cell to the substrate. After 30-min culture, the cell adhesion forces were 38.4 nN for the smooth specimen, 140.8 nN for C3, 124.2 nN for C4, and 67.1 nN for C5. The results indicate that the cell adhesion force is influenced by cell shape and the Ca-P grooved patterns affect the cell shape and cytoskeletal structure, thus influence cell proliferation and cell adhesion force. The cytodetachment test with nanonewton resolution is a sensitive method for studying cell-biomaterial interaction. - Highlights: Black-Right-Pointing-Pointer We fabricate different sizes of bioceramic groove surfaces which control the cell physiology. Black-Right-Pointing-Pointer The mechanobiology was investigated by a cytodetachment test. Black-Right-Pointing-Pointer The narrow size Ca-P micropatterns have better biocompatibility. Black

  10. Nano zinc phosphate coatings for enhanced corrosion resistance of mild steel

    International Nuclear Information System (INIS)

    Highlights: • Nano zinc phosphate coating on mild steel was developed. • Nano zinc phosphate coatings on mild steel showed enhanced corrosion resistance. • The nano ZnO increases the number of nucleating sites for phosphating. • Faster attainment of steady state during nano zinc phosphating. - Abstract: Nano crystalline zinc phosphate coatings were developed on mild steel surface using nano zinc oxide particles. The chemical composition and morphology of the coatings were analyzed by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The particles size of the nano zinc phosphate coating developed was also characterized by TEM analysis. Potentiodynamic polarization and electrochemical impedance studies were carried out in 3.5% NaCl solution. Significant variations in the coating weight, morphology and corrosion resistance were observed as nano ZnO concentrations were varied from 0.25 to 2 g/L in the phosphating baths. The results showed that nano ZnO particles in the phosphating solution yielded phosphate coatings of higher coating weight, greater surface coverage and enhanced corrosion resistance than the normal zinc phosphate coatings (developed using normal ZnO particles in the phosphating baths). Better corrosion resistance was observed for coatings derived from phosphating bath containing 1.5 g/L nano ZnO. The activation effect brought about by the nano ZnO reduces the amount of accelerator (NaNO2) required for phosphating

  11. In vitro osteoblast-like and endothelial cells' response to calcium silicate/calcium phosphate cement

    International Nuclear Information System (INIS)

    This study aims to investigate the interaction between calcium silicate/calcium phosphate cement (CS/CPC) and osteogenesis, in particular the in vitro osteoblast-like and endothelial cells' response to CS/CPC. The effect of CS/CPC on cell attachment, proliferation and differentiation of murine osteoblast-like cell MC3T3-E1, as well as the influence on the cell attachment and proliferation of human umbilical vein endothelial cell (HUVEC), was studied in detail. Our results indicated that CS/CPC exhibited excellent biocompatibility to the osteoblast-like cells. Moreover, the morphology and cytoskeleton organization of MC3T3-E1 cultured on the CS/CPC disks suggested that CS/CPC induced better cell adhesion and cell spreading. Simultaneously, cell proliferation and alkaline phosphatase (ALP) activity of MC3T3-E1 were significantly improved after 3 and 7 days of culture on CS/CPC disks in comparison with CPC disks. Additionally, on CS/CPC disks, HUVEC attached well on day 1 and cell proliferation was also greatly enhanced by day 7. Collectively, these results suggest that the introduction of calcium silicate may improve the cell response involved in the osteogenesis and thus may be beneficial to further modify CPC as a better bone repairing material.

  12. Randomized crossover study comparing the phosphate-binding efficacy of calcium ketoglutarate versus calcium carbonate in patients on chronic hemodialysis.

    Science.gov (United States)

    Bro, S; Rasmussen, R A; Handberg, J; Olgaard, K; Feldt-Rasmussen, B

    1998-02-01

    The objective of the study was to evaluate the phosphate-binding efficacy, side effects, and cost of therapy of calcium ketoglutarate granulate as compared with calcium carbonate tablets in patients on chronic hemodialysis. The study design used was a randomized, crossover open trial, and the main outcome measurements were plasma ionized calcium levels, plasma phosphate levels, plasma intact parathyroid hormone (PTH) levels, requirements for supplemental aluminum-aminoacetate therapy, patient tolerance, and cost of therapy. Nineteen patients on chronic hemodialysis were treated with a dialysate calcium concentration of 1.25 mmol/L and a fixed alfacalcidol dose for at least 2 months. All had previously tolerated therapy with calcium carbonate. Of the 19 patients included, 10 completed both treatment arms. After 12 weeks of therapy, the mean (+/-SEM) plasma ionized calcium level was significantly lower in the ketoglutarate arm compared with the calcium carbonate arm (4.8+/-0.1 mg/dL v 5.2+/-0.1 mg/dL; P = 0.004), whereas the mean plasma phosphate (4.5+/-0.3 mg/dL v 5.1+/-0.1 mg/dL) and PTH levels (266+/-125 pg/mL v 301+/-148 pg/mL) did not differ significantly between the two treatment arms. Supplemental aluminum-aminoacetate was not required during calcium ketoglutarate treatment, while two patients needed this supplement when treated with calcium carbonate. Five of 17 (29%) patients were withdrawn from calcium ketoglutarate therapy within 1 to 2 weeks due to intolerance (anorexia, vomiting, diarrhea, general uneasiness), whereas the remaining 12 patients did not experience any side effects at all. The five patients with calcium ketoglutarate intolerance all had pre-existing gastrointestinal symptoms; four of them had received treatment with cimetidine or omeprazol before inclusion into the study. Calculations based on median doses after 12 weeks showed that the cost of the therapy in Denmark was 10 times higher for calcium ketoglutarate compared with calcium

  13. Assessment of Protective Effect of Amorphous Calcium Phosphate-Caseine

    Directory of Open Access Journals (Sweden)

    Anousheh Rashed-Mohassel

    2014-07-01

    Full Text Available Background: One of the complications of Iron drop recommended for 6-24 months children is the potential reduction in microhardness of primary tooth enamel because of low pH. The objective of this study is to assess the protective effect of amorphous calcium phosphate caseine phosphopeptide (ACP-CPP and silicone oil in primary teeth. Materials and Methods: Thirty extracted primary anterior teeth were divided into three equal groups. The initial micro hardness was measured by Vicker’s microhardness tester. The first group without a protective layer and the second and third group after application of ACP-CPP and silicone oil respectively, were immersed in iron drop. Microhardness was remeasured. One tooth in each group along with a tooth not exposed to iron drop were randomly chosen for SEM qualitative analysis. Analysis was performed with Repeated measures ANOVA with SPSS-18. Results: All groups exhibited significant decrease of micro hardness (p=0.001, however, no contrasting pattern was found between various groups. Conclusion: Neither ACP-CPP nor silicone oil could not provide a significant protection against micro hardness reduction after exposure to iron drop

  14. The bactericidal and biocompatible characteristics of reinforced calcium phosphate cements

    International Nuclear Information System (INIS)

    Infection remains a serious medical problem in orthopaedic surgery. Antibiotic administration can be available either systemically via the blood stream or locally, directly into the infected bone. One of the main limitations of antibiotic administration is the development of multi-antibiotic-resistant bacterial strains. In this study, we developed bactericidal calcium phosphate cements (CPC) by incorporation of different molecular weight chitosan and hydroxypropyltrimethyl ammonium chloride chitosan (HACC). Two standard strains, S. epidermidis (ATCC35984) and S. aureus (ATCC25923), and one clinical isolate, methicillin-resistant S. epidermidis (MRSE), were selected to evaluate the antibacterial activity of these bone cements. Our data showed that the CPC loaded with low molecular weight chitosan and HACC significantly inhibited the bacterial adhesion and biofilm formation. In addition, HACC-containing CPC has no cytotoxic effects on both mouse pluripotent C3H10T1/2cell line and a murine L929 fibroblast cell line. We propose that HACC-containing CPC represents a promising polymer-based bactericidal bone scaffold in controlling orthopaedic surgery-related infection. (paper)

  15. Dibasic calcium phosphate dihydrate, USP material compatibility with gamma radiation

    Science.gov (United States)

    Betancourt Quiles, Maritza

    Gamma radiation is a commonly used method to reduce the microbial bioburden in compatible materials when it is applied at appropriate dose levels. Gamma irradiation kills bacteria and mold by breaking down the organism’s DNA and inhibiting cell division. The purpose of this study is to determine the radiation dosage to be used to treat Dibasic Calcium Phosphate Dihydrate, USP (DCPD) and to evaluate its physicochemical effects if any, on this material. This material will be submitted to various doses of gamma radiation that were selected based on literature review and existing regulations that demonstrate that this method is effective to reduce or eliminate microbial bioburden in natural source and synthetic materials. Analytical testing was conducted to the DCPD exposed material in order to demonstrate that gamma radiation does not alter the physicochemical properties and material still acceptable for use in the manufacture of pharmaceutical products. The results obtained through this study were satisfactory and demonstrated that the gamma irradiation dosages from 5 to 30 kGy can be applied to DCPD without altering its physicochemical properties. These are supported by the Assay test data evaluation of lots tested before and after gamma irradiation implementation that show no significant statistical difference between irradiated and non irradiated assay results. The results of this study represent an achievement for the industry since they provide as an alternative the use of Gamma irradiation technology to control the microbial growth in DCPD.

  16. Effect of casein phosphopeptide-amorphous calcium phosphate and acidulated phosphate fluoride gel on erosive enamel wear

    OpenAIRE

    Maryam HajeNorouz Ali Tehrani; Maryam Ghafournia; Pouran Samimi; Omid Savabi; Iman Parisay; Navid Askari; Seyed-Hossein Abtahi

    2011-01-01

    Background: Some studies have shown that casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and acidulated phosphate fluoride (APF) gel can protect teeth against erosion. The aim of this study was to assess whether CPP-ACP and fluoride could reduce enamel wear rates under erosive conditions simulating abrasion and acidic diet regimen. Materials and Methods: Enamel specimens consisted of 3 experimental groups (receiving CPP-ACP, APF or both) and a control group. Specimens were sub...

  17. Effect of casein phosphopeptide-amorphous calcium phosphate and acidulated phosphate fluoride gel on erosive enamel wear

    OpenAIRE

    Tehrani, Maryam HajeNorouz Ali; Ghafournia, Maryam; Samimi, Pouran; Savabi, Omid; Parisay, Iman; Askari, Navid; Abtahi, Seyed-Hossein

    2011-01-01

    Background: Some studies have shown that casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and acidulated phosphate fluoride (APF) gel can protect teeth against erosion. The aim of this study was to assess whether CPP-ACP and fluoride could reduce enamel wear rates under erosive conditions simulating abrasion and acidic diet regimen. Materials and Methods: Enamel specimens consisted of 3 experimental groups (receiving CPP-ACP, APF or both) and a control group. Specimens were subject...

  18. Polyelectrolyte addition effect on the properties of setting hydraulic cements based on calcium phosphate

    International Nuclear Information System (INIS)

    In the present work the effects of the addition of some poly electrolytes (sodium alginate and poly acrylic acid) on the solubility, crystalline phases, pH and mechanical strength under compression of three calcium phosphate cements were studied. (author)

  19. Balloon vetebroplasty with calcium phosphate cement augmentation for direct restoration of traumatic thoracolumbar vertebral fractures

    NARCIS (Netherlands)

    Verlaan, JJ; van Helden, WH; Oner, FC; Verbout, AJ; Dhert, WJA

    2002-01-01

    Study Design. A human cadaveric model was used to evaluate balloon vertebroplasty in traumatic vertebral fractures. Objectives. To assess the feasibility and safety of balloon vertebroplasty followed by calcium phosphate cement augmentation to prevent recurrent kyphosis. Summary of Background Data.

  20. Evaluation of Calcium Phosphate Cement As a Root Canal Sealer Filling Material

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Calcium phosphate cement for root end sealing was obtained by mixing α-tricalcium phosphate and additives with an aqueous solution of citric. Powder and liquid were mixed at a ratio of 1.25g/mL. The biocompatibility of this material was investigated primarily by subcutaneous implantation tests. Then calcium phosphate cement was used to fill three adult dogs' root canal, both calcium hydroxide paste and hydroxyapatite paste as control. The animals were killed at 4,12,20 weeks postoperatively respectively. The effects of different materials on the apical closure, restoration of periapical tissues and adaptability to the dentinal surface were examined by optical and electronic microscope. The observation at 20 weeks shows that the calcium phosphate cement has the potentialities of being a root canal sealer filling material available for pulpless teeth with open-apex and destructive periapical tissue.

  1. Reflections on the Mechanism of Calcium Phosphate Nucleation on Titanium in Simulated Body Fluids

    Institute of Scientific and Technical Information of China (English)

    F. T. Cheng

    2005-01-01

    The results and main findings of studies reported in the literature in relation to the deposition of calcium phosphate on Ti in simulated body fluids are summarized. The effects of the surface hydroxyl groups and the sign of surface charge on the nucleation of calcium phosphate are reviewed. One major controversy among the conclusions of different studies is the order of adsorption of the calcium ions and the phosphate ions in the initial stage of immersion. A simple model based on the amphoteric nature of the hydroxyl groups on Ti is proposed in an attempt to delineate the nucleation process for calcium phosphate on Ti in simulated body fluids. HPO42- ions interact with the hydroxyl groups via ion exchange and/or electrostatic attraction, and Ca2+ ions, via electrostatic attraction only. There is no preferential order of adsorption. Seemingly inconsistent results in different studies possibly arise from different prior treatments of the samples, which affect the adsorption properties.

  2. Multiple characterization study on porosity and pore structure of calcium phosphate cements

    OpenAIRE

    Pastorino Carraz, David; Canal Barnils, Cristina; Ginebra Molins, Maria Pau

    2015-01-01

    Characterization of the intricate pore structure of calcium phosphate cements is a key step to successfully link the structural properties of these synthetic bone grafts with their most relevant properties, such as in vitro or in vivo behaviour, drug loading and release properties, or degradation over time. This is a challenging task due to the wide range of pore sizes in calcium phosphate cements, compared to most other ceramic biomaterials. This work provides a critical assessment of three ...

  3. Cytotoxicity assessment of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste

    OpenAIRE

    Sandra Kalil Bussadori; Elaine Marcilio Santos; Carolina Cardoso Guedes; Lara Jansiski Motta; Kristianne Porta Santos Fernandes; Raquel Agnelli Mesquita-Ferrari; Laura Hermida Bruno; Diana Ram

    2010-01-01

    Introduction: Casein phosphopeptides (CPP) have been shown to be good carriers of calcium, phosphate, and hydroxide ions to promote enamel remineralization with applications in oral care products, professional dental products, and food products. Objectives: Evaluate the cytotoxicity of a casein phosphopeptideamorphous calcium phosphate (CPP-ACP) paste in rat fibroblasts. Materials and methods: Cytotoxicity was measured by the Trypan blue dye exclusion assay and the MTT assay. Results: Long te...

  4. Comparison of Calcium Phosphate and Zinc Oxide Nanoparticles as Dermal Penetration Enhancers for Albumin

    OpenAIRE

    Shokri, Narges; Javar, H. A.

    2015-01-01

    Dermal drug delivery is highly preferred by patients due to its several advantages. Protein therapeutics have attracted huge attention recently. Since dermal delivery of proteins encounter problems, in this investigation, zinc oxide nanoparticles and calcium phosphate nanoparticles were compared as enhancers for dermal permeation of albumin. Albumin was applied simultaneously with zinc oxide nanoparticles or calcium phosphate nanoparticles on pieces of mouse skin. Skin permeation of albumin o...

  5. Influence of Ethylene Glycol on the Formation of Calcium Phosphate Nanocrystals

    Institute of Scientific and Technical Information of China (English)

    Yi ZUO; Yubao LI; Jie WEI; Yonggang YAN

    2003-01-01

    A synthesis route of using calcium hydroxide Ca(OH)2 with ethylene glycol solvent and orthophosphoric acid (H3PO4)as reagents is described. Three ratios of ethylene glycol to distilled water 1:0, 1:1 and 0:1 are used as diluting media for Ca(OH)2. Crystals of different morphology and composition are formed under weak alkaline circumstance at pH 7.0~8.0. Acicular calcium phosphate nanocrystals are prepared in pure ethylene glycol while rod-like calcium phosphate nanocrystals form in pure distilled water. The nanograde size of the former is smaller than that of the latter. Calcium-deficient apatite (CDAP) is obtained with a Ca/P molar ratio of 1.66. Therefore, it was deduced that the usage of ethylene glycol solvent could influence the formation of calcium phosphate crystal lattice.

  6. Bioactivity and Surface Reactivity of RF-sputtered Calcium Phosphate Thin Films

    Science.gov (United States)

    van der Wal, Edwin

    2003-10-01

    Calcium phosphates (CaP) are known to be bioactive, i.e. able to bond to bone. This makes CaPs very suitable to be aplied as thin coatings on bone-implants. In this work we studied the physicochemical behaviour of CaP coatings applied with radio frequency (RF) magnetron sputtering, a deposition technique that can produce thin ( 100 nm), homogeneous, and well-adhereing coatings. As-deposited CaP coatings are amorphous and can be crystallized by a heat-treatment of 30 minutes at 650C, resulting in a mainly apatitic structure. Firstly, we have studied the behaviour of these CaP coatings in so-called simulated body fluid (SBF or SBF1), an anorganic equivalent of human blood plasma. Amorphous CaP coatings dissolve in SBF and even in SBF with twice the Ca and PO4 concentrations (SBF2). After a heat-treatment CaP coatings remain inert in SBF for days, i.e. coatings do not dissolve and no crystals are formed from the solution on the coating surface. However, formation of crystals is possible in SBF2. At room temperature, the formation of crystals is preceeded by an induction time, in which rod-shaped sediments can be found on the coating surface, but no significant growth is observed. Only after completion of the induction period growth of CaP crystals is allowed. Growth can proceed in solutions with lower concentrations like SBF1. Only within a limited range of Ca over PO4 ratio of the coatings, formation of CaP crystals from SBF2 is possible. In a rat bone marrow (RBM) cell-culture CaP was compared to RF-sputtered coatings of other bioceramics like alumina (Al2O3) and titania (TiO2). Alumina is a known bioinert material. However, there is still discussion on the biocompatibility of titania. It was found that cell behavior on CaP coatings significantly differed from alumina. CaP coatings showed decreased early proliferation, increased differentiation, and increased mature osteoblast activity compared to alumina. Results for titania were intermediate compared to CaP and

  7. Effects of calcium phosphate/chitosan composite on bone healing in rats: calcium phosphate induces osteon formation.

    Science.gov (United States)

    Fernández, Tulio; Olave, Gilberto; Valencia, Carlos H; Arce, Sandra; Quinn, Julian M W; Thouas, George A; Chen, Qi-Zhi

    2014-07-01

    Vascularization of an artificial graft represents one of the most significant challenges facing the field of bone tissue engineering. Over the past decade, strategies to vascularize artificial scaffolds have been intensively evaluated using osteoinductive calcium phosphate (CaP) biomaterials in animal models. In this work, we observed that CaP-based biomaterials implanted into rat calvarial defects showed remarkably accelerated formation and mineralization of new woven bone in defects in the initial stages, at a rate of ∼60 μm/day (0.8 mg/day), which was considerably higher than normal bone growth rates (several μm/day, 0.1 mg/day) in implant-free controls of the same age. Surprisingly, we also observed histological evidence of primary osteon formation, indicated by blood vessels in early-region fibrous tissue, which was encapsulated by lamellar osteocyte structures. These were later fully replaced by compact bone, indicating complete regeneration of calvarial bone. Thus, the CaP biomaterial used here is not only osteoinductive, but vasculogenic, and it may have contributed to the bone regeneration, despite an absence of osteons in normal rat calvaria. Further investigation will involve how this strategy can regulate formation of vascularized cortical bone such as by control of degradation rate, and use of models of long, dense bones, to more closely approximate repair of human cortical bone. PMID:24460696

  8. Lipid-Calcium Phosphate Nanoparticles for Delivery to the Lymphatic System and SPECT/CT Imaging of Lymph Node Metastases

    OpenAIRE

    Tseng, Yu-cheng; Xu, Zhenghong; Guley, Kevin; Yuan, Hong; Huang, Leaf

    2014-01-01

    A lipid/calcium/phosphate (LCP) nanoparticle (NP) formulation (particle diameter ~25 nm) with superior siRNA delivery efficiency was developed and reported previously. Here, we describe the successful formulation of 111In into LCP for SPECT/CT imaging. Imaging and biodistribution studies showed that, polyethylene glycol grafted 111In-LCP preferentially accumulated in the lymph nodes at ~70% ID/g in both C57BL/6 and nude mice when the improved surface coating method was used. Both the liver an...

  9. Osteogenic and antimicrobial nanoparticulate calcium phosphate and poly-(D,L-lactide-co-glycolide) powders for the treatment of osteomyelitis

    Energy Technology Data Exchange (ETDEWEB)

    Uskoković, Vuk, E-mail: vuk21@yahoo.com [Therapeutic Micro and Nanotechnology Laboratory, Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA (United States); Hoover, Charles [Department of Cell and Tissue Biology, University of California, San Francisco, CA (United States); Vukomanović, Marija [Institute of Technical Sciences, Serbian Academy of Sciences and Arts, Belgrade (Serbia); Advanced Materials Department, Jožef Stefan Institute, Ljubljana (Slovenia); Uskoković, Dragan P. [Institute of Technical Sciences, Serbian Academy of Sciences and Arts, Belgrade (Serbia); Desai, Tejal A. [Therapeutic Micro and Nanotechnology Laboratory, Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA (United States)

    2013-08-01

    Development of a material for simultaneous sustained and localized delivery of antibiotics and induction of spontaneous regeneration of hard tissues affected by osteomyelitis stands for an important clinical need. In this work, a comparative analysis of the bacterial and osteoblastic cell response to two different nanoparticulate carriers of clindamycin, an antibiotic commonly prescribed in the treatment of bone infection, one composed of calcium phosphate and the other comprising poly-(D,L-lactide-co-glycolide)-coated calcium phosphate, was carried out. Three different non-cytotoxic phases of calcium phosphate, exhibiting dissolution and drug release profiles in the range of one week to two months to one year, respectively, were included in the analysis: monetite, amorphous calcium phosphate and hydroxyapatite. Spherical morphologies and narrow size distribution of both types of nanopowders were confirmed in transmission and scanning electron microscopic analyses. The antibiotic-containing powders exhibited sustained drug release contingent upon the degradation rate of the carrier. Assessment of the antibacterial performance of the antibiotic-encapsulated powders against Staphylococcus aureus, the most common pathogen isolated from infected bone, yielded satisfactory results both in broths and on blood agar plates for all the analyzed powders. In contrast, no cytotoxic behavior was detected upon the incubation of the antibiotic powders with the osteoblastic MC3T3-E1 cell line for up to three weeks. The cells were shown to engage in a close contact with the antibiotic-containing particles, irrespective of their internal or surface phase composition, polymeric or mineral. At the same time, both types of particles upregulated the expression of osteogenic markers osteocalcin, osteopontin, Runx2 and protocollagen type I, suggesting their ability to promote osteogenesis and enhance remineralization of the infected site in addition to eliminating the bacterial source of

  10. Osteogenic and antimicrobial nanoparticulate calcium phosphate and poly-(D,L-lactide-co-glycolide) powders for the treatment of osteomyelitis

    International Nuclear Information System (INIS)

    Development of a material for simultaneous sustained and localized delivery of antibiotics and induction of spontaneous regeneration of hard tissues affected by osteomyelitis stands for an important clinical need. In this work, a comparative analysis of the bacterial and osteoblastic cell response to two different nanoparticulate carriers of clindamycin, an antibiotic commonly prescribed in the treatment of bone infection, one composed of calcium phosphate and the other comprising poly-(D,L-lactide-co-glycolide)-coated calcium phosphate, was carried out. Three different non-cytotoxic phases of calcium phosphate, exhibiting dissolution and drug release profiles in the range of one week to two months to one year, respectively, were included in the analysis: monetite, amorphous calcium phosphate and hydroxyapatite. Spherical morphologies and narrow size distribution of both types of nanopowders were confirmed in transmission and scanning electron microscopic analyses. The antibiotic-containing powders exhibited sustained drug release contingent upon the degradation rate of the carrier. Assessment of the antibacterial performance of the antibiotic-encapsulated powders against Staphylococcus aureus, the most common pathogen isolated from infected bone, yielded satisfactory results both in broths and on blood agar plates for all the analyzed powders. In contrast, no cytotoxic behavior was detected upon the incubation of the antibiotic powders with the osteoblastic MC3T3-E1 cell line for up to three weeks. The cells were shown to engage in a close contact with the antibiotic-containing particles, irrespective of their internal or surface phase composition, polymeric or mineral. At the same time, both types of particles upregulated the expression of osteogenic markers osteocalcin, osteopontin, Runx2 and protocollagen type I, suggesting their ability to promote osteogenesis and enhance remineralization of the infected site in addition to eliminating the bacterial source of

  11. Influence of whole-body irradiation on calcium and phosphate homeostasis in the rat

    International Nuclear Information System (INIS)

    Previous irradiation studies have revealed marked alterations in calcium metabolism. Moreover, the maintenance of calcium homeostasis with parathyroid hormone or calcium salts has been reported to reduce radiation lethality. Therefore, the present study was designed to evaluate the influence of irradiation on calcium homeostasis in the rat. Nine hundred rad of whole-body irradiation produced a significant depression of both plasma calcium and phosphate at 4 days postirradiation. This effect of irradiation was observed to be dose-dependent over a range of 600 to 1200 rad, and possibly related to irradiation-induced anorexia. The physiological significance of these observations is discussed

  12. Low temperature method for the production of calcium phosphate fillers

    Directory of Open Access Journals (Sweden)

    Nastro Alfonso

    2004-03-01

    Full Text Available Abstract Background Calcium phosphate manufactured samples, prepared with hydroxyapatite, are used as either spacers or fillers in orthopedic surgery, but these implants have never been used under conditions of mechanical stress. Similar conditions also apply with cements. Many authors have postulated that cements are a useful substitute material when implanted in vivo. The aim of this research is to develop a low cristalline material similar to bone in porosity and cristallinity. Methods Commercial hydroxyapatite (HAp and monetite (M powders are mixed with water and compacted to produce cylindrical samples. The material is processed at a temperature of 37–120 degrees C in saturated steam to obtain samples that are osteoconductive. The samples are studied by X-ray powder diffraction (XRD, Vickers hardness test (HV, scanning electron microscopy (SEM, and porosity evaluation. Results The X-ray diffractions of powders from the samples show patterns typical of HAp and M powders. After thermal treatment, no new crystal phase is formed and no increase of the relative intensity of the peaks is obtained. Vicker hardness data do not show any relationship with treatment temperature. The total porosity decreases by 50–60% according to the specific thermal treatment. Scanning electron microscopy of the surfaces of the samples with either HAp 80%-M 20% (c or Hap 50%-M 50% (f, show cohesion of the powder grains. Conclusions The dissolution-reprecipitation process is more intesive in manufactured samples (c and (f, according to Vickers hardness data. The process occurs in a steam saturated environment between 37 degrees and 120 degrees C. (c (f manufactured samples show pore dimension distributions useful to cellular repopulation in living tissues.

  13. ANTICORROSION PROPERTIES OF ORGANIC COATINGS CONTAINING POLYPHENYLENEDIAMINE PHOSPHATE

    Directory of Open Access Journals (Sweden)

    Miroslav Kohl

    2015-11-01

    Full Text Available The present work was aimed at the synthesis of polyphenylenediamine, its description and determination of parameters whose knowledge is required for the formulation of organic coatings pigmented with this compound. Polyphenylenediamine phosphate was prepared by oxidation polymerization in acidic environment. Phosphoric acid was used as the doping acid. Based on the results, pigmented organic coatings containing polyphenylenediamine at volume concentrations of 0%, 0.5%, 1%, 3%; 5%, and 10% were formed. The effect of the conductive polymer on the organic coatings‘ corrosion properties was examined via accelerated corrosion tests. From the results of an accelerated corrosion test it follows that if added to an epoxy-ester coating, this pigment improves appreciably the coating‘s corrosion resistance, especially at low pigment volume concentrations.

  14. Increased osteoblast adhesion on nanograined hydroxyapatite and tricalcium phosphate containing calcium titanate.

    Science.gov (United States)

    Ergun, Celaletdin; Liu, Huinan; Halloran, John W; Webster, Thomas J

    2007-03-15

    Depending on the coating method utilized and subsequent heat treatments (such as through the use of plasma-spray deposition), inter-diffusion of atomic species across titanium (Ti) and hydroxyapatite (HA) coatings may result. These events may lead to structural and compositional changes that consequently cause unanticipated HA phase transformations which may clearly influence the performance of an orthopedic implant. Thus, the objective of the present in vitro study was to compare the cytocompatibility properties of chemistries that may form at the Ti:HA interface, specifically HA, tricalcium phosphate (TCP), HA doped with Ti, and those containing calcium titanate (CaTiO(3)). In doing so, results of this study showed that osteoblast (bone-forming cells) adhesion increased with greater CaTiO(3) substitutions in either HA or TCP. Specifically, osteoblast adhesion on HA and TCP composites with CaTiO(3) was almost 4.5 times higher than that over pure HA. Material characterization studies revealed that enhanced osteoblast adhesion on these compacts may be due to increasing shrinkage in the unit lattice parameters and decreasing grain size. Although all CaTiO(3) composites exhibited excellent osteoblast adhesion results, Ca(9)HPO(4)(PO(4))(5)OH phase transformation into TCP/CaTiO(3) increased osteoblast adhesion the most; because of these reasons, these materials should be further studied for orthopedic applications. PMID:17120201

  15. Understanding the Biocompatibility of Sintered Calcium Phosphate with Ratio of [Ca]/[P] = 1.50

    OpenAIRE

    Feng-Lin Yen; Wei-Jen Shih; Min-Hsiung Hon; Hui-Ting Chen; I-Ming Hung; Homg-Huey Ko; Moo-Chin Wang

    2012-01-01

    Biocompatibility of sintered calcium phosphate pellets with [Ca]/[P] = 1.50 was determined in this study. Calcium pyrophosphate (CPP) phase formed on the sintered pellets immersed in a normal saline solution for 14 d at 37∘C. The intensities of hydroxyapatite (HA) reflections in the X-ray diffraction (XRD) patterns of the pellets were retrieved to as-sintered state. The pellet surface morphology shows that CPP crystallites were clearly present and make an amorphous calcium phosphate (ACP) to ...

  16. Double coating protection of Nd–Fe–B magnets: Intergranular phosphating treatment and copper plating

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jingwu; Chen, Haibo; Qiao, Liang [College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014 (China); Lin, Min [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering Chinese Academy of Science, Ningbo 315201 (China); Jiang, Liqiang; Che, Shenglei [College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014 (China); Hu, Yangwu, E-mail: 346648086@qq.com [College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014 (China); Wenzhou Institute of Industry and Science, Wenzhou 325000 (China)

    2014-12-15

    In this work, a double coating protection technique of phosphating treatment and copper plating was made to improve the corrosion resistance of sintered Nd–Fe–B magnets. In other words, the intergranular region of sintered Nd–Fe–B is allowed to generate passive phosphate conversion coating through phosphating treatment, followed by the copper coating on the surface of sintered Nd–Fe–B. The morphology and corrosion resistance of the phosphated sintered Nd–Fe–B were observed using SEM and electrochemical method respectively. The phosphate conversion coating was formed more preferably on the intergranular region of sintered Nd–Fe–B than on the main crystal region; just after a short time of phosphating treatment, the intergranular region of sintered Nd–Fe–B has been covered by the phosphate conversion coating and the corrosion resistance is significantly improved. With the synergistic protection of the intergranular phosphorization and the followed copper electrodeposition, the corrosion resistance of the sintered Nd–Fe–B is significantly better than that with a single phosphate film or single plating protection. - Highlights: • We combined intergranular phosphating and copper plating to protect Nd–Fe–B. • The phosphate conversion coating was formed preferably on the intergranular region. • The phosphating coating can obviously improve the corrosion resistance of Nd–Fe–B. • The corrosion resistance of Nd–Fe–B was improved by double coating protection.

  17. Immobilization of calcium and phosphate ions improves the osteoconductivity of titanium implants.

    Science.gov (United States)

    Sunarso; Toita, Riki; Tsuru, Kanji; Ishikawa, Kunio

    2016-11-01

    In this work, to elevate weak osteoconductivity of titanium (Ti) implant, we prepared a Ti implant having both calcium and phosphate ions on its surface. To modify calcium and phosphate ions onto Ti, phosphate ions were first immobilized by treating the Ti with a NaH2PO4 solution, followed by CaCl2 treatment to immobilize calcium ions, which created the calcium and phosphate ions-modified Ti (Ca-P-Ti). X-ray photoelectron spectroscopy and thin-layer X-ray diffraction measurement confirmed that both phosphate and calcium ions were co-immobilized onto the Ti surface on the molecular level. Three-hour after seeding MC3T3-E1 murine pre-osteoblast cells on substrates, cell number on Ca-P-Ti was much larger than that of Ti and phosphate-modified Ti (P-Ti), but was similar to that of calcium-modified Ti (Ca-Ti). Also, MC3T3-E1 cells on Ca-P-Ti expressed larger amount of vinculin, a focal adhesion protein, than those on other substrates, probably resulting in larger cell size as well as greater cell proliferation on Ca-P-Ti than those on other substrates. Alkaline phosphatase activity of cells on Ca-P-Ti was greater than those on Ti and P-Ti, but was almost comparable to that of Ca-Ti. Moreover, the largest amount of bone-like nodule formation was observed on Ca-P-Ti. These results provide evidence that calcium and phosphate ions-co-immobilization onto Ti increased the osteoconductivity of Ti by stimulating the responses of pre-osteoblast cells. This simple modification would be promising technique for bone tissue implant including dental and orthopedic implants. PMID:27524023

  18. Discrimination between biologically relevant calcium phosphate phases by surface-analytical techniques

    International Nuclear Information System (INIS)

    The spatially resolved phase identification of biologically relevant calcium phosphate phases (CPPs) in bone tissue is essential for the elucidation of bone remodeling mechanisms and for the diagnosis of bone diseases. Analytical methods with high spatial resolution for the discrimination between chemically quite close phases are rare. Therefore the applicability of state-of-the-art ToF-SIMS, XPS and EDX as chemically specific techniques was investigated. The eight CPPs hydroxyapatite (HAP), β-tricalcium phosphate (β-TCP), α-tricalcium phosphate (α-TCP), octacalcium phosphate (OCP), dicalcium phosphate dihydrate (DCPD), dicalcium phosphate (DCP), monocalcium phosphate (MCP) and amorphous calcium phosphate (ACP) were either commercial materials in high purity or synthesized by ourselves. The phase purity was proven by XRD analysis. All of the eight CPPs show different mass spectra and the phases can be discriminated by applying the principal component analysis method to the mass spectrometric data. The Ca/P ratios of all phosphates were determined by XPS and EDX. With both methods some CPPs can be distinguished, but the obtained Ca/P ratios deviate systematically from their theoretical values. It is necessary in any case to determine a calibration curve, respectively the ZAF values, from appropriate standards. In XPS also the O(1s)-satellite signals are correlated to the CPPs composition. Angle resolved and long-term XPS measurements of HAP clearly prove that there is no phosphate excess at the surface. Decomposition due to X-ray irradiation has not been observed.

  19. Discrimination between biologically relevant calcium phosphate phases by surface-analytical techniques

    Energy Technology Data Exchange (ETDEWEB)

    Kleine-Boymann, Matthias, E-mail: matthias.kleine-boymann@phys.chemie.uni-giessen.de; Rohnke, Marcus, E-mail: marcus.rohnke@phys.chemie.uni-giessen.de; Henss, Anja, E-mail: anja.henss@phys.chemie.uni-giessen.de; Peppler, Klaus, E-mail: klaus.peppler@phys.chemie.uni-giessen.de; Sann, Joachim, E-mail: joachim.sann@phys.chemie.uni-giessen.de; Janek, Juergen, E-mail: juergen.janek@phys.chemie.uni-giessen.de

    2014-08-01

    The spatially resolved phase identification of biologically relevant calcium phosphate phases (CPPs) in bone tissue is essential for the elucidation of bone remodeling mechanisms and for the diagnosis of bone diseases. Analytical methods with high spatial resolution for the discrimination between chemically quite close phases are rare. Therefore the applicability of state-of-the-art ToF-SIMS, XPS and EDX as chemically specific techniques was investigated. The eight CPPs hydroxyapatite (HAP), β-tricalcium phosphate (β-TCP), α-tricalcium phosphate (α-TCP), octacalcium phosphate (OCP), dicalcium phosphate dihydrate (DCPD), dicalcium phosphate (DCP), monocalcium phosphate (MCP) and amorphous calcium phosphate (ACP) were either commercial materials in high purity or synthesized by ourselves. The phase purity was proven by XRD analysis. All of the eight CPPs show different mass spectra and the phases can be discriminated by applying the principal component analysis method to the mass spectrometric data. The Ca/P ratios of all phosphates were determined by XPS and EDX. With both methods some CPPs can be distinguished, but the obtained Ca/P ratios deviate systematically from their theoretical values. It is necessary in any case to determine a calibration curve, respectively the ZAF values, from appropriate standards. In XPS also the O(1s)-satellite signals are correlated to the CPPs composition. Angle resolved and long-term XPS measurements of HAP clearly prove that there is no phosphate excess at the surface. Decomposition due to X-ray irradiation has not been observed.

  20. The EIS investigation of powder polyester coatings on phosphated low carbon steel: The effect of NaNO2 in the phosphating bath

    International Nuclear Information System (INIS)

    Highlights: → The effect of NaNO2 on surface morphology of iron-phosphate coatings were determined. → Better corrosion stability of polyester coating on phosphated steel without NaNO2. → EIS results and microscopic examinations correlate well with adhesion measurements. - Abstract: The effect of different type of iron-phosphate coatings on corrosion stability and adhesion characteristic of top powder polyester coating on steel was investigated. Iron-phosphate coatings were deposited on steel in the novel phosphating bath with or without NaNO2 as an accelerator. The corrosion stability of the powder polyester coating was evaluated by electrochemical impedance spectroscopy (EIS), adhesion by pull-off and NMP test, while surface morphology of phosphate coatings were investigated by atomic force microscopy (AFM). The adhesion and corrosion stability of powder polyester coatings were improved with pretreatment based on iron-phosphate coating deposited from NaNO2-free bath.

  1. The role of casein phosphopeptide-amorphous calcium phosphate products in remineralization of incipient enamel lesions and its substantivity

    OpenAIRE

    Abhay Taranath; Deepika Pai; Kalyan Chakravarthy

    2014-01-01

    Objective: Milk derived calcium, phosphate and casein were known to be anti-cariogenic but in the modern era of early interception of caries the agents like casien phosphopeptide-amorphous calcium phosphate (CPP-ACP) derived from milk are known to also repair early lesions. This in vitro study was designed to evaluate the remineralizing potential of CPP-ACP and CPP-amorphous calcium phosphate fluoride (ACPF) on smooth surface carious lesions of the enamel and its substantivity following demin...

  2. Calcium phosphate thin films synthesized by pulsed laser deposition: Physico-chemical characterization and in vitro cell response

    Science.gov (United States)

    Mihailescu, I. N.; Torricelli, P.; Bigi, A.; Mayer, I.; Iliescu, M.; Werckmann, J.; Socol, G.; Miroiu, F.; Cuisinier, F.; Elkaim, R.; Hildebrand, G.

