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Sample records for calcium phosphates

  1. 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.

  2. 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)....

  3. 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)....

  4. 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)....

  5. 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...

  6. Sintering of calcium phosphate bioceramics.

    Science.gov (United States)

    Champion, E

    2013-04-01

    Calcium phosphate ceramics have become of prime importance for biological applications in the field of bone tissue engineering. This paper reviews the sintering behaviour of these bioceramics. Conventional pressureless sintering of hydroxyapatite, Ca10(PO4)6(OH)2, a reference compound, has been extensively studied. Its physico-chemistry is detailed. It can be seen as a competition between two thermally activated phenomena that proceed by solid-state diffusion of matter: densification and grain growth. Usually, the objective is to promote the first and prevent the second. Literature data are analysed from sintering maps (i.e. grain growth vs. densification). Sintering trajectories of hydroxyapatite produced by conventional pressureless sintering and non-conventional techniques, including two-step sintering, liquid phase sintering, hot pressing, hot isostatic pressing, ultrahigh pressure, microwave and spark plasma sintering, are presented. Whatever the sintering technique may be, grain