    2005-07-01

    We review the progress made by us using pulsed laser deposition (PLD) of two bioactive calcium phosphates: octacalcium phosphate (OCP) and Mn doped carbonated hydroxyapatite (Mn-CHA). Coatings of these materials well suited for biomimetic medical prostheses and pivots were synthesized on titanium substrates with a pulsed KrF* UV laser source. The best deposition conditions for Mn-CHA thin films were 13 Pa O 2, 400 °C with post heat treatment of 6 h in air enriched with water vapours. The coatings are stoichiometric and crystalline. For OCP, deposition at 150 °C in 50 Pa water vapor atmosphere, post treated by 6 h annealing in hot flux of water vapours, resulted in stoichiometric, but poorly-crystallized films. Degradation tests show different behavior for the OCP and Mn-CHA coatings. In vitro cell growth shows excellent adherence and biocompatibility of osteoblasts and fibroblasts in both OCP and Mn-CHA coatings. Human osteoblasts display normal proliferation and viability, and good differentiation behaviour.

  3. Calcium phosphate thin films synthesized by pulsed laser deposition: Physico-chemical characterization and in vitro cell response

    Energy Technology Data Exchange (ETDEWEB)

    Mihailescu, I.N. [National Institute for Lasers, Plasma and Radiation Physics, 77125 Bucharest-Magurele (Romania)]. E-mail: mihailes@ifin.nipne.ro; Torricelli, P. [Servizio di Chirurgia Sperimentale-Istituto di Ricerca Codivilla PuttiIOR, Bologna (Italy); Bigi, A. [Department of Chemistry ' G. Ciamician' , University of Bologna, 40126 Bologna (Italy); Mayer, I. [Department of Inorganic and Analytical Chemistry, Hebrew University of Jerusalem, 91904 Jerusalem (Israel); Iliescu, M. [Institute of Physics and Chemistry of Materials, 67037 Strasbourg (France); Werckmann, J. [Institute of Physics and Chemistry of Materials, 67037 Strasbourg (France); Socol, G. [National Institute for Lasers, Plasma and Radiation Physics, 77125 Bucharest-Magurele (Romania); Miroiu, F. [National Institute for Lasers, Plasma and Radiation Physics, 77125 Bucharest-Magurele (Romania); Cuisinier, F. [Institut National de la Sante et de la Recherche Medicale, 67085 Strasbourg (France); Elkaim, R. [Institut National de la Sante et de la Recherche Medicale, 67085 Strasbourg (France); Hildebrand, G. [IBA e.V., Department of Biomaterials, Rosenhof, D-37308 Heilbad Heiligenstadt (Germany)

    2005-07-30

    We review the progress made by us using pulsed laser deposition (PLD) of two bioactive calcium phosphates: octacalcium phosphate (OCP) and Mn doped carbonated hydroxyapatite (Mn-CHA). Coatings of these materials well suited for biomimetic medical prostheses and pivots were synthesized on titanium substrates with a pulsed KrF* UV laser source. The best deposition conditions for Mn-CHA thin films were 13 Pa O{sub 2}, 400 deg. C with post heat treatment of 6 h in air enriched with water vapours. The coatings are stoichiometric and crystalline. For OCP, deposition at 150 deg. C in 50 Pa water vapor atmosphere, post treated by 6 h annealing in hot flux of water vapours, resulted in stoichiometric, but poorly-crystallized films. Degradation tests show different behavior for the OCP and Mn-CHA coatings. In vitro cell growth shows excellent adherence and biocompatibility of osteoblasts and fibroblasts in both OCP and Mn-CHA coatings. Human osteoblasts display normal proliferation and viability, and good differentiation behaviour.

  4. Calcium phosphate thin films synthesized by pulsed laser deposition: Physico-chemical characterization and in vitro cell response

    International Nuclear Information System (INIS)

    We review the progress made by us using pulsed laser deposition (PLD) of two bioactive calcium phosphates: octacalcium phosphate (OCP) and Mn doped carbonated hydroxyapatite (Mn-CHA). Coatings of these materials well suited for biomimetic medical prostheses and pivots were synthesized on titanium substrates with a pulsed KrF* UV laser source. The best deposition conditions for Mn-CHA thin films were 13 Pa O2, 400 deg. C with post heat treatment of 6 h in air enriched with water vapours. The coatings are stoichiometric and crystalline. For OCP, deposition at 150 deg. C in 50 Pa water vapor atmosphere, post treated by 6 h annealing in hot flux of water vapours, resulted in stoichiometric, but poorly-crystallized films. Degradation tests show different behavior for the OCP and Mn-CHA coatings. In vitro cell growth shows excellent adherence and biocompatibility of osteoblasts and fibroblasts in both OCP and Mn-CHA coatings. Human osteoblasts display normal proliferation and viability, and good differentiation behaviour

  5. Polymer Coating for Immobilizing Soluble Ions in a Phosphate Ceramic Product

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Dileep; Wagh, Arun S.; Patel, Kartikey D.

    1999-05-05

    A polymer coating is applied to the surface of a phosphate ceramic composite to effectively immobilize soluble salt anions encapsulated within the phosphate ceramic composite. The polymer coating is made from ceramic materials, including at least one inorganic metal compound, that wet and adhere to the surface structure of the phosphate ceramic composite, thereby isolating the soluble salt anions from the environment and ensuring long-term integrity of the phosphate ceramic composite.

  6. Pathogenic role of basic calcium phosphate crystals in destructive arthropathies.

    Directory of Open Access Journals (Sweden)

    Hang-Korng Ea

    Full Text Available basic calcium phosphate (BCP crystals are commonly found in osteoarthritis (OA and are associated with cartilage destruction. BCP crystals induce in vitro catabolic responses with the production of metalloproteases and inflammatory cytokines such as interleukin-1 (IL-1. In vivo, IL-1 production induced by BCP crystals is both dependant and independent of NLRP3 inflammasome. We aimed to clarify 1/ the role of BCP crystals in cartilage destruction and 2/ the role of IL-1 and NLRP3 inflammasome in cartilage degradation related to BCP crystals.synovial membranes isolated from OA knees were analysed by alizarin Red and FTIR. Pyrogen free BCP crystals were injected into right knees of WT, NLRP3 -/-, ASC -/-, IL-1α -/- and IL-1β-/- mice and PBS was injected into left knees. To assess the role of IL-1, WT mice were treated by intra-peritoneal injections of anakinra, the IL-1Ra recombinant protein, or PBS. Articular destruction was studied at d4, d17 and d30 assessing synovial inflammation, proteoglycan loss and chondrocyte apoptosis. BCP crystals were frequently found in OA synovial membranes including low grade OA. BCP crystals injected into murine knee joints provoked synovial inflammation characterized by synovial macrophage infiltration that persisted at day 30, cartilage degradation as evidenced by loss of proteoglycan staining by Safranin-O and concomitant expression of VDIPEN epitopes, and increased chondrocyte apoptosis. BCP crystal-induced synovitis was totally independent of IL-1α and IL-1β signalling and no alterations of inflammation were observed in mice deficient for components of the NLRP3-inflammasome, IL-1α or IL-1β. Similarly, treatment with anakinra did not prevent BCP crystal effects. In vitro, BCP crystals elicited enhanced transcription of matrix degrading and pro-inflammatory genes in macrophages.intra-articular BCP crystals can elicit synovial inflammation and cartilage degradation suggesting that BCP crystals have a direct

  7. Templating route for mesostructured calcium phosphates with carboxylic acid- and amine-type surfactants.

    Science.gov (United States)

    Ikawa, Nobuaki; Hori, Hideki; Kimura, Tatsuo; Oumi, Yasunori; Sano, Tsuneji

    2008-11-18

    Mesostructured calcium phosphates constructed by ionic frameworks were synthesized using carboxylic acid- and amine-type surfactants in mixed solvent systems of ethanol and water. A lamellar mesostructured calcium phosphate was prepared using palmitic acid as an anionic surfactant, as in the case using n-alkylamines. A wormhole-like mesostructured calcium phosphate can be obtained using dicarboxyl N-lauroyl- l-glutamic acid, whose headgroup is larger than that of palmitic acid. Similar mesostructured product was obtained using 4-dodecyldiethylenetriamine with a large headgroup containing two primary amine groups. Interactions of carboxyl and primary amino groups in the surfactant molecules with inorganic species are quite important for the formation of mesostructured calcium phosphates. The Ca/P molar ratio of mesostructured calcium phosphates was strongly affected by the molecular structure of surfactants containing carboxyl and primary amino groups. Ca-rich materials can be obtained using carboxylic acid-type surfactants (Ca/P approximately 1.7) rather than amine-type surfactants (Ca/P approximately 1.0). PMID:18947246

  8. Sorption behavior of Zn(II) ions on synthetic apatitic calcium phosphates

    Science.gov (United States)

    Sebei, Haroun; Pham Minh, Doan; Nzihou, Ange; Sharrock, Patrick

    2015-12-01

    The synthesis, characterization and the reactivity of apatitic calcium phosphates (Ca-HA, chemical formula Ca10(PO4)6(OH)2) is reported. Calcium carbonate (CaCO3) and potassium dihydrogen orthophosphate (KH2PO4) were selected as economical starting materials for the synthesis of Ca-HA under atmospheric conditions. Monocalcium phosphate monohydrate (MCPM), dicalcium phosphate dihydrate (DCPD), and octacalcium phosphate pentahydrate (OCP) were identified as the main intermediates of the synthesis reaction. The product obtained after 48 h of reaction contains mainly low-crystalline Ca-HA and small amounts of other calcium phosphates such as octacalcium phosphate (OCP), B-type carbonate apatite (CAP), as well as unreacted calcium carbonate. This Ca-HA was found to be active for the removal of Zn2+ from an aqueous solution. Its sorption capacity reached up to 120 mg of Zn2+ per g of Ca-HA powder after 24 h of reaction. The monitoring of soluble Zn, Ca and P during the sorption experiment allowed characterizing the mechanism of Zn uptake. Dissolution-precipitation, ionic exchange and surface complexation are the three main mechanisms involved in the sorption processes. The contribution of these mechanisms is discussed in detail.

  9. Molecular mechanism of crystallization impacting calcium phosphate cements

    Energy Technology Data Exchange (ETDEWEB)

    Giocondi, J L; El-Dasher, B S; Nancollas, G H; Orme, C A

    2009-05-31

    theoretical modeling. The question changes from 'What types of molecules will inhibit brushite growth' to 'What type of molecule will interact with the [10-1]{sub Cc} step?' Similarly, to increase resorption rate, it would be most efficacious to target the slow moving [-100] step, perhaps by targeting the hydroxyl group which seem to stabilize this step compared to its otherwise similar mirror, [100]. In short, there are a number of opportunities where molecular scale imaging can provide new information that has the prospect to aid in optimizing calcium phosphate cements.

  10. The use of calcium phosphate cement in vertebroplasty of the base of odontoid process.

    Science.gov (United States)

    Zapałowicz, Krzysztof; Wojdyn, Maciej; Zieliński, Krzysztof Włodzimierz; Snopkowska-Wiaderna, Dorota

    2013-01-01

    The authors describe the use of bone cement containing calcium phosphate for vertebroplasty of the cavity in the base of odontoid process. A 23-year-old female patient was operated on by incision in lateral cervical area (anterior open access). After a blunt dissection, the working cannula (Kyphon) was introduced under fluoroscopic guidance through the C2 vertebral body to the cavity in the base of the odontoid process. Intraoperatively, biopsy of the lesion was taken and histo-pathological examination excluded the presence of neoplasm. The cavity, presumably haemangioma, was successfully filled with calcium phosphate bone cement KyphOsTM FS (Ky-phon). The proper filling without paravertebral cement leak was confirmed by postoperative computed tomography (CT). The CT and magnetic resonance imaging performed 9 months after the procedure showed that cement was still present in the cavity. This is the first use of calcium phosphate cement to conduct the vertebroplasty of C2 vertebra. PMID:24375006

  11. Effect of solute concentration on fibroin regulated biomineralization of calcium phosphate

    International Nuclear Information System (INIS)

    In this paper we used UV/Visible method to study the effect of solute concentration on fibroin regulated biomineralization of calcium phosphate. During the reaction process, ultraviolet-visible spectrophotometer was used to track the extinction in the reaction solution. It is found that kinetics of the biomineralization can be strongly affected by the presence of fibroin. Fibroin with higher concentration has more positive effect on the biomineralization process. Under the appropriate reaction conditions, wave crest and wave trough appear in the kinetic curves of fibroin biomineralization. The wave crest and wave trough phenomenon is mainly related with the process of phase separation. X-ray Diffraction (XRD) result shows the calcium phosphate before the wave trough is mainly amorphous calcium phosphate, while after the wave trough crystal of hydroxyapatite (HA) and brushite (DCPD) are the mainly ingredients

  12. The Calcium Phosphate Matrix of FGF-2-Apatite Composite Layers Contributes to Their Biological Effects

    Directory of Open Access Journals (Sweden)

    Hirotaka Mutsuzaki

    2014-06-01

    Full Text Available The purpose of the present study was to fabricate fibroblast growth factor (FGF-2-apatite composite layers on titanium (Ti pins in one step at 25 °C using a supersaturated calcium phosphate (CaP solution, and to evaluate the physicochemical characteristics and biological effects of the coated Ti pins compared with coated Ti pins fabricated at 37 °C. Ti pins were immersed in a supersaturated CaP solution containing 0.5, 1.0, or 2.0 µg/mL FGF-2 at 25 °C for 24 h (25F0.5, 25F1.0, and 25F2.0 or containing 4.0 µg/mL FGF-2 at 37 °C for 48 h (37F4.0. Except for the 25F0.5, the chemical compositions and the mitogenic activity levels of FGF-2 of the composite layers formed by these two methods were similar, except for the Ca/P molar ratio, which was markedly smaller at 25 °C (1.55–1.56 ± 0.01–0.02, p = 0.0008–0.0045 than at 37 °C (1.67 ± 0.11. Thus, either the apatite was less mature or the amount of amorphous calcium phosphate was higher in the composite layer formed at 25 °C. In vivo, the pin tract infection rate by visual inspection for 37F4.0 (45% was lower than that for 25F1.0 (80%, p = 0.0213, and the rate of osteomyelitis for 37F4.0 (35% was lower than that for 25F0.5 (75%, p = 0.0341. The extraction torque for 37F4.0 (0.276 ± 0.117 Nm was higher than that for 25F0.5 (0.192 ± 0.117 Nm, p = 0.0142 and that for 25F1.0 (0.176 ± 0.133 Nm, p = 0.0079. The invasion rate of S. aureus for 37F4.0 (35% was lower than that for 25F0.5 (75%, p = 0.0110. On the whole, the FGF-2-apatite composite layer formed at 25 °C tended to be less effective at improving fixation strength in the bone-pin interface and resisting pin tract infections. These results suggest that the chemistry of the calcium phosphate matrix that embeds FGF-2, in addition to FGF-2 content and activity, has a significant impact on composite infection resistance and fixation strength.

  13. Magnetic hyperthermia in phosphate coated iron oxide nanofluids

    Science.gov (United States)

    Lahiri, B. B.; Muthukumaran, T.; Philip, John

    2016-06-01

    We study the magnetic field induced hyperthermia in water based phosphate coated Fe3O4 nanofluids, synthesized by a co-precipitation method using ferrous and ferric salt solutions, ammonia and orthophosphoric acid. The specific absorption rate (SAR) values were measured at a fixed frequency of 126 kHz and at extremely low field amplitudes. The SAR values were determined from the initial rate of temperature rise curves under non-adiabatic conditions. It was observed that the SAR initially increases with sample concentration, attains a maximum at an optimum concentration and beyond which SAR decreases. The decrease in SAR values beyond the optimum concentration was attributed to the enhancement of dipolar interaction and agglomeration of the particles. The system independent intrinsic loss power (ILP) values, obtained by normalizing the SAR values with respect to field amplitude and frequency, were found to vary between 158-125 nHm2 kg-1, which were the highest benchmark values reported in the biologically safe experimental limit of 1.03-0.92×108 Am-1 s-1. The very high value of ILP observed in the bio-compatible phosphate coated iron oxide nanofluids may find practical applications for these nanoparticles in tumor targeted hyperthermia treatment.

  14. Ossification Vesicles with Calcium Phosphate in the Eyes of the Insect Copium teucrii (Hemiptera: Tingidae

    Directory of Open Access Journals (Sweden)

    Javier Garcia-Guinea

    2011-01-01

    Full Text Available Arthropod eyes are built of repeating units named ommatidia. Each single ommatidium unit contains a cluster of photoreceptor cells surrounded by support cells and pigment cells. The insect Copium eye ommatidia include additional calcium-phosphate deposits, not described in insects to date, which can be examined today using a combined set of modern microscopy and spectroscopy techniques. Teucrium gnaphalodes L'Her plants, growing in central Spain, develop galls induced by Copium insects. A survey of C. teucrii adult specimens resulted in surprising environmental scanning electron microscopy (ESEM images, showing that their bright red eyes contain a calcium-phosphate mineralization. A complete survey of Copium eye specimens was performed by ESEM using energy-dispersive spectroscopy, backscattered electron detector and cathodoluminescence (CL probes, field emission scanning electron microscopy, micro-Raman spectroscopy, and confocal laser scanning microscopy in order to learn ommatidia features, such as chemical composition, molecular structure, cell membrane, and internal ommatidium eye fluids and calcium-phosphate distribution deposits. The CL panchromatic images distinguish between the calcium-phosphate ommatidium and calcium-phosphate setae, which are more apatite rich. They show Raman bands attributable to bone tissue apatite biomaterials, such as bone, collagen, lipids, and blood, i.e., peptides, amide-S, amide-II, amide-III, and cytochrome P-450scc. The chemical composition of both galls and leaves of T. gnaphalodes was determined by gas chromatography – mass spectrometry (GC-MS of their extracts. The spectrometric and microscopic images reveal that the calcium-phosphate mineralization is formed and constrained to Copium ommatidia, which are both matrix vesicles generating mixtures of apatite collagen and operational compound eyes of the insect.

  15. Phosphate recovery using calcium zeolite in ultrafiltration pilot plant

    OpenAIRE

    La Rotonda Ferrer, Pablo

    2015-01-01

    One of the most important ecological problems is the eutrophication, this process consist in the uncontrolled growing of algae and phytoplankton, which can destroy entire aquatic ecosystems. The reason of this process is the excess of nutrients, as for example, phosphate coming from human activities. This project focus on the study of synthetic zeolites capacity to absorb phosphate from wastewater. Zeolites are porous minerals of the alumina-silicates family with high capacity ...

  16. The effects of citric acid on the hydration of calcium phosphate cement

    Institute of Scientific and Technical Information of China (English)

    DAI Hong-lian; YAN Yu-hua; WANG You-fa; LI Shi-pu

    2001-01-01

    @@ INTRODUCTION Calcium phosphate cements (CPC) overcome the practical disadvantages of blocks or granulesl can be handled as a paste and sit in situ. Their structure and composition close to that of HAP make them biocompatible materials. 2 The conventional calcium phosphate cement had some problems such as long setting time (30~60 min) and low compressive strength, etc. In our system, an α-TCP/TTCP powder mixture was mixed with water containing citric acid to control the setting time and compressive strength. In this paper, the effects of various concentration citric acid solutions on the properties of the cement are reported.

  17. Interactions between calcium phosphate and heavy metal ions in aqueous solution

    OpenAIRE

    Fernane F.; Boudia S.; Saouli H.

    2013-01-01

    Synthetic and natural calcium phosphates were tested for removal metallic pollution in aqueous solution. Calcium phosphates with Ca/P ratio between 1,33 and 1,67 are fluently called apatite. They have a strong capacity to immobilize metallic ions when they are brought into contact with aqueous solutions. Ca2+ ions can substituted completely or partly by cations such as metallic ions (Ni2+; Cu2+; Co2+ and Cd2+). PO43− ions can be replaced by anions such as AsO43−, CO32−, … etc. Sorption of Cu2...

  18. Synthesis and characterization of porous calcium phosphate; Sintesis y caracterizacion del fosfato de calcio poroso

    Energy Technology Data Exchange (ETDEWEB)

    Granados C, F.; Serrano G, J.; Bonifacio M, J. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: fgc@nuclear.inin.mx

    2007-07-01

    The porous calcium phosphate was prepared by the continuous precipitation method using Ca(NO{sub 3}){sub 2}.4H{sub 2}O and NH{sub 4}H{sub 2}PO{sub 4} salts. The synthesized material was structurally and superficially characterized using the XRD, BET, IR TGA and SEM techniques. The obtained inorganic material was identified as calcium phosphate that presents a great specific area for what can be efficiently used as adsorbent material for adsorption studies in the radioactive wastes treatment present in aqueous solution. (Author)

  19. Casein Phosphopeptide-Amorphous Calcium Phosphate and Shear Bond Strength of Adhesives to Primary Teeth Enamel

    OpenAIRE

    Farokh Gisovar, Elham; Hedayati, Nassim; Shadman, Niloofar; Shafiee, Leila

    2015-01-01

    Background: CPP-ACP (Phosphopeptide-Amorphous Calcium Phosphate) has an important role in caries prevention in pediatric patients. This study was done, because of the great use of CPP-ACP and the need for restoration for teeth treated with CPP-ACP as well as the importance of shear bond strength of adhesives in the success of restorations. Objectives: This study aimed to evaluate the effect of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on shear bond strength of dental adhesiv...

  20. A two-step roll coating phosphate/molybdate passivation treatment for hot-dip galvanized steel sheet

    International Nuclear Information System (INIS)

    A two-step roll coating passivation treatment employing phosphate followed by molybdate solutions has been performed on hot-dip galvanized (GI) steel sheet. The phosphate coating was primarily porous, amorphous Zn phosphate. A second step coating treatment resulted in more hemispherical Zn phosphate particles and the incorporation of molybdate ions and molybdenum oxide into the existing phosphate coating, giving rise to an improved corrosion resistance. The coating reaction during the second step roll coating treatment and the corrosion protection afforded by the second step molybdate treatment are discussed, with emphases on the comparison with the coating formed via immersion.

  1. Remineralization potential of bioactive glass and casein phosphopeptide-amorphous calcium phosphate on initial carious lesion: An in-vitro pH-cycling study

    OpenAIRE

    Adit Bharat Mehta; Veena Kumari; Rani Jose; Vajiheh Izadikhah

    2014-01-01

    Aims: The aim of this study was to evaluate and compare the remineralization potential of bioactive-Glass (BAG) (Novamin; /Calcium-sodium-phosphosilicate) and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) containing dentifrice. Materials and Methods: A total of 30 sound human premolars were decoronated, coated with nail varnish except for a 4 mm Χ 4 mm window on the buccal surface of crown and were randomly divided in two groups (n = 15). Group A - BAG dentifrice and Group B...

  2. Calcium-acidic phospholipid-phosphate complexes in human hydroxyapatite-containing pathologic deposits.

    OpenAIRE

    Boskey, A. L.; Bullough, P. G.; Vigorita, V.; Di Carlo, E

    1988-01-01

    The deposition of calcium-containing crystals in tissues is due to a combination of factors: elevation in the concentrations of precipitating ions, formation of specific nucleators, and removal of macromolecules that inhibit crystal deposition. This study tested the hypothesis that calcium acidic phospholipid phosphate complexes, which promote hydroxyapatite deposition both in vitro and in vivo, are associated only with hydroxyapatite deposits, and furthermore, that the presence of these comp...

  3. Systemic delivery of siRNA by hyaluronan-functionalized calcium phosphate nanoparticles for tumor-targeted therapy

    Science.gov (United States)

    Qiu, Chong; Wei, Wei; Sun, Jing; Zhang, Hai-Tao; Ding, Jing-Song; Wang, Jian-Cheng; Zhang, Qiang

    2016-06-01

    In this study, hyaluronan (HA)-functionalized calcium phosphate nanoparticles (CaP-AHA/siRNA NPs) were developed for an injectable and targetable delivery of siRNA, which were prepared by coating the alendronate-hyaluronan graft polymer (AHA) around the surface of calcium phosphate-siRNA co-precipitates. The prepared CaP-AHA/siRNA NPs had a uniform spherical core-shell morphology with an approximate size of 170 nm and zeta potential of -12 mV. The coating of hydrophilic HA improved the physical stability of nanoparticles over one month due to the strong interactions between phosphonate and calcium. In vitro experiments demonstrated that the negatively charged CaP-AHA/siRNA NPs could effectively deliver EGFR-targeted siRNA into A549 cells through CD44-mediated endocytosis and significantly down-regulate the level of EGFR expression. Also, the internalized CaP-AHA/siRNA NPs exhibited a pH-responsive release of siRNA, indicating that the acidification of lysosomes probably facilitated the disassembling of nanoparticles and the resultant ions sharply increased the inner osmotic pressure and thus expedited the release of siRNA from late lysosomes into the cytoplasm. Furthermore, in vivo tumor therapy demonstrated that high accumulation of CaP-AHA/siEGFR NPs in tumor led to a significant tumor growth inhibition with a specific EGFR gene silencing effect after intravenous administration in nude mice xenografted with A549 tumor, along with a negligible body weight loss. These results suggested that the CaP-AHA/siRNA NPs could be an effective and safe systemic siRNA delivery system for a RNAi-based tumor targeted therapy strategy.In this study, hyaluronan (HA)-functionalized calcium phosphate nanoparticles (CaP-AHA/siRNA NPs) were developed for an injectable and targetable delivery of siRNA, which were prepared by coating the alendronate-hyaluronan graft polymer (AHA) around the surface of calcium phosphate-siRNA co-precipitates. The prepared CaP-AHA/siRNA NPs had a uniform

  4. Magnesium substitution in the structure of orthopedic nanoparticles: A comparison between amorphous magnesium phosphates, calcium magnesium phosphates, and hydroxyapatites

    International Nuclear Information System (INIS)

    As biocompatible materials, magnesium phosphates have received a lot of attention for orthopedic applications. During the last decade multiple studies have shown advantages for magnesium phosphate such as lack of cytotoxicity, biocompatibility, strong mechanical properties, and high biodegradability. The present study investigates the role of Mg+2 and Ca+2 ions in the structure of magnesium phosphate and calcium phosphate nanoparticles. To directly compare the effect of Mg+2 and Ca+2 ions on structure of nanoparticles and their biological behavior, three groups of nanoparticles including amorphous magnesium phosphates (AMPs) which release Mg+2, calcium magnesium phosphates (CMPs) which release Mg+2 and Ca+2, and hydroxyapatites (HAs) which release Ca+2 were studied. SEM, TEM, XRD, and FTIR were used to evaluate the morphology, crystallinity, and chemical properties of the particles. AMP particles were homogeneous nanospheres, whereas CMPs were combinations of heterogeneous nanorods and nanospheres, and HAs which contained heterogeneous nanosphere particles. Cell compatibility was monitored in all groups to determine the cytotoxicity effect of particles on studied MC3T3-E1 preosteoblasts. AMPs showed significantly higher attachment rate than the HAs after 1 day and both AMPs and CMPs showed significantly higher proliferation rate when compared to HAs after 7 days. Gene expression level of osteoblastic markers ALP, COL I, OCN, OPN, RUNX2 were monitored and they were normalized to GAPDH housekeeping gene. Beta actin expression level was monitored as the second housekeeping gene to confirm the accuracy of results. In general, AMPs and CMPs showed higher expression level of osteoblastic genes after 7 days which can further confirm the stimulating role of Mg+2 and Ca+2 ions in increasing the proliferation rate, differentiation, and mineralization of MC3T3-E1 preosteoblasts. - Highlights: • Role of Mg2+ and Ca2+ ions in proliferation, and differentiation of

  5. Composition, structure and properties of sputter deposited calcium phosphate thin films

    International Nuclear Information System (INIS)

    The provision of calcium phosphate (Ca-P) coatings as part of medical (or dental) implants in order to provide a bioactive response in-vivo, and thereby improve bone apposition at the implant-tissue interface is a high priority research area. Bioceramic coatings derived from hydroxyapatite (HA, Ca10(PO4)6(OH)2), are now commonly used in a range of hard tissue implants for many clinical applications. Currently, plasma spraying is the main method used to deposit such coatings. However, the nature of the resultant coatings is often inappropriate for long term implant applications, the more so in younger patients who expect to have an active life post-operatively. Deposition by alternative methods, in particular Radio Frequency (RF) magnetron sputtering, has been found to offer significant advantages over plasma spraying. Effective utilisation of the sputtering process is, however, critically dependent on obtaining reproducible coatings with controlled properties. This thesis reports an extensive body of research undertaken to provide improved HA and related thin film coatings by the RF magnetron sputtering technique. Emphasis has been placed on providing a detailed understanding of how both the target materials and the deposition conditions employed influence key properties of the sputtered films. The experimental work focuses on several key points, including, the detailed characterisation of a range of commercially available Ca-P bioceramics and a comparison of these materials with the HA-type systems produced using a wet precipitation method and microwave assisted techniques. Subsequently, the work concentrates on the deposition of thin HA coatings onto a range of substrates using RF magnetron sputtering at deposition powers of less than 200 W. The targets used for these sputter deposition experiments were manufactured by both pressure filtration and standard dry pressing techniques. The Ca-P films produced have been compared to plasma sprayed coatings both

  6. Microstructure and property of zinc phosphate coating on die-casting magnesium alloy AZ91D

    Institute of Scientific and Technical Information of China (English)

    LI Guang-yu; LIAN Jian-she; NIU Li-yuan; JIANG Zhong-hao

    2006-01-01

    A surface treatment method was described, which can form a uniform and dense phosphate conversion coating on the die -casting magnesium alloy AZ91D in a non-chromate and non-nitrite bath. The coating consists of Zn3(PO4)2-4H2O, Zn, AlPO4 and MgZn2(PO4)2 analyzed by XRD. The SEM results show that the microstructure of the zinc phosphate coating transfers from flower-like to slab-like crystals with the increase of immersion time of magnesium alloy samples in the phosphating bath. The zinc phosphate coating formed in the bath with immersion time of 1 min is denser because metallic Zn and insoluble phosphate crystals co-deposit on the magnesium alloy surface and the growth of the crystals are restricted by each others. The zinc phosphate coating on the magnesium alloy is used as the base layer for further cataphoric and powder paintings. The cataphoric painting on AZ91D alloy based on phosphate coating has similar adhesion and corrosion-resistance to that based on the chromate conversion coating. But for powder painting, the former exhibits better adhesion property than the latter, due to the uneven microstructure and the enough thickness of the phosphate coating.

  7. Effect of Cationic and Anionic Surfactants on the Application of Calcium Carbonate Nanoparticles in Paper Coating

    CERN Document Server

    Barhoum, Ahmed; Abou-Zaied, Ragab Esmail; Rehan, Mohamed; Dufour, Thierry; Hill, Gavin; Dufresne, Alain

    2016-01-01

    Modification of calcium carbonate particles with surfactant significantly improves the properties of the calcium carbonate coating on paper. Unmodified and CTAB and oleate-modified calcium carbonate nanoparticles were prepared using the wet carbonation technique for paper coating. CTAB (cationic surfactant) and sodium oleate (anionic surfactant) were used to modify the size, morphology, and surface properties of the precipitated nanoparticles. The obtained particles were characterized by XRD, FT-IR spectroscopy, zeta potential measurements, TGA and TEM. Coating colors were formulated from the prepared unmodified and modified calcium carbonates and examined by creating a thin coating layer on reference paper. The effect of calcium carbonate particle size and surface modification on paper properties, such as coating thickness, coating weight, surface roughness, air permeability, brightness, whiteness, opacity, and hydrophobicity, were investigated and compared with GCC calcium carbonate-coated papers. The obtai...

  8. The role of a zinc phosphate pigment in the corrosion of scratched epoxy-coated steel

    International Nuclear Information System (INIS)

    The roles of a zinc phosphate pigment in the corrosion of scratched epoxy-coated steel were studied by means of electrochemical impedance spectroscopy, electrochemical noise measurement and scanning electrochemical microscopy. The experimental results of electrochemical noise measurement and electrochemical impedance spectroscopy revealed that zinc phosphate exhibited inhibition effect on the corrosion of the scratched epoxy-coated steel. The scanning electrochemical microscopy results implied that the scratched surface under zinc phosphate coating was re-healed by an insulating film. The mechanism of the inhibition effect of a zinc phosphate pigment was analyzed based upon the combined stochastic theory and shot noise theory using the Weibull distribution and Gumbel distribution function

  9. Effects of Silicate, Phosphate, and Calcium on the Stability of Aldopentoses

    Science.gov (United States)

    Nitta, Sakiko; Furukawa, Yoshihiro; Kakegawa, Takeshi

    2016-06-01

    Ribose is an important constituent of RNA: ribose connects RNA bases and forms a strand of sugar phosphates. Accumulation of ribose on prebiotic Earth was difficult because of its low stability. Improvement in the yield of ribose by the introduction of borate or silicate in a formose-like reaction has been proposed. The effects of borates have been further analyzed and confirmed in subsequent studies. Nonetheless, the effects of silicates and phosphates remain unclear. In the present study, we incubated aldopentoses in a highly alkaline aqueous solution at a moderate temperature to determine the effects of silicate or phosphate on the degradation rates of ribose and its isomeric aldopentoses. The formation of a complex of silicate (or phosphate) with ribose was also analyzed in experiments with 29Si and 31P nuclear magnetic resonance (NMR). We found that silicate or phosphate complexes of ribose were not detectable under our experimental conditions. The stability of ribose and lyxose improved after addition of 40-fold molar excess (relative to a pentose) of sodium silicate or sodium phosphate to the alkaline solution. The stability was not improved further when an 80-fold molar excess of sodium silicate or sodium phosphate was added. Calcium was removed from these solutions by precipitation of calcium salts. The drop in Ca2+ concentration might have improved the stability of ribose and lyxose, which are susceptible to aldol addition. The improvement of ribose stability by the removal of Ca2+ and by addition of silicate or phosphate was far smaller than the improvement by borate. Furthermore, all aldopentoses showed similar stability in silicate- and phosphate-containing solutions. These results clearly show that selective stabilization of ribose by borate cannot be replaced by the effects of silicate or phosphate; this finding points to the importance of borate in prebiotic RNA formation.

  10. Effects of Silicate, Phosphate, and Calcium on the Stability of Aldopentoses.

    Science.gov (United States)

    Nitta, Sakiko; Furukawa, Yoshihiro; Kakegawa, Takeshi

    2016-06-01

    Ribose is an important constituent of RNA: ribose connects RNA bases and forms a strand of sugar phosphates. Accumulation of ribose on prebiotic Earth was difficult because of its low stability. Improvement in the yield of ribose by the introduction of borate or silicate in a formose-like reaction has been proposed. The effects of borates have been further analyzed and confirmed in subsequent studies. Nonetheless, the effects of silicates and phosphates remain unclear. In the present study, we incubated aldopentoses in a highly alkaline aqueous solution at a moderate temperature to determine the effects of silicate or phosphate on the degradation rates of ribose and its isomeric aldopentoses. The formation of a complex of silicate (or phosphate) with ribose was also analyzed in experiments with (29)Si and (31)P nuclear magnetic resonance (NMR). We found that silicate or phosphate complexes of ribose were not detectable under our experimental conditions. The stability of ribose and lyxose improved after addition of 40-fold molar excess (relative to a pentose) of sodium silicate or sodium phosphate to the alkaline solution. The stability was not improved further when an 80-fold molar excess of sodium silicate or sodium phosphate was added. Calcium was removed from these solutions by precipitation of calcium salts. The drop in Ca(2+) concentration might have improved the stability of ribose and lyxose, which are susceptible to aldol addition. The improvement of ribose stability by the removal of Ca(2+) and by addition of silicate or phosphate was far smaller than the improvement by borate. Furthermore, all aldopentoses showed similar stability in silicate- and phosphate-containing solutions. These results clearly show that selective stabilization of ribose by borate cannot be replaced by the effects of silicate or phosphate; this finding points to the importance of borate in prebiotic RNA formation. PMID:26559965

  11. Grafting cyclodextrins to calcium phosphate ceramics for biomedical applications

    DEFF Research Database (Denmark)

    Jacobsen, P.A.L.; Nielsen, J.L.; Juhl, M.V.;

    2012-01-01

    The grafting of hydroxyapatite/beta-tricalcium phosphate with β-cyclodextrin was achieved using a two step reaction with (3-glycidyloxypropyl)trimethoxysilane as a linker. Firstly, the silane group was brought to react with the hydroxyl groups at the surface of the hydroxyapatite/beta-tricalcium ...

  12. The determination of calcium in phosphate, carbonate, and silicate rocks by flame photometer

    Science.gov (United States)

    Kramer, Henry

    1956-01-01

    A method has been developed for the determination of calcium in phosphate, carbonate, and silicate rocks using the Beckman flame photometer, with photomultiplier attachement. The sample is dissolved in hydrofluoric, nitric, and perchloric acids, the hydrofluoric and nitric acids are expelled, a radiation buffer consisting of aluminum, magnesium, iron, sodium, potassium, phosphoric acid, and nitric acid is added, and the solution is atomized in an oxy-hydrogen flame with an instrument setting of 554 mµ. Measurements are made by comparison against calcium standards, prepared in the same manner, in the 0 to 50 ppm range. The suppression of calcium emission by aluminum and phosphate was overcome by the addition of a large excess of magnesium. This addition almost completely restores the standard curve obtained from a solution of calcium nitrate. Interference was noted when the iron concentration in the aspirated solution (including the iron from the buffer) exceeded 100 ppm iron. Other common rock-forming elements did not interfere. The results obtained by this procedure are within ± 2 percent of the calcium oxide values obtained by other methods in the range 1 to 95 percent calcium oxide. In the 0 to 1 percent calcium oxide range the method compares favorably with standard methods.

  13. Surface modification of porous polycaprolactone/biphasic calcium phosphate scaffolds for bone regeneration in rat calvaria defect.

    Science.gov (United States)

    Kim, Ji-Hyun; Linh, Nguyen T B; Min, Young K; Lee, Byong-Taek

    2014-10-01

    In this study, polycaprolactone scaffolds fabricated by a salt-leaching process were loaded with biphasic calcium phosphate successfully to improve the osteoconductivity in bone regeneration. The surface of polycaprolactone/biphasic calcium phosphate scaffolds was aminolyzed by 1,6-hexamethylenediamine to introduce amino groups onto the surface, which was verified qualitatively by ninhyrin staining. Collagen was further immobilized on the aminolyzed porous polycaprolactone via N-ethyl-N'-(3-dimethylaminopropy) carbodiimide hydrochloride/hydroxy-2,5-dioxopyrolidine-3-sulfonic acid sodium cross-linking. The pore size of polycaprolactone/biphasic calcium phosphate-collagen scaffolds was 200-300 µm, which was suitable for bone in-growth. The X-ray photoelectron spectroscopy confirmed the coupling of collagen immobilized on the surface of polycaprolactone/biphasic calcium phosphate. In vitro results demonstrated that the spreading and viability of MC3T3-E1 cells were remarkably improved in the polycaprolactone/biphasic calcium phosphate-collagen scaffolds. The in vivo study was carried out by implanting the porous polycaprolactone, polycaprolactone/biphasic calcium phosphate, and polycaprolactone/biphasic calcium phosphate-collagen to the skulls of rats. Although the addition of biphasic calcium phosphate particles in the polycaprolactone scaffolds does not have a strong effect on the new bone formation, the immobilization of collagen on the polycaprolactone/biphasic calcium phosphate scaffolds significantly improved the bone regeneration even though the implantation time was short, 6 weeks. The present results provide more evidence that functionalizing polycaprolactone with biphasic calcium phosphate and collagen may be a feasible way to improve the osteoconduction in bone regeneration. PMID:24939961

  14. Silicon-stabilized α-tricalcium phosphate and its use in a calcium phosphate cement: characterization and cell response.

    Science.gov (United States)

    Mestres, Gemma; Le Van, Clemence; Ginebra, Maria-Pau

    2012-03-01

    α-Tricalcium phosphate (α-TCP) is widely used as a reactant in calcium phosphate cements. This work aims at doping α-TCP with silicon with a twofold objective. On the one hand, to study the effect of Si addition on the stability and reactivity of this polymorph. On the other, to develop Si-doped cements and to evaluate the effect of Si on their in vitro cell response. For this purpose a calcium-deficient hydroxyapatite was sintered at 1250°C with different amounts of silicon oxide. The high temperature polymorph α-TCP was stabilized by the presence of silicon, which inhibited reversion of the β→α transformation, whereas in the Si-free sample α-TCP completely reverted to the β-polymorph. However, the β-α transformation temperature was not affected by the presence of Si. Si-α-TCP and its Si-free counterpart were used as reactants for a calcium phosphate cement. While Si-α-TCP showed faster hydrolysis to calcium-deficient hydroxyapatite, upon complete reaction the crystalline phases, morphology and mechanical properties of both cements were similar. An in vitro cell culture study, in which osteoblast-like cells were exposed to the ions released by both materials, showed a delay in cell proliferation in both cases and stimulation of cell differentiation, more marked for the Si-containing cement. These results can be attributed to strong modification of the ionic concentrations in the culture medium by both materials. Ca-depletion from the medium was observed for both cements, whereas continuous Si release was detected for the Si-containing cement. PMID:22154863

  15. Lead Retention in a Calcareous Soil Influenced by Calcium and Phosphate Amendments

    Science.gov (United States)

    Phosphate amendments in calcareous lead (Pb)-contaminated soils to immobilize Pb may be hindered due to competition of Pb with calcium (Ca) that may inhibit the retention of Pb as a precipitation mechanism. This study explored the retention of Pb in a calcareous soil spiked and ...

  16. Adjuvant effects of chitosan and calcium phosphate particles in an inactivated Newcastle disease vaccine

    Science.gov (United States)

    The adjuvant activity of chitosan and calcium phosphate-particles (CAP) was studied following intranasal coadministration of commercial chickens with inactivated Newcastle disease virus (NDV) vaccine. After three vaccinations with inactivated NDV in combination with chitosan or CAP an increase in an...

  17. Theoretical and experimental approach to test the cohesion of calcium phosphate pastes

    Directory of Open Access Journals (Sweden)

    M Bohner

    2006-08-01

    Full Text Available Recent studies have revealed that the ability of a calcium phosphate cement paste to harden in a physiological environment without desintegrating into small particles might be a key property to ensure a safe and reliable clinical use of calcium phosphate cements. However, this property called cohesion is not well understood and has not been studied extensively. The goal of the present study was to better understand which factors affect the cohesion of a calcium phosphate paste using the combination of a theoretical and experimental approach. In the theoretical approach, factors expected to influence the paste cohesion such as Van der Waals forces, electrostatic and steric interactions, as well as osmotic effects were listed and discussed. In the experimental approach, a new method to measure the cohesion of a non-setting calcium phosphate paste was presented and used to assess the effects of various factors on this property. The new method allowed a continuous measurement of cohesion and gave reproducible results. The experimental results confirmed the theoretical predictions: an increase of the liquid-to-powder ratio of the paste and of the powder particle size, as well as the addition of citrate ions and in limited cases dissolved xanthan polymer chains reduced the paste cohesion.

  18. Mechanical evaluation of implanted calcium phosphate cement incorporated with PLGA microparticles.

    NARCIS (Netherlands)

    Link, D.P.; Dolder, J. van den; Jurgens, W.J.; Wolke, J.G.C.; Jansen, J.A.

    2006-01-01

    In this study, the mechanical properties of an implanted calcium phosphate (CaP) cement incorporated with 20wt% poly (dl-lactic-co-glycolic acid) (PLGA) microparticles were investigated in a rat cranial defect. After 2, 4 and 8 weeks of implantation, implants were evaluated mechanically (push-out te

  19. Transformation of amorphous calcium phosphate to crystalline dahillite in the radular teeth of chitons.

    Science.gov (United States)

    Lowenstam, H A; Weiner, S

    1985-01-01

    A comparison of infrared spectra from individual teeth along the radula of a chiton (Polyplacophora, Mollusca) shows that the first-formed calcium phosphate mineral is amorphous. Over a period of weeks the mineral transforms to dahllite. The c axes of the dahllite crystals are aligned approximately perpendicular to the tooth surface. PMID:17810022

  20. Transformation of Amorphous Calcium Phosphate to Crystalline Dahllite in the Radular Teeth of Chitons

    Science.gov (United States)

    Lowenstam, H. A.; Weiner, S.

    1985-01-01

    A comparison of infrared spectra from individual teeth along the radula of a chiton (Polyplacophora, Mollusca) shows that the first-formed calcium phosphate mineral is amorphous. Over a period of weeks the mineral transforms to dahllite. The c axes of the dahllite crystals are aligned approximately perpendicular to the tooth surface.

  1. In vivo performance of microstructured calcium phosphate formulated in novel water-free carriers

    NARCIS (Netherlands)

    Davison, N.L.; Yuan, H.; Bruijn, de J.D.; Barrere-de Groot, F.YF.

    2012-01-01

    Osteoinductive calcium phosphate (CaP) ceramics can be combined with polymeric carriers to make shapeable bone substitutes as an alternative to autologous bone; however, carriers containing water may degrade the ceramic surface microstructure, which is crucial to bone formation. In this study five n

  2. Evaluation of a porosity measurement method for wet calcium phosphate cements.

    Science.gov (United States)

    Ajaxon, Ingrid; Maazouz, Yassine; Ginebra, Maria-Pau; Öhman, Caroline; Persson, Cecilia

    2015-11-01

    The porosity of a calcium phosphate cement is a key parameter as it affects several important properties of the cement. However, a successful, non-destructive porosity measurement method that does not include drying has not yet been reported for calcium phosphate cements. The aim of this study was to evaluate isopropanol solvent exchange as such a method. Two different types of calcium phosphate cements were used, one basic (hydroxyapatite) and one acidic (brushite). The cements were allowed to set in an aqueous environment and then immersed in isopropanol and stored under three different conditions: at room temperature, at room temperature under vacuum (300 mbar) or at 37℃. The specimen mass was monitored regularly. Solvent exchange took much longer time to reach steady state in hydroxyapatite cements compared to brushite cements, 350 and 18 h, respectively. Furthermore, the immersion affected the quasi-static compressive strength of the hydroxyapatite cements. However, the strength and phase composition of the brushite cements were not affected by isopropanol immersion, suggesting that isopropanol solvent exchange can be used for brushite calcium phosphate cements. The main advantages with this method are that it is non-destructive, fast, easy and the porosity can be evaluated while the cements remain wet, allowing for further analysis on the same specimen. PMID:26163278

  3. Methotrexate loaded self stabilized calcium phosphate nanoparticles: a novel inorganic carrier for intracellular drug delivery.

    Science.gov (United States)

    Mukesh, Ukawala; Kulkarni, Vijay; Tushar, Rajyaguru; Murthy, R S R

    2009-02-01

    Calcium phosphate is considered as a potential biomaterial for drug and gene delivery because of its excellent features. In this study, we reported the formulation and characterization of calcium phosphate nanoparticle containing anticancer drug, methotrexate (MTX). Calcium phosphate nanoparticles containing MTX (CaPi-MTX) were prepared by reverse micelles technique. CaPi-MTX nanoparticles of average size 262 +/- 47.64 nm with entrapment efficiency of 58.04 +/- 4.09% were obtained. The IR spectrum of CaPi-MTX showed characteristics of composite formation of hydroxyapatite with MTX. X-RD analysis revealed that, CaPi-MTX nanoparticles were crystalline and in hydroxyapatite form. TEM studies showed that CaPi-MTX nanoparticles were spherical in shape. In vitro release study of CaPi-MTX nanoparticles showed slow release of MTX at physiological pH (pH 7.4) while > 90% release was observed within 3-4 hours at endosomal pH (pH 5.5 and pH 6.0). Confocal microscopy was performed using CHO cell lines, showed intracellular localization of FITC-Dextran loaded calcium phosphate nanoparticles. Results indicate that prepared CaPi-MTX nanoparticles could serve the purpose for intracellular drug delivery. PMID:20055112

  4. An injectable calcium phosphate cement for the local delivery of paclitaxel to bone

    NARCIS (Netherlands)

    Lopez-Heredia, M.A.; Kamphuis, G.J.; Thune, P.C.; Oner, F.C.; Jansen, J.A.; Walboomers, X.F.

    2011-01-01

    Bone metastases are usually treated by surgical removal, fixation and chemotherapeutic treatment. Bone cement is used to fill the resection voids. The aim of this study was to develop a local drug delivery system using a calcium phosphate cement (CPC) as carrier for chemotherapeutic agents. CPC cons

  5. Preparation and Compressive Strength of Calcium Phosphate Bone Cement Containing N, O-carboxymethyl Chitosan

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    N, O-carboxymethyl chitosan ( CMCTS ), a kind of biodegradable organic substance, was added to calcium phosphate bone cement (CPC) to produce a composite more similar in composition to human bone. The compressive strength of the new material was increased by 10 times compared with conventional CPC.

  6. The role of prenucleation clusters in surface-induced calcium phosphate crystallization

    Science.gov (United States)

    Dey, Archan; Bomans, Paul H. H.; Müller, Frank A.; Will, Julia; Frederik, Peter M.; de With, Gijsbertus; Sommerdijk, Nico A. J. M.

    2010-12-01

    Unravelling the processes of calcium phosphate formation is important in our understanding of both bone and tooth formation, and also of pathological mineralization, for example in cardiovascular disease. Serum is a metastable solution from which calcium phosphate precipitates in the presence of calcifiable templates such as collagen, elastin and cell debris. A pathological deficiency of inhibitors leads to the uncontrolled deposition of calcium phosphate. In bone and teeth the formation of apatite crystals is preceded by an amorphous calcium phosphate (ACP) precursor phase. ACP formation is thought to proceed through prenucleation clusters-stable clusters that are present in solution already before nucleation-as was recently demonstrated for CaCO3 (refs 15,16). However, the role of such nanometre-sized clusters as building blocks for ACP has been debated for many years. Here we demonstrate that the surface-induced formation of apatite from simulated body fluid starts with the aggregation of prenucleation clusters leading to the nucleation of ACP before the development of oriented apatite crystals.

  7. Reinforcement of freeze-dried chitosan scaffolds with multiphasic calcium phosphate short fibers.

    Science.gov (United States)

    Mohammadi, Zahra; Mesgar, Abdorreza Sheikh-Mehdi; Rasouli-Disfani, Fariba

    2016-08-01

    The composite scaffolds of the chitosan and multiphasic calcium phosphate (HW) short fibers were prepared by freeze drying and characterized by X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM and FE-SEM). The mechanical properties of the scaffolds were assessed by compression test. The incorporation of HW fibers consisting three phases of hydroxyapatite (HA), beta-tricalcium phosphate (β-TCP) and calcium pyrophosphate (CPP) into the chitosan matrices was associated with an increase in pore size, density and compressive strength and modulus, and a decrease in porosity and swelling ratio of the scaffolds. The strongest composite scaffolds in this study with a chitosan: HW fibers weight ratio of 1:1 showed a mean porosity of 69% and a mean strength and modulus of 420kPa and 3.87MPa, respectively. The in vitro bioactivity of the composites was confirmed by the formation of a calcium phosphate rich layer on the surface of soaked scaffolds in simulated body fluid. The findings of this initial work indicate that the chitosan-multiphasic calcium phosphate short fibers may be a suitable material for bone scaffolding. PMID:27179144

  8. In-situ observation on the transformation of calcium phosphate cement into hydroxyapatite

    International Nuclear Information System (INIS)

    In the present study, the in-situ transformation of calcium phosphate cement into hydroxyapatite (HAp) within the first hour is monitored with a synchrotron X-ray beam. A disodium hydrogen phosphate solution is used as cement liquid to activate the reaction between dicalcium phosphate anhydrous (DCPA) and calcium hydroxide (Ca(OH)2). The XRD analysis indicates that the amounts of DCPA and Ca(OH)2 first decrease within the first min of the reaction. Then, the intensity of DCPA's XRD peaks starts to increase instead in the period of 5 to 20 min. After 20 min, the DCPA particles are consumed slowly to form fine HAp particles. Large pores are evident upon the completion of reaction.

  9. Solid-state P-31 MR studies of bone mineral and calcium phosphate bone cements

    International Nuclear Information System (INIS)

    Calcium phosphate bone cements have recently been used to promote bone healing and remodeling, but little is known of their bioabsorption. The purpose of this paper to characterize and quantitate bone mineral and calcium phosphate bone cements with the use of solid-state P-31 NMR imaging to establish a model for bioabsorption studies. Pulverized cortical rabbit bone, octacalcium phosphate spherulites, and two synthetic apatite formulations (A and B, Norian, Mountain View, Calif) were evaluated in vitro. A 9.4-T Varian VXR-400S spectrometer operating at 161.9 MHz for P-31 was used to obtain NMR imaging spectra with the magic-angel spinning technique at a sample spin frequency of 6-7.5 kHz, utilizing an external 85% phosphoric acid reference. T1 was determined in a static 90 degrees τ 90 degrees experiment. Quantitation was attempted in mixed samples

  10. Calcium phosphate holmium-166 ceramic to addition in bone cement: synthesis and characterization

    International Nuclear Information System (INIS)

    Spine metastases are a common and painful complication of cancer. The treatment often consists of bone cement injection (vertebroplasty or kyphoplasty) within vertebral body for vertebrae stabilization, followed by external beam radiation therapy. Recently, researchers introduced the concept of radioactive bone cement for spine tumors therapy. Then, investigations about bioactive and radioactive materials became interesting. In this study, we present the synthesis of calcium phosphate incorporated holmium (CaP-Ho) via sol-gel technique, and its characterization by XRD, FT-IR, NA and SEM. Results showed a multiphasic bioceramic composed mainly of hydroxyapatite, β-tricalcium phosphate, holmium phosphate and traces of calcium pyrophosphate. Furthermore, the nuclide Ho-166 was the major radioisotope produced. Despite that, the radioactive bioceramic CaP-166Ho must be investigated in clinical trials to assure its efficacy and safety on spine tumors treatment (author)

  11. Calcium phosphate holmium-166 ceramic to addition in bone cement: synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Donanzam, Blanda A.; Campos, Tarcisio P.R., E-mail: campos@nuclear.ufmg.b [Universidade do Federal de Minas Gerais (DEN/UFMG), Belo Horizonte, MG (Brazil). Escola de Engenharia. Dept. de Engenharia Nuclear; Dalmazio, Ilza; Valente, Eduardo S., E-mail: id@cdtn.b, E-mail: valente@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2011-07-01

    Spine metastases are a common and painful complication of cancer. The treatment often consists of bone cement injection (vertebroplasty or kyphoplasty) within vertebral body for vertebrae stabilization, followed by external beam radiation therapy. Recently, researchers introduced the concept of radioactive bone cement for spine tumors therapy. Then, investigations about bioactive and radioactive materials became interesting. In this study, we present the synthesis of calcium phosphate incorporated holmium (CaP-Ho) via sol-gel technique, and its characterization by XRD, FT-IR, NA and SEM. Results showed a multiphasic bioceramic composed mainly of hydroxyapatite, {beta}-tricalcium phosphate, holmium phosphate and traces of calcium pyrophosphate. Furthermore, the nuclide Ho-166 was the major radioisotope produced. Despite that, the radioactive bioceramic CaP-{sup 166}Ho must be investigated in clinical trials to assure its efficacy and safety on spine tumors treatment (author)

  12. Preparation of calcium carbonate particles coated with titanium dioxide

    Institute of Scientific and Technical Information of China (English)

    Hai Lin; Ying-bo Dong; Le-yong Jiang

    2009-01-01

    The preparation of a new mineral composite material, calcium carbonate particles coated with titanium dioxide, was stud-ied. The mechanism of the preparation process was proposed. The new mineral composite material was made by the mechanochemi-eal method under the optimum condition that the mass ratio of calcium carbonate particles to titanium dioxide was 6.5:3.5. The mass ratios of two different types of titanium dioxide (anatase to rutile) and grinding media to grinded materials were 8:2 and 4:1 respec-tively, and the modified density was 60%. Under this condition, the new material was capable of forming after 120-min modification.The hiding power and oil absorption of this new material were 29.12 g/m~2 and 23.30%, respectively. The results show that the modi-fication is based on surface hydroxylation. After coating with titanium dioxide, the hiding power of calcium carbonate can be im-proved greatly. The new mineral composite materials can be used as the substitute for titanium dioxide.

  13. Kinetics and Mechanism of Adsorption of Phosphate on Fluorine-containing Calcium Silicate

    Institute of Scientific and Technical Information of China (English)

    ZHU Xinhua; ZHANG Zhao; SHEN Jun

    2016-01-01

    The nanowires-reticulated calcium silicate with a speciifc surface area more than 100 m2/g was prepared by a hydrothermal process using hydrated lime (Ca(OH)2, HL) and silica containing soluble lfuoride, which was a by-product of lfuorine industry, and the soluble lfuoride in raw silica was ifxed as CaSiF6 at the same time. The kinetic characteristics and mechanism of adsorbing phosphate by lfuorine-containing calcium silicate were investigated in the experiments of phosphorus (P) removal from aqueous solution. The results show that the prepared lfuorine-containing calcium silicate has excellent performance for adsorbing phosphate, the adsorption process appears to follow pseudo-second-order reaction kinetics and the process is mainly controlled by chemisorption. The product resulted from P adsorption is mainly composed of hydroxyapatite (HAP) and lfuorapatite (FAP), which are further used as adsorbents of heavy metal ion Cd2+ in aqueous solution and display excellent performance.

  14. Rapid biomimetic deposition of octacalcium phosphate coatings on zirconia ceramics (Y-TZP) for dental implant applications

    Science.gov (United States)

    Stefanic, Martin; Krnel, Kristoffer; Pribosic, Irena; Kosmac, Tomaz

    2012-03-01

    Octacalcium phosphate (OCP) coatings on zirconia oral implants have a great potential to improve the osseointegration of already existing ceramic implants, owing to high osteoconductive characteristics of OCP and its possibility of use as a drug delivery system. Such OCP coatings can be prepared with a simple two-step biomimetic procedure investigated in our study. In the first step, zirconia discs were immersed into the solution with a pH 7.4 and after 1 h of soaking a thin nanostructured calcium phosphate (Ca-P) layer was precipitated on the ceramic substrate via three stages: (i) precipitation of an amorphous Ca-P; (ii) precipitation of the OCP; and (iii) the transformation of the OCP to apatite. This Ca-P layer later served as a template for the rapid deposition of a thicker OCP coating in the second step of the synthesis where the substrate was immersed into the solution with pH 7.0. The main benefits of the method are a relatively quick synthesis, simplicity and a good reproducibility. Moreover, the coatings show good tensile adhesion strength according to the tape tests (ASTM D-3359). In addition, mild physiological conditions of the synthesis may allow incorporation of biologically active molecules in the coating.

  15. Structure and properties of calcium iron phosphate glasses

    International Nuclear Information System (INIS)

    The structural properties of xCaO–(100 − x) (0.4Fe2O3–0.6P2O5) (x = 0, 10, 20, 30, 40, 50 mol%) glasses have been investigated by XRD, DTA, IR and Raman spectroscopy. XRD analysis has confirmed that the majority of samples are X-ray amorphous, and EDS analysis indicates that the glass matrix can accommodate ≈30 mol% CaO. IR and Raman spectra show that the glass structure consists predominantly of pyrophosphate (Q1) units. IR spectra indicate that the phosphate network is depolymerized with the addition of CaO content. The density and glass transition temperature (Tg) increase with increasing CaO content for the glasses. This behavior indicates that the addition of CaO improves the strength of the cross-links between the phosphate chains of the glass

  16. Phase stability of silver particles embedded calcium phosphate bioceramics

    Indian Academy of Sciences (India)

    Brajendra Singh; Samayendra Kumar; Naresh Saha; Bikramjit Basu; Rajeev Gupta

    2015-04-01

    In this paper, we report the compositional variation-dependent phase stability of hydroxyapatite (Ca10(PO4)6(OH)2) on doping with silver. The transformation of hydroxyapatite to (/) tricalcium phosphate phases during sintering has been explored using Raman spectroscopy and X-ray diffraction techniques. The optical absorption spectroscopy analysis reveals the presence of Ag+ ions at low doping levels. As the doping increases, abundance of Ag particles is enhanced.

  17. Development of nano SiO2 incorporated nano zinc phosphate coatings on mild steel

    International Nuclear Information System (INIS)

    Highlights: • Nano SiO2 incorporated nano zinc phosphate coating on mild steel was developed. • Coatings showed enhanced corrosion resistance. • The nano SiO2 is adsorbed on mild steel surface and become nucleation sites. • The nano SiO2 accelerates the phosphating process. - Abstract: This paper reports the development of nano SiO2 incorporated nano zinc phosphate coatings on mild steel at low temperature for achieving better corrosion protection. A new formulation of phosphating bath at low temperature with nano SiO2 was attempted to explore the possibilities of development of nano zinc phosphate coatings on mild steel with improved corrosion resistance. The coatings developed were studied by Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDX), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Electrochemical measurements. Significant variation in the coating weight, morphology and corrosion resistance was observed as nano SiO2 concentrations varied from 0.5–4 g/L. The results showed that, the nano SiO2 in the phosphating solution changed the initial potential of the interface between mild steel substrate and phosphating solution and reduce the activation energy of the phosphating process, increase the nucleation sites and yielded zinc phosphate coatings of higher coating weight, greater surface coverage and enhanced corrosion resistance. Better corrosion resistance was observed for coatings derived from phosphating bath containing 1.5 g/L nano SiO2. The new formulation reported in the present study was free from Ni or Mn salts and had very low concentration of sodium nitrite (0.4 g/L) as accelerator

  18. Development of nano SiO{sub 2} incorporated nano zinc phosphate coatings on mild steel

    Energy Technology Data Exchange (ETDEWEB)

    Tamilselvi, M. [Department of Chemistry, Thiru Kolanjiappar Government Arts College, Virudhachalam 606001 (India); Kamaraj, P. [Department of Chemistry, SRM University, Kattankulathur 603203 (India); Arthanareeswari, M., E-mail: arthanareeswari@gmail.com [Department of Chemistry, SRM University, Kattankulathur 603203 (India); Devikala, S.; Selvi, J. Arockia [Department of Chemistry, SRM University, Kattankulathur 603203 (India)

    2015-03-30

    Highlights: • Nano SiO{sub 2} incorporated nano zinc phosphate coating on mild steel was developed. • Coatings showed enhanced corrosion resistance. • The nano SiO{sub 2} is adsorbed on mild steel surface and become nucleation sites. • The nano SiO{sub 2} accelerates the phosphating process. - Abstract: This paper reports the development of nano SiO{sub 2} incorporated nano zinc phosphate coatings on mild steel at low temperature for achieving better corrosion protection. A new formulation of phosphating bath at low temperature with nano SiO{sub 2} was attempted to explore the possibilities of development of nano zinc phosphate coatings on mild steel with improved corrosion resistance. The coatings developed were studied by Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDX), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Electrochemical measurements. Significant variation in the coating weight, morphology and corrosion resistance was observed as nano SiO{sub 2} concentrations varied from 0.5–4 g/L. The results showed that, the nano SiO{sub 2} in the phosphating solution changed the initial potential of the interface between mild steel substrate and phosphating solution and reduce the activation energy of the phosphating process, increase the nucleation sites and yielded zinc phosphate coatings of higher coating weight, greater surface coverage and enhanced corrosion resistance. Better corrosion resistance was observed for coatings derived from phosphating bath containing 1.5 g/L nano SiO{sub 2}. The new formulation reported in the present study was free from Ni or Mn salts and had very low concentration of sodium nitrite (0.4 g/L) as accelerator.

  19. Dynamic changes in calcium and phosphate plasma concentrations in the patients on peritoneal dialysis

    Directory of Open Access Journals (Sweden)

    Jovanović Nataša

    2006-01-01

    Full Text Available Background/Aim. The disturbances of active forms of vitamin D synthesis and disturbances in calcium and posphate metabolism develop early in chronic renal failure, when creatinine clearance is about 30 ml/min. Chronic hemodialysis and peritoneal dialysis only partially correct the biochemical environment of patients on chronic renal replacement therapy because of end-stage renal disease. These dialysis modalities can’t significantly affect the endocrine disturbances of chronic renal failure and they have minimal modulatory effect. The management of disturbed calcium (Ca and phosphate (P metabolism and the maintainance of Ca × P product below 4.4 mmol/l thanks to the use of dialysate solutions with the appropriate calcium concentration and the careful dosage of phosphate binders, calcium and active vitamin D metabolits, are extremely important for the prevention of renal osteodystrophy, secondary hyperparathyroidism as well as low-bone turnover disease. The aim of the study was to analyze the plasma levels of calcium, phosphate, albumin, alkaline phosphatase and parathormon (PTH in 58 patients who were treated with continuous ambulatory peritoneal dialysis (CAPD from March to August 2003. The use of phosphate binders and the substitution with active vitamin D metabolits were also analyzed. Methods. We examined 58 patients, 30 males and 28 female, mean-age 52 years (range, 26-78 years, affected by end-stage renal disease of the different leading cause. The average time on peritoneal dialysis program was 20 months (2-66 months. Most of the patients were treated by CAPD, while only few of them performed automatic, cyclic or intermittent peritoneal dialysis. Most of the patients used a dialysate with 1.75 mmol/l calcium concentration. Results. The study showed that our patients on chronic CAPD program during several months had normal calcemia, phosphatemia and the level of alkaline phosphatase, and that they had Ca × P product in the recommended

  20. Electrocrystallization, growth and characterization of calcium phosphate ceramics on magnesium alloys

    International Nuclear Information System (INIS)

    Highlights: • HA coating preparation on Mg-alloy includes electrochemical and chemical processes. • Two step coating formation is a convenient method for bone-like coating formation. • Electrochemically assisted deposition enables to coat implants with a complex shape. • Electrocrystallization of CaHPO4 film occurs as 3D instantaneous nucleation. • Bioactive properties of HA coatings were directly identified with Ca/P mole ratio. -- Abstract: In order to make biodegradable magnesium alloys corrosion resistant for a potential orthopaedic and bio-implant application, their surface should be modified with bioactive bone-like hydroxyapatite (HA) coatings. In the present paper, the initial step of coating formation on Mg alloy was studied by electrochemical techniques. The electrocrystallization and growth of the surface film occur as an instantaneous 3D nucleation under diffusion control, as was extracted from a fitting procedure of current-time transient data to the various nucleation models. Electrodeposited calcium hydrogenphosphate coatings were converted into bone-like HA (calcium deficient HA) in an alkaline treatment. The bioactive properties of HA coatings have been directly identified with a Ca/P mole ratio. Their morphology, composition and barrier properties were identified using scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS), and voltammetry

  1. Calcium Carbonate versus Sevelamer Hydrochloride as Phosphate Binders after Long-Term Disease Progression in 5/6 Nephrectomized Rats

    Directory of Open Access Journals (Sweden)

    Suvi Törmänen

    2014-01-01

    Full Text Available Our aim was to compare the effects of calcium carbonate and sevelamer-HCl treatments on calcium-phosphate metabolism and renal function in 5/6 nephrectomized (NX rats so that long-term disease progression preceded the treatment. After 15-week progression, calcium carbonate (3.0%, sevelamer-HCl (3.0%, or control diets (0.3% calcium were given for 9 weeks. Subtotal nephrectomy reduced creatinine clearance (−40%, plasma calcidiol (−25%, and calcitriol (−70% and increased phosphate (+37%, parathyroid hormone (PTH (11-fold, and fibroblast growth factor-23 (FGF-23 (4-fold. In NX rats, calcium carbonate diet increased plasma (+20% and urinary calcium (6-fold, reduced plasma phosphate (−50% and calcidiol (−30%, decreased creatinine clearance (−35% and FGF 23 (−85%, and suppressed PTH without influencing blood pH. In NX rats, sevelamer-HCl increased urinary calcium (4-fold and decreased creatinine clearance (−45%, PTH (−75%, blood pH (by 0.20 units, plasma calcidiol (−40%, and calcitriol (−65%. Plasma phosphate and FGF-23 were unchanged. In conclusion, when initiated after long-term progression of experimental renal insufficiency, calcium carbonate diet reduced plasma phosphate and FGF-23 while sevelamer-HCl did not. The former induced hypercalcemia, the latter induced acidosis, while both treatments reduced vitamin D metabolites and deteriorated renal function. Thus, delayed initiation influences the effects of these phosphate binders in remnant kidney rats.

  2. Effect of Fluoride, Casein Phosphopeptide–Amorphous Calcium Phosphate and Casein Phosphopeptide–Amorphous Calcium Phosphate Fluoride on Enamel Surface Microhardness After Microabrasion: An In Vitro Study

    Directory of Open Access Journals (Sweden)

    Ghazaleh Ahmadi Zenouz

    2016-03-01

    Full Text Available Objectives: This study aimed to assess the effect of applying casein phosphopeptide–amorphous calcium phosphate (CPP-ACP paste, casein phosphopeptide–amorphous calcium phosphate fluoride (CPP-ACPF paste and sodium fluoride gel on surface microhardness of enamel after microabrasion.Materials and Methods: Thirty freshly extracted human premolars were selected. All samples were subjected to hardness indentations made with the Vickers hardness machine and the average value was recorded as the initial surface microhardness. The specimens were then randomly divided into three groups (n=10 of CPP-ACPF, fluoride and CPP-ACP. The teeth were micro-abraded with Opalustre. Microhardness test was performed to assess the post-abrasion hardness. Three remineralization modalities were performed on samples of each group. The enamel surface microhardness measurements were performed. To compare the difference between groups, the rehardening and softening values were defined. One-way ANOVA and Tukey’s post hoc test at a significance level of 5% were used for statistical analysis.Results: The mean microhardness value (MMV had a significant decrease after microabrasion from baseline. The MMV had a significant increase after remineralization in all groups. The MMV of CPP-ACPF group was significantly more than that of fluoride group (P=0.027. The rehardening value of fluoride group was significantly more than that of other groups (P<0.001.Conclusion: All the remineralizing agents were effective for rehardening the enamel after microabrasion. The CPP-ACP and CPP-ACPF pastes are effective, but to a lesser extent than neutral sodium fluoride gel in remineralizing enamel surface. Incorporation of fluoride to CPP-ACP formulation does not provide any additional remineralizing potential.Keywords: Casein phosphopeptide-amorphous calcium phosphate nanocomplex; Enamel Microabrasion; Hardness; Sodium Fluoride

  3. Synthesis and characterization of calcium phosphate/collagen biocomposites doped with Zn{sup 2+}

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Maria Helena [Department of Dentistry, Federal University of Vales do Jequitinhonha e Mucuri-UFVJM, mailbox 38, Zip:39100-000, Diamantina, MG (Brazil)], E-mail: mariahelena.santos@gmail.com; Dias Heneine, Luis Guilherme [Department of Health Science, Ezequiel Dias Foundation, Belo Horizonte, MG (Brazil); Sander Mansur, Herman [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais, Belo Horizonte, MG (Brazil)

    2008-05-01

    Composites were developed using calcium phosphate (CaP)/collagen (COL) doped with Zn{sup +2} to attempt the materials association with adequate properties for biological applications in the recovery of the bone tissue by trauma or pathogenies. Hydroxyapatite (HAP) and hydroxyapatite-{beta}tricalcium phosphate (HAP{beta}TCP) were synthesized and doped with zinc nitrate. High purity grade type I collagen was extracted and purified from bovine pericardium. CaP doped and undoped with Zn{sup +2} were produced with COL and the composites were developed using a simple mixture process. All samples were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction analysis (XRD. In addition, biocompatibility and cell viability were assessed by MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide) using osteoblast cell culture. The results have indicated that both morphological and structural features and chemical composition of the composites were very similar to their precursors, collagen and calcium phosphate components. Also, the biocomposites presented a homogeneous aspect with the calcium phosphate particles aggregated to the collagen fibers. The biological evaluation of the composites in vitro showed cellular viability, presenting proliferation of the osteoblasts compared to the control cells (P < 0.05). The composites showed appropriate physical and biological properties creating more biologically active scaffolds that may support bone growth. Therefore, the novel developed biocomposites have high potential to be used for rebuilding small lesions in bone tissue engineering.

  4. Structural characterization of anion-calcium-humate complexes in phosphate-based fertilizers.

    Science.gov (United States)

    Baigorri, Roberto; Urrutia, Oscar; Erro, Javier; Mandado, Marcos; Pérez-Juste, Ignacio; Garcia-Mina, José María

    2013-07-01

    Fertilizers based on phosphate-metal-humate complexes are a new family of compounds that represents a more sustainable and bioavailable phosphorus source. The characterization of this type of complex by using solid (31)P NMR in several fertilizers, based on single superphosphate (SSP) and triple superphosphate (TSP) matrices, yielded surprising and unexpected trends in the intensity and fine structure of the (31)P NMR peaks. Computational chemistry methods allowed the characterization of phosphate-calcium-humate complexes in both SSP and TSP matrices, but also predicted the formation of a stable sulfate-calcium-humate complex in the SSP fertilizers, which has not been described previously. The stability of this complex has been confirmed by using ultrafiltration techniques. Preference towards the humic substance for the sulfate-metal phase in SSP allowed the explanation of the opposing trends that were observed in the experimental (31)P NMR spectra of SSP and TSP samples. Additionally, computational chemistry has provided an assignment of the (31)P NMR signals to different phosphate ligands as well as valuable information about the relative strength of the phosphate-calcium interactions within the crystals. PMID:23670945

  5. Synthesis and characterization of calcium phosphate/collagen biocomposites doped with Zn2+

    International Nuclear Information System (INIS)

    Composites were developed using calcium phosphate (CaP)/collagen (COL) doped with Zn+2 to attempt the materials association with adequate properties for biological applications in the recovery of the bone tissue by trauma or pathogenies. Hydroxyapatite (HAP) and hydroxyapatite-βtricalcium phosphate (HAPβTCP) were synthesized and doped with zinc nitrate. High purity grade type I collagen was extracted and purified from bovine pericardium. CaP doped and undoped with Zn+2 were produced with COL and the composites were developed using a simple mixture process. All samples were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction analysis (XRD. In addition, biocompatibility and cell viability were assessed by MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide) using osteoblast cell culture. The results have indicated that both morphological and structural features and chemical composition of the composites were very similar to their precursors, collagen and calcium phosphate components. Also, the biocomposites presented a homogeneous aspect with the calcium phosphate particles aggregated to the collagen fibers. The biological evaluation of the composites in vitro showed cellular viability, presenting proliferation of the osteoblasts compared to the control cells (P < 0.05). The composites showed appropriate physical and biological properties creating more biologically active scaffolds that may support bone growth. Therefore, the novel developed biocomposites have high potential to be used for rebuilding small lesions in bone tissue engineering

  6. Development of a fully injectable calcium phosphate cement for orthopedic and dental applications

    Indian Academy of Sciences (India)

    Manoj Komath; H K Varma

    2003-06-01

    A study on the development of a fully injectable calcium phosphate cement for orthopedic and dental applications is presented. The paper describes its characteristic properties including results of bio- compatibility studies. A conventional two-component calcium phosphate cement formulation (having a powder part containing dry mixture of acidic and basic calcium phosphate particles and a liquid part containing phosphate solution) is modified with a biocompatible gelling agent, to induce flow properties and cohesion. The quantity of the gelling agent is optimized to get a viscous paste, which is smoothly injectable through an 18-gauge needle, with clinically relevant setting parameters. The new formulation has a setting time of 20 min and a compressive strength of 11 MPa. The X-ray diffraction, Fourier transform infrared spectrometry, and energy dispersive electron microprobe analyses showed the phase to be hydroxyapatite, the basic bone mineral. Scanning electron microscopy revealed a porous structure with particle sizes of a few micrometers. The cement did not show any appreciable dimensional or thermal change during setting. The injectability is estimated by extruding through needle and the cohesive property is assessed by water contact method. The cement passed the in vitro biocompatibility screening (cytotoxicity and haemolysis) tests.

  7. Hereditary deafness with hydrops and anomalous calcium phosphate deposits

    Energy Technology Data Exchange (ETDEWEB)

    Johnsson, L.G.; Rouse, R.C.; Hawkins, J.E. Jr.; Kingsley, T.C.; Wright, C.G.

    1981-11-01

    The temporal bones from a 58-year-old white woman who had had hereditary congenital deafness were examined with the techniques of microdissection and surface preparations followed by sectioning of the modiolus. There was bilateral, almost total sensorineural degeneration, which also involved the saccule. The degeneration of the distal processes of the cochlear neurons in the osseous spiral lamina was almost complete, whereas numerous ganglion cells and proximal processes remained in the modiolus and the internal auditory canal. Severe cochleo-saccular hydrops was present in the left ear with Reissner's membrane bulging into the horizontal canal. X-ray diffraction and electron probe analysis were used to study the abnormal crystalline deposits in both ears. On the left side the saccular otoconia were composed of calcite, but the utricular macula was covered by a crust of apatite spherulites. More apatite occurred around the maculae and in the scala media. The cupulae were composed of apatite and octacalcium phosphate. On the right side the utricular otoconia were of normal calcite, but there was a deposit of apatite on the macula sacculi. The upper part of the scala media was completely filled by a deposit of apatite and octacalcium phosphate.

  8. Hereditary deafness with hydrops and anomalous calcium phosphate deposits

    International Nuclear Information System (INIS)

    The temporal bones from a 58-year-old white woman who had had hereditary congenital deafness were examined with the techniques of microdissection and surface preparations followed by sectioning of the modiolus. There was bilateral, almost total sensorineural degeneration, which also involved the saccule. The degeneration of the distal processes of the cochlear neurons in the osseous spiral lamina was almost complete, whereas numerous ganglion cells and proximal processes remained in the modiolus and the internal auditory canal. Severe cochleo-saccular hydrops was present in the left ear with Reissner's membrane bulging into the horizontal canal. X-ray diffraction and electron probe analysis were used to study the abnormal crystalline deposits in both ears. On the left side the saccular otoconia were composed of calcite, but the utricular macula was covered by a crust of apatite spherulites. More apatite occurred around the maculae and in the scala media. The cupulae were composed of apatite and octacalcium phosphate. On the right side the utricular otoconia were of normal calcite, but there was a deposit of apatite on the macula sacculi. The upper part of the scala media was completely filled by a deposit of apatite and octacalcium phosphate

  9. Investigation into the role of NaOH and calcium ions in the synthesis of calcium phosphate nanoshells

    Directory of Open Access Journals (Sweden)

    C. H. Yeo

    2012-03-01

    Full Text Available Calcium phosphate (CaP nanoshells were prepared using negatively charged liposomes (1,2-dioleoyl-sn-glycero-3-phosphate sodium salt (DOPA as a template by base titration synthesis at various concentrations of NaOH and calcium ions. The elemental composition, morphology, particle size, particle size distribution and zeta potential of the products were determined via various characterisation techniques, such as energy-dispersive X-ray spectrometry (EDX, transmission electron microscopy (TEM, dynamic light scattering (DLS, laser Doppler velocimetry (LDV and Fourier transform infrared spectroscopy (FTIR. The best results showed that stable spherical CaP nanoshells with a mean particle size of 197.5 ± 5.8 nm and a zeta potential of -34.5 ± 0.6 mV were successfully formed when 0.100 M sodium hydroxide (NaOH and 0.100 M calcium ions were used. Moreover, an optimal pH of 10.52 and a final Ca/P molar ratio of 0.97 were achieved under these conditions.

  10. Synthesis of some calcium phosphate crystals using the useful biomass for immobilization of microorganisms

    Science.gov (United States)

    Kohiruimaki, T.

    2011-10-01

    Three sources of biomass generated by primary industry were used as the raw material for the synthesis of calcium phosphate crystals. Phosphoric acid was extracted from burned rice chaff using a 30% nitric acid solution, while scallop shells and gypsum of plasterboard were used as calcium sources. The calcium phosphate crystals were synthesized by a method involving homogeneous precipitation, and the relationship between the composition and shape of the crystals and the pH at the time of the precipitation was investigated. Monetite crystals in a petal form with a diameter ranging from 0.1 to 2 μm were precipitated at pH 2.0, while granular apatite crystals with a mean diameter of 1 μm were precipitated at pH 6.0. We also investigated the ability of the synthesized calcium phosphate crystals to immobilize lactic acid bacteria for practical use in industrial bioreactor. It was determined that monetite crystals with a diameter of 2 μm had the highest ability to fix lactic acid bacteria. The population of lactic acid bacteria was estimated to exceed 1,300 bacteria per crystal surface of 50 μm2 suggesting that these crystals may be of practical use in industrial fermenters.

  11. Synthesis of some calcium phosphate crystals using the useful biomass for immobilization of microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Kohiruimaki, T, E-mail: kohi@hi-tech.ac.jp [Department of Technology, Hachinohe Institute of Technology, 88-1 Myo-oobiraki, Hachinohe-shi 031-8501 (Japan)

    2011-10-29

    Three sources of biomass generated by primary industry were used as the raw material for the synthesis of calcium phosphate crystals. Phosphoric acid was extracted from burned rice chaff using a 30% nitric acid solution, while scallop shells and gypsum of plasterboard were used as calcium sources. The calcium phosphate crystals were synthesized by a method involving homogeneous precipitation, and the relationship between the composition and shape of the crystals and the pH at the time of the precipitation was investigated. Monetite crystals in a petal form with a diameter ranging from 0.1 to 2 {mu}m were precipitated at pH 2.0, while granular apatite crystals with a mean diameter of 1 {mu}m were precipitated at pH 6.0. We also investigated the ability of the synthesized calcium phosphate crystals to immobilize lactic acid bacteria for practical use in industrial bioreactor. It was determined that monetite crystals with a diameter of 2 {mu}m had the highest ability to fix lactic acid bacteria. The population of lactic acid bacteria was estimated to exceed 1,300 bacteria per crystal surface of 50 {mu}m{sup 2} suggesting that these crystals may be of practical use in industrial fermenters.

  12. Bisphosphonate/ polysaccharide/ calcium phosphate coatings on titanium surfaces

    Czech Academy of Sciences Publication Activity Database

    Kubies, Dana; Pop-Georgievski, Ognen; Zemek, Josef; Mázl Chánová, Eliška; Neykova, Neda; Houska, Milan; Filová, Elena; Himmlová, L.; Bačáková, Lucie; Rypáček, František

    Praha : Ústav makromolekulární chemie AV ČR, v. v. i, 2014. s. 84-85. ISBN 978-80-85009-81-1. [Česko-slovenská konference POLYMERY 2014 /8./. 06.10.2014-09.10.2014, Třešť] R&D Projects: GA MZd(CZ) NT13297; GA MŠk(CZ) EE2.3.30.0029; GA ČR(CZ) GAP108/11/1857; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 ; RVO:68378271 ; RVO:67985823 Keywords : titanium * surface modification Subject RIV: CD - Macromolecular Chemistry; BM - Solid Matter Physics ; Magnetism (FZU-D); EI - Biotechnology ; Bionics (FGU-C)

  13. Bisphosphonate/polysacharide/calcium phosphate coatings of titanium

    Czech Academy of Sciences Publication Activity Database

    Kubies, Dana; Pop-Georgievski, Ognen; Zemek, Josef; Mázl Chánová, Eliška; Neykova, Neda; Filová, Elena; Himmlová, L.; Bačáková, Lucie; Rypáček, František

    Riva del Garda : Elsevier, 2015. P2.150. [International Symposium Frontiers in Polymer Science /4./ - POLY 2015. 20.05.2015-22.05.2015, Riva del Garda] R&D Projects: GA MZd(CZ) NT13297; GA MŠk(CZ) ED1.1.00/02.0109; GA MŠk(CZ) EE2.3.30.0029 Institutional support: RVO:61389013 ; RVO:68378271 ; RVO:67985823 Keywords : surface modification * bioactive surface * titanium Subject RIV: CD - Macromolecular Chemistry

  14. Magnesium substitution in the structure of orthopedic nanoparticles: A comparison between amorphous magnesium phosphates, calcium magnesium phosphates, and hydroxyapatites

    Energy Technology Data Exchange (ETDEWEB)

    Nabiyouni, Maryam, E-mail: maryam.nabiyouni@rockets.utoledo.edu [Department of Bioengineering, University of Toledo, Toledo, OH (United States); Ren, Yufu [Department of Mechanical, Industrial and Manufacturing Engineering, University of Toledo, Toledo, OH (United States); Bhaduri, Sarit B. [Department of Mechanical, Industrial and Manufacturing Engineering, University of Toledo, Toledo, OH (United States); Department of Surgery (Dentistry), University of Toledo, Toledo, OH (United States)

    2015-07-01

    As biocompatible materials, magnesium phosphates have received a lot of attention for orthopedic applications. During the last decade multiple studies have shown advantages for magnesium phosphate such as lack of cytotoxicity, biocompatibility, strong mechanical properties, and high biodegradability. The present study investigates the role of Mg{sup +2} and Ca{sup +2} ions in the structure of magnesium phosphate and calcium phosphate nanoparticles. To directly compare the effect of Mg{sup +2} and Ca{sup +2} ions on structure of nanoparticles and their biological behavior, three groups of nanoparticles including amorphous magnesium phosphates (AMPs) which release Mg{sup +2}, calcium magnesium phosphates (CMPs) which release Mg{sup +2} and Ca{sup +2}, and hydroxyapatites (HAs) which release Ca{sup +2} were studied. SEM, TEM, XRD, and FTIR were used to evaluate the morphology, crystallinity, and chemical properties of the particles. AMP particles were homogeneous nanospheres, whereas CMPs were combinations of heterogeneous nanorods and nanospheres, and HAs which contained heterogeneous nanosphere particles. Cell compatibility was monitored in all groups to determine the cytotoxicity effect of particles on studied MC3T3-E1 preosteoblasts. AMPs showed significantly higher attachment rate than the HAs after 1 day and both AMPs and CMPs showed significantly higher proliferation rate when compared to HAs after 7 days. Gene expression level of osteoblastic markers ALP, COL I, OCN, OPN, RUNX2 were monitored and they were normalized to GAPDH housekeeping gene. Beta actin expression level was monitored as the second housekeeping gene to confirm the accuracy of results. In general, AMPs and CMPs showed higher expression level of osteoblastic genes after 7 days which can further confirm the stimulating role of Mg{sup +}2 and Ca{sup +2} ions in increasing the proliferation rate, differentiation, and mineralization of MC3T3-E1 preosteoblasts. - Highlights: • Role of Mg{sup 2

  15. Modulating calcium phosphate formation using CO2 laser engineering of a polymeric material

    International Nuclear Information System (INIS)

    The use of simulated body fluid (SBF) is widely used as a screening technique to assess the ability of materials to promote calcium phosphate formation. This paper details the use of CO2 laser surface treatment of nylon® 6,6 to modulate calcium phosphate formation following immersion in SBF for 14 days. Through white light interferometry (WLI) it was determined that the laser surface processing gave rise to maximum Ra and Sa parameters of 1.3 and 4.4 μm, respectively. The use of X-ray photoelectron spectroscopy (XPS) enabled a maximum increase in surface oxygen content of 5.6%at. to be identified. The laser-induced surface modifications gave rise to a modulation in the wettability characteristics such that the contact angle, θ, decreased for the whole area processed samples, as expected, and increased for the patterned samples. The increase in θ can be attributed to a transition in wetting nature to a mixed-state wetting regime. It was seen for all samples that calcium phosphate formed on each surface following 14 days. The largest increase in mass, Δg, owed to calcium phosphate formation, was brought about by the whole area processed sample irradiated with a fluence of 51 J cm−2. No correlation between the calcium phosphate formation and the laser patterned surface properties was determined due to the likely affect of the mixed-state wetting regime. Strong correlations between θ, the surface energy parameters and the calcium phosphate formation for the whole area processed samples allow one to realize the potential for this surface treatment technique in predicting the bone forming ability of laser processed materials. - Highlights: ► Surface modifications brought about a modulation in the wetting of nylon 6,6. ► An increase in θ can be attributed to a mixed-state wetting regime. ► Laser surface treatment modulated the ability to promote apatite formation. ► Mixed-state wetting regime affected the promotion of uniform apatite formation. ► Method

  16. Effect of carbonate and phosphate ratios on the transformation of calcium orthophosphates

    International Nuclear Information System (INIS)

    Graphical abstract: Complexes among phosphate, carbonate and calcium have been prepared via a facile hydrothermal route. The synthesized product at the low (0.15) and the high (1.8) molar ratio of PO43−/CO32− is calcium phosphate hydrate and hydroxylapatite (HAp), respectively. Molar ratios of PO43−/CO32− are effective on the reduction of carbonate activity during the crystallization of HAp. - Highlights: • Formation of different complexes from CO32−, PO43− and Ca2+ solutions at 60 °C. • Molar ratios of PO43−/CO32 cause changes in phase and size of synthesized products. • Addition of PO43 inhibited the activity of CO32− during bound with Ca2+. • The phase transformation was completed, when CO32− peaks disappeared in FTIR. • PO43−, CO32− and Ca2+ distributed heterogeneously on the surface of precipitation. - Abstract: Complexes among phosphate, carbonate and calcium have been synthesized by a designed hydrothermal method. Effects of carbonate and phosphate ratios on the transformation of calcium-orthophosphates were investigated. With X-ray diffraction measurement the synthesized product at the low (0.15) and the high (1.8) molar ratio of PO43−/CO32− is calcium phosphate hydrate at pH 9.0, and hydroxylapatite (HAp) at pH 8.0, respectively. Fourier transform infrared spectroscopy of product at the high ratio (1.8) of PO43−/CO32− shows that the CO32− peaks disappear, and the strong peaks at 1412 and 1460 cm−1 are assigned to the vibrations of PO43− in HAp. 31P nuclear magnetic resonance spectra of products at the low (0.15–0.6) to the high (1.2–1.8) ratios of PO43−/CO32− are obtained at 2.9 and 2.7 ppm, respectively. Molar ratios of PO43−/CO32− are effective on the reduction of carbonate activity during the formation and infiltration events of calcium-phosphate surface precipitates, and are subsequently enclosed during HAp formation

  17. The progress of early phase bone healing using porous granules produced from calcium phosphate cement

    Directory of Open Access Journals (Sweden)

    Jungbluth P

    2010-05-01

    Full Text Available Abstract Objective Bone grafting is a vital component in many surgical procedures to facilitate the repair of bone defects or fusions. Autologous bone has been the gold standard to date in spite of associated donor-site morbidity and the limited amount of available donor bone. The aim of this study was to investigate the progress of bone regeneration and material degradation of calcium phosphate granules (CPG produced from a calcium phosphate self-setting cement powder compared to the use of autologous bone grafting in the treatment of "critical size defects" on load-bearing long bones of minipigs. Methods A critical size defect in the tibial metaphysis of 16 mini-pigs was filled either with autologous cancellous graft or with micro- and macroporous carbonated, apatic calcium phosphate granules (CPG produced from a calcium phosphate self-setting cement powder. After 6 weeks, the specimens were assessed by X-ray and histological evaluation. The amount of new bone formation was analysed histomorphometrically. Results The semi-quantitative analysis of the radiological results showed a complete osseous bridging of the defect in three cases for the autograft group. In the same group five animals showed a beginning, but still incomplete bridging of the defect, whereas in the CPG group just two animals developed this. All other animals of the CPG group showed only a still discontinuous new bone formation. Altogether, radiologically a better osseous bridging was observed in the autograft group compared to the CPG group. Histomorphometrical analysis after six weeks of healing revealed that the area of new bone was significantly greater in the autograft group concerning the central area of the defect zone (p Conclusions Within the limits of the present study it could be demonstrated that autologous cancellous grafts lead to a significantly better bone regeneration compared to the application of calcium phosphate granules (CPG produced from a calcium

  18. An experimental approach to the study of the rheology behaviour of synthetic bone calcium phosphate cements

    Energy Technology Data Exchange (ETDEWEB)

    Friberg, J.; Fernandez, E.; Sarda, S.; Nilsson, M.; Ginebra, M.P.; Planell, J.A. [Universidad Politecnica de Catalunya, Barcelona (Spain). Dept. of Materials Science and Metallurgical Engineering; Martinez, S. [Barcelona Univ. (Spain). Mineralogia i Recursos Minerals

    2001-07-01

    Calcium phosphate cements were developed to fit surgical needs in biomedical fields such as odontology or traumatology. Nowadays, a broad field of new applications have been found for this kind of materials. Drug delivery systems, tissue-engineering scaffolds and osteoporotic bone filling applications are some of the new fields that are being benefited with these materials. Looking at both, commercial and new experimental calcium phosphate cements it is found that {alpha}-tricalcium phosphate is the main reactive powder responsible for the setting and the hardening of the cement. Thus, it is important to know how {alpha}-tricalcium phosphate affects injectability of these cements. The aim of this study was to investigate the rheological behaviour of {alpha}-tricalcium phosphate slurries in order to know how the cement injectability should be modified. Factors such as liquid to powder ratio, particle size of the main reactive powder and the addition of dispersants have been considered. The results showed that viscosity decreased when particle size of reactant was increased and when liquid to powder ratio was increased. It was also found that a minimum of viscosity exists at an optimum value of the weight percentage of dispersant. (orig.)

  19. Ultrasonic irradiation and its application for improving the corrosion resistance of phosphate coatings on aluminum alloys.

    Science.gov (United States)

    Sheng, Minqi; Wang, Chao; Zhong, Qingdong; Wei, Yinyin; Wang, Yi

    2010-01-01

    In this paper, ultrasonic irradiation was utilized for improving the corrosion resistance of phosphate coatings on aluminum alloys. The chemical composition and morphology of the coatings were analyzed by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The effect of ultrasonic irradiation on the corrosion resistance of phosphate coatings was investigated by polarization curves and electrochemical impedance spectroscopy (EIS). Various effects of the addition of Nd(2)O(3) in phosphating bath on the performance of the coatings were also investigated. Results show that the composition of phosphate coating were Zn(3)(PO(4))(2).4H(2)O(hopeite) and Zn crystals. The phosphate coatings became denser with fewer microscopic holes by utilizing ultrasonic irradiation treatment. The addition of Nd(2)O(3) reduced the crystallinity of the coatings, with the additional result that the crystallites were increasingly nubby and spherical. The corrosion resistance of the coatings was also significantly improved by ultrasonic irradiation treatment; both the anodic and cathodic processes of corrosion taking place on the aluminum alloy substrate were suppressed consequently. In addition, the electrochemical impedance of the coatings was also increased by utilizing ultrasonic irradiation treatment compared with traditional treatment. PMID:19692286

  20. Effect of phosphate additives on the microstructure, bioactivity, and degradability of microarc oxidation coatings on Mg-Zn-Ca-Mn alloy.

    Science.gov (United States)

    Dou, Jinhe; You, Qiongya; Gu, Guochao; Chen, Chuanzhong; Zhang, Xihua

    2016-01-01

    Calcium phosphate coatings were prepared on the surface of self-designed Mg-Zn-Ca-Mn alloy using microarc oxidization technology. To characterize the microstructures, cross-section morphologies, and compositions of the coatings, the authors used scanning electron microscopy equipped with an energy-disperse spectrometer, x-ray diffraction, and Fourier transform infrared spectroscopy. Potentiodynamic polarization in the simulated body fluid (SBF) was used to evaluate the corrosion behaviors of the samples. An SBF immersion test was used to evaluate the coating bioactivity and degradability. After the immersion tests, some bonelike apatite formed on the coating surfaces indicate that bioactivity of the coatings is excellent. The coating prepared in electrolyte containing (NaPO3)6 had slower degradation rate after immersion test for 21 days. PMID:27440396

  1. Corrosion protection of metals by phosphate coatings and ecologically beneficial alternatives. Properties and mechanisms

    International Nuclear Information System (INIS)

    The corrosion and protection characteristics of inorganic zinc and manganese phosphate coatings in aqueous solution have been examined by physical methods, accelerated corrosion tests and electrochemical polarization and impedance measurements. Some water-soluble organic films have been evaluated for the temporary protection of metal parts as the ecologically beneficial alternatives to phosphate coatings. The results show that zinc phosphate is a better insulator than manganese phosphate, but the porosity of the former is inferior to that of the latter. In neutral and alkaline solutions the anodic current of both zinc and manganese phosphates decreases and their open potential moves in a positive direction. In acidic medium both the polarization current and the open potential are close to those of the substrate. Confirmed by the impedance measurements, the corrosion of phosphated steel in acidic solution is controlled by a dissolution reaction, in neutral medium is first reaction controlled then diffusion controlled, and in alkaline environment only diffusion controlled. The insulation of acrylate+copolymer, epoxy and inhibitor+bonding materials is superior to that of zinc or manganese phosphates. In general, most of the alternatives can afford a better temporary protection for metal parts compared to inorganic phosphate coatings. The corrosion failure of inorganic phosphate coatings is mainly induced by the electrochemical dissolution of the substrate. This electrochemical process initiates at the bottom of the pores within the coating. In neutral solution, the hydrolysis of corrosion products decrease the pH value of the solution in the anodic zone, resulting in an acidic dissolution of phosphate coatings. At the same time, the depolarization of oxygen increases the pH value in the cathodic zone, causing an alkaline hydrolysis of phosphates. (author) figs., tabs., 149 refs

  2. Interaction between hydroxypropyl methylcellulose and biphasic calcium phosphate after steam sterilisation: capillary gas chromatography studies.

    OpenAIRE

    Bourges, Xavier; Schmitt, Michel; Amouriq, Yves; Daculsi, Guy; Legeay, Gilbert; Pierre WEISS

    2001-01-01

    The purpose of this study was to check the chemical stability of an injectable bone substitute (IBS) composed of a 50/50 w/w mixture of a 2.92% hydroxypropyl methylcellulose (HPMC) solution in deionised water containing biphasic calcium phosphate (BCP) granules (60% hydroxyapatite/40% β-tricalcium phosphate w/w). After separation of the organic and mineral phases, capillary gas chromatography (GC) was used to study the possible modification of HPMC due to the contact with BCP granules followi...

  3. Calcium thorium phosphate (Whitlockite-type mineral). Synthesis and structure refinement

    International Nuclear Information System (INIS)

    The crystal structure of a new calcium thorium phosphate has been refined by the full-profile Rietveld method using X-ray powder diffraction data. The sample has been synthesized by the sol-gel technique. The phosphate has been identified by X-ray powder diffraction and IR spectroscopy. The refined composition is represented by the formula Ca10.26Th0.12(PO4)7. The CaOn and PO4 polyhedra are distorted compared to the corresponding polyhedra in the basic compound β-Ca3(PO4)2.

  4. Identification and quantitive analysis of calcium phosphate microparticles in intestinal tissue by nuclear microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Morilla, Inmaculada [Advanced Technology Institute, University of Surrey, Guildford GU2 7XH (United Kingdom)]. E-mail: i.gomez-morilla@surrey.ac.uk; Thoree, Vinay [Gastrointestinal Laboratory, Rayne Institute, St. Thomas' Hospital, London SE1 7EH (United Kingdom); Powell, Jonathan J. [MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge CB1 9NL (United Kingdom); Kirkby, Karen J. [Advanced Technology Institute, University of Surrey, Guildford GU2 7XH (United Kingdom); Grime, Geoffrey W. [Department of Physics, University of Surrey, GU2 7XH (United Kingdom)

    2006-08-15

    Microscopic particles (0.5-2 {mu}m diameter), rich in calcium and phosphorus, are found in the lumen of the mid-distal gut of all mammals investigated, including humans, and these may play a role in immuno-surveillance and immune regulation of antigens from food and symbiotic bacteria that are contained in the gut. Whether these particles can cross in to tissue of the intestinal mucosa is unclear. If so, characterising their morphology and chemical composition is an important task in elucidating their function. The analysis of calcium phosphate in biological tissues has been approached in several ways including optical microscopy, scanning electron microscopy and, most recently in this work, with nuclear microscopy. In this paper, we describe the use of microPIXE and microRBS to locate these particles and to determine, accurately, the ratio of phosphorus to calcium using the information on sample thickness obtained from RBS to allow the PIXE ratios to be corrected. A commercial sample of hydroxy apatite was used to demonstrate accuracy and precision of the technique. Then, in a pilot study on intestinal tissue of mice, we demonstrated the presence of calcium phosphate microparticles, consistent with confocal microscopy observations, and we identified the average molar P:Ca molar ratio as 1.0. Further work will confirm the exact chemical speciation of these particles and will examine the influence of differing calcium containing diets on the formation of these microparticles.

  5. Identification and quantitive analysis of calcium phosphate microparticles in intestinal tissue by nuclear microscopy

    International Nuclear Information System (INIS)

    Microscopic particles (0.5-2 μm diameter), rich in calcium and phosphorus, are found in the lumen of the mid-distal gut of all mammals investigated, including humans, and these may play a role in immuno-surveillance and immune regulation of antigens from food and symbiotic bacteria that are contained in the gut. Whether these particles can cross in to tissue of the intestinal mucosa is unclear. If so, characterising their morphology and chemical composition is an important task in elucidating their function. The analysis of calcium phosphate in biological tissues has been approached in several ways including optical microscopy, scanning electron microscopy and, most recently in this work, with nuclear microscopy. In this paper, we describe the use of microPIXE and microRBS to locate these particles and to determine, accurately, the ratio of phosphorus to calcium using the information on sample thickness obtained from RBS to allow the PIXE ratios to be corrected. A commercial sample of hydroxy apatite was used to demonstrate accuracy and precision of the technique. Then, in a pilot study on intestinal tissue of mice, we demonstrated the presence of calcium phosphate microparticles, consistent with confocal microscopy observations, and we identified the average molar P:Ca molar ratio as 1.0. Further work will confirm the exact chemical speciation of these particles and will examine the influence of differing calcium containing diets on the formation of these microparticles

  6. Calcific tendinitis of the shoulder in basic calcium phosphate crystal deposition disease

    International Nuclear Information System (INIS)

    Basic calcium phosphate (BCP) crystal deposition can lead to periarticular collections associated with typical radiographic findings, most frequently observed in the shoulder. Moreover, these deposits may be revealed in other articular sites (i.e.,wrist, hand, foot, elbow, hip, etc.). Initially, the calcium deposits may appear poorly defined (cloudlike); sequently, they may reveal different patterns (linear, triangular or circular areas), changing in size, configuration and site. Adjacent bone may be normal, altough osteoporosis, cystic lesions and reactive sclerosis are reported. The radiographic appearance of calcifications will depend upon the exact location of the deposits in the specific tendon of the rotator cuff, the adjacent bursae and the soft tissues

  7. A Black Phosphate Conversion Coating on Steel Surface Using Antimony(III)-Tartrate as an Additive

    Science.gov (United States)

    Li, Feng; Wang, Guiping

    2016-05-01

    A novel black phosphate conversion coating was formed on steel surface through a Zn-Mn phosphating bath containing mainly ZnO, H3PO4, Mn(H2PO4)2, and Ca(NO3)2, where antimony(III)-tartrate was used as the blackening agent of phosphatization. The surface morphology and composition of the coating were characterized by scanning electron microscopy, energy dispersion spectroscopy, and x-ray photoelectron spectroscopy. Corrosion resistance of the coating was studied by potentiodynamic polarization curves and electrochemical impedance spectroscopy. The pH value of the solution had significant influence on the formation and corrosion resistance of the coating. The experimental results indicated that the Sb plays a vital role in the blackening of phosphate conversion coating. The optimal concentration of antimony(III)-tartrate in the phosphating bath used in this experiment was 1.0 g L-1, as higher values reduced the corrosion resistance of the coating. In addition, by saponification and oil seals, the corrosion duration of the black phosphate coating in a copper sulfate spot test can be as long as 20 min.

  8. Investigation on the biomimetic influence of biopolymers on calcium phosphate precipitation-Part 1: Alginate

    International Nuclear Information System (INIS)

    The understanding of how macromocules act in precipitation of inorganic phases is the key knowledge that is needed to establish the foundation to mimic nature and produce materials with high mechanical modulus besides outstanding optical and thermal properties. This study investigated how addition of small amounts of alginate (7-70 ppm), that presents many carboxylic groups, affects phase distribution and morphology of calcium phosphates, obtained through precipitation and further submitted to calcination and sintering. The results lead to the conclusion that alginate action is dynamic, where alginate molecules act as templates to nucleation, and most of the biopolymer remains in solution even when all calcium phosphate has precipitated. However, despite the effect on phase composition being mainly related to the system's kinetics, alginate does present thermodynamic interaction with the precipitates. It is probable that it acts by reducing the free energy of nucleation, as in heterogeneous nucleation processes.

  9. Preparation of novel bioactive nano-calcium phosphate-hydrogel composites

    Energy Technology Data Exchange (ETDEWEB)

    Juhasz, Judith A; Best, Serena M; Bonfield, William, E-mail: jaj33@cam.ac.u [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom)

    2010-02-15

    Nano-sized hydroxyapatite (nHA) and carbonate-substituted hydroxyapatite (nCHA) particles were incorporated into a poly-2-hydroxyethylmethacrylate/polycaprolactone (PHEMA/PCL) hydrogel at a filler content of 10 wt%. Fourier transform infrared absorption, transmission electron microscopy, x-ray diffraction and scanning electron microscopy were used to analyse the physical and chemical characteristics of the calcium phosphate fillers and resultant composites. Nano-sized calcium phosphate particles were produced with a needle-like morphology, average length of 50 nm and an aspect ratio of 3. The nanoparticles were uniformly distributed in the polymer matrix. The addition of both HA and CHA in nano-form enhanced the bioactivity and biocompatibility of the PHEMA/PCL matrix. The carbonate-substitution has allowed for improved bioactivity and biocompatibility of the resultant composite, indicating the potential of this material for use in bone tissue engineering.

  10. Calcium phosphate nanoparticles as versatile carrier for small and large molecules across cell membranes

    International Nuclear Information System (INIS)

    The successful transport of molecules across the cell membrane is a key point in biology and medicine. In most cases, molecules alone cannot penetrate the cell membrane, therefore an efficient carrier is needed. Calcium phosphate nanoparticles (diameter: 100–250 nm, depending on the functionalization) were loaded with fluorescent oligonucleotides, peptide, proteins, antibodies, polymers or porphyrins and characterized by dynamic light scattering, nanoparticle tracking analysis and scanning electron microscopy. Any excess of molecules was removed by ultracentrifugation, and the dissolved molecules at the same concentration were used as control. The uptake of such fluorescence-labeled nanoparticles into HeLa cells was monitored by fluorescence microscopy and confocal laser scanning microscopy. Calcium phosphate nanoparticles were able to transport all molecules across the cell membrane, whereas the dissolved molecules alone were taken up only to a very small extent or even not at all.

  11. Preparation of novel bioactive nano-calcium phosphate-hydrogel composites

    International Nuclear Information System (INIS)

    Nano-sized hydroxyapatite (nHA) and carbonate-substituted hydroxyapatite (nCHA) particles were incorporated into a poly-2-hydroxyethylmethacrylate/polycaprolactone (PHEMA/PCL) hydrogel at a filler content of 10 wt%. Fourier transform infrared absorption, transmission electron microscopy, x-ray diffraction and scanning electron microscopy were used to analyse the physical and chemical characteristics of the calcium phosphate fillers and resultant composites. Nano-sized calcium phosphate particles were produced with a needle-like morphology, average length of 50 nm and an aspect ratio of 3. The nanoparticles were uniformly distributed in the polymer matrix. The addition of both HA and CHA in nano-form enhanced the bioactivity and biocompatibility of the PHEMA/PCL matrix. The carbonate-substitution has allowed for improved bioactivity and biocompatibility of the resultant composite, indicating the potential of this material for use in bone tissue engineering.

  12. The adhesion of epoxy cataphoretic coating on phosphatized hot-dip galvanized steel

    Directory of Open Access Journals (Sweden)

    Bajat Jelena B.

    2006-01-01

    Full Text Available The influence of hot-dip galvanized steel surface pretreatment on the adhesion of epoxy cataphoretic coating was investigated. Phosphate coatings were deposited on hot-dip galvanized steel and the influence of fluoride ions in the phosphating plating bath, as well as the deposition temperature of the plating bath, were investigated. The dry and wet adhesion of epoxy coating were measured by a standard pull-off method. The surface roughness of phosphatized galvanized steel was determined, as well as the wettability of the metal surface by emulsion of the epoxy resin in water. The adhesion of epoxy coatings on phosphatized hot-dip galvanized steel was investigated in 3wt.%NaCI.

  13. Manufacturing of calcium phosphate scaffolds by pseudomorphic transformation of gypsum

    Energy Technology Data Exchange (ETDEWEB)

    Araujo Batista, H. de.; Batista Cardoso, M.; Sales Vasconcelos, A.; Vinicius Lia Fook, M.; Rodriguez Barbero, M. A.; Garcia Carrodeguas, R.

    2016-08-01

    Carbonated hydroxyapatite (CHAp) and β-tricalcium phosphate (β-TCP) have been employed for decades as constituents of scaffolds for bone regeneration because they chemically resemble bone mineral. In this study, the feasibility to manufacture CHAp/β-TCP scaffolds by pseudomorphic transformation of casted blocks of gypsum was investigated. The transformation was carried out by immersing the precursor gypsum block in 1 M (NH{sub 4}){sub 2}HPO{sub 4}/1.33 M NH{sub 4}OH solution with liquid/solid ratio of 10 mL/g and autoclaving at 120 degree centigrade and 203 kPa (2 atm) for 3 h at least. Neither shape nor dimensions significantly changed during transformation. The composition of scaffolds treated for 3 h was 70 wt.% CHAp and 30 wt.% β-TCP, and their compressive and diametral compressive strengths were 6.5 ± 0.7 and 5.3 ±0.7 MPa, respectively. By increasing the time of treatment to 6 h, the composition of the scaffold enriched in β-TCP (60 wt.% CHAp and 40 wt.% β-TCP) but its compressive and diametral compressive strengths were not significantly affected (6.7 ± 0.9 and 5.4 ± 0.6 MPa, respectively). On the basis of the results obtained, it was concluded that this route is a good approach to the manufacturing of biphasic (CHAp/β-TCP) scaffolds from previously shaped pieces of gypsum. (Author)

  14. Studies on the mechanisms underlying the transfer of calcium and phosphate from bone to blood

    Energy Technology Data Exchange (ETDEWEB)

    Brommage, Robert J. Jr.

    1978-01-01

    The skeleton is recognized as a crucial organ in the minute-to-minute regulation of the blood levels of calcium and phosphate. The fluxes of calcium and phosphate to and from bone greatly exceed the entry and exit of these ions occurring in the intestine and kidneys. Parathyroid hormone, calcitonin, and 1,25-dihydroxyvitamin D/sub 3/ (1,25-(OH)/sub 2/D/sub 3/ are known to influence the transfer of calcium and phosphate from bone to blood. Three mechanisms have been proposed to explain the hormonal control of the calcium and phosphate effluxes from bone. The concept of a bone membrane maintaining a distinct bone extracellular fluid composition has led to the pump and pH gradient theories. An alternate solubilizer theory proposes that bone cells secrete a substance which increases the solubility of the bone mineral. The bone membrane concept was originally proposed to explain the presence of the apparent anomalously high concentrations of potassium in the bone extracellular fluid. However, the available evidence does not allow an unambiguous decision concerning the presence of a bone membrane. Calvarial lactate production was unaltered by 1,25-(OH)/sub 2/D/sub 3/ treatment and consequently 1,25-(OH)/sub 2/D/sub 3/ does not appear to promote the mobilization of bone mineral through a lactate-mediated pH gradient mechanism. 1,25-(OH)/sub 2/D/sub 3/ did increase the solubility of non-vital bone, clearly demonstrating that the solubilizer mechanism is at least partially responsible for the mobilization of bone mineral and the regulation of blood levels of calcium and phosphate. Vitamin D-deficient female rats fed a 0.2% calcium, 0.4% phosphorous diet and supplemented with daily injections of 0.75 pmole of 1,25-(OH)/sub 2/D/sub 3/ were shown to be capable of bearing young. When the injections of 1,25-(OH)/sub 2/D/sub 3/ were terminated at delivery, the dams and pups showed signs of vitamin D deficiency approximately one week later.

  15. Remineralization of early enamel lesions using casein phosphopeptide amorphous calcium Phosphate: An ex-vivo study

    OpenAIRE

    Ruchi Vashisht; Anil Kumar; Indira, R; Srinivasan, M R; Ramachandran, S.

    2010-01-01

    Objective: This study aimed at qualitatively evaluating the remineralization potential of casein phosphopeptide amorphous calcium phosphate on artificial early enamel lesions in an ex-vivo scenario by observing the treated tooth surface using a scanning electron microscope (SEM). Materials and Methods: This randomized study was conducted on 10 subjects undergoing orthodontic treatment with premolar extraction as part of their treatment. Artificial white lesions were created with the applicati...

  16. Protective potential of casein phosphopeptide amorphous calcium phosphate containing paste on enamel surfaces

    OpenAIRE

    Padmini Somasundaram; Vimala, N; Lalita Gauri Mandke

    2013-01-01

    Background: Dental caries remains the most common dental disease facing mankind. Prevention of initiation and interruption in progression of early lesions are the desirable modes of caries management. There is a scope for agents, which may be used to enhance anti - caries activity. This need has redirected research to develop novel preventive agents that can act as an adjunct to fluoride or independent of it. Casein Phosphopeptide - Amorphous Calcium Phosphate (CPP-ACP) is one such agent that...

  17. Effect of different calcium phosphate scaffold ratios on odontogenic differentiation of human dental pulp cells

    Energy Technology Data Exchange (ETDEWEB)

    AbdulQader, Sarah Talib [School of Dental Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia); Department of Pedodontic and Preventive Dentistry, College of Dentistry, University of Baghdad, Baghdad (Iraq); Kannan, Thirumulu Ponnuraj, E-mail: kannan@usm.my [School of Dental Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia); Human Genome Centre, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia); Rahman, Ismail Ab [School of Dental Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia); Ismail, Hanafi [School of Materials and Minerals Resource Engineering, Universiti Sains Malaysia, 14300 Penang (Malaysia); Mahmood, Zuliani [School of Dental Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia)

    2015-04-01

    Calcium phosphate (CaP) scaffolds have been widely and successfully used with osteoblast cells for bone tissue regeneration. However, it is necessary to investigate the effects of these scaffolds on odontoblast cells' proliferation and differentiation for dentin tissue regeneration. In this study, three different hydroxyapatite (HA) to beta tricalcium phosphate (β-TCP) ratios of biphasic calcium phosphate (BCP) scaffolds, BCP20, BCP50, and BCP80, with a mean pore size of 300 μm and 65% porosity were prepared from phosphoric acid (H{sub 2}PO{sub 4}) and calcium carbonate (CaCO{sub 3}) sintered at 1000 °C for 2 h. The extracts of these scaffolds were assessed with regard to cell viability and differentiation of odontoblasts. The high alkalinity, more calcium, and phosphate ions released that were exhibited by BCP20 decreased the viability of human dental pulp cells (HDPCs) as compared to BCP50 and BCP80. However, the cells cultured with BCP20 extract expressed high alkaline phosphatase activity and high expression level of bone sialoprotein (BSP), dental matrix protein-1 (DMP-1), and dentin sialophosphoprotein (DSPP) genes as compared to that cultured with BCP50 and BCP80 extracts. The results highlighted the effect of different scaffold ratios on the cell microenvironment and demonstrated that BCP20 scaffold can support HDPC differentiation for dentin tissue regeneration. - Highlights: • BCPs of different HA/β-TCP ratios influence cell microenvironment. • BCP20 decreases cell viability of HDPCs as compared to BCP50 and BCP80. • HDPCs cultured with BCP20 express highest ALP activity. • HDPCs cultured with BCP20 up-regulate BSP, DMP-1 and DSPP gene expressions. • BCP20 can support HDPC differentiation for dentin tissue regeneration.

  18. Evaluation of implant calcium-phosphate materials depending on their mineral content

    Directory of Open Access Journals (Sweden)

    I. A. Talashova

    2016-03-01

    Full Text Available Biocompatibility of original implant calcium-phosphate materials was evaluated in the experiment on animals. The methods of radiological electron-probe microanalysis (REMA and light and scan electron microscopy (SEM were used. Studied materials had the properties of biodegradation, osteoinduction and osteoconduction at different extent. The materials with the composite maximally close to the the bone tissue had the greatest grade of biocompatibility.

  19. Optimizing and Evaluating the Biocompatibility of Fiber Composites with Calcium Phosphate Additives

    Czech Academy of Sciences Publication Activity Database

    Suchý, Tomáš; Balík, Karel; Sucharda, Zbyněk; Sochor, M.; Lapčíková, Monika; Sedláček, R.

    2011-01-01

    Roč. 161, 19/20 (2011), s. 493-502. ISSN 0043-5341 R&D Projects: GA ČR(CZ) GAP108/10/1457; GA ČR(CZ) GA106/06/1576 Institutional research plan: CEZ:AV0Z30460519; CEZ:AV0Z40500505 Keywords : biocomposites * calcium phosphate * polyamide fibers Subject RIV: JI - Composite Materials http://www.springerlink.com/content/047q753g04h4l836/

  20. Calcium Phosphate Nanocomposite Particles for In Vitro Imaging and Encapsulated Chemotherapeutic Drug Delivery to Cancer Cells

    OpenAIRE

    Kester, Mark; Heakal, Y.; Sharma, A.; Robertson, Gavin P.; Morgan, Thomas T.; İ Altinoğlu, Erhan; Tabaković, Amra; Parette, Mylisa R.; Rouse, Sarah; Ruiz-Velasco, Victor; Adair, James H.

    2008-01-01

    Paradigm-shifting modalities to more efficiently deliver drugs to cancerous lesions require the following attributes: nanoscale-size, targetability and stability under physiological conditions. Often, these nanoscale drug delivery vehicles are limited due to agglomeration, poor solubility or cytotoxicity. Thus, we have designed a methodology to encapsulate hydrophobic antineoplastic chemotherapeutics within a 20-30 nm diameter, pH-responsive, non-agglomerating, non-toxic calcium phosphate nan...

  1. Ionic liquid-assisted formation of cellulose/calcium phosphate hybrid materials

    OpenAIRE

    Ahmed Salama; Mike Neumann; Christina Günter; Andreas Taubert

    2014-01-01

    Cellulose/calcium phosphate hybrid materials were synthesized via an ionic liquid-assisted route. Scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis/differential thermal analysis show that, depending on the reaction conditions, cellulose/hydroxyapatite, cellulose/chlorapatite, or cellulose/monetite composites form. Preliminary studies with MC3T3-E1 pre-osteoblasts show t...

  2. The In-situ Reinforcement of Calcium Phosphate Cement and Its Micro-structural Analysis

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Carbon nanotubes ( CNTs ) and polyacrylic acid were employed to modify the setting process and hydration products of β- TCP/ TTCP calcium phosphate cement. The micro-structure of hydration product and the fashion of how additives and hydration particles interconnected were investigated. With the modification effect of CNTs, the setting particles and CNTs got winded and interconnected and thus made the composite more compact and denser.

  3. Ability of Pit and Fissure Sealant-containing Amorphous Calcium Phosphate to inhibit Enamel Demineralization

    OpenAIRE

    Zawaideh, Feda I; Owais, Arwa I; Kawaja, Wasan

    2016-01-01

    ABSTRACT Aim: To evaluate the effect of amorphous calcium phosphate (ACP)-containing pit and fissure sealant on inhibition of enamel demineralization in vitro. Materials and methods: Enamel specimens (n = 75) were prepared using freshly extracted noncarious human third molars. Box-shaped cavities (8 × 2 × 2 mm) on the buccal or lingual surfaces were prepared and restored with resin-based sealant (Concise™), ACP-containing sealant (Aegis®) or fluoride-containing sealant (Conseal-F™). The sampl...

  4. Calcium phosphate preservation of faecal bacterial negative moulds in hyaena coprolites

    OpenAIRE

    Pesquero, María Dolores; Souza Egipsy, Virginia; Alcalá, Luis; Ascaso, Carmen; Fernández Jalvo, Yolanda

    2014-01-01

    The vertebrate fossil locality of La Roma 2, Spain (Upper Miocene, Late Vallesian, MN10) is characterised by a high abundance of mammalian coprolites, which provide direct clues to the diets and habitats of the organisms that produced them. X-ray diffraction analysis showed a sample of hyaena (cf. Lycyaena chaeretis) coprolites to be mostly composed of calcium phosphate. Ultrastructural SEM and TEM studies revealed three successive phases of preservation, including an initial phase of mineral...

  5. Trace element doping in calcium phosphate ceramics to Understand osteogenesis and angiogenesis

    OpenAIRE

    Bose, Susmita; Fielding, Gary; Tarafder, Solaiman; Bandyopadhyay, Amit

    2013-01-01

    The general trends in synthetic bone grafting materials are shifting towards approaches that can illicit osteoinductive properties. Pharmacologics and biologics have been used in combination with calcium phosphate (CaP) ceramics, however, recently have become the target of scrutiny over the safety. The importance of trace elements in natural bone health is well documented. Ions, e.g. lithium, zinc, magnesium, manganese, silicon, strontium etc. have shown to increase osteogenesis and neovascul...

  6. Development and characterisation of injectable calcium phosphate cements for use in vertebroplasty

    OpenAIRE

    Pittet, Christian; Lemaître, Jacques

    2007-01-01

    The global objective of this thesis was to understand how the starting components of brushite cements influence the cement properties relevant for its use in vertebroplasty. Therefore, this work focussed on the following cement properties : mechanical strength, X-ray opacity and heat release upon setting. To carry out the global objective, a test protocol was first developed to characterise the mechanical properties of calcium phosphate cements. The Mohr's circles representation allowed to un...

  7. Development and characterisation of injectable calcium phosphate cements for use in vertebroplasty

    OpenAIRE

    Pittet, Christian

    2002-01-01

    The global objective of this thesis was to understand how the starting components of brushite cements influence the cement properties relevant for its use in vertebroplasty. Therefore, this work focussed on the following cement properties : mechanical strength, X-ray opacity and heat release upon setting. To carry out the global objective, a test protocol was first developed to characterise the mechanical properties of calcium phosphate cements. The Mohr's circles representation allowed to un...

  8. Nano-sized calcium phosphate (CaP) carriers for non-viral gene deilvery

    International Nuclear Information System (INIS)

    Highlights: ► Nanostructured calcium phosphates (NanoCaPs): comprehensive review. ► Non viral gene delivery mechanisms: detailed mechanisms are outlined. ► Barriers to non-viral gene delivery: detailed barriers are discussed. - Abstract: Gene therapy has garnered much interest due to the potential for curing multiple inherited and/or increases in the acquired diseases. As a result, there has been intense activity from multiple research groups for developing effective delivery methods and carriers, which is a critical step in advancing gene delivery technologies. In order for the carriers to effectively deliver the genetic payloads, multiple extracellular and intracellular barriers need to be overcome. Although overcoming these challenges to improve the effectiveness is critical, the development of safe gene delivery agents is even more vital to assure its use in clinical applications. The development of safe and effective strategies has therefore been a major challenge impeding gene therapy progress. In this regard, calcium phosphate (CaP) based nano-particles has been considered as one of the candidate non-viral gene delivery vehicles, but has been plagued by inconsistent and low transfection efficiencies limiting its progress. There has been major research effort to improve the consistency and effectiveness of CaP based vectors. Currently, it is therefore thought that by controlling the various synthesis factors such as Ca/P ratio, mode of mixing, and type of calcium phosphate phase, such variability and inefficiency could be modulated. This review attempts to provide a comprehensive analysis of the current research activity in the development of CaP based ceramic and polymer-ceramic hybrid systems for non-viral gene delivery. Preliminary transfection results of hydroxyapatite (HA or NanoCaPs), amorphous calcium phosphate (ACP) and brushite phases are also compared to assess the effect of various CaP phases, and correspondingly, changes in the dissolution

  9. Effect of different calcium phosphate scaffold ratios on odontogenic differentiation of human dental pulp cells

    International Nuclear Information System (INIS)

    Calcium phosphate (CaP) scaffolds have been widely and successfully used with osteoblast cells for bone tissue regeneration. However, it is necessary to investigate the effects of these scaffolds on odontoblast cells' proliferation and differentiation for dentin tissue regeneration. In this study, three different hydroxyapatite (HA) to beta tricalcium phosphate (β-TCP) ratios of biphasic calcium phosphate (BCP) scaffolds, BCP20, BCP50, and BCP80, with a mean pore size of 300 μm and 65% porosity were prepared from phosphoric acid (H2PO4) and calcium carbonate (CaCO3) sintered at 1000 °C for 2 h. The extracts of these scaffolds were assessed with regard to cell viability and differentiation of odontoblasts. The high alkalinity, more calcium, and phosphate ions released that were exhibited by BCP20 decreased the viability of human dental pulp cells (HDPCs) as compared to BCP50 and BCP80. However, the cells cultured with BCP20 extract expressed high alkaline phosphatase activity and high expression level of bone sialoprotein (BSP), dental matrix protein-1 (DMP-1), and dentin sialophosphoprotein (DSPP) genes as compared to that cultured with BCP50 and BCP80 extracts. The results highlighted the effect of different scaffold ratios on the cell microenvironment and demonstrated that BCP20 scaffold can support HDPC differentiation for dentin tissue regeneration. - Highlights: • BCPs of different HA/β-TCP ratios influence cell microenvironment. • BCP20 decreases cell viability of HDPCs as compared to BCP50 and BCP80. • HDPCs cultured with BCP20 express highest ALP activity. • HDPCs cultured with BCP20 up-regulate BSP, DMP-1 and DSPP gene expressions. • BCP20 can support HDPC differentiation for dentin tissue regeneration

  10. Current and Future Theranostic Applications of the Lipid-Calcium-Phosphate Nanoparticle Platform

    OpenAIRE

    Satterlee, Andrew B.; Huang, Leaf

    2016-01-01

    Over the last four years, the Lipid-Calcium-Phosphate (LCP) nanoparticle platform has shown success in a wide range of treatment strategies, recently including theranostics. The high specific drug loading of radiometals into LCP, coupled with its ability to efficiently encapsulate many types of cytotoxic agents, allows a broad range of theranostic applications, many of which are yet unexplored. In addition to providing an overview of current medical imaging modalities, this review highlights ...

  11. Effects of Calcium Phosphate Nanocrystals on Osseointegration of Titanium Implant in Irradiated Bone

    OpenAIRE

    2015-01-01

    Radiotherapy may compromise the integration of implant and cause implant loss. Implant surface modifications have the possibility of promoting cell attachment, cell growth, and bone formation which ultimately enhance the osseointegration process. The present study aimed to investigate the effects of calcium phosphate nanocrystals on implant osseointegration in irradiated bone. Sixteen rabbits were randomly assigned into control and nano-CaP groups, receiving implants with dual acid-etched sur...

  12. The effect of calcium phosphate nanoparticles on hormone production and apoptosis in human granulosa cells

    Directory of Open Access Journals (Sweden)

    Gao Li

    2010-04-01

    Full Text Available Abstract Objectives Although many nanomaterials are being used in academia, industry and daily life, there is little understanding about the effects of nanoparticles on the reproductive health of vertebral animals, including human beings. An experimental study was therefore performed here to explore the effect of calcium phosphate nanoparticles on both steroid hormone production and apoptosis in human ovarian granulosa cells. Methods Calcium phosphate nanoparticles uptaking was evaluated by transmission electron microscopy (TEM. The cell cycle was assessed with propidium iodide-stained cells (distribution of cells in G0/G1, S, and G2/M phases by flow cytometry. The pattern of cell death (necrosis and apoptosis was analyzed by flow cytometry with annexin V-FITC/PI staining. The expression of mRNAs encoding P450scc, P450arom and StAR were determined by RT-PCR. Progesterone and estradiol levels were measured by radioimmunoassay. Results TEM results confirmed that calcium phosphate nanoparticles could enter into granulosa cells, and distributed in the membranate compartments, including lysosome and mitochondria and intracellular vesicles. The increased percentage of cells in S phase when cultured with nanoparticles indicated that there was an arrest at the checkpoint from phase S-to-G2/M (from 6.28 +/- 1.55% to 11.18 +/- 1.73%, p Conclusion Calcium phosphate nanoparticles interfered with cell cycle of cultured human ovarian granulosa cells thus increasing cell apoptosis. This pilot study suggested that effects of nanoparticles on ovarian function should be extensively investigated.

  13. Mechanical and acid neutralizing properties and bacteria inhibition of amorphous calcium phosphate dental nanocomposite

    OpenAIRE

    Moreau, Jennifer L.; Sun, Limin; Chow, Laurence C.; Xu, Hockin H. K.

    2011-01-01

    Dental composites do not hinder bacteria colonization and plaque formation. Caries at the restoration margins is a frequent reason for replacement of existing restorations, which accounts for 50 to 70% of all restorations. The objectives of this study were to examine the filler level effect on nanocomposite containing nanoparticles of amorphous calcium phosphate (NACP) and investigate the load-bearing and acid-neutralizing properties and bacteria inhibition. NACP with 116-nm particle size wer...

  14. EVALUATION OF ACTIVITY OF POLYPHENOLOXIDASE ENZYME AND INTERCALATION OF THE CALCIUM PHOSPHATE WITH TETRABUTYLAMMONIUM HYDROXIDE

    OpenAIRE

    CESÁRIO, Moisés Rômolos; MOURA, Danyelle Medeiros de Araújo; MACEDO, Daniel Araújo de; LIMA, Cícero Bosco Alves de

    2011-01-01

    Biosensors are digital devices composed of semiconductors connected to a biological component, usually an immobilized enzyme, which are used to measure the concentration of a specific substrate. This study aimed to obtain and purify the polyphenol oxidase enzyme (PPO) obtained from the crude extract of yam (Alocasia macrorhiza), and study the exfoliation reaction of calcium phosphate (CaP) with tetrabutylammonium hydroxide (TBA+OH-). The thermogravimetric study indicated the formation of t...

  15. Formation of calcium phosphates by vapour diffusion in highly concentrated ionic micro-droplets

    Energy Technology Data Exchange (ETDEWEB)

    Iafisco, M. [Alma Mater Studiorum Universita di Bologna, Dipartimento di Chimica ' ' G. Ciamician' ' , Via Selmi 2, 40126 Bologna (Italy); Universita del Piemonte Orientale, Dipartimento di Scienze Mediche, Via Solaroli 4, 28100 Novara (Italy); Delgado-Lopez, J.M.; Gomez-Morales, J.; Hernandez-Hernandez, M.A.; Rodriguez-Ruiz, I. [Laboratorio de Estudios Cristalograficos, IACT CSIC-UGR, Edificio Lopez Neyra, Avenida del Conocimiento, s/n 18100 Armilla (Spain); Roveri, N. [Alma Mater Studiorum Universita di Bologna, Dipartimento di Chimica ' ' G. Ciamician' ' , Via Selmi 2, 40126 Bologna (Italy)

    2011-08-15

    In this work we have used the sitting drop vapour diffusion technique, employing the ''crystallization mushroom '' to analyze the evolution of calcium phosphate crystallization in micro-droplets containing high initial concentrations of Ca{sup 2+} and HPO{sub 4}{sup 2-}. The decomposition of NH{sub 4}HCO{sub 3} solution produces vapours of NH{sub 3} and CO{sub 2} which diffuse through the droplets containing an aqueous solution of Ca(CH{sub 3}COO){sub 2} and (NH{sub 4}){sub 2}HPO{sub 4}. The result is the increase of pH by means of the diffusion of NH{sub 3} gas and the doping of the calcium phosphate with CO{sub 3}{sup 2-} ions by means of the diffusion of CO{sub 2} gas. The pH of the crystallization process is monitored and the precipitates at different times are characterized by XRD, FTIR, TGA, SEM and TEM techniques. The slow increase of pH and the high concentration of Ca{sup 2+} and HPO{sub 4}{sup 2-} in the droplets induce the crystallization of three calcium phosphate phases: dicalcium phosphate dihydrate (DCPD, brushite), octacalcium phosphate (OCP) and carbonate-hydroxyapatite (HA). The amount of HA nanocrystals with needle-like morphology and dimensions of about 100 nm, closely resembling the inorganic phase of bones, gradually increases, with the precipitation time up to 7 days, whereas the amount of DCPD, growing along the b axis, increases up to 3 days. Then, DCDP crystals start to hydrolyze yielding OCP nanoribbons and HA nanocrystals. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Cell response of calcium phosphate based ceramics, a bone substitute material

    Directory of Open Access Journals (Sweden)

    Juliana Marchi

    2013-01-01

    Full Text Available The aim of this study was to characterize calcium phosphate ceramics with different Ca/P ratios and evaluate cell response of these materials for use as a bone substitute. Bioceramics consisting of mixtures of hydroxyapatite (HAp and β-tricalcium phosphate (β-TCP powders in different proportions were pressed and sintered. The physical and chemical properties of these bioceramics were then characterized. Characterization of the biological properties of these materials was based on analysis of cell response using cultured fibroblasts. The number of cells attached to the samples was counted from SEM images of samples exposed to cell culture solution for different periods. These data were compared by analysis of variance (ANOVA complemented by the Tukey's test. The TCP sample had higher surface roughness and lower density. The adherence and growth of FMM1 cells on samples from all groups was studied. Even though the different calcium based ceramics exhibited properties which made them suitable as bone substitutes, those with higher levels of β-TCP revealed improved cell growth on their surfaces. These observations indicated two-phase calcium phosphate based materials with a β-TCP surface layer to be a promising bone substitute.

  17. Tri-calcium phosphate (ß-TCP) can be artificially synthesized by recycling dihydrate gypsum hardened.

    Science.gov (United States)

    Han-Cheol, Cho; Hori, Masaharu; Yoshida, Takakazu; Yamada, Naoko; Komada, Yuko; Tamaki, Yukimichi; Miyazaki, Takashi

    2014-01-01

    Calcium phosphate is known as a major component of biological hard tissues. This study aimed to produce calcium phosphate by recycling kneaded surplus gypsum. β-dihydrate gypsum was derived from commercial dental β-hemihydrate gypsum, which was mechanically powdered and mixed with the liquid component of a commercial zinc phosphate cement. This mixture was fired at 1,200°C and evaluated by XRD analysis, thermal analysis and scanning electron microscopy (SEM). An acceptable ratio of mixing was 4 g of β-dihydrate gypsum powder to 1.5 mL of phosphoric acid liquid. XRD peaks were monotonic below 800°C, but new ß-TCP was formed by firing at 900°C or more, although TG-DTA analysis of synthetic ß-TCP suggested that some residual dihydrate gypsum remained in the sample. SEM images indicated a fused-block bone-like structure covered with phosphorus and calcium. These results suggest that production of synthetic β-TCP is possible through ecological techniques using recycled materials. PMID:25483384

  18. In vitro biocompatibility of chitosan/hyaluronic acid-containing calcium phosphate bone cements.

    Science.gov (United States)

    Hesaraki, Saeed; Nezafati, Nader

    2014-08-01

    The need for bone repair has increased as the population ages. In this research, calcium phosphate cements, with and without chitosan (CS) and hyaluronic acid (HA), were synthesized. The composition and morphological properties of cements were evaluated by X-ray diffraction and scanning electron microscopy. The acellular in vitro bioactivity revealed that different apatite morphologies were formed on the surfaces of cements after soaking in simulated body fluid. The in vitro osteoblastic cell biocompatibility of in situ forming cements was evaluated and compared with those of conventional calcium phosphate cements (CPCs). The viability and growth rate of the cells were similar for all CPCs, but better alkaline phosphatase activity was observed for CPC with CS and HA. Calcium phosphate cements supported attachment of osteoblastic cells on their surfaces. Spindle-shaped osteoblasts with developed cytoplasmic membrane were found on the surfaces of cement samples after 7 days of culture. These results reveal the potential of the CPC-CS/HA composites to be used in bone tissue engineering. PMID:24399509

  19. Europium-doped amorphous calcium phosphate porous nanospheres: preparation and application as luminescent drug carriers.

    Science.gov (United States)

    Chen, Feng; Zhu, Ying-Jie; Zhang, Kui-Hua; Wu, Jin; Wang, Ke-Wei; Tang, Qi-Li; Mo, Xiu-Mei

    2011-01-01

    Calcium phosphate is the most important inorganic constituent of biological tissues, and synthetic calcium phosphate has been widely used as biomaterials. In this study, a facile method has been developed for the fabrication of amorphous calcium phosphate (ACP)/polylactide-block-monomethoxy(polyethyleneglycol) hybrid nanoparticles and ACP porous nanospheres. Europium-doping is performed to enable photoluminescence (PL) function of ACP porous nanospheres. A high specific surface area of the europium-doped ACP (Eu3+:ACP) porous nanospheres is achieved (126.7 m2/g). PL properties of Eu3+:ACP porous nanospheres are investigated, and the most intense peak at 612 nm is observed at 5 mol% Eu3+ doping. In vitro cytotoxicity experiments indicate that the as-prepared Eu3+:ACP porous nanospheres are biocompatible. In vitro drug release experiments indicate that the ibuprofen-loaded Eu3+:ACP porous nanospheres show a slow and sustained drug release in simulated body fluid. We have found that the cumulative amount of released drug has a linear relationship with the natural logarithm of release time (ln(t)). The Eu3+:ACP porous nanospheres are bioactive, and can transform to hydroxyapatite during drug release. The PL properties of drug-loaded nanocarriers before and after drug release are also investigated. PMID:21711603

  20. Development of a Calcium Phosphate Nanocomposite for Fast Fluorogenic Detection of Bacteria

    Directory of Open Access Journals (Sweden)

    Claudio R. Martínez

    2014-09-01

    Full Text Available Current procedures for the detection and identification of bacterial infections are laborious, time-consuming, and require a high workload and well-equipped laboratories. Therefore the work presented herein developed a simple, fast, and low cost method for bacterial detection based on hydroxyapatite nanoparticles with a nutritive mixture and the fluorogenic substrate. Calcium phosphate ceramic nanoparticles were characterized and integrated with a nutritive mixture for the early detection of bacteria by visual as well as fluorescence spectroscopy techniques. The composite was obtained by combining calcium phosphate nanoparticles (Ca:P ratio, 1.33:1 with a nutritive mixture of protein hydrolysates and carbon sources, which promote fast bacterial multiplication, and the fluorogenic substrate 4-methylumbellipheryl-β-d-glucuronide (MUG. The composite had an average particle size of 173.2 nm and did not show antibacterial activity against Gram-negative or Gram-positive bacteria. After an Escherichia coli suspension was in contact with the composite for 60–90 min, fluorescence detected under UV light or by fluorescence spectrophotometer indicated the presence of bacteria. Intense fluorescence was observed after incubation for a maximum of 90 min. Thus, this calcium phosphate nanocomposite system may be useful as a model for the development of other nanoparticle composites for detection of early bacterial adhesion.

  1. Synthesis and characterization of nanocomposite powders of calcium phosphate/silica-gel

    International Nuclear Information System (INIS)

    In the recent years ceramics of calcium phosphate are pointed out as an outstanding material in substitution and regeneration in defects from osseous tissue, in reason of their similar mineralogical characteristics of apatite of bone structure. However, the challenge with phosphate calcium ceramics find out about the mechanical properties and the development of biomaterials similar of the bone structure, what sometimes is not so easy, about fragile materials. The aim of this work focused in synthesis and characterization nanocomposites powders of calcium phosphate/silica-gel with percentages 1, 2, 3 e 5% of nanometric silica. The method synthesis used for the compositions elaboration was dissolution-precipitation. The presented results are related with the optimization to method elaboration of nanostructured powders, the mineralogical characterization with X-ray diffraction, thermal behavior with thermal differential analysis, differential scanning calorimetry here is ADT and dilatometer. The scanning electronic microscopy was used to help of morphological characterization the nanostructured powders and the surfaces from body test recovered from the mechanical test. (author)

  2. Europium-doped amorphous calcium phosphate porous nanospheres: preparation and application as luminescent drug carriers

    Directory of Open Access Journals (Sweden)

    Zhang Kui-Hua

    2011-01-01

    Full Text Available Abstract Calcium phosphate is the most important inorganic constituent of biological tissues, and synthetic calcium phosphate has been widely used as biomaterials. In this study, a facile method has been developed for the fabrication of amorphous calcium phosphate (ACP/polylactide-block-monomethoxy(polyethyleneglycol hybrid nanoparticles and ACP porous nanospheres. Europium-doping is performed to enable photoluminescence (PL function of ACP porous nanospheres. A high specific surface area of the europium-doped ACP (Eu3+:ACP porous nanospheres is achieved (126.7 m2/g. PL properties of Eu3+:ACP porous nanospheres are investigated, and the most intense peak at 612 nm is observed at 5 mol% Eu3+ doping. In vitro cytotoxicity experiments indicate that the as-prepared Eu3+:ACP porous nanospheres are biocompatible. In vitro drug release experiments indicate that the ibuprofen-loaded Eu3+:ACP porous nanospheres show a slow and sustained drug release in simulated body fluid. We have found that the cumulative amount of released drug has a linear relationship with the natural logarithm of release time (ln(t. The Eu3+:ACP porous nanospheres are bioactive, and can transform to hydroxyapatite during drug release. The PL properties of drug-loaded nanocarriers before and after drug release are also investigated.

  3. Mineralization of Annexin-5-containing Lipid-Calcium-Phosphate Complexes: MODULATION BY VARYING LIPID COMPOSITION AND INCUBATION WITH CARTILAGE COLLAGENS*

    OpenAIRE

    Genge, Brian R.; Wu, Licia N. Y.; Wuthier, Roy E.

    2008-01-01

    Matrix vesicles (MVs) in the growth plate bind to cartilage collagens and initiate mineralization of the extracellular matrix. Native MVs have been shown to contain a nucleational core responsible for mineral formation that is comprised of Mg2+-containing amorphous calcium phosphate and lipid-calcium-phosphate complexes (CPLXs) and the lipid-dependent Ca2+-binding proteins, especially annexin-5 (Anx-5), which greatly enhances mineral formation. Incorporation of non-Ca2...

  4. Biomimetic synthesis of modified calcium phosphate fine powders and their in vitro studies

    Energy Technology Data Exchange (ETDEWEB)

    Gergulova, R., E-mail: rumigg@yahoo.com; Tepavitcharova, S., E-mail: rumigg@yahoo.com; Rabadjieva, D., E-mail: rumigg@yahoo.com; Sezanova, K., E-mail: rumigg@yahoo.com; Ilieva, R., E-mail: rumigg@yahoo.com [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 11, 1113 Sofia (Bulgaria); Alexandrova, R.; Andonova-Lilova, B. [Institute of Experimental Morphology, Pathology and Anthropology with Museum, BAS, Acad. G. Bonchev Str., Bl. 25, Sofia (Bulgaria)

    2013-12-16

    Biomimetic approach and subsequent high-temperature treatment were used to synthesize ion modified calcium phosphate fine powders. Thus, using Simulated Body Fluid (SBF) as an ion modifier, a bi-phase mixture of ion modified β-tricalcium phosphate and hydroxyapatite (β-TCP + HA) was prepared. The use of SBF electrolyte solution enriched with Mg{sup 2+} or Zn{sup 2+} yielded monophase β-tricalcium phosphate additionally modified with Mg{sup 2+} or Zn{sup 2+} (Mg-β-TCP or Zn-β-TCP). The in vitro behavior of the prepared powders on cell viability and proliferation of murine BALB/c 3T3 fibroblasts and of human Lep 3 cells was studied by MTT test assays and Mosmann method after 72 h incubation. The relative cell viability was calculated.

  5. Biomimetic synthesis of modified calcium phosphate fine powders and their in vitro studies

    International Nuclear Information System (INIS)

    Biomimetic approach and subsequent high-temperature treatment were used to synthesize ion modified calcium phosphate fine powders. Thus, using Simulated Body Fluid (SBF) as an ion modifier, a bi-phase mixture of ion modified β-tricalcium phosphate and hydroxyapatite (β-TCP + HA) was prepared. The use of SBF electrolyte solution enriched with Mg2+ or Zn2+ yielded monophase β-tricalcium phosphate additionally modified with Mg2+ or Zn2+ (Mg-β-TCP or Zn-β-TCP). The in vitro behavior of the prepared powders on cell viability and proliferation of murine BALB/c 3T3 fibroblasts and of human Lep 3 cells was studied by MTT test assays and Mosmann method after 72 h incubation. The relative cell viability was calculated

  6. Chemical synthesis and characterization of magnesium substituted amorphous calcium phosphate (MG-ACP)

    International Nuclear Information System (INIS)

    Amorphous calcium phosphate (ACP) was synthesized by a simple aqueous precipitation using CaCl2 and Na3PO4 in the presence of MgCl2 to ensure the formation of the ACP phase at room temperature. Magnesium substituted ACP phases corresponding to two different compositions representing the two most prominent calcium phosphate phases (hydroxyapatite: Ca + Mg/P = 1.67 and tricalcium phosphate: Ca + Mg/P = 1.5) were synthesized by this simple approach. Both compositions of ACP phases resulted in their transformation into β-tricalcium phosphate upon heat treatment in air at 600 deg. C. X-ray diffraction (XRD), heat treatment, scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) and Brunauer-Emmett-Teller (BET) analyses were used to characterize the phase, thermal stability, surface area, and morphology of the synthesized ACP powders corresponding to the two different nominal Ca/P compositions. Although it is known that α-TCP is the phase that appears upon heat treatment at 600 deg. C unsubstituted ACP, substitution of magnesium ion in ACP (both TCP and HA composition) stabilized the structure of β-TCMP phase at 600 deg. C. Moreover, FT-IR analysis revealed that the ACP phase regardless of the composition, exhibited characteristic bands corresponding to that of HA, with the exception of the ACP corresponding to HA composition which exhibited a prominent OH vibrational mode.

  7. Comparative study on in vivo response of porous calcium carbonate composite ceramic and biphasic calcium phosphate ceramic.

    Science.gov (United States)

    He, Fupo; Ren, Weiwei; Tian, Xiumei; Liu, Wei; Wu, Shanghua; Chen, Xiaoming

    2016-07-01

    In a previous study, robust calcium carbonate composite ceramics (CC/PG) were prepared by using phosphate-based glass (PG) as an additive, which showed good cell response. In the present study the in vivo response of porous CC/PG was compared to that of porous biphasic calcium phosphate ceramics (BCP), using a rabbit femoral critical-size grafting model. The materials degradation and bone formation processes were evaluated by general observation, X-ray radiography, micro-computed tomography, and histological examination. The results demonstrated excellent biocompatibility and osteoconductivity, and progressive degradation of CC/PG and BCP. Although the in vitro degradation rate of CC/PG was distinctly faster than that of BCP, at 4week post-implantation, the bone generation and material degradation of CC/PG were less than those of BCP. Nevertheless, at postoperative week 8, the increment of bone formation and material degradation of CC/PG was pronouncedly larger than that of BCP. These results show that CC/PG is a potential resorbable bone graft aside from the traditional synthetic ones. PMID:27127035

  8. Improved Biocompatibility of Novel Biodegradable Scaffold Composed of Poly-L-lactic Acid and Amorphous Calcium Phosphate Nanoparticles in Porcine Coronary Artery

    Directory of Open Access Journals (Sweden)

    Dongsheng Gu

    2016-01-01

    Full Text Available Using poly-L-lactic acid for implantable biodegradable scaffold has potential biocompatibility issue due to its acidic degradation byproducts. We have previously reported that the addition of amorphous calcium phosphate improved poly-L-lactic acid coating biocompatibility. In the present study, poly-L-lactic acid and poly-L-lactic acid/amorphous calcium phosphate scaffolds were implanted in pig coronary arteries for 28 days. At the follow-up angiographic evaluation, no case of stent thrombosis was observed, and the arteries that were stented with the copolymer scaffold had significantly less inflammation and nuclear factor-κB expression and a greater degree of reendothelialization. The serum levels of vascular endothelial growth factor and nitric oxide, as well the expression of endothelial nitric oxide synthase and platelet-endothelial cell adhesion molecule-1, were also significantly higher. In conclusion, the addition of amorphous calcium phosphate to biodegradable poly-L-lactic acid scaffold minimizes the inflammatory response, promotes the growth of endothelial cells, and accelerates the reendothelialization of the stented coronary arteries.

  9. Identification of the hydrate gel phases present in phosphate-modified calcium aluminate binders

    International Nuclear Information System (INIS)

    The conversion of hexagonal calcium aluminate hydrates to cubic phases in hydrated calcium aluminate cements (CAC) can involve undesirable porosity changes and loss of strength. Modification of CAC by phosphate addition avoids conversion, by altering the nature of the reaction products, yielding a stable amorphous gel instead of the usual crystalline hydrate products. Here, details of the environments of aluminium and phosphorus in this gel were elucidated using solid-state NMR and complementary techniques. Aluminium is identified in both octahedral and tetrahedral coordination states, and phosphorus is present in hydrous environments with varying, but mostly low, degrees of crosslinking. A 31P/27Al rotational echo adiabatic passage double resonance (REAPDOR) experiment showed the existence of aluminium–phosphorus interactions, confirming the formation of a hydrated calcium aluminophosphate gel as a key component of the binding phase. This resolves previous disagreements in the literature regarding the nature of the disordered products forming in this system

  10. Identification of the hydrate gel phases present in phosphate-modified calcium aluminate binders

    Energy Technology Data Exchange (ETDEWEB)

    Chavda, Mehul A.; Bernal, Susan A. [Department of Materials Science and Engineering, The University of Sheffield, Sheffield S1 3JD (United Kingdom); Apperley, David C. [Solid-State NMR Group, Department of Chemistry, Durham University, Durham DH1 3LE (United Kingdom); Kinoshita, Hajime [Department of Materials Science and Engineering, The University of Sheffield, Sheffield S1 3JD (United Kingdom); Provis, John L., E-mail: j.provis@sheffield.ac.uk [Department of Materials Science and Engineering, The University of Sheffield, Sheffield S1 3JD (United Kingdom)

    2015-04-15

    The conversion of hexagonal calcium aluminate hydrates to cubic phases in hydrated calcium aluminate cements (CAC) can involve undesirable porosity changes and loss of strength. Modification of CAC by phosphate addition avoids conversion, by altering the nature of the reaction products, yielding a stable amorphous gel instead of the usual crystalline hydrate products. Here, details of the environments of aluminium and phosphorus in this gel were elucidated using solid-state NMR and complementary techniques. Aluminium is identified in both octahedral and tetrahedral coordination states, and phosphorus is present in hydrous environments with varying, but mostly low, degrees of crosslinking. A {sup 31}P/{sup 27}Al rotational echo adiabatic passage double resonance (REAPDOR) experiment showed the existence of aluminium–phosphorus interactions, confirming the formation of a hydrated calcium aluminophosphate gel as a key component of the binding phase. This resolves previous disagreements in the literature regarding the nature of the disordered products forming in this system.

  11. Electrophoretic deposition of bioactive silica-calcium phosphate nanocomposite on Ti-6Al-4V orthopedic implant.

    Science.gov (United States)

    Aniket; El-Ghannam, Ahmed

    2011-11-01

    Bioactive silica-calcium phosphate nanocomposite (SCPC) has been coated on Ti-6Al-4V implant employing an electrophoretic deposition (EPD) technique. The effects of composition and pH of the suspending medium on the zeta potential of three different SCPC formulations; SCPC25, SCPC50 and SCPC75 were analyzed. The average zeta potential of SCPC50 in pure ethanol was more negative than that of SCPC25 or SCPC75; however, the difference was not statistically significant. Discs of Ti-6Al-4V were passivated, coated with SCPC50 (200 nm-10 μm) and thermally treated at 600-800°C to produce a coating thickness in the range of 43.1 ± 5.7 to 30.1 ± 4.6 μm. After treatment at 600, 700, and 800°C, the adhesion strength at the SCPC50/Ti-6Al-4V interface was 42.6 ± 3.6, 44.7 ± 8.7, and 47.2 ± 4.3 MPa, respectively. SEM-EDX analyses of SCPC50-coated Ti-6Al-4V preimmersed in PBS for 7 days showed the formation of a Ca-deficient hydroxyapatite surface layer. ICP-OES analyses of the immersing solution (n = 6) showed an increase in the ionic concentration of Si from 3.3 ± 0.9 to 5.0 ± 1.2 ppm between days 1 and 4; after which no significant change in the Si concentration was measured. Bone marrow mesenchymal stem cells attached to the SCPC50-coated implants expressed significantly higher (p < 0.05) alkaline phosphatase activity (82.4 ± 25.6 nmoles p-NP/mg protein/min) than that expressed by cells attached to HA-coated or uncoated implants. Results of the study suggest that bioactive SCPC50 can efficiently be coated on Ti-6Al-4V using EPD. The SCPC50 coating has the potential to enhance bone integration with the orthopedic implant. PMID:21948397

  12. Surface acidity of calcium phosphate and calcium hydroxyapatite: FTIR spectroscopic study of low-temperature CO adsorption

    International Nuclear Information System (INIS)

    The surface properties of calcium phosphate precursor (CP) and crystalline calcium hydroxyapatite (HA) prepared biomimetically have been studied by IR spectroscopy of adsorbed CO. Both samples are characterized by the absence of Bronsted acidity. Low-temperature CO adsorption on CP evacuated at 523 K leads to formation of only one family of Ca2+-CO species (2168 cm-1). The analysis indicates that the respective calcium ions on the surface are not isolated. Similar spectra were obtained with HA evacuated at 573 K. In this case, however, the Ca2+-CO band was detected at 2165 cm-1 due to enhanced lateral interaction between the adsorbed CO molecules. Another family of Ca2+ sites (Ca2+-CO band at 2178 cm-1) was created after evacuation of the HA sample at 673 K. These sites were assumed to be a result of sample dehydroxylation. The results demonstrate the absence of any protonic acidity of the samples (i.e. P-OH surface groups) and weak electrostatic Lewis acidity caused by coordinatively unsaturated Ca2+ cations.

  13. In vitro osteoblast-like and endothelial cells' response to calcium silicate/calcium phosphate cement

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Qinghui; Qian Jiangchao [State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhou Huanjun; Yuan Yuan; Mao Yuhao; Liu Changsheng, E-mail: jiangchaoqian@ecust.edu.c, E-mail: csliu@sh163.ne [Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China)

    2010-06-01

    This study aims to investigate the interaction between calcium silicate/calcium phosphate cement (CS/CPC) and osteogenesis, in particular the in vitro osteoblast-like and endothelial cells' response to CS/CPC. The effect of CS/CPC on cell attachment, proliferation and differentiation of murine osteoblast-like cell MC3T3-E1, as well as the influence on the cell attachment and proliferation of human umbilical vein endothelial cell (HUVEC), was studied in detail. Our results indicated that CS/CPC exhibited excellent biocompatibility to the osteoblast-like cells. Moreover, the morphology and cytoskeleton organization of MC3T3-E1 cultured on the CS/CPC disks suggested that CS/CPC induced better cell adhesion and cell spreading. Simultaneously, cell proliferation and alkaline phosphatase (ALP) activity of MC3T3-E1 were significantly improved after 3 and 7 days of culture on CS/CPC disks in comparison with CPC disks. Additionally, on CS/CPC disks, HUVEC attached well on day 1 and cell proliferation was also greatly enhanced by day 7. Collectively, these results suggest that the introduction of calcium silicate may improve the cell response involved in the osteogenesis and thus may be beneficial to further modify CPC as a better bone repairing material.

  14. Surface acidity of calcium phosphate and calcium hydroxyapatite: FTIR spectroscopic study of low-temperature CO adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Pekounov, Yassen; Chakarova, Kristina [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Hadjiivanov, Konstantin, E-mail: kih@svr.igic.bas.bg [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

    2009-05-05

    The surface properties of calcium phosphate precursor (CP) and crystalline calcium hydroxyapatite (HA) prepared biomimetically have been studied by IR spectroscopy of adsorbed CO. Both samples are characterized by the absence of Bronsted acidity. Low-temperature CO adsorption on CP evacuated at 523 K leads to formation of only one family of Ca{sup 2+}-CO species (2168 cm{sup -1}). The analysis indicates that the respective calcium ions on the surface are not isolated. Similar spectra were obtained with HA evacuated at 573 K. In this case, however, the Ca{sup 2+}-CO band was detected at 2165 cm{sup -1} due to enhanced lateral interaction between the adsorbed CO molecules. Another family of Ca{sup 2+} sites (Ca{sup 2+}-CO band at 2178 cm{sup -1}) was created after evacuation of the HA sample at 673 K. These sites were assumed to be a result of sample dehydroxylation. The results demonstrate the absence of any protonic acidity of the samples (i.e. P-OH surface groups) and weak electrostatic Lewis acidity caused by coordinatively unsaturated Ca{sup 2+} cations.

  15. Crystallization Behavior of Phosphate Glasses with Hydrophobic Coating Materials

    Directory of Open Access Journals (Sweden)

    Jaeyeop Chung

    2015-01-01

    Full Text Available We analyzed the effect of the addition of Li2O3, TiO2, and Fe2O3 on the crystallization behavior of P2O5–CaO–SiO2–K2O glasses and the effect of the crystallization behavior on the roughness and hydrophobicity of the coated surface. Exothermic behavior, including a strong exothermic peak in the 833–972 K temperature range when Fe2O3, TiO2, or Li2O3 was added, was confirmed by differential thermal analysis. The modified glass samples (PFTL1–3 showed diffraction peaks when heated at 1073 and 1123 K for 5 min; the crystallized phase corresponds to Fe3(PO42, that is, graftonite. We confirmed that the intensity of the diffraction peaks increases at high temperatures and with increasing Li2O3 content. In the case of the PFTL3 glass, a Li3Fe2(PO42 phase, that is, trilithium diiron(III tris[phosphate(V], was observed. Through scanning electron microscopy and the contact angles of the surfaces with water, we confirmed that the increase in surface roughness, correlated to the crystallization of the glass frit, increases hydrophobicity of the surface. The calculated values of the local activation energies for the growth of Fe3(PO42 on the PTFL1, PTFL2, and PFTL3 glass were 237–292 kJ mol−1, 182–258 kJ mol−1, and 180–235 kJ mol−1.

  16. Effect of heat treatment on the microstructure and electrochemical behavior of manganese phosphate coating

    International Nuclear Information System (INIS)

    The effect of heat treatment on the microstructure and electrochemical behavior of manganese phosphate coating formed on the surface of CrMoV alloyed steel was investigated. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were performed to investigate the dehydration and decomposition behaviors. The surface morphologies and crystal structures of various heat-treated phosphate coatings were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The associated changes of the electrochemical properties were evaluated by measuring the open circuit potential (OCP) and conducting electrochemical impedance spectroscopy (EIS). The results showed that the as-deposited phosphate coatings mainly consisted of (Fe,Mn)5H2(PO4)4.4H2O (Mn,Fe-hureaulite). The coating underwent a two-step dehydration process if it was heat treated below 325 deg. C. Decomposition of the phosphate coating occurred at 340 deg. C resulted in the formation of Fe0.5Mn2.5(PO4)2 with poor crystallinity. The polarization resistance of the phosphate coating was greatly affected by the loss of structural water, the heat treatment-induced crack and the formation of Fe0.5Mn2.5(PO4)2

  17. Development of cadmium-free quantum dot for intracellular labelling through electroporation or lipid-calcium-phosphate

    Science.gov (United States)

    Liu, Ying-Feng; Hung, Wei-Ling; Hou, Tzh-Yin; Huang, Hsiu-Ying; Lin, Cheng-An J.

    2016-04-01

    Traditional fluorescent labelling techniques has severe photo-bleaching problem such as organic dyes and fluorescent protein. Quantum dots made up of traditional semiconductor (CdSe/ZnS) material has sort of biological toxicity. This research has developed novel Cd-free quantum dots divided into semiconductor (Indium phosphide, InP) and noble metal (Gold). Former has lower toxicity compared to traditional quantum dots. Latter consisting of gold (III) chloride (AuCl3) and toluene utilizes sonochemical preparation and different stimulus to regulate fluorescent wavelength. Amphoteric macromolecule surface technology and ligand Exchange in self-Assembled are involved to develop hydrophilic nanomaterials which can regulate the number of grafts per molecule of surface functional groups. Calcium phosphate (CaP) nanoparticle (NP) with an asymmetric lipid bilayer coating technology developed for intracellular delivery and labelling has synthesized Cd-free quantum dots possessing high brightness and multi-fluorescence successfully. Then, polymer coating and ligand exchange transfer to water-soluble materials to produce liposome nanomaterials as fluorescent probes and enhancing medical applications of nanotechnology.

  18. Plasma Calcium, Inorganic Phosphate and Magnesium During Hypocalcaemia Induced by a Standardized EDTA Infusion in Cows

    Directory of Open Access Journals (Sweden)

    Enemark JMD

    2001-06-01

    Full Text Available The intravenous Na2EDTA infusion technique allows effective specific chelation of circulating Ca2+ leading to a progressive hypocalcaemia. Methods previously used were not described in detail and results obtained by monitoring total and free ionic calcium were not comparable due to differences in sampling and analysis. This paper describes a standardized EDTA infusion technique that allowed comparison of the response of calcium, phosphorus and magnesium between 2 groups of experimental cows. The concentration of the Na2EDTA solution was 0.134 mol/l and the flow rate was standardized at 1.2 ml/kg per hour. Involuntary recumbency occurred when ionised calcium dropped to 0.39 – 0.52 mmol/l due to chelation. An initial fast drop of ionized calcium was observed during the first 20 min of infusion followed by a fluctuation leading to a further drop until recumbency. Pre-infusion [Ca2+] between tests does not correlate with the amount of EDTA required to induce involuntary recumbence. Total calcium concentration measured by atomic absorption remained almost constant during the first 100 min of infusion but declined gradually when the infusion was prolonged. The concentration of inorganic phosphate declined gradually in a fluctuating manner until recumbency. Magnesium concentration remained constant during infusion. Such electrolyte responses during infusion were comparable to those in spontaneous milk fever. The standardized infusion technique might be useful in future experimental studies.

  19. Polycaprolactone coated porous tricalcium phosphate scaffolds for controlled release of protein for tissue engineering

    OpenAIRE

    Xue, Weichang; Bandyopadhyay, Amit; Bose, Susmita

    2009-01-01

    Polycaprolactone (PCL) was coated on porous tricalcium phosphate (TCP) scaffolds to achieve controlled protein delivery. Porous TCP scaffolds were fabricated using reticulated polyurethane foam as sacrificial scaffold with a porosity of 70–90 vol %. PCL was coated on sintered porous TCP scaffolds by dipping-drying process. The compressive strength of TCP scaffolds increased significantly after PCL coating. The highest strength of 2.41 MPa at a porosity of 70% was obtained for the TCP scaffold...

  20. Some studies on calcium phosphate embedded in polyvinyl alcohol matrix before and after γ-irradiation

    International Nuclear Information System (INIS)

    The Ca-P ratio in polymer matrix was adjusted to 1.67 as in hydroxyapatite. The complexed polyvinyl alcohol (PVA) materials exhibit the characteristic absorption bands of phosphate at 601 and 962 cm-1 indicating the presence of (HPO4)-1 anions in the structure. The X-ray diffraction (XRD) revealed that the reaction between Ca and P ions in the PVA medium has a great effect on polymeric matrix crystallization. After irradiation, XRD results for sample c showed more sharp peaks indicating that irradiation can break the principal chemical bonds and favoring additional crystallization processes and therefore the crystallinity increases. An improvement in the thermal stability of PVA doped with calcium phosphate could be seen with the increase of calcium phosphate intercalated with PVA. The surfaces of films were analyzed by scanning electron microscope (SEM) before and after γ-irradiation. The formation of hydroxyapatite is confirmed by energy dispersive X-ray spectroscopy (EDX analysis). The electric conduction data were interpreted on the basis of an intrachain one-dimensional interpolaron hopping model of Kuivalainen.

  1. Tribological properties of adaptive phosphate composite coatings with addition of silver and molybdenum disulfide

    International Nuclear Information System (INIS)

    Highlights: • A new kind of adaptive coatings was fabricated using relatively simple spraying techniques. • The tribological properties of Ag/MoS2 phosphate composite coatings were investigated at the temperature from 20 °C to 700 °C. • The composition and wear mechanisms of Ag/MoS2 phosphate composite coatings were also discussed. • The Ag/MoS2 phosphate composite coatings have self-repairing capability in the rubbing process at 700 °C. - Abstract: Adaptive phosphate composite coatings with addition of solid lubricants of molybdenum disulfide (MoS2) and silver (Ag) using aluminum chromium phosphate as the binder were fabricated on high-temperature steel. The tribological properties of phosphate composite coatings were evaluated from room temperature (RT) to 700 °C. The phase composition and microstructure were investigated according to the characterization by power X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). The results show that the composite coating with the Ag/MoS2 mass ratio of 2:1 exhibits the stable and low friction coefficients from RT to 700 °C and relative low wear rates at all testing temperatures. The tribo-chemical reaction between Ag and MoS2 occurred in the rubbing process to form silver molybdates compounds lubricating film. The temperature-adaptive tribological properties were attributed to the formation of lubricating films composed of lubricants silver, MoS2 and silver molybdates phases on the worn surfaces of the composites coatings in a wide-temperature range

  2. Tribological properties of adaptive phosphate composite coatings with addition of silver and molybdenum disulfide

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Cancan [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou (China); University of Chinese Academy of Sciences, Beijing (China); Chen, Lei, E-mail: chenlei@lzb.ac.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou (China); Zhou, Jiansong, E-mail: jszhou@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou (China); Zhou, Huidi; Chen, Jianmin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou (China)

    2014-05-01

    Highlights: • A new kind of adaptive coatings was fabricated using relatively simple spraying techniques. • The tribological properties of Ag/MoS{sub 2} phosphate composite coatings were investigated at the temperature from 20 °C to 700 °C. • The composition and wear mechanisms of Ag/MoS{sub 2} phosphate composite coatings were also discussed. • The Ag/MoS{sub 2} phosphate composite coatings have self-repairing capability in the rubbing process at 700 °C. - Abstract: Adaptive phosphate composite coatings with addition of solid lubricants of molybdenum disulfide (MoS{sub 2}) and silver (Ag) using aluminum chromium phosphate as the binder were fabricated on high-temperature steel. The tribological properties of phosphate composite coatings were evaluated from room temperature (RT) to 700 °C. The phase composition and microstructure were investigated according to the characterization by power X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). The results show that the composite coating with the Ag/MoS{sub 2} mass ratio of 2:1 exhibits the stable and low friction coefficients from RT to 700 °C and relative low wear rates at all testing temperatures. The tribo-chemical reaction between Ag and MoS{sub 2} occurred in the rubbing process to form silver molybdates compounds lubricating film. The temperature-adaptive tribological properties were attributed to the formation of lubricating films composed of lubricants silver, MoS{sub 2} and silver molybdates phases on the worn surfaces of the composites coatings in a wide-temperature range.

  3. Understanding the Biocompatibility of Sintered Calcium Phosphate with Ratio of [Ca]/[P] = 1.50

    Directory of Open Access Journals (Sweden)

    Feng-Lin Yen

    2012-01-01

    Full Text Available Biocompatibility of sintered calcium phosphate pellets with [Ca]/[P] = 1.50 was determined in this study. Calcium pyrophosphate (CPP phase formed on the sintered pellets immersed in a normal saline solution for 14 d at 37∘C. The intensities of hydroxyapatite (HA reflections in the X-ray diffraction (XRD patterns of the pellets were retrieved to as-sintered state. The pellet surface morphology shows that CPP crystallites were clearly present and make an amorphous calcium phosphate (ACP to discriminate against become to the area of slice join together. In addition, the intensities of the CPP reflections in the XRD patterns were the highest when the pellets were immersed for 28 d. When the CPP powders were extracted from the pellets after immersion in the solution for 14 d, the viability of 3T3 cells remained above 90% for culture times from 1 to 4 d. The pellet surface morphology observed using optical microscopy showed that the cells did not adhere to the bottom of the sintered pellets when cultured for 4 d; however, some CPP phase precipitates were formed, as confirmed by XRD. In consequence, the results suggest that the sintered HA powders are good materials for use in biomedical applications because of their good biocompatibility.

  4. Effects of 1,25-dihydroxicolecalciferol and dietary calcium-phosphate on distribution of lead to tissues during growth

    International Nuclear Information System (INIS)

    The susceptibility to the toxic effects of lead (Pb) is mainly mediated by age and nutritional and hormonal status, and children are among the most vulnerable to them. During growth, an increase in calcium, phosphate and vitamin D in diet is recommended to enhance calcium and phosphate intestinal absorption and bone deposit. Calcium and phosphate reduce lead intestinal absorption, and 1,25-dihydroxicolecalciferol (1,25(OH)2D3) (active metabolite of vitamin D) increases both lead and calcium intestinal absorption. However, the effects of 1,25(OH)2D3 on lead bone deposit and redistribution to soft tissues are not well known. In this study, we examined the effects of calcium-phosphate diet supplementation and the administration of 1,25(OH)2D3 on Pb distribution to soft tissue and bone in growing rats exposed to Pb. Rats (21 days old) were exposed for 28 days to 100 ppm of Pb solution in drinking water. Calcium and phosphate in diet were increased from 1 to 2.5% and from 0.65 to 1.8%, respectively, and 1,25(OH)2D3 was administrated by intraperitoneal injection of 7.2 ng/kg every 7 days. Between 21 and 49 days, the body weight increased about 5 times. The results showed that high calcium-phosphate diet led to lower Pb concentration in blood and in bone, but Pb liver and kidney concentrations increased, which indicates that absorption and bone deposit redistribution of Pb decreased. On the other hand, no effect of this diet rich in calcium-phosphate in Pb concentration was observed in brain. Blood and bone Pb concentrations increased even more when the high calcium-phosphate diet included 1,25(OH)2D3. In the rats treated only with 1,25(OH)2D3, blood and bone Pb concentrations were lower. Higher concentrations of lead in the soft organs were observed also in rats treated under a high calcium-phosphate diet plus 1,25(OH)2D3 administration. The above mentioned results suggested that 1,25(OH)2D3 induces an increased absorption and redistribution of Pb, and therefore, it may

  5. Effect of carbonate and phosphate ratios on the transformation of calcium orthophosphates

    Energy Technology Data Exchange (ETDEWEB)

    Eliassi, Mohammad Daoud, E-mail: eliassi2007@gmail.com [Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070 (China); Zhao, Wei [State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences, Yangling 712100 (China); Tan, Wen Feng, E-mail: wenfeng.tan@hotmail.com [Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070 (China)

    2014-07-01

    Graphical abstract: Complexes among phosphate, carbonate and calcium have been prepared via a facile hydrothermal route. The synthesized product at the low (0.15) and the high (1.8) molar ratio of PO{sub 4}{sup 3−}/CO{sub 3}{sup 2−} is calcium phosphate hydrate and hydroxylapatite (HAp), respectively. Molar ratios of PO{sub 4}{sup 3−}/CO{sub 3}{sup 2−} are effective on the reduction of carbonate activity during the crystallization of HAp. - Highlights: • Formation of different complexes from CO{sub 3}{sup 2−}, PO{sub 4}{sup 3−} and Ca{sup 2+} solutions at 60 °C. • Molar ratios of PO{sub 4}{sup 3−}/CO{sub 3}{sup 2} cause changes in phase and size of synthesized products. • Addition of PO{sub 4}{sup 3} inhibited the activity of CO{sub 3}{sup 2−} during bound with Ca{sup 2+}. • The phase transformation was completed, when CO{sub 3}{sup 2−} peaks disappeared in FTIR. • PO{sub 4}{sup 3−}, CO{sub 3}{sup 2−} and Ca{sup 2+} distributed heterogeneously on the surface of precipitation. - Abstract: Complexes among phosphate, carbonate and calcium have been synthesized by a designed hydrothermal method. Effects of carbonate and phosphate ratios on the transformation of calcium-orthophosphates were investigated. With X-ray diffraction measurement the synthesized product at the low (0.15) and the high (1.8) molar ratio of PO{sub 4}{sup 3−}/CO{sub 3}{sup 2−} is calcium phosphate hydrate at pH 9.0, and hydroxylapatite (HAp) at pH 8.0, respectively. Fourier transform infrared spectroscopy of product at the high ratio (1.8) of PO{sub 4}{sup 3−}/CO{sub 3}{sup 2−} shows that the CO{sub 3}{sup 2−} peaks disappear, and the strong peaks at 1412 and 1460 cm{sup −1} are assigned to the vibrations of PO{sub 4}{sup 3−} in HAp. {sup 31}P nuclear magnetic resonance spectra of products at the low (0.15–0.6) to the high (1.2–1.8) ratios of PO{sub 4}{sup 3−}/CO{sub 3}{sup 2−} are obtained at 2.9 and 2.7 ppm, respectively. Molar ratios of PO

  6. Co-crystallization of cholesterol and calcium phosphate as related to atherosclerosis

    Science.gov (United States)

    Hirsch, Danielle; Azoury, Reuven; Sarig, Sara

    1990-09-01

    Calcification of atherosclerotic plaques occurs very frequently and aggravates the disease. In biological systems, epitaxial relationships between crystal structures may be important in nucleating the deposit of a solid phase. The biologically preferred calcium phosphate species, apatite, and cholesterol crystal have structurally compatible crystallographic faces which allow epitaxial growth of one crystal upon another. The present study describes a new approach to explore, in vitro, the crystallization processes of calcium phosphate (CaP) with cholesterol (CS) and cholestanol (CN) which are related to atherosclerosis. Aqueous solutions containing calcium and phosphate ions or CaP crystals as hydroxyapatite were added into saturated ethanolic solutions of CS or CS and 10% CN. After precipitation, crystals were collected and analyzed by nuclear magnetic resonance (NMR), infra-red (IR), X-ray, scanning electron microscope (SEM-LINK), differential scanning calorimeter (DSC) and atomic absorption. The principal result is the well-formed crystals precipitation when an aqueous solution and CaP seed crystals were added to saturated solutions of CS and 10% CN. Cholesterol-cholestanol dihydrate (CC2W) crystals precipitated in the presence of CaP seeds were compared to the CC2W crystals obtained without the mineral compound. The results of this comparison indicate a special link between crystals of CaP and CC2W, and support the epitaxial relationship between the two kinds of crystals. The potential of CC2W crystals to be precipitated by CaP seed crystals prove likewise the possible significant role of the cholestanol metabolite in the process of cholesterol crystallization and calcification in the arteries.

  7. Novel tea polyphenol-modified calcium phosphate nanoparticle and its remineralization potential.

    Science.gov (United States)

    He, Libang; Deng, Dongmei; Zhou, Xuedong; Cheng, Lei; ten Cate, Jacob M; Li, Jiyao; Li, Xudong; Crielaard, Wim

    2015-11-01

    Tea polyphenols (TP) are not only potent antimicrobial and antioxidant agents but also effective modifiers in the formation of nanosized crystals. Since nano-hydroxyapatite (n-HA) is known to enhance remineralization of dental hard tissue, our aims were to synthesize nanosized calcium phosphate particles incorporating TP and to test their potential as caries preventive agent. An ammonia water diffusion method was used to synthesize nanosized calcium phosphate particles (TP-CaP) in the presence of various amounts of TP. The resultant products were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The remineralization potential of the nano TP-CaP was then investigated in a 12-day pH-cycling model. Nano TP-CaP slurries, at pH 7.0 and pH 5.5, were applied onto preformed enamel lesions 4 × 3 min per day. n-HA slurries at pH 7.0 and pH 5.5 were used as positive controls, and deionized water was served as a negative control. SEM showed nanosized particles were only formed at 27 mg/mL of TP. Further characterization of the nanosized particles revealed the components were amorphous calcium phosphate, HA, and TP. Both surface microhardness and transverse microradiography analyses showed that nano TP-CaP at pH 5.5, but not at pH 7.0, significantly enhanced remineralization, to the same extent as the n-HA controls. Furthermore, significantly higher amount of TP was found in the supernatant of TP-CaP at pH 5.5 than those at pH 7.0. Since TP can inhibit bacterial growth and enzyme activities, the novel nanosized TP-CaP particle, at low pH, is a potential dual-functional-remineralization and antibacteria-product. PMID:25470574

  8. Direct 3D powder printing of biphasic calcium phosphate scaffolds for substitution of complex bone defects

    International Nuclear Information System (INIS)

    The 3D printing technique based on cement powders is an excellent method for the fabrication of individual and complex bone substitutes even in the case of large defects. The outstanding bone remodeling capacity of biphasic calcium phosphates (BCPs) containing hydroxyapatite (HA) as well as tricalcium phosphate (TCP) in varying ratios makes the adaption of powder systems resulting in BCP materials to this fabrication technique a desirable aim. This study presents the synthesis and characterization of a novel powder system for the 3D printing process, intended for the production of complexly shaped BCP scaffolds by a hydraulic setting reaction of calcium carbonate and TCP with phosphoric acid. The HA/TCP ratio in the specimens could be tailored by the calcium/phosphate ratio of the starting powder. The scaffolds could be fabricated with a dimensional accuracy of >96.5% and a minimal macro pore size of 300 µm. Independent of the phase composition the printed specimens showed a microporosity of approximately 68%, while the compressive strength strongly depended on the chemical composition and increased with rising TCP content in the scaffolds to a maximum of 1.81 MPa. Post-treatment of the scaffolds with a polylactic-co-glycolic acid-solution enhanced the mechanical properties by a factor of 8. In vitro studies showed that all BCP scaffolds were cytocompatible and enhanced the cell viability as well as the cell proliferation, as compared with pure TCP. Cell proliferation is even better on BCP when compared to HA and cell viability is in a similar range on these materials. (paper)

  9. Synthesis and characterization of Ag-containing calcium phosphates with various Ca/P ratios

    International Nuclear Information System (INIS)

    Ag-containing calcium phosphate (CaP) powders were synthesized by a precipitation method using aqueous solutions of calcium nitrate, silver nitrate, and ammonium phosphate. The powders were sintered at temperatures ranging from 1173 to 1473 K. The charged atomic ratios of (Ca + Ag)/P and Ag/(Ca + Ag) in solution were varied from 1.33 to 1.67 and from 0 to 0.30, respectively. The Ag content in the as-precipitated CaP powders increased with the charged Ag/(Ca + Ag) atomic ratio in solution and was lower than the charged Ag/(Ca + Ag) value. The as-precipitated CaP powders consisted of hydroxyapatite (HA) as the main phase. Ag nanoparticles were observed on the as-precipitated HA particles under all conditions of Ag addition. After the sintering, HA, β-TCP (tricalcium phosphate), α-TCP, and β-CPP (calcium pyrophosphate) were mainly detected as CaPs on the basis of the Ca/P atomic ratio of the as-precipitated powders. The addition of Ag stabilized the β-TCP phase, and the distribution of Ag in β-TCP was homogeneous. A metallic Ag phase coexisted with HA. The solubility of Ag in HA was estimated to be 0.0019–0.0061 (Ag/(Ca + Ag)) atomic ratio, which was lower than that in β-TCP (higher than 0.0536) and higher than that of β-CPP (below the detection limit of analyses). - Highlights: • The HA powders with Ag nanoparticles were synthesized by a precipitation method. • Metallic Ag particles were detected with the HA phase after sintering. • The distribution of Ag in β-TCP was homogeneous after sintering. • The addition of Ag stabilized the β-ΤCP phase. • β-TCP exhibited higher solubility of Ag than HA and β-CPP

  10. In-situ high temperature XRD of calcium phosphate biomaterial using DEHPA as the starting material

    International Nuclear Information System (INIS)

    A process to produce calcium phosphate biomaterial was done using an organic based phosphoric acid (DEHPA) as its starting material. The gel obtained from this reaction was used to study calcium phosphate transformation using in-situ XRD with temperature ranges from room temperature to 1300 degree C. The results obtained from this analysis show the following phase transformation: Gel β-Ca2P2O7 β-TCP + HA α-TCP + HA, β-Ca2P2O7 forms at 400 degree C and as we heat the sample at 1000 degree C peaks belonging to β- TCP and HA appears showing the transformation of the β-Ca2P2O7 phase. When the sample is heated up further to 1200 degree C, β-TCP is transform into α-TCP. In the cold in-situ study, XRD analysis was performed on the sample from room temperature to -140 degree C. At room the XRD diffractogram shows the sample as an amorphous material and as the temperature was further lowered sharp peaks begins to form indicating that the material had becomes crystalline. The peaks were identified to be that calcium hydrogen phosphate (Ca(H2PO4)2) and this indicates that there is no hydroxyl group removal during the cooling process. The relative crystallinity values obtained for the different cooling temperatures show a slow exponential increase on the initial cooling of 0 to -100 degree C and at further cooling temperatures resulted fast and linear process. Also unlike the in-situ XRD analysis performs at high temperature no phase transformation occurred at this low temperature. (Author)

  11. Antibacterial amorphous calcium phosphate nanocomposites with a quaternary ammonium dimethacrylate and silver nanoparticles

    Science.gov (United States)

    Cheng, Lei; Weir, Michael D.; Xu, Hockin H. K.; Antonucci, Joseph M.; Kraigsley, Alison M.; Lin, Nancy J.; Lin-Gibson, Sheng; Zhou, Xuedong

    2012-01-01

    Objectives Calcium and phosphate ion-releasing resin composites are promising for remineralization. However, there has been no report on incorporating antibacterial agents to these composites. The objective of this study was to develop antibacterial and mechanically-strong nanocomposites incorporating a quaternary ammonium dimethacrylate (QADM), nanoparticles of silver (NAg), and nanoparticles of amorphous calcium phosphate (NACP). Methods The QADM, bis(2-methacryloyloxyethyl) dimethylammonium bromide (ionic dimethacrylate-1), was synthesized from 2-(N,N-dimethylamino)ethyl methacrylate and 2-bromoethyl methacrylate. Ng was synthesized by dissolving Ag 2-ethylhexanoate salt in 2-(tertbutylamino)ethyl methacrylate. Mechanical properties were measured in three-point flexure with bars of 2×2×25 mm (n = 6). Composite disks (diameter = 9 mm, thickness = 2 mm) were inoculated with Streptococcus mutans. The metabolic activity and lactic acid production of biofilms were measured (n = 6). Two commercial composites were used as controls. Results Flexural strength and elastic modulus of NACP+QADM, NACP+NAg, and NACP+QADM+NAg matched those of commercial composites with no antibacterial property (p > 0.1). The NACP+QADM+NAg composite decreased the titer counts of adherent S. mutans biofilms by an order of magnitude, compared to the commercial composites (p calcium phosphate composite for the first time. NACP+QADM+NAg was strongly-antibacterial and greatly reduced the titer counts, metabolic activity, and acid production of S. mutans biofilms, while possessing mechanical properties similar to commercial composites. These nanocomposites are promising to have the double benefits of remineralization and antibacterial capabilities to inhibit dental caries. PMID:22305716

  12. Synthesis and characterization of Ag-containing calcium phosphates with various Ca/P ratios

    Energy Technology Data Exchange (ETDEWEB)

    Gokcekaya, Ozkan, E-mail: gokcekaya@dc.tohoku.ac.jp [Department of Materials Processing, Tohoku University, 6-6-02 Aza Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Ueda, Kyosuke; Narushima, Takayuki [Department of Materials Processing, Tohoku University, 6-6-02 Aza Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Ergun, Celaletdin [Faculty of Mechanical Engineering, Istanbul Technical University, 65 Inonu Street, Gumussuyu, Istanbul 34437 (Turkey)

    2015-08-01

    Ag-containing calcium phosphate (CaP) powders were synthesized by a precipitation method using aqueous solutions of calcium nitrate, silver nitrate, and ammonium phosphate. The powders were sintered at temperatures ranging from 1173 to 1473 K. The charged atomic ratios of (Ca + Ag)/P and Ag/(Ca + Ag) in solution were varied from 1.33 to 1.67 and from 0 to 0.30, respectively. The Ag content in the as-precipitated CaP powders increased with the charged Ag/(Ca + Ag) atomic ratio in solution and was lower than the charged Ag/(Ca + Ag) value. The as-precipitated CaP powders consisted of hydroxyapatite (HA) as the main phase. Ag nanoparticles were observed on the as-precipitated HA particles under all conditions of Ag addition. After the sintering, HA, β-TCP (tricalcium phosphate), α-TCP, and β-CPP (calcium pyrophosphate) were mainly detected as CaPs on the basis of the Ca/P atomic ratio of the as-precipitated powders. The addition of Ag stabilized the β-TCP phase, and the distribution of Ag in β-TCP was homogeneous. A metallic Ag phase coexisted with HA. The solubility of Ag in HA was estimated to be 0.0019–0.0061 (Ag/(Ca + Ag)) atomic ratio, which was lower than that in β-TCP (higher than 0.0536) and higher than that of β-CPP (below the detection limit of analyses). - Highlights: • The HA powders with Ag nanoparticles were synthesized by a precipitation method. • Metallic Ag particles were detected with the HA phase after sintering. • The distribution of Ag in β-TCP was homogeneous after sintering. • The addition of Ag stabilized the β-ΤCP phase. • β-TCP exhibited higher solubility of Ag than HA and β-CPP.

  13. Synthesis and characterization of Ag-containing calcium phosphates with various Ca/P ratios.

    Science.gov (United States)

    Gokcekaya, Ozkan; Ueda, Kyosuke; Narushima, Takayuki; Ergun, Celaletdin

    2015-08-01

    Ag-containing calcium phosphate (CaP) powders were synthesized by a precipitation method using aqueous solutions of calcium nitrate, silver nitrate, and ammonium phosphate. The powders were sintered at temperatures ranging from 1173 to 1473 K. The charged atomic ratios of (Ca+Ag)/P and Ag/(Ca+Ag) in solution were varied from 1.33 to 1.67 and from 0 to 0.30, respectively. The Ag content in the as-precipitated CaP powders increased with the charged Ag/(Ca+Ag) atomic ratio in solution and was lower than the charged Ag/(Ca+Ag) value. The as-precipitated CaP powders consisted of hydroxyapatite (HA) as the main phase. Ag nanoparticles were observed on the as-precipitated HA particles under all conditions of Ag addition. After the sintering, HA, β-TCP (tricalcium phosphate), α-TCP, and β-CPP (calcium pyrophosphate) were mainly detected as CaPs on the basis of the Ca/P atomic ratio of the as-precipitated powders. The addition of Ag stabilized the β-TCP phase, and the distribution of Ag in β-TCP was homogeneous. A metallic Ag phase coexisted with HA. The solubility of Ag in HA was estimated to be 0.0019-0.0061 (Ag/(Ca+Ag)) atomic ratio, which was lower than that in β-TCP (higher than 0.0536) and higher than that of β-CPP (below the detection limit of analyses). PMID:26042697

  14. Three dimensional biphasic calcium phosphate nanocomposites for load bearing bioactive bone grafts.

    Science.gov (United States)

    Garai, Subhadra; Sinha, Arvind

    2016-02-01

    Mimicking matrix mediated bio-mineralization process, three dimensional blocks of biphasic calcium phosphate (BCP, hydroxyapatite (HA) and β-tricalcium phosphate (TCP)) nanocomposites, having three different stoichiometries have been synthesized for possible application as load bearing synthetic bone graft or scaffolds. Biphasic blocks with three weight ratios of 20:80, 25:75 and 30:70 of HA and TCP respectively have been synthesized. Detailed structural and chemical characterization of the samples revealed a strong dependence of porosity and mechanical properties on the stoichiometry of biphasic blocks. Effect of physiological medium on the microstructure and mechanical properties of the three different blocks has also been studied. Bioactivity of the BCP block, exhibiting highest compressive strength in air as well as in physiological medium, has been evaluated through adhesion, proliferation and differentiation of mesenchymal stem cells using different markers. PMID:26652386

  15. Continuous cellularization of calcium phosphate hybrid scaffolds induced by plasma polymer activation.

    Science.gov (United States)

    Bergemann, Claudia; Cornelsen, Matthias; Quade, Antje; Laube, Thorsten; Schnabelrauch, Matthias; Rebl, Henrike; Weißmann, Volker; Seitz, Hermann; Nebe, Barbara

    2016-02-01

    The generation of hybrid materials based on β-tricalcium phosphate (TCP) and various biodegradable polymers like poly(l-lactide-co-d,l-lactide) (PLA) represents a common approach to overcoming the disadvantages of pure TCP devices. These disadvantages lie in TCP's mechanical properties, such as brittleness. The positive characteristic of PLA - improvement of compressive strength of calcium phosphate scaffolds - is diametrically opposed to its cell attractiveness. Therefore, the objective of this work was to optimize osteoblast migration and cellularization inside a three-dimensionally (3D) printed, PLA polymer stabilized TCP hybrid scaffold by a plasma polymer process depositing amino groups via allylamine. MG-63 osteoblastic cells inside the 10mm hybrid scaffold were dynamically cultivated for 14days in a 3D model system integrated in a perfusion reactor. The whole TCP/PLA hybrid scaffold was continuously colonized due to plasma polymerized allylamine activation inducing the migration potential of osteoblasts. PMID:26652403

  16. Injectable Hydrogel Composite Based Gelatin-PEG and Biphasic Calcium Phosphate Nanoparticles for Bone Regeneration

    Science.gov (United States)

    Van, Thuy Duong; Tran, Ngoc Quyen; Nguyen, Dai Hai; Nguyen, Cuu Khoa; Tran, Dai Lam; Nguyen, Phuong Thi

    2016-05-01

    Gelatin hydrogels have recently attracted much attention for tissue regeneration because of their biocompatibility. In this study, we introduce poly-ethylene glycol (PEG)—grafted gelatin containing tyramine moieties which have been utilized for in situ enzyme-mediated hydrogel preparation. The hydrogel can be used to load nanoparticles of biphasic calcium phosphate, a mixture of hydroxyapatite and β-tricalcium phosphate, and forming injectable bio-composites. Proton nuclear magnetic resonance (1H NMR) spectra indicated that tyramine-functionalized polyethylene glycol-nitrophenyl carbonate ester was conjugated to the gelatin. The hydrogel composite was rapidly formed in situ (within a few seconds) in the presence of horseradish peroxidase and hydrogen peroxide. In vitro experiments with bio-mineralization on the hydrogel composite surfaces was well-observed after 2 weeks soaking in simulated body fluid solution. The obtained results indicated that the hydrogel composite could be a potential injectable material for bone regeneration.

  17. The Properties of Sintered Calcium Phosphate with [Ca]/[P] = 1.50

    Directory of Open Access Journals (Sweden)

    Moo-Chin Wang

    2012-10-01

    Full Text Available In order to obtain the properties of the sintered as-dried calcium phosphate with [Ca]/[P] = 1.50, the characteristics of sintered pellets have been investigated using X-ray diffraction (XRD, inductively coupled plasma-mass spectrometry (ICP-MS, Fourier-transform infrared (FT-IR spectra, Vickers hardness indentation and scanning electron microscopy (SEM. When the pellet samples were sintered between 700 °C and 1200 °C for 4 h, the hydroxyapatite (Ca10(PO46(OH2, HA still maintained the major phase, accompanied with the rhenanite (NaCaPO4 as the secondary phase and β-tricalcium phosphate (β-Ca3(PO42, β-TCP as the minor phases. In addition, the HA partially transformed to α-tricalcium phosphate (α-Ca3(PO42, α-TCP and tetracalcium phosphate (Ca4(PO42O, TTCP, when the pellet samples were sintered at 1300 °C and 1400 °C, respectively, for 4 h. The maximum density and Vickers Hardness (HV of sintered pellet samples were 2.85 g/cm3 (90.18% theoretical density (T.D. and 407, which appeared at 1200 °C and 900 °C, respectively.

  18. Calcium phosphate/microgel composites for 3D powderbed printing of ceramic materials.

    Science.gov (United States)

    Birkholz, Mandy-Nicole; Agrawal, Garima; Bergmann, Christian; Schröder, Ricarda; Lechner, Sebastian J; Pich, Andrij; Fischer, Horst

    2016-06-01

    Composites of microgels and calcium phosphates are promising as drug delivery systems and basic components for bone substitute implants. In this study, we synthesized novel composite materials consisting of pure β-tricalcium phosphate and stimuli-responsive poly(N-vinylcaprolactam-co-acetoacetoxyethyl methacrylate-co-vinylimidazole) microgels. The chemical composition, thermal properties and morphology for obtained composites were extensively characterized by Fourier transform infrared, X-ray photoelectron spectroscopy, IGAsorp moisture sorption analyzer, thermogravimetric analysis, granulometric analysis, ESEM, energy dispersive X-ray spectroscopy and TEM. Mechanical properties of the composites were evaluated by ball-on-three-balls test to determine the biaxial strength. Furthermore, initial 3D powderbed-based printing tests were conducted with spray-dried composites and diluted 2-propanol as a binder to evaluate a new binding concept for β-tricalcium phosphate-based granulates. The printed ceramic bodies were characterized before and after a sintering step by ESEM. The hypothesis that the microgels act as polymer adhesive agents by efficient chemical interactions with the β-tricalcium phosphate particles was confirmed. The obtained composites can be used for the development of new scaffolds. PMID:25870955

  19. Development of a novel fluorapatite-forming calcium phosphate cement with calcium silicate: in vitro and in vivo characteristics.

    Science.gov (United States)

    Suzuki, Yusuke; Hayashi, Makoto; Yasukawa, Takuya; Kobayashi, Hiroshi; Makino, Kosuke; Hirano, Yoriyuki; Takagi, Shozo; Chow, Laurence C; Ogiso, Bunnai

    2015-01-01

    Aim of this study was to develop a novel fluorapatite-forming calcium phosphate cement (FA-CPC) with tricalcium silicate (TCS) for endodontic applications and to examine its in vitro and in vivo characteristics. The FA-CPC powder consisted of 62.8% CaHPO4, 30.8% CaCO3, and 6.4% NaF. One part of TCS was combined with 9 parts of FA-CPC powder (FA-CPC with TCS). A 1.5 M phosphate solution was used as cement liquid. Setting time (ST), diametral tensile strength (DTS), phase composition by X-ray diffraction (XRD), and cement alkalinity were analyzed. Cement biocompatibility was assessed using rat subcutaneous model. Cement ST was 10.3±0.6 min and DTS was 3.89±0.76 MPa. XRD patterns showed that highly crystalline apatitic material was the only significant phase present and pH value was approximate 11.0. FA-CPC with TCS demonstrated similar biocompatibility as that of mineral trioxide aggregate control. These results suggest that FA-CPC with TCS may be useful for endodontic applications. PMID:25740309

  20. Effect of polydopamine on the biomimetic mineralization of mussel-inspired calcium phosphate cement in vitro

    International Nuclear Information System (INIS)

    Inspired by the excellent adhesive property of mussel adhesive protein, we added polydopamine (PDA) to calcium phosphate cement (PDA–CPC) to enhance its compressive strength previously. The mineralization and mechanism on PDA–CPC were investigated by soaking it in simulated body fluid in this study. The results indicated that PDA promoted the conversion of dicalcium phosphate dihydrate and α-tricalcium phosphate to hydroxyapatite (HA) in the early stage but inhibited this conversion subsequently. PDA promoted the rapid mineralization on PDA–CPC to form a layer of nanoscale calcium phosphate (CaP) whereas there was no CaP formation on the control-CPC after 1 d of soaking. This layer of nanoscale CaP was similar to that of natural bone, which was always observed during soaking. X-ray photoelectron spectroscopy showed that the peak of C=O of PDA existed in the newly formed CaP on PDA–CPC, indicating the co-precipitation of CaP with PDA. Furthermore, the newly formed CaP on PDA–CPC was HA confirmed by transmission electron microscopy, which the newly formed HA was in association with PDA. Therefore, PDA increased the capacity of mineralization of CPC and induced the formation of nanoscale bone-like apatite on PDA–CPC. Thus, this provides the feasible route for surface modification on CPC. - Highlights: • Effect of polydopamine (PDA) on the in vitro mineralization of PDA-CPC was studied. • PDA promoted the rapid mineralization on PDA-CPC to form a nanoscale HA layer. • The precipitation of the nanoscale HA layer on PDA-CPC accompanied with PDA. • Polydopamine induced mineralization is feasible for surface modification of CaP

  1. Effect of polydopamine on the biomimetic mineralization of mussel-inspired calcium phosphate cement in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zongguang [Key Lab of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Qu, Shuxin, E-mail: qushuxin@swjtu.edu.cn [Key Lab of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Zheng, Xiaotong; Xiong, Xiong [Key Lab of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Fu, Rong; Tang, Kuangyun; Zhong, Zhendong [Department of Plastic Surgery, Academy of Medical Sciences and Sichuan Provincial People' s Hospital, Chengdu 610041 (China); Weng, Jie [Key Lab of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China)

    2014-11-01

    Inspired by the excellent adhesive property of mussel adhesive protein, we added polydopamine (PDA) to calcium phosphate cement (PDA–CPC) to enhance its compressive strength previously. The mineralization and mechanism on PDA–CPC were investigated by soaking it in simulated body fluid in this study. The results indicated that PDA promoted the conversion of dicalcium phosphate dihydrate and α-tricalcium phosphate to hydroxyapatite (HA) in the early stage but inhibited this conversion subsequently. PDA promoted the rapid mineralization on PDA–CPC to form a layer of nanoscale calcium phosphate (CaP) whereas there was no CaP formation on the control-CPC after 1 d of soaking. This layer of nanoscale CaP was similar to that of natural bone, which was always observed during soaking. X-ray photoelectron spectroscopy showed that the peak of C=O of PDA existed in the newly formed CaP on PDA–CPC, indicating the co-precipitation of CaP with PDA. Furthermore, the newly formed CaP on PDA–CPC was HA confirmed by transmission electron microscopy, which the newly formed HA was in association with PDA. Therefore, PDA increased the capacity of mineralization of CPC and induced the formation of nanoscale bone-like apatite on PDA–CPC. Thus, this provides the feasible route for surface modification on CPC. - Highlights: • Effect of polydopamine (PDA) on the in vitro mineralization of PDA-CPC was studied. • PDA promoted the rapid mineralization on PDA-CPC to form a nanoscale HA layer. • The precipitation of the nanoscale HA layer on PDA-CPC accompanied with PDA. • Polydopamine induced mineralization is feasible for surface modification of CaP.

  2. Electrospun gelatin/poly(epsilon-caprolactone) fibrous scaffold modified with calcium phosphate for bone tissue engineering

    OpenAIRE

    Rajzer, Izabella; Menaszek, Elzbieta; Kwiatkowski, Ryszard; Castaño Linares, Óscar; Planell Estany, Josep Anton

    2014-01-01

    In this study gelatin (Gel) modified with calcium phosphate nanoparticles (SG5) and polycaprolactone (PCL) were used to prepare a 3D bi-layer scaffold by collecting electrospun PCL and gelatin/SG5 fibers separately in the same collector. The objective of this study was to combine the desired properties of PCL and Gel/SG5 in the same scaffold in order to enhance mineralization, thus improving the ability of the scaffold to bond to the bone tissue. The scanning electron microscopy (SEM), Fourie...

  3. Mechanical evaluation of implanted calcium phosphate cement incorporated with PLGA microparticles

    OpenAIRE

    Link, Dennis P.; VAN DEN DOLDER, Juliette; Jurgens, J. F. M.; Wolke, Joop G.; Jansen, John A.

    2006-01-01

    In this study, the mechanical properties of an implanted calcium phosphate (CaP) cement incorporated with 20wt% poly (DL-lactic-coglycolic acid) (PLGA) microparticles were investigated in a rat cranial defect. After 2, 4 and 8 weeks of implantation, implants were evaluated mechanically (push-out test) and morphologically (Scanning Electron Microscopy (SEM) and histology). The results of the push-out test showed that after 2 weeks the shear strength of the implants was 0.4470.44MPa (a...

  4. Microwave-Assisted Hydrothermal Rapid Synthesis of Calcium Phosphates: Structural Control and Application in Protein Adsorption

    OpenAIRE

    Zhu-Yun Cai; Fan Peng; Yun-Peng Zi; Feng Chen; Qi-Rong Qian

    2015-01-01

    Synthetic calcium phosphate (CaP)-based materials have attracted much attention in the biomedical field. In this study, we have investigated the effect of pH values on CaP nanostructures prepared using a microwave-assisted hydrothermal method. The hierarchical nanosheet-assembled hydroxyapatite (HAP) nanostructure was prepared under weak acidic conditions (pH 5), while the HAP nanorod was prepared under neutral (pH 7) and weak alkali (pH 9) condition. However, when the pH value increases to ...

  5. Ionic liquid-assisted formation of cellulose/calcium phosphate hybrid materials

    Directory of Open Access Journals (Sweden)

    Ahmed Salama

    2014-09-01

    Full Text Available Cellulose/calcium phosphate hybrid materials were synthesized via an ionic liquid-assisted route. Scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis/differential thermal analysis show that, depending on the reaction conditions, cellulose/hydroxyapatite, cellulose/chlorapatite, or cellulose/monetite composites form. Preliminary studies with MC3T3-E1 pre-osteoblasts show that the cells proliferate on the hybrid materials suggesting that the ionic liquid-based process yields materials that are potentially useful as scaffolds for regenerative therapies.

  6. Enhancement of biodegradation and osseointegration of poly(ε-caprolactone)/calcium phosphate ceramic composite screws for osteofixation using calcium sulfate.

    Science.gov (United States)

    Wu, Chang-Chin; Hsu, Li-Ho; Tsai, Yuh-Feng; Sumi, Shoichiro; Yang, Kai-Chiang

    2016-04-01

    Internal fixation devices, which can stabilize and realign fractured bone, are widely used in fracture management. In this paper, a biodegradable composite fixator, composed of poly(ε-caprolactone), calcium phosphate ceramic and calcium sulfate (PCL/CPC/CS), is developed. The composition of CS, which has a high dissolution rate, was expected to create a porous structure to improve osteofixation to the composite fixator. PCL, PCL/CPC, and PCL/CPC/CS samples were prepared and their physical properties were characterized in vitro. In vivo performance of the composite screws was verified in the distal femurs of rabbits. Results showed that the PCL/CPC/CS composite had a higher compressive strength (28.55 ± 3.32 MPa) in comparison with that of PCL (20.64 ± 1.81 MPa) (p enhanced apatite formation of the PCL/CPC composite screw. This osteoconductive PCL/CPC/CS is a good candidate material for internal fixation devices. PMID:27041468

  7. Formation of Solution-derived Hydroxyapatite Coatings on Titanium Alloy in the Presence of Magnetron-sputtered Alumina Bond Coats

    OpenAIRE

    Zykova, Anna; Safonov, Vladimir; Yanovska, Anna; Sukhodub, Leonid; Rogovskaya, Renata; Smolik, Jerzy; Yakovin, Stas

    2015-01-01

    Hydroxyapatite Ca10(PO4)6(OH)2 (HAp) and calcium phosphate ceramic materials and coatings are widely used in medicine and dentistry because of their ability to enhance the tissue response to implant surfaces and promote bone ingrowth and osseoconduction processes. The deposition conditions have a great influence on the structure and biofunctionality of calcium phosphate coatings. Corrosion processes and poor adhesion to substrate material reduce the lifetime of implants with calcium phosphate...

  8. The combined mechanism of bone morphogenetic protein- and calcium phosphate-induced skeletal tissue formation by human periosteum derived cells.

    Science.gov (United States)

    Bolander, J; Ji, W; Geris, L; Bloemen, V; Chai, Y C; Schrooten, J; Luyten, F P

    2016-01-01

    When combining osteogenic progenitor cells such as human periosteum derived cells (hPDCs) with osteoconductive biomaterials like calcium phosphate (CaP)-scaffolds, in vivo bone formation can be achieved. This process is dependent on the early activation of Bone morphogenetic protein (BMP)-signalling. However, the bone forming process is slow and routinely only a limited amount of bone and bone marrow is formed. Therefore, we hypothesised that a robust clinically relevant outcome could be achieved by adding more physiological levels of potent BMP-ligands to these cell- and CaP-based constructs. For this, hPDCs were characterised for their responsiveness to BMP-ligands upon in vitro 2D stimulation. BMP-2, -4, -6 and -9 robustly induced osteochondrogenic differentiation. Subsequently, these ligands were coated onto clinically approved CaP-scaffolds, BioOss® and CopiOs®, followed by hPDC-seeding. Protein lysates and conditioned media were investigated for activation of BMP signalling pathways. Upon in vivo implantation, the most abundant bone formation was found in BMP-2 and BMP-6-coated scaffolds. Implanted cells actively contributed to the newly formed bone. Remnants of cartilage could be observed in BMP-coated CopiOs®-constructs. Computational analysis displayed that the type of BMP-ligand as well as the CaP-scaffold affects skeletal tissue formation, observed in a qualitative as well as quantitative manner. Furthermore, the in vitro mechanism appears to predict the in vivo outcome. This study presents further evidence for the potential of BMP-technology in the development of clinically relevant cell-based constructs for bone regenerative strategies. PMID:26728496

  9. Surface characterization and corrosion behavior of calcium phosphate-base composite layer on titanium and its alloys via plasma electrolytic oxidation: A review paper.

    Science.gov (United States)

    Rafieerad, A R; Ashra, M R; Mahmoodian, R; Bushroa, A R

    2015-12-01

    In recent years, calcium phosphate-base composites, such as hydroxyapatite (HA) and carbonate apatite (CA) have been considered desirable and biocompatible coating layers in clinical and biomedical applications such as implants because of the high resistance of the composites. This review focuses on the effects of voltage, time and electrolytes on a calcium phosphate-base composite layer in case of pure titanium and other biomedical grade titanium alloys via the plasma electrolytic oxidation (PEO) method. Remarkably, these parameters changed the structure, morphology, pH, thickness and crystallinity of the obtained coating for various engineering and biomedical applications. Hence, the structured layer caused improvement of the biocompatibility, corrosion resistance and assignment of extra benefits for Osseo integration. The fabricated layer with a thickness range of 10 to 20 μm was evaluated for physical, chemical, mechanical and tribological characteristics via XRD, FESEM, EDS, EIS and corrosion analysis respectively, to determine the effects of the applied parameters and various electrolytes on morphology and phase transition. Moreover, it was observed that during PEO, the concentration of calcium, phosphor and titanium shifts upward, which leads to an enhanced bioactivity by altering the thickness. The results confirm that the crystallinity, thickness and contents of composite layer can be changed by applying thermal treatments. The corrosion behavior was investigated via the potentiodynamic polarization test in a body-simulated environment. Here, the optimum corrosion resistance was obtained for the coating process condition at 500 V for 15 min in Ringer solution. This review has been summarized, aiming at the further development of PEO by producing more adequate titanium-base implants along with desired mechanical and biomedical features. PMID:26354281

  10. Phosphate coating on stainless steel 304 sensitized;Recubrimiento fosfatado sobre acero inoxidable 304 sensibilizado

    Energy Technology Data Exchange (ETDEWEB)

    Cruz V, J. P. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Altamira, Km. 14.5 Carretera Tampico-Puerto Industrial Altamira, 89600 Altamira, Tamaulipas (Mexico); Vite T, J. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Castillo S, M.; Vite T, M., E-mail: jpcruz@ipn.m [IPN, Escuela Superior de Ingenieria Mecanica y Electrica, Seccion de Estudios de Posgrado e Investigacion, Unidad Profesional -Adolfo Lopez Mateos-, Zacatenco, 07738 Mexico, D. F. (Mexico)

    2009-07-01

    The stainless steel 304 can be sensitized when welding processes are applied, that causes the precipitation of chromium carbide in the grain limits, being promoted in this way the formation of galvanic cells and consequently the corrosion process. Using a phosphate coating is possible to retard the physiochemical damages that can to happen in the corrosion process. The stainless steel 304 substrate sensitized it is phosphate to base of Zn-Mn, in a immersion cell very hot. During the process was considered optimization values, for the characterization equipment of X-rays diffraction and scanning electron microscopy was used. The XRD technique confirmed the presence of the phases of manganese phosphate, zinc phosphate, as well as the phase of the stainless steel 304. When increasing the temperature from 60 to 90 C in the immersion process a homogeneous coating is obtained. (Author)

  11. Study on aluminum phosphate binder and related Al2O3-SiC ceramic coating

    International Nuclear Information System (INIS)

    Refractory and wear-resistant Al2O3-SiC ceramic coatings have been fabricated on A3 steel using alumina (Al2O3), silicon carbide (SiC), aluminum phosphate binder (inorganic binder), and other additives as starting materials. The powder X-ray diffraction (XRD), thermogravimetric analysis/differential thermal analysis (TG/DTA), and scanning electron microscopy (SEM) techniques are applied to investigate the chemical compositions of the in-house synthesized aluminum phosphate binder and the morphologies of the fabricated ceramic coatings after abrasion test. The XRD results indicate that monoaluminum phosphate (Al(H2PO4)3) is the most effective binding phase in the synthesized aluminum phosphate binder. The TG/DTA analysis shows that two phase transformations occur at 100.7 and 217.7 deg. C when the synthesized aluminum phosphate binder is heated in a range 60-1000 deg. C and the binder after heat treatment is a mixture of several phases. The wear test results show that the wear durability of the A3 steel covered with Al2O3-SiC ceramic coatings is about two times that of the uncoated A3 steel. The results also indicate that the wear properties of Al2O3-SiC ceramic coatings are dependent on fabrication conditions such as the weight ratio of ceramics (Al2O3 and SiC) to the binder (RCB), the distribution of particle size of ceramics, the density of the aluminum phosphate binder, and the Al/P atomic ratio in the aluminum phosphate binder. Upon the above results, optimal fabrication conditions for achieving good wear resistance of Al2O3-SiC ceramic coatings are suggested in this paper

  12. A biomimetic strategy to form calcium phosphate crystals on type I collagen substrate

    International Nuclear Information System (INIS)

    Objective: The aim of this study is to induce mineralization of collagen by introducing phosphate groups onto type I collagen from eggshell membrane (ESM) by treating with sodium trimetaphosphate (STMP). This strategy is based on the hypothesis that phosphate groups introduced on collagen can mimic the nucleating role of phosphorylated non-collagenous proteins bound to collagen for inducing mineralization in natural hard tissue. Method: The collagen membrane was phosphorylated by treating it with a solution of STMP and saturated calcium hydroxide. The phosphorylated collagen was subsequently exposed to a mineralization solution and the pattern of mineralization on the surface of phosphorylated collagen substrate was analyzed. Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), field emission electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and microhardness test were used to characterize the collagen substrate and the pattern of minerals formed on the collagen surface. Results: The FTIR and EDX results indicated that the phosphate groups were incorporated onto the collagen surface by treatment with STMP. During the mineralization process, the plate-like mineral, octacalcium phosphate (OCP), which was initially formed on the surface of ESM, was later transformed into needle-like hydroxyapatite (HAP) as indicated by the SEM, FESEM, EDX and XRD findings. The microhardness test displayed significant increase in the Knoop hardness number of the mineralized collagen. Conclusions: Phosphate groups can be introduced onto type I collagen surface by treating it with STMP and such phosphorylated collagen can induce the mineralization of type I collagen.

  13. A biomimetic strategy to form calcium phosphate crystals on type I collagen substrate

    Energy Technology Data Exchange (ETDEWEB)

    Xu Zhang [Department of Restorative Dentistry, Faculty of Dentistry, National University of Singapore, 5 Lower Kent Ridge Road 119074, Singapore (Singapore); Neoh, Koon Gee [Department of Chemical and Biomolecular Engineering, National University of Singapore, Kent Ridge 119260, Singapore (Singapore); Kishen, Anil, E-mail: anil.kishen@utoronto.ca [Discipline of Endodontics, Faculty of Dentistry, University of Toronto, 124 Edward Street, Toronto, ON (Canada)

    2010-07-20

    Objective: The aim of this study is to induce mineralization of collagen by introducing phosphate groups onto type I collagen from eggshell membrane (ESM) by treating with sodium trimetaphosphate (STMP). This strategy is based on the hypothesis that phosphate groups introduced on collagen can mimic the nucleating role of phosphorylated non-collagenous proteins bound to collagen for inducing mineralization in natural hard tissue. Method: The collagen membrane was phosphorylated by treating it with a solution of STMP and saturated calcium hydroxide. The phosphorylated collagen was subsequently exposed to a mineralization solution and the pattern of mineralization on the surface of phosphorylated collagen substrate was analyzed. Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), field emission electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and microhardness test were used to characterize the collagen substrate and the pattern of minerals formed on the collagen surface. Results: The FTIR and EDX results indicated that the phosphate groups were incorporated onto the collagen surface by treatment with STMP. During the mineralization process, the plate-like mineral, octacalcium phosphate (OCP), which was initially formed on the surface of ESM, was later transformed into needle-like hydroxyapatite (HAP) as indicated by the SEM, FESEM, EDX and XRD findings. The microhardness test displayed significant increase in the Knoop hardness number of the mineralized collagen. Conclusions: Phosphate groups can be introduced onto type I collagen surface by treating it with STMP and such phosphorylated collagen can induce the mineralization of type I collagen.

  14. Remineralization of early enamel lesions using casein phosphopeptide amorphous calcium Phosphate: An ex-vivo study

    Directory of Open Access Journals (Sweden)

    Ruchi Vashisht

    2010-01-01

    Full Text Available Objective: This study aimed at qualitatively evaluating the remineralization potential of casein phosphopeptide amorphous calcium phosphate on artificial early enamel lesions in an ex-vivo scenario by observing the treated tooth surface using a scanning electron microscope (SEM. Materials and Methods: This randomized study was conducted on 10 subjects undergoing orthodontic treatment with premolar extraction as part of their treatment. Artificial white lesions were created with the application of 37% phosphoric acid for 20 mins. Teeth were then divided into two groups: one experimental and the other control. Customised orthodontic band with a window was luted with intermediate restorative material in the experimental group whereas in the control group, band without a window was luted. The casein phosphopeptide amorphous calcium phosphate (GC TOOTH MOUSSE paste was then applied on the window region of the experimental group for 3 mins thrice daily after meals for 14 days, whereas no paste was applied in the control group. After 14 days, teeth were extracted and viewed under an SEM. Results: The study groups showed remineralization of the lesions as compared with the control group in most of the samples. Conclusion: Casein phophopeptide could significantly remineralize the artificial enamel lesions in vivo.

  15. Cytotoxicity assessment of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP paste

    Directory of Open Access Journals (Sweden)

    Sandra Kalil Bussadori

    2010-01-01

    Full Text Available Introduction: Casein phosphopeptides (CPP have been shown to be good carriers of calcium, phosphate, and hydroxide ions to promote enamel remineralization with applications in oral care products, professional dental products, and food products. Objectives: Evaluate the cytotoxicity of a casein phosphopeptideamorphous calcium phosphate (CPP-ACP paste in rat fibroblasts. Materials and methods: Cytotoxicity was measured by the Trypan blue dye exclusion assay and the MTT assay. Results: Long term (1, 3, 5, and 7 days and short term tests (0, 4, 8, and 12 hours were performed with the Trypan blue dye exclusion assay. Data were analyzed with ANOVA and Kruskall Wallis tests. After one day, the cell viability of the CPP-ACP study group was between 80 and 100%. In the short term experiments, a reduction of cell viability in the study group was observed compared with the control group; yet viable cells were present over the evaluation period. With the MTT assay, a viability of 76.43% was observed in the study group, a significant difference from the control group (P = 0.003. Conclusion: CPP-ACP paste demonstrates low cytotoxicity in rat fibroblast culture.

  16. Chlorhexidine-calcium phosphate nanoparticles - Polymer mixer based wound healing cream and their applications.

    Science.gov (United States)

    Viswanathan, Kaliyaperumal; Monisha, P; Srinivasan, M; Swathi, D; Raman, M; Dhinakar Raj, G

    2016-10-01

    In this work, we developed a wound healing cream composed of two different polymers, namely chitosan and gelatin with chlorhexidine along with calcium phosphate nanoparticles. The physicochemical properties of the prepared cream were investigated based on SEM, EDX, Raman, FTIR and the results indicated that the cream contained gelatin, chitosan, calcium phosphate nanoparticles and chlorhexidine. The maximum swelling ratio studies indicated that the ratio was around of 52±2.2 at pH7.4 and the value was increased in acidic and alkaline pH. The antimicrobial activity was tested against bacteria and the results indicated that, both chlorhexidine and the hybrid cream devoid of chlorhexidine exhibited antimicrobial activity but the chlorhexidine impregnated cream showed three fold higher antimicrobial activity than without chlorhexidine. In vivo wound healing promoting activities of hybrid cream containing 0.4mg/L chlorhexidine were evaluated on surgically induced dermal wounds in mice. The results indicated that the cream with incorporated chlorhexidine significantly enhanced healing compared with the control samples. For the field validations, the veterinary clinical animals were treated with the cream and showed enhanced healing capacity. In conclusion, a simple and efficient method for design of a novel wound healing cream has been developed for veterinary applications. PMID:27287150

  17. Mechanochemical-hydrothermal synthesis of calcium phosphate powders with coupled magnesium and carbonate substitution

    Science.gov (United States)

    Suchanek, Wojciech L.; Byrappa, Kullaiah; Shuk, Pavel; Riman, Richard E.; Janas, Victor F.; TenHuisen, Kevor S.

    2004-03-01

    Magnesium- and carbonate-substituted calcium phosphate powders (Mg-, CO 3-CaP) with various crystallinity levels were prepared at room temperature via a heterogeneous reaction between MgCO 3/Ca(OH) 2 powders and an (NH 4) 2HPO 4 solution using the mechanochemical-hydrothermal route. X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis were performed. It was determined that the powders containing both Mg 2+ and CO 32- ions were incorporated uniformly into an amorphous calcium phosphate phase while in contrast, the as-prepared powder free of these dopants was crystalline phase-pure, stoichiometric hydroxyapatite. Dynamic light scattering revealed that the average particle size of the room temperature Mg-, CO 3-CaP powders was in the range of 482 nm-700 nm with a specific surface area between 53 and 91 m 2/g. Scanning electron microscopy confirmed that the Mg-, CO 3-CaP powders consisted of agglomerates of equiaxed, ≈20-35 nm crystals.

  18. Preparation, Physical-Chemical Characterization, and Cytocompatibility of Polymeric Calcium Phosphate Cements

    Directory of Open Access Journals (Sweden)

    Rania M. Khashaba

    2011-01-01

    Full Text Available Aim. Physicochemical mechanical and in vitro biological properties of novel formulations of polymeric calcium phosphate cements (CPCs were investigated. Methods. Monocalcium phosphate, calcium oxide, and synthetic hydroxyapatite were combined with either modified polyacrylic acid, light activated polyalkenoic acid, or polymethyl vinyl ether maleic acid to obtain Types I, II, and III CPCs. Setting time, compressive and diametral strength of CPCs was compared with zinc polycarboxylate cement (control. Specimens were characterized using X-ray diffraction, scanning electron microscopy, and infrared spectroscopy. In vitro cytotoxicity of CPCs and control was assessed. Results. X-ray diffraction analysis showed hydroxyapatite, monetite, and brushite. Acid-base reaction was confirmed by the appearance of stretching peaks in IR spectra of set cements. SEM revealed rod-like crystals and platy crystals. Setting time of cements was 5–12 min. Type III showed significantly higher strength values compared to control. Type III yielded high biocompatibility. Conclusions. Type III CPCs show promise for dental applications.

  19. Multiple prismatic calcium phosphate layers in the jaws of present-day sharks (Chondrichthyes; Selachii).

    Science.gov (United States)

    Dingerkus, G; Séret, B; Guilbert, E

    1991-01-15

    Jaws of large individuals, over 2 m in total length, of the shark species Carcharodon carcharias (great white shark) and Isurus oxyrinchus (mako shark) of the family Lamnidae, and Galeocerdo cuvieri (tiger shark) and Carcharhinus leucas (bull shark) of the family Carcharhinidae were found to have multiple, up to five, layers of prismatic calcium phosphate surrounding the cartilages. Smaller individuals of these species and other known species of living chondrichthyans have only one layer of prismatic calcium phosphate surrounding the cartilages, as also do most species of fossil chondrichthyans. Two exceptions are the fossil shark genera Xenacanthus and Tamiobatis. Where it is found in living forms, this multiple layered calcification does not appear to be phylogenetic, as it appears to be lacking in other lamnid and carcharhinid genera and species. Rather it appears to be functional, only appearing in larger individuals and species of these two groups, and hence may be necessary to strengthen the jaw cartilages of such individuals for biting. PMID:1999241

  20. An ultrasonic through-transmission technique for monitoring the setting of injectable calcium phosphate cement.

    Science.gov (United States)

    Rajzer, Izabella; Piekarczyk, Wojciech; Castaño, Oscar

    2016-10-01

    An ultrasound through-transmission method to monitor the setting process of injectable calcium phosphate bone cements in body fluids is presented. This method can be used to determine the acoustic properties of the bone cement as it sets, which are linked to its material properties and provide some information about changes occurring within the cement. The development of the methodology of ultrasonic testing and execution of velocity measurements of the longitudinal and transverse waves using the through-transmission method made it possible to determine the material constants of samples during the setting and hardening process of an injectable cement paste in physiological fluids (i.e. the Young's modulus (E), the Poisson ratio (ν) and the shear modulus (G)), and to determine the degree of anisotropy of wave velocity in the samples. A strong advantage of the proposed method is that it is non-destructive, and the same sample can be used to monitor the whole process of the cement setting. The testing was performed on premixed and injectable calcium phosphate (CPC)/chitosan blend, where glycerol was used as a liquid phase. Comparisons between ultrasonic velocity and empirical tests such as compressive strength, porosity measurement, FTIR, SEM and XRD analysis at different days of immersion in Ringer's solutions showed that the ultrasonic velocity can be very useful to provide in situ information about changes occurring within the cement. PMID:27287094

  1. A histological evaluation on osteogenesis and resorption of methotrexate-loaded calcium phosphate cement in vivo

    International Nuclear Information System (INIS)

    In this study, we investigated the resorption of in vivo methotrexate-loaded calcium phosphate cement (MTX-CPC) implants and their effect on osteogenesis. MTX-CPC implants containing 1% methotrexate (MTX) (weight/weight) were preset and implanted into the femoral condyle of rabbits. Calcium phosphate cement (CPC) without MTX was used as the control. The femurs were harvested at day 1 and at 1, 3 and 6 months after implantation and radiological examination were performed. Decalcified sections were examined by hematoxylin and eosin (HE) staining, alkaline phosphatase (ALPase) immunohistochemistry and tartrate-resistant acid phosphatase (TRAPase) enzyme histochemistry. Then, we performed histomorphometric analysis, including determination of the percentage of newly formed bone and osteoblast and osteoclast counts. The results indicated that MTX-CPC implants were biocompatible, biodegradable and osteoconducive. However, MTX release from the implantation site inhibited osteogenesis in the initial period; this inhibition weakened with time, and no difference was observed between CPC and MTX-CPC at 6 months after implantation. Hence, MTX-CPC is an excellent material for filling defects and can be used for preparing effective drug delivery systems to achieve local control of invasive bone tumors.

  2. A histological evaluation on osteogenesis and resorption of methotrexate-loaded calcium phosphate cement in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Li Dong; Yang Zhiping; Li Xin; Li Zhenfeng; Li Jianmin [Department of Orthopedics, Qilu Hospital of Shandong University, Shandong (China); Yang Jingyan, E-mail: yangzhiping@medmail.com.c [Department of Pathology, 2nd Affiliated Hospital of Shandong University, Shandong (China)

    2010-04-15

    In this study, we investigated the resorption of in vivo methotrexate-loaded calcium phosphate cement (MTX-CPC) implants and their effect on osteogenesis. MTX-CPC implants containing 1% methotrexate (MTX) (weight/weight) were preset and implanted into the femoral condyle of rabbits. Calcium phosphate cement (CPC) without MTX was used as the control. The femurs were harvested at day 1 and at 1, 3 and 6 months after implantation and radiological examination were performed. Decalcified sections were examined by hematoxylin and eosin (HE) staining, alkaline phosphatase (ALPase) immunohistochemistry and tartrate-resistant acid phosphatase (TRAPase) enzyme histochemistry. Then, we performed histomorphometric analysis, including determination of the percentage of newly formed bone and osteoblast and osteoclast counts. The results indicated that MTX-CPC implants were biocompatible, biodegradable and osteoconducive. However, MTX release from the implantation site inhibited osteogenesis in the initial period; this inhibition weakened with time, and no difference was observed between CPC and MTX-CPC at 6 months after implantation. Hence, MTX-CPC is an excellent material for filling defects and can be used for preparing effective drug delivery systems to achieve local control of invasive bone tumors.

  3. Bioactive calcium sulfate/magnesium phosphate cement for bone substitute applications

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Guangyong [Department of Orthopaedics, Taizhou Hospital of Zhejiang Province, Linhai Zhejiang, 317000 (China); Department of Orthopaedic Surgery, Second Affiliated Hospital of Wenzhou Medical College, Wenzhou, Zhejiang, 325000 (China); Liu, Jianli [Trauma Center, Affiliated Hospital of Hainan Medical University, Haikou, Hainan, 570206 (China); Division of Functional Materials and Nanodevices, Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences (CAS), Ningbo, Zhejiang, 315201 (China); Li, Fan; Pan, Zongyou; Ni, Xiao; Shen, Yue [Department of Orthopaedic Surgery, Second Affiliated Hospital of Wenzhou Medical College, Wenzhou, Zhejiang, 325000 (China); Xu, Huazi, E-mail: spinexu@163.com [Department of Orthopaedic Surgery, Second Affiliated Hospital of Wenzhou Medical College, Wenzhou, Zhejiang, 325000 (China); Huang, Qing, E-mail: huangqing@nimte.ac.cn [Division of Functional Materials and Nanodevices, Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences (CAS), Ningbo, Zhejiang, 315201 (China)

    2014-02-01

    A novel calcium sulfate/magnesium phosphate cement (CSMPC) composite was prepared and studied in the present work. The physical properties including the phases, the microstructures, the setting properties and the compressive strengths of the CSMPCs were studied. The bio-performances of the CSMPCs were comprehensively evaluated using in vitro simulated body fluid (SBF) method and in vitro cell culture. The dependence of the physical and chemical properties of the CSMPC on its composition and microstructure was studied in detail. It is found that the CSMPC composites exhibited mediate setting times (6–12 min) compared to the calcium sulfate (CS) and the magnesium phosphate cement (MPC). They showed an encapsulation structure in which the unconverted hexagonal prism CSH particles were embedded in the xerogel-like MPC matrix. The phase compositions and the mechanical properties of the CSMPCs were closely related to the content of MPC and the hardening process. The CSMPCs exhibited excellent bioactivity and good biocompatibility to support the cells to attach and proliferate on the surface. The CSMPC composite has the potential to serve as bone grafts for the bone regeneration. - Highlights: • The mechanical strength and degradation rate of CSMPC composites are discussed. • The CSMPC composites exhibited good bioactivity to form bone-like apatite. • The CSMPC composites also show good biocompatibility.

  4. Bioactive calcium sulfate/magnesium phosphate cement for bone substitute applications

    International Nuclear Information System (INIS)

    A novel calcium sulfate/magnesium phosphate cement (CSMPC) composite was prepared and studied in the present work. The physical properties including the phases, the microstructures, the setting properties and the compressive strengths of the CSMPCs were studied. The bio-performances of the CSMPCs were comprehensively evaluated using in vitro simulated body fluid (SBF) method and in vitro cell culture. The dependence of the physical and chemical properties of the CSMPC on its composition and microstructure was studied in detail. It is found that the CSMPC composites exhibited mediate setting times (6–12 min) compared to the calcium sulfate (CS) and the magnesium phosphate cement (MPC). They showed an encapsulation structure in which the unconverted hexagonal prism CSH particles were embedded in the xerogel-like MPC matrix. The phase compositions and the mechanical properties of the CSMPCs were closely related to the content of MPC and the hardening process. The CSMPCs exhibited excellent bioactivity and good biocompatibility to support the cells to attach and proliferate on the surface. The CSMPC composite has the potential to serve as bone grafts for the bone regeneration. - Highlights: • The mechanical strength and degradation rate of CSMPC composites are discussed. • The CSMPC composites exhibited good bioactivity to form bone-like apatite. • The CSMPC composites also show good biocompatibility

  5. Chapter 9: Model Systems for Formation and Dissolution of Calcium Phosphate Minerals

    Energy Technology Data Exchange (ETDEWEB)

    Orme, C A; Giocondi, J L

    2006-07-29

    Calcium phosphates are the mineral component of bones and teeth. As such there is great interest in understanding the physical mechanisms that underlie their growth, dissolution, and phase stability. Control is often achieved at the cellular level by the manipulation of solution states and the use of crystal growth modulators such as peptides or other organic molecules. This chapter begins with a discussion of solution speciation in body fluids and relates this to important crystal growth parameters such as the supersaturation, pH, ionic strength and the ratio of calcium to phosphate activities. We then discuss the use of scanning probe microscopy as a tool to measure surface kinetics of mineral surfaces evolving in simplified solutions. The two primary themes that we will touch on are the use of microenvironments that temporally evolve the solution state to control growth and dissolution; and the use of various growth modifiers that interact with the solution species or with mineral surfaces to shift growth away from the lowest energy facetted forms. The study of synthetic minerals in simplified solution lays the foundation for understand mineralization process in more complex environments found in the body.

  6. Biomimetic nanoparticles with polynucleotide and PEG mixed-monolayers enhance calcium phosphate mineralization

    International Nuclear Information System (INIS)

    Biomineralization of hydroxyapatite (Ca10(PO4)6(OH)2) is of significant importance in biomedical applications such as bone and dental repair, and biomimetic control of mineral formation may lead to more effective restorative procedures. Gold nanoparticles are functional scaffolds on which to assemble multi-component monolayers capable of mimicking protein activity in the templated synthesis of calcium phosphate. The goal of this research was to explore nanoparticle templates with mixed-monolayers of uncharged polar polyethylene glycol (PEG) molecules and highly charged polynucleotide and amino acid molecules in their ability to influence mineralization rates and mineral particle size and morphology. This research demonstrates through time-resolved optical density and dynamic light scattering measurements that the combination of tiopronin, PEG, and DNA presented on a nanoparticle surface decreases nanoparticle aggregation from 59 to 21 nm solvated radius, increases mineralization kinetics from 1.5 × 10−3 to 3.1 × 10−3 OD/min, and decreases mineral particle size from 685 to 442 nm average radius. FT-IR and TEM data demonstrate that mineralized material, while initially amorphous, transforms to a semi-crystalline material when guided by template interactions. This demonstrates that surface-tailored monolayer protected cluster scaffolds are successful and controllable mineralization templates with further potential for biomedical applications involving calcium phosphate and other biomaterials

  7. Microwave-Assisted Hydrothermal Rapid Synthesis of Calcium Phosphates: Structural Control and Application in Protein Adsorption

    Directory of Open Access Journals (Sweden)

    Zhu-Yun Cai

    2015-07-01

    Full Text Available Synthetic calcium phosphate (CaP-based materials have attracted much attention in the biomedical field. In this study, we have investigated the effect of pH values on CaP nanostructures prepared using a microwave-assisted hydrothermal method. The hierarchical nanosheet-assembled hydroxyapatite (HAP nanostructure was prepared under weak acidic conditions (pH 5, while the HAP nanorod was prepared under neutral (pH 7 and weak alkali (pH 9 condition. However, when the pH value increases to 11, a mixed product of HAP nanorod and tri-calcium phosphate nanoparticle was obtained. The results indicated that the pH value of the initial reaction solution played an important role in the phase and structure of the CaP. Furthermore, the protein adsorption and release performance of the as-prepared CaP nanostructures were investigated by using hemoglobin (Hb as a model protein. The sample that was prepared at pH = 11 and consisted of mixed morphologies of nanorods and nanoprisms showed a higher Hb protein adsorption capacity than the sample prepared at pH 5, which could be explained by its smaller size and dispersed structure. The results revealed the relatively high protein adsorption capacity of the as-prepared CaP nanostructures, which show promise for applications in various biomedical fields such as drug delivery and protein adsorption.

  8. Biomimetic nanoparticles with polynucleotide and PEG mixed-monolayers enhance calcium phosphate mineralization

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcellos, Kayla B.; McHugh, Sean M.; Dapsis, Katherine J.; Petty, Alexander R.; Gerdon, Aren E., E-mail: gerdoar@emmanuel.edu [Emmanuel College (United States)

    2013-09-15

    Biomineralization of hydroxyapatite (Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}) is of significant importance in biomedical applications such as bone and dental repair, and biomimetic control of mineral formation may lead to more effective restorative procedures. Gold nanoparticles are functional scaffolds on which to assemble multi-component monolayers capable of mimicking protein activity in the templated synthesis of calcium phosphate. The goal of this research was to explore nanoparticle templates with mixed-monolayers of uncharged polar polyethylene glycol (PEG) molecules and highly charged polynucleotide and amino acid molecules in their ability to influence mineralization rates and mineral particle size and morphology. This research demonstrates through time-resolved optical density and dynamic light scattering measurements that the combination of tiopronin, PEG, and DNA presented on a nanoparticle surface decreases nanoparticle aggregation from 59 to 21 nm solvated radius, increases mineralization kinetics from 1.5 Multiplication-Sign 10{sup -3} to 3.1 Multiplication-Sign 10{sup -3} OD/min, and decreases mineral particle size from 685 to 442 nm average radius. FT-IR and TEM data demonstrate that mineralized material, while initially amorphous, transforms to a semi-crystalline material when guided by template interactions. This demonstrates that surface-tailored monolayer protected cluster scaffolds are successful and controllable mineralization templates with further potential for biomedical applications involving calcium phosphate and other biomaterials.

  9. Effects of Monocarboxylic Acid Addition on Crystallization of Calcium Phosphate in a Hydrogel Matrix

    International Nuclear Information System (INIS)

    In biomineralization, it is thought that water-soluble organic substances control crystal growth of minerals in hard tissues. The roles of organic substances are not well understood, because the biomineralization process is established by complicated parameters. Crystal growth in hydrogel matrixes can be regarded as simplified model system of biomineralization. In the present study, we investigated the effects of propionic acid (Pro) on crystalline phases and crystal morphologies of calcium phosphate formed in polymeric hydrogel matrixes as the model system of biomineralization. Crystalline phase of the precipitates was octacalcium phosphate (OCP) with spherical shape regardless of Pro concentrations. The fibrous crystals formed under the condition without addition of Pro. The crystal morphologies composing spherical crystals were changed from fibrous to plate-like shape with increasing Pro concentrations. Generally, OCP crystal has plate-like shape exposing (100) face, which calcium ions exist on. Therefore, crystal growth rate of [100] direction of OCP was decreased by Pro adsorbed on (100) face. As a result, crystal morphology composing spherulite became plate-like shape with increasing Pro concentrations.

  10. Effects of collagen types II and X on the kinetics of crystallization of calcium phosphate in biomineralization

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The effects of the components of cartilages matrix on the process of endochondral ossification and the kinetics of crystal growth of calcium phosphate have been studied in the presence of type II or X collagen. During the experiments, type I collagen was added as the seed material. FT-IR analysis shows that calcium phosphate crystallized on the surface of type I collagen was mainly hydroxyapatite. Both type II and X collagens could reduce the growth rate of calcium phosphate crystals, and the effect of type X collagen is more obvious. The reaction was in the fourth order in the presence of type II collagen. The results showed that type II or X collagen had the ability to make Ca2+ accumulate in the process of endochondral ossification, but has little effect on crystal growth and the product of biomineralization.

  11. Short-term in vivo evaluation of zinc-containing calcium phosphate using a normalized procedure

    Energy Technology Data Exchange (ETDEWEB)

    Calasans-Maia, Monica, E-mail: monicacalasansmaia@gmail.com [Dental Clinical Research Center, Dentistry School, Fluminense Federal University, Niteroi, Rio de Janeiro (Brazil); Calasans-Maia, José, E-mail: josecalasans@gmail.com [Dental Clinical Research Center, Dentistry School, Fluminense Federal University, Niteroi, Rio de Janeiro (Brazil); Santos, Silvia, E-mail: silviaquimica@gmail.com [LABIOMAT, Brazilian Center for Physics Research, CBPF, Rio de Janeiro (Brazil); Mavropoulos, Elena, E-mail: elena@cbpf.br [LABIOMAT, Brazilian Center for Physics Research, CBPF, Rio de Janeiro (Brazil); Farina, Marcos, E-mail: mfarina@anato.ufrj.br [Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro (Brazil); Lima, Inayá, E-mail: inayacorrea@gmail.com [Nuclear Instrumentation Laboratory, Nuclear Engineering Program, COPPE, Federal University of Rio de Janeiro, Rio de Janeiro (Brazil); Lopes, Ricardo Tadeu [Nuclear Instrumentation Laboratory, Nuclear Engineering Program, COPPE, Federal University of Rio de Janeiro, Rio de Janeiro (Brazil); Rossi, Alexandre, E-mail: rossi@cbpf.br [LABIOMAT, Brazilian Center for Physics Research, CBPF, Rio de Janeiro (Brazil); Granjeiro, José Mauro, E-mail: jmgranjeiro@gmail.com [Dental Clinical Research Center, Dentistry School, Fluminense Federal University, Niteroi, Rio de Janeiro (Brazil); Bioengineering Division, National Institute of Metrology, Quality and Technology, Duque de Caxias, Rio de Janeiro (Brazil)

    2014-08-01

    The effect of zinc-substituted calcium phosphate (CaP) on bone osteogenesis was evaluated using an in vivo normalized ISO 10993-6 protocol. Zinc-containing hydroxyapatite (ZnHA) powder with 0.3% by wt zinc (experimental group) and stoichiometric hydroxyapatite (control group) were shaped into cylindrical implants (2 × 6 mm) and were sintered at 1000 °C. Thermal treatment transformed the ZnHA cylinder into a biphasic implant that was composed of Zn-substituted HA and Zn-substituted β-tricalcium phosphate (ZnHA/βZnTCP); the hydroxyapatite cylinder was a highly crystalline and poorly soluble HA implant. In vivo tests were performed in New Zealand White rabbits by implanting two cylinders of ZnHA/βZnTCP in the left tibia and two cylinders of HA in the right tibia for 7, 14 and 28 days. Incorporation of 0.3% by wt zinc into CaP increased the rate of Zn release to the biological medium. Microfluorescence analyses (μXRF-SR) using synchrotron radiation suggested that some of the Zn released from the biomaterial was incorporated into new bone near the implanted region. In contrast with previous studies, histomorphometric analysis did not show significant differences between the newly formed bone around ZnHA/βZnTCP and HA due to the dissolution profile of Zn-doped CaP. Despite the great potential of Zn-containing CaP matrices for future use in bone regeneration, additional in vivo studies must be conducted to explain the mobility of zinc at the CaP surface and its interactions with a biological medium. - Highlights: • We produced a hydroxyapatite containing a low concentration (0.3 wt.%) of zinc. • The biomaterial underwent characterization before and after in vivo implant. • In vivo tests were performed according to ISO 10993-6. • Zinc-containing calcium phosphate promotes osteoconduction and bone regeneration. • Zinc-containing calcium phosphate may be useful for clinical applications.

  12. Short-term in vivo evaluation of zinc-containing calcium phosphate using a normalized procedure

    International Nuclear Information System (INIS)

    The effect of zinc-substituted calcium phosphate (CaP) on bone osteogenesis was evaluated using an in vivo normalized ISO 10993-6 protocol. Zinc-containing hydroxyapatite (ZnHA) powder with 0.3% by wt zinc (experimental group) and stoichiometric hydroxyapatite (control group) were shaped into cylindrical implants (2 × 6 mm) and were sintered at 1000 °C. Thermal treatment transformed the ZnHA cylinder into a biphasic implant that was composed of Zn-substituted HA and Zn-substituted β-tricalcium phosphate (ZnHA/βZnTCP); the hydroxyapatite cylinder was a highly crystalline and poorly soluble HA implant. In vivo tests were performed in New Zealand White rabbits by implanting two cylinders of ZnHA/βZnTCP in the left tibia and two cylinders of HA in the right tibia for 7, 14 and 28 days. Incorporation of 0.3% by wt zinc into CaP increased the rate of Zn release to the biological medium. Microfluorescence analyses (μXRF-SR) using synchrotron radiation suggested that some of the Zn released from the biomaterial was incorporated into new bone near the implanted region. In contrast with previous studies, histomorphometric analysis did not show significant differences between the newly formed bone around ZnHA/βZnTCP and HA due to the dissolution profile of Zn-doped CaP. Despite the great potential of Zn-containing CaP matrices for future use in bone regeneration, additional in vivo studies must be conducted to explain the mobility of zinc at the CaP surface and its interactions with a biological medium. - Highlights: • We produced a hydroxyapatite containing a low concentration (0.3 wt.%) of zinc. • The biomaterial underwent characterization before and after in vivo implant. • In vivo tests were performed according to ISO 10993-6. • Zinc-containing calcium phosphate promotes osteoconduction and bone regeneration. • Zinc-containing calcium phosphate may be useful for clinical applications

  13. Porous hydroxyapatite and biphasic calcium phosphate ceramics promote ectopic osteoblast differentiation from mesenchymal stem cells

    Directory of Open Access Journals (Sweden)

    Lingli Zhang, Nobutaka Hanagata, Megumi Maeda, Takashi Minowa, Toshiyuki Ikoma, Hongsong Fan and Xingdong Zhang

    2009-01-01

    Full Text Available Because calcium phosphate (Ca–P ceramics have been used as bone substitutes, it is necessary to investigate what effects the ceramics have on osteoblast maturation. We prepared three types of Ca–P ceramics with different Ca–P ratios, i.e. hydroxyapatite (HA, beta-tricalcium phosphate (β-TCP, and biphasic calcium phosphate (BCP ceramics with dense-smooth and porous structures. Comprehensive gene expression microarray analysis of mouse osteoblast-like cells cultured on these ceramics revealed that porous Ca–P ceramics considerably affected the gene expression profiles, having a higher potential for osteoblast maturation. In the in vivo study that followed, porous Ca–P ceramics were implanted into rat skeletal muscle. Sixteen weeks after the implantation, more alkaline-phosphatase-positive cells were observed in the pores of hydroxyapatite and BCP, and the expression of the osteocalcin gene (an osteoblast-specific marker in tissue grown in pores was also higher in hydroxyapatite and BCP than in β-TCP. In the pores of any Ca–P ceramics, 16 weeks after the implantation, we detected the expressions of marker genes of the early differentiation stage of chondrocytes and the complete differentiation stage of adipocytes, which originate from mesenchymal stem cells, as well as osteoblasts. These marker gene expressions were not observed in the muscle tissue surrounding the implanted Ca–P ceramics. These observations indicate that porous hydroxyapatite and BCP had a greater potential for promoting the differentiation of mesenchymal stem cells into osteoblasts than β-TCP.

  14. Preparation of porous chitosan-poly(acrylic acid)-calcium phosphate hybrid nanoparticles via mineralization

    Institute of Scientific and Technical Information of China (English)

    CHEN ChangJing; DENG Yu; YAN ErYun; HU Yong; JIANG XiQun

    2009-01-01

    In this work,the preparation of chitosan-poly(acrylic acid)-calcium phosphate hybrid nanoparticles (CS-PAA-CaP NP) based on the mineralization of calcium phosphate (CAP) on the surface of chitosan-poly (acrylic acid) nanoparticles (CS-PAA NPs) was reported. CS-PAA-CaP NPs were achieved by directly adding ammonia to the aqueous solution of CS-PAA nanoparticles or by thermal decomposition of urea in the aqueous solution of CS-PAA nanoparticles,resulting in the mineralization of CaP on the surface of CS-PAA NPs. Through these two routes,especially using urea as a pH-regulator,the precipitation of CS-PAA NPs,a common occurrence in basic environment,was avoided. The size,morphology and ingredient of CS-PAA-CaP hybrid nanoparticles were characterized by dynamic light scattering (DLS),transmission electron microscope (TEM),scanning electron microscope (SEM),thermogravimetry analysis (TGA) and X-ray diffractometer (XRD). When urea was used as the pH regulator to facilitate the mineralization during the thermal urea decomposition procedure,regular CS-PAA-CaP hybrid nanoparticles with a porosity-structural CaP shells and 400-600 nm size were obtained. TGA result revealed that the hybrid NPs contained approximately 23% inorganic component,which was consistent with the ratio of starting materials. The XRD spectra of hybrid nanoparticles indicated that dicalcium phosphate (DCP:CaHPO4) crystal was a dominant component of mineralization.The porous structure of the CS-PAA-CaP hybrid NPs might be greatly useful in pharmaceutical and other medical applications.

  15. A New Type of Biphasic Calcium Phosphate Cement as a Gentamicin Carrier for Osteomyelitis

    Directory of Open Access Journals (Sweden)

    Wen-Yu Su

    2013-01-01

    Full Text Available Osteomyelitis therapy is a long-term and inconvenient procedure for a patient. Antibiotic-loaded bone cements are both a complementary and alternative treatment option to intravenous antibiotic therapy for the treatment of osteomyelitis. In the current study, the biphasic calcium phosphate cement (CPC, called α-TCP/HAP (α-tricalcium phosphate/hydroxyapatite biphasic cement, was prepared as an antibiotics carrier for osteomyelitis. The developed biphasic cement with a microstructure of α-TCP surrounding the HAP has a fast setting time which will fulfill the clinical demand. The X-ray diffraction and Fourier transform infrared spectrometry analyses showed the final phase to be HAP, the basic bone mineral, after setting for a period of time. Scanning electron microscopy revealed a porous structure with particle sizes of a few micrometers. The addition of gentamicin in α-TCP/HAP would delay the transition of α-TCP but would not change the final-phase HAP. The gentamicin-loaded α-TCP/HAP supplies high doses of the antibiotic during the initial 24 hours when they are soaked in phosphate buffer solution (PBS. Thereafter, a slower drug release is produced, supplying minimum inhibitory concentration until the end of the experiment (30 days. Studies of growth inhibition of Staphylococcus aureus and Pseudomonas aeruginosa in culture indicated that gentamicin released after 30 days from α-TCP/HAP biphasic cement retained antibacterial activity.

  16. VS-501: a novel, nonabsorbed, calcium- and aluminum-free, highly effective phosphate binder derived from natural plant polymer

    OpenAIRE

    Wu-Wong, J Ruth; Chen, Yung-wu; Gaffin, Robert; Hall, Andy; Wong, Jonathan T; Xiong, Joseph; Wessale, Jerry L

    2014-01-01

    Inadequate control of serum phosphate in chronic kidney disease can lead to pathologies of clinical importance. Effectiveness of on-market phosphate binders is limited by safety concerns and low compliance due to high pill size/burden and gastrointestinal (GI) discomfort. VS-501 is a nonabsorbed, calcium- and aluminum-free, chemically modified, plant-derived polymer. In vitro studies show that VS-501 has a high density and a low swell volume when exposed to simulated gastric fluid (vs. sevela...

  17. The Dual Role of Fibrinogen as Inhibitor and Nucleator of Calcium Phosphate Phases: The Importance of Structure.

    Science.gov (United States)

    Tsortos; Ohki; Zieba; Baier; Nancollas

    1996-01-15

    Constant composition and free drift methods have been used to investigate the abilities of human serum albumin (HSA) and fibrinogen to influence calcium phosphate precipitation. Both molecules inhibit hydroxyapatite (HAP) crystal growth when present in the solution phase. Fibrinogen, when immobilized at hydrophobicized germanium or silica surfaces, is able to nucleate calcium phosphate phases; at clean germanium or silica surfaces, it appears to be inactive. The apparent configuration of fibrinogen molecules at germanium or silica surfaces on which octadecyltrichlorosilane (OTS) was deposited probably exposes more negative sites for participation in nucleation. PMID:10479440

  18. Ectopic bone formation in bone marrow stem cell seeded calcium phosphate scaffolds as compared to autograft and (cell seeded allograft

    Directory of Open Access Journals (Sweden)

    J O Eniwumide

    2007-08-01

    Full Text Available Improvements to current therapeutic strategies are needed for the treatment of skeletal defects. Bone tissue engineering offers potential advantages to these strategies. In this study, ectopic bone formation in a range of scaffolds was assessed. Vital autograft and devitalised allograft served as controls and the experimental groups comprised autologous bone marrow derived stem cell seeded allograft, biphasic calcium phosphate (BCP and tricalcium phosphate (TCP, respectively. All implants were implanted in the back muscle of adult Dutch milk goats for 12 weeks. Micro-computed tomography (µCT analysis and histomorphometry was performed to evaluate and quantify ectopic bone formation. In good agreement, both µCT and histomorphometric analysis demonstrated a significant increase in bone formation by cell-seeded calcium phosphate scaffolds as compared to the autograft, allograft and cell-seeded allograft implants. An extensive resorption of the autograft, allograft and cell-seeded allograft implants was observed by histology and confirmed by histomorphometry. Cell-seeded TCP implants also showed distinct signs of degradation with histomorphometry and µCT, while the degradation of the cell-seeded BCP implants was negligible. These results indicate that cell-seeded calcium phosphate scaffolds are superior to autograft, allograft or cell-seeded allograft in terms of bone formation at ectopic implantation sites. In addition, the usefulness of µCT for the efficient and non-destructive analysis of mineralised bone and calcium phosphate scaffold was demonstrated.

  19. Assessment of salivary calcium, phosphate, magnesium, pH, and flow rate in healthy subjects, periodontitis, and dental caries

    Directory of Open Access Journals (Sweden)

    K S Rajesh

    2015-01-01

    Full Text Available Aim: This study was conducted to estimate and compare inorganic salivary calcium, phosphate, magnesium, salivary flow rate, and pH of unstimulated saliva and oral hygiene status of healthy subjects, subjects with periodontitis and dental caries, and to correlate salivary calcium level with number of intact teeth. Materials and Methods: The study population consisted of 48 systemically healthy subjects in the age group of 18-55 years, which was further divided into three groups: healthy, periodontitis, and dental caries. Oral hygiene index-simplified, probing pocket depth, clinical attachment level, the number of intact teeth, and active carious lesions were recorded. Estimation of inorganic salivary calcium, phosphate, and magnesium was performed spectrophotometrically using Vitros 5.1 FS. Statistical analysis was performed using the one-way analysis of variance test at 5% significance level. Results: There was a statistically significant increase in inorganic salivary calcium, phosphate, pH, flow rate, and poor oral hygiene status in periodontitis group compared to dental caries and healthy group. Conclusion: Subjects with increased inorganic salivary calcium, phosphate, pH, flow rate, and poor oral hygiene are at a higher risk of developing periodontitis. Since there is increased remineralization potential, these subjects have more number of intact teeth compared to the dental caries group.

  20. Continuous reaction crystallization of struvite from phosphate(V) solutions containing calcium ions

    Energy Technology Data Exchange (ETDEWEB)

    Hutnik, N.; Wierzbowska, B.; Matynia, A. [Wroclaw University of Technology, Faculty of Chemistry, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Piotrowski, K. [Silesian University of Technology, Department of Chemical and Process Engineering, ks. M. Strzody 7, 44-101 Gliwice (Poland)

    2011-05-15

    Continuous reaction crystallization of struvite from water solutions containing phosphate(V) (1.0 mass%) and calcium ions (from 0.01 to 0.20 mass%) was investigated. Process was carried out in temperature 298 K in continuous DT MSMPR type crystallizer with internal circulation of suspension. Influence of pH (from 9 to 11) and mean residence time of suspension in crystallizer (from 900 to 3600 s) on product crystal size distribution, mean size, population homogeneity and shape of crystals, as well as chemical composition of solid phase was tested. Within the investigated process parameter ranges struvite crystals of mean size from 18 to ca. 50 {mu}m were produced. With the increase in calcium ions concentration in a feed mean crystal size decreased from 34.2 to 18.4 {mu}m (pH 9, {tau} 900 s). Coexistence of struvite and hydroxyapatite crystals in the solid product was confirmed analytically (Ca content in solid product from 0.3 to 8.4 mass%). Presence of calcium ions favoured crystallization of struvite in a form of tubular crystals, characterized by lengthwise cracks and irregular edges. Co-precipitated hydroxyapatite particles showed relatively small sizes, even below 1 {mu}m, forming agglomerates on the surface of larger struvite crystals and individual agglomerates. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Contact nanofatigue shows crack growth in amorphous calcium phosphate on Ti, Co-Cr and Stainless steel.

    Science.gov (United States)

    Saber-Samandari, Saeed; Gross, Karlis A

    2013-03-01

    Fatigue testing of load-bearing coated implants is usually very time-consuming and so a new contact nanofatigue test using a nanoindenter has been evaluated. A cube corner indenter provided the fastest indication of failure, through crack formation, compared to a spherical indenter. Contact nanofatigue was performed on a sintered hydroxyapatite and then on amorphous calcium phosphate splats produced on titanium, stainless steel and Co-Cr surfaces, made either at room temperature or on 250°C preheated surfaces. Sintered hydroxyapatite showed continual plastic deformation, but this is not that apparent for splats on metal surfaces. Substrate preheating was found to induce cracking in splats, explained by greater thermal residual stresses. Endurance during contact nanofatigue, measured as time to crack formation, was the lowest for splats on titanium followed by Co-Cr and stainless steel. The splat on titanium showed both cracking and plastic deformation during testing. Good agreement has been reached with previous studies with cracking directed to the substrate without splat delamination. Contact nanofatigue with the nanoindenter easily and quickly identifies cracking events that previously required detection with acoustic emission, and shows good feasibility for mechanical testing of discs and splats produced by thermal spraying, spray forming, laser-ablation, aerosol jet and ink jet printing. PMID:23164945

  2. Poly(lactic acid) porous scaffold with calcium phosphate mineralized surface and bone marrow mesenchymal stem cell growth and differentiation

    International Nuclear Information System (INIS)

    This work aims to modify the surface of a poly(lactic acid) (PLA) porous scaffold with calcium phosphate (CaP) via a simple solution-based technique, and to evaluate the effects of this modification on the responses of rat bone marrow mesenchymal stem cells (rBMMSCs). Under appropriate modification conditions involving stepwise-treatments in the Ca-and-P supersaturated solution under gentle agitation, a thin, poorly crystallized CaP layer was deposited. The BMMSCs derived from adult rats were shown to adhere quite well to the CaP-coated scaffold, and to proliferate actively with culturing time, although some down-regulation was noted with regard to the unmodified PLA scaffold. The osteogenic differentiation of rBMMSCs was significantly higher on the CaP-modified scaffold than on the unmodified scaffold, as confirmed by alkaline phosphatase (ALP) activity. Moreover, the expression of genes associated with bone, including collagen type I, osteopontin and bone sialoprotein, was stimulated better on the CaP-modified PLA scaffold. Based on these results, the currently used CaP-treatment was deemed effective in stimulating the osteogenic development of rBMMSCs on the PLA-based scaffold, and the CaP-treated PLA scaffold may be useful for future bone tissue engineering.

  3. ANNUAL REPORT. THE INFLUENCE OF CALCIUM CARBONATE GRAIN COATINGS ON CONTAMINANT REACTIVITY IN VADOSE ZONE SEDIMENTS

    Science.gov (United States)

    The primary objective of this project is to investigate the role of calcium carbonate grain coatings on adsorption and heterogeneous reduction reactions of key chemical and radioactive contaminants in sediments on the Hanford Site. Research will ascertain whether these coatings p...

  4. Assessment of salivary calcium, phosphate, magnesium, pH, and flow rate in healthy subjects, periodontitis, and dental caries

    OpenAIRE

    Rajesh, K S; Zareena,; Shashikanth Hegde; Arun Kumar, M S.

    2015-01-01

    Aim: This study was conducted to estimate and compare inorganic salivary calcium, phosphate, magnesium, salivary flow rate, and pH of unstimulated saliva and oral hygiene status of healthy subjects, subjects with periodontitis and dental caries, and to correlate salivary calcium level with number of intact teeth. Materials and Methods: The study population consisted of 48 systemically healthy subjects in the age group of 18-55 years, which was further divided into three groups: healthy, perio...

  5. Association of salivary calcium, phosphate, pH and flow rate on oral health: A study on 90 subjects

    OpenAIRE

    Fiyaz, Mohamed; Ramesh, Amitha; Ramalingam, Karthikeyan; Thomas, Biju; Shetty, Sucheta; Prakash, Prashanth

    2013-01-01

    Background and Objectives: This study was designed to compare inorganic salivary calcium, phosphate, flow rate and pH of un-stimulated saliva and oral hygiene of healthy subjects, patients with periodontitis and dental caries and to correlate salivary calcium level with the number of intact teeth. Materials and Methods: The present study consisted of 90 patients aged between 18 and 55 years and were divided into three groups, periodontitis, dental caries and controls. Oral hygiene index-simpl...

  6. Augmentation of femoral neck fracture fixation with an injectable calcium-phosphate bone mineral cement.

    Science.gov (United States)

    Stankewich, C J; Swiontkowski, M F; Tencer, A F; Yetkinler, D N; Poser, R D

    1996-09-01

    The first goal of this study was to determine if augmentation with an injectable, in situ setting, calcium-phosphate cement that is capable of being remodeled and was designed to mimic bone mineral significantly improved the strength and stiffness of fixation in a cadaveric femoral neck fracture model. The second goal was to determine if greater increases in fixation strength were achieved as the bone density of the specimen decreased. Sixteen pairs of fresh cadaveric human femora with a mean age of 70.9 years (SD = 17.2 years) were utilized. The bone density of the femoral neck was measured with dual-energy x-ray absorptiometry. The femoral head was impacted vertically with the femoral shaft fixed in 12 degrees of adduction using a materials testing machine to create a fully displaced fracture. Following fracture, 30% inferior comminution was created in each specimen. One randomly chosen femur from each pair underwent anatomic reduction and fixation with three cannulated cancellous bone screws, 7 mm in diameter, in an inverted triangle configuration. The contralateral femur underwent the same fixation augmented with calcium-phosphate cement. Specimens were preconditioned followed by 1.000 cycles to one body weight (611.6 N) at 0.5 Hz to simulate single-limb stance loading. The stiffness in the first cycle was observed to be significantly greater in cement-augmented specimens compared with unaugmented controls (p bone mineral cement failed at a mean of 4,573 N (SD = 1,243 N); this was significantly greater (p bone density (p = 0.25, R2 = 0.09), was weakly correlated to the volume of cement injected (p = 0.07, R2 = 0.22), and was inversely related to the fixation failure load of the control specimen (p = 0.001, R2 = 0.54). There was a mean relative improvement in fixation strength of 169.6% (SD = 77.5). These findings suggest that calcium-phosphate cement provides initial beneficial augmentation to fixation of femoral neck fractures. PMID:8893773

  7. Calcium Phosphate as a Key Material for Socially Responsible Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Vuk Uskoković

    2016-06-01

    Full Text Available Socially responsible technologies are designed while taking into consideration the socioeconomic, geopolitical and environmental limitations of regions in which they will be implemented. In the medical context, this involves making therapeutic platforms more accessible and affordable to patients in poor regions of the world wherein a given disease is endemic. This often necessitates going against the reigning trend of making therapeutic nanoparticles ever more structurally complex and expensive. However, studies aimed at simplifying materials and formulations while maintaining the functionality and therapeutic response of their more complex counterparts seldom provoke a significant interest in the scientific community. In this review we demonstrate that such compositional simplifications are meaningful when it comes to the design of a solution for osteomyelitis, a disease that is in its natural, non-postoperative form particularly prevalent in the underdeveloped parts of the world wherein poverty, poor sanitary conditions, and chronically compromised defense lines of the immune system are the norm. We show that calcium phosphate nanoparticles, which are inexpensive to make, could be chemically designed to possess the same functionality as a hypothetic mixture additionally composed of: (a a bone growth factor; (b an antibiotic for prophylactic or anti-infective purposes; (c a bisphosphonate as an antiresorptive compound; (d a viral vector to enable the intracellular delivery of therapeutics; (e a luminescent dye; (f a radiographic component; (g an imaging contrast agent; (h a magnetic domain; and (i polymers as viscous components enabling the injectability of the material and acting as carriers for the sustained release of a drug. In particular, calcium phosphates could: (a produce tunable drug release profiles; (b take the form of viscous and injectable, self-setting pastes; (c be naturally osteo-inductive and inhibitory for osteoclastogenesis

  8. Synthesis and characterization of nanosized calcium phosphates by flame spray pyrolysis, and their effect on osteogenic differentiation of stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Ataol, Sibel; Tezcaner, Ayşen [Middle East Technical University, Department of Biomedical Engineering (Turkey); Duygulu, Ozgur [TUBITAK Marmara Research Center, Materials Institute (Turkey); Keskin, Dilek [Middle East Technical University, Department of Biomedical Engineering (Turkey); Machin, Nesrin E., E-mail: nesrinmachin@gmail.com [Kocaeli University, Department of Chemical Engineering (Turkey)

    2015-02-15

    The present study evaluates the synthesis of biocompatible osteoconductive and osteoinductive nano calcium phosphate (CaP) particles by industrially applied, aerosol-derived flame spray pyrolysis method for biomedical field. Calcium phosphate nanoparticles were produced in a range of calcium-to-phosphorus ratio, (1.20–2.19) in order to analyze the morphology and crystallinity changes, and to test the bioactivity of particles. The characterization results confirmed that nanometer-sized, spherical calcium phosphate particles were produced. The average primary particle size was determined as 23 nm by counting more than 500 particles in TEM pictures. XRD patterns, HRTEM, SAED, and SEM analyses revealed the amorphous nature of the as-prepared nano calcium phosphate particles at low Ca/P ratios. Increases in the specific surface area and crystallinity were observed with the increasing Ca/P ratio. TGA–DTA analysis showed that the thermally stable crystal phases formed after 700 °C. Cell culture studies were conducted with urine-derived stem cells that possess the characteristics of mesenchymal stem cells. Synthesized amorphous nanoparticles did not have cytotoxic effect at 5–50 μg/ml concentration range. Cells treated with the as-prepared nanoparticles had higher alkaline phosphatase (ALP) enzyme activity than control cells, indicating osteogenic differentiation of cells. A slight decrease in ALP activity of cells treated with two highest Ca:P ratios at 50 μg/ml concentration was observed at day 7. The findings suggest that calcium phosphate nanoparticles produced in this work have a potential to be used as biomaterials in biomedical applications.

  9. Synthesis and characterization of nanosized calcium phosphates by flame spray pyrolysis, and their effect on osteogenic differentiation of stem cells

    International Nuclear Information System (INIS)

    The present study evaluates the synthesis of biocompatible osteoconductive and osteoinductive nano calcium phosphate (CaP) particles by industrially applied, aerosol-derived flame spray pyrolysis method for biomedical field. Calcium phosphate nanoparticles were produced in a range of calcium-to-phosphorus ratio, (1.20–2.19) in order to analyze the morphology and crystallinity changes, and to test the bioactivity of particles. The characterization results confirmed that nanometer-sized, spherical calcium phosphate particles were produced. The average primary particle size was determined as 23 nm by counting more than 500 particles in TEM pictures. XRD patterns, HRTEM, SAED, and SEM analyses revealed the amorphous nature of the as-prepared nano calcium phosphate particles at low Ca/P ratios. Increases in the specific surface area and crystallinity were observed with the increasing Ca/P ratio. TGA–DTA analysis showed that the thermally stable crystal phases formed after 700 °C. Cell culture studies were conducted with urine-derived stem cells that possess the characteristics of mesenchymal stem cells. Synthesized amorphous nanoparticles did not have cytotoxic effect at 5–50 μg/ml concentration range. Cells treated with the as-prepared nanoparticles had higher alkaline phosphatase (ALP) enzyme activity than control cells, indicating osteogenic differentiation of cells. A slight decrease in ALP activity of cells treated with two highest Ca:P ratios at 50 μg/ml concentration was observed at day 7. The findings suggest that calcium phosphate nanoparticles produced in this work have a potential to be used as biomaterials in biomedical applications

  10. New Low-Temperature Technology of Producing Calcium Feed Phosphate with Microelements

    Directory of Open Access Journals (Sweden)

    Józef Hoffmann

    2007-01-01

    Full Text Available he possibility of producing feed calcium phosphates in a way ensuring a low physical water content in the product was investigated in laboratory conditions. For this purpose the process use of a phosphoric acid solution with a higher (than in conventional methods P2O5 content (53-63% by wt. P2O5 with CaO (molar fraction of 0.5-0.8 and CaCO3 in the phosphoric acid neutralizing mixture was tested. Phosphates with a high content of phosphorous forms highly assimilable by animals, soluble in 0.4% HCl (94-99%, were obtained. The physical water content of 1-4% by wt. H2O was obtained when a phosphoric acid solution with a 59% by wt. P2O5 content and a CaO molar fraction of 0.8 in the neutralizing mixture were used and for a phosphoric acid solution with a 63 % by wt. P2O5 content. A temperature above 160°C was obtained when respectively phosphoric acid with a 59% by wt. P2O5 content and the highest CaO fraction in the neutralizing mixture and a phosphoric acid solution with a 63% by wt. P2O5 content were used. An elevated CO2 content in the products, indicating an increase in the unreacted calcium carbonate content, was found when a phosphoric acid solution containing 59% by wt. P2O5 and a CaO fraction of 0.8 in the neutralizing mixture were used and also for a phosphoric acid solution with a 63% by wt. P2O5 content and a CaO fraction of 0.7-0.8 in the neutralizing mixture. By supplementing extraction phosphorous acid composition with microelements (Se, Cu and Zn compounds at the stage of extraction phosphoric acid production one can obtain a product with a homogenous content of the elements, but this entails losses as high as 70-80% caused by the separation of phosphogypsum from the phosphorous material decomposition product. Because of the different mass fractions of microelement salts and feed phosphates a homogenous selenium compound content in feed phosphate is obtained only after 8 hours of mixing. Mixing time is twice shorter for copper and

  11. Preparation and characterization of calcium phosphate ceramics and composites as bone substitutes

    Science.gov (United States)

    Zhang, Xing

    Marine CaCO3 skeletons have tailored architectures created by nature, which give them structural support and other functions. For example, seashells have dense lamellar structures, while coral, cuttlebone and sea urchin spines have interconnected porous structures. In our experiments, seashells, coral and cuttlebone were hydrothermally converted to hydroxyapatite (HAP), and sea urchin spines were converted to Mg-substituted tricalcium phosphate (beta-TCMP), while maintaining their original structures. Partially converted shell samples have mechanical strength, which is close to that of compact human bone. After implantation of converted shell and spine samples in rat femoral defects for 6 weeks, there was newly formed bone growth up to and around the implants. Some new bone was found to migrate through the pores of converted spine samples and grow inward. These results show good bioactivity and osteoconductivity of the implants, indicating the converted shell and spine samples can be used as bone defect fillers. Calcium phosphate powders were prepared through different synthesis methods. Micro-size HAP rods were synthesized by hydrothermal method through a nucleation-growth mechanism. On the other hand, HAP particles, which have good crystallinity, were prepared by wet precipitation with further hydrothermal treatment. beta-TCP or beta-TCMP powders were prepared by a two-step process: wet precipitation of apatitic tricalcium phosphate ('precursor') and calcination of the precursor at 800°C for 3 hours. beta-TCMP or beta-TCP powders were also prepared by solid-state reactions from CaHPO4 and CaCO 3 with/without MgO. Biphasic calcium phosphate, which is mixture of HAP and beta-TCP, can be prepared though mechanical mixing of HAP and beta-TCP powders synthesized as above. Dense beta-TCP and beta-TCMP ceramics can be produced by pressing green bodies at 100MPa and further sintering above 1100°C for 2 hours. beta-TCMP ceramics ˜99.4% relative dense were prepared by

  12. Effect of Coated Urea with Humic-Calcium on Transformation of Nitrogen in Coastal Sandy Soil: A Soil Column Method

    OpenAIRE

    Sulakhudin; Abdul Syukur; Dja’far Shiddieq; Triwibowo Yuwono

    2010-01-01

    Effect of Coated Urea with Humic-Calcium on Transformation of Nitrogen in Coastal Sandy Soil: A Soil ColumnMethod (Sulakhudin, A Syukur, D Shiddieq and T Yuwono): In coastal sandy soil, mainly nitrogen losses due toleaching resulted to low fertilizer efficiency. Slow-release N fertilizers are proposed to minimize these losses, andhumic-calcium coated urea has been examined. A soil column method was used to compare the effects of coated ureawith humic-calcium on transformation and leaching los...

  13. Structural characterization of pure and doped calcium phosphate bioceramics prepared by simple solid state method

    International Nuclear Information System (INIS)

    Calcium Phosphate based bioceramic materials, in pure and doped forms have been successfully synthesized from egg shells by using solid-state method for the first time. Considering the diverse role of zinc and fluoride in biological functions, these two ions were chosen to develop the substituted bioceramic materials. Structural characterizations of these developed bioceramics were performed by using FTIR, XRD, SEM and EDS techniques. The results revealed that the fluoride doped apatite was formed in single phase containing hydroxyapatite while pure and Zinc doped apatites contained -TCP with hydroxyapatite. Experimental results and the crystallographic parameters matched well with the literature values indicating that the present experimental protocol favoured the formation of the desired bioceramics. However, to synthesize the (Ca (PO)) based bioceramic materials, such a simple solid-state approach would obviously be very helpful, not only in making the process economically feasible, but also in creating an effective material recycling technology for waste-management. (author)

  14. A Review of Casein Phosphopeptide- Amorphous Calcium Phosphate (CPP-ACP) and Enamel Remineralization.

    Science.gov (United States)

    Gupta, Neetu; Mohan Marya, Charu; Nagpal, Ruchi; Singh Oberoi, Sukhvinder; Dhingra, Chandan

    2016-01-01

    White-spot lesions are the earliest macroscopic evidence of enamel caries. In such a situation, the enamel surface layer stays intact during subsurface demineralization, but without treatment the subsurface loss will continue, and eventually the surface layer will collapse and lead to a cavity formation. By introducing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) at this stage the lesion can be reversed. CPP-ACP is a unique, naturally derived protein-based remineralizing technology that is now used globally in chewing gums and topical creams. The aim of this review is to expound on the potential for reversal of demineralization through the use of products such as CPP-ACP, and to provide guidance to clinicians considering remineralization as a viable treatment option. PMID:26863219

  15. Thermally stimulated luminescence and electron paramagnetic resonance studies on uranium doped calcium phosphate

    CERN Document Server

    Natarajan, V; Veeraraghavan, R; Sastry, M D

    2003-01-01

    Thermally stimulated luminescence (TSL) and electron paramagnetic resonance (EPR) studies on uranium doped calcium phosphate yielded mechanistic information on the observed glow peaks at 365, 410 and 450 K. TSL spectral studies of the glow peaks showed that UO sub 2 sup 2 sup + acts as the luminescent center. Electron paramagnetic resonance studies on gamma-irradiated samples revealed that the predominant radiation induced centers are H sup 0 , PO sub 4 sup 2 sup - , PO sub 3 sup 2 sup - and O sup - ion. Studies on the temperature dependence studies of the EPR spectra of samples annealed to different temperatures indicate the role of H sup 0 and PO sub 4 sup 2 sup - ions in the main glow peak at 410 K.

  16. Modifications on the properties of a calcium phosphate cement by additions of sodium alginate

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, W.T.; Fernandes, J.M.; Vieira, R.S.; Thurmer, M.B.; Santos, L.A., E-mail: trajano@ufrgs.br, E-mail: julianafernandes2@yahoo.com.br, E-mail: rsvieira.eng@gmail.com, E-mail: monicathurmer@yahoo.com.br, E-mail: luis.santos@ufrgs.br [Universidade Federal do Rio Grande do Sul (PPG/LABIOMAT/UFRGS), RS (Brazil)

    2012-07-01

    The Calcium Phosphate Cement (CPC) are bone substitutes with great potential for use in orthopedics, traumatology and dentistry due to its biocompatibility, bioactivity and osteoconductivity, and form a paste that can be easily shaped and placed into the surgical site. However, CPCs have low mechanical strength, which equals the maximum mechanical strength of trabecular bone. In order to assess the strength and time to handle a CPC composed primarily of alpha phase, were added sodium alginate (1%, 2% and 3% wt) and an accelerator in an aqueous solution. The cement powder was mixed with liquid of setting, shaped into specimens and evaluated for apparent density and porosity by Archimedes method, X-ray diffraction and compressive strength. A significant increase in compressive strength by adding sodium alginate was verified. (author)

  17. Treatment of post-orthodontic white spot lesions with casein phosphopeptide-stabilised amorphous calcium phosphate

    DEFF Research Database (Denmark)

    Bröchner, Ann; Christensen, Carsten; Kristensen, Bjarne;

    2010-01-01

    This study aims to investigate the effect of topical applications of 10% casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on white spot lesions (WSL) detected after treatment with fixed orthodontic appliances. Sixty healthy adolescents with >/=1 clinically visible WSL at debonding were...... recruited and randomly allocated to a randomised controlled trial with two parallel groups. The intervention group was instructed to topically apply a CPP-ACP -containing agent (Tooth Mousse, GC Europe) once daily and the subjects of the control group brushed their teeth with standard fluoride toothpaste...... included in the final evaluation. A statistically significant (p <0.05) regression of the WSL was disclosed in both study groups compared to baseline, but there was no difference between the groups. The mean area of the lesions decreased by 58% in the CPP-ACP group and 26% in the fluoride group (p = 0...

  18. Modifications on the properties of a calcium phosphate cement by additions of sodium alginate

    International Nuclear Information System (INIS)

    The Calcium Phosphate Cement (CPC) are bone substitutes with great potential for use in orthopedics, traumatology and dentistry due to its biocompatibility, bioactivity and osteoconductivity, and form a paste that can be easily shaped and placed into the surgical site. However, CPCs have low mechanical strength, which equals the maximum mechanical strength of trabecular bone. In order to assess the strength and time to handle a CPC composed primarily of alpha phase, were added sodium alginate (1%, 2% and 3% wt) and an accelerator in an aqueous solution. The cement powder was mixed with liquid of setting, shaped into specimens and evaluated for apparent density and porosity by Archimedes method, X-ray diffraction and compressive strength. A significant increase in compressive strength by adding sodium alginate was verified. (author)

  19. Preparation and osteogenic properties of magnesium calcium phosphate biocement scaffolds for bone regeneration

    International Nuclear Information System (INIS)

    The regenerative treatment of large osseous defects remains a formidable challenge in today. In the present study, we have synthesized biodegradable magnesium calcium phosphate biocement (MCPB) scaffolds with interconnected macroporous structure (100–600 μm), as well as good bioactivity, biocompatibility and proper degradatibility. The results revealed that the porosity increased from 52% to 80% of MCPB scaffolds while the compressive strength decreased from 6.1 MPa to 1.2 MPa. We further assessed the effects of scaffolds on the rabbit femur cavity defect model in vivo by using synchrotron radiation X-ray microCT and microCT imaging, indicating that the MCPB scaffolds underwent gradually degradation and promoted the extensive neo-bone formation

  20. Monitoring of hardening and hygroscopic induced strains in a calcium phosphate bone cement using FBG sensor.

    Science.gov (United States)

    Bimis, A; Karalekas, D; Bouropoulos, N; Mouzakis, D; Zaoutsos, S

    2016-07-01

    This study initially deals with the investigation of the induced strains during hardening stage of a self-setting calcium phosphate bone cement using fiber-Bragg grating (FBG) optical sensors. A complementary Scanning Electron Microscopy (SEM) investigation was also conducted at different time intervals of the hardening period and its findings were related to the FBG recordings. From the obtained results, it is demonstrated that the FBG response is affected by the microstructural changes taking place when the bone cement is immersed into the hardening liquid media. Subsequently, the FBG sensor was used to monitor the absorption process and hygroscopic response of the hardened and dried biocement when exposed to a liquid/humid environment. From the FBG-based calculated hygric strains as a function of moisture concentration, the coefficient of moisture expansion (CME) of the examined bone cement was obtained, exhibiting two distinct linear regions. PMID:26807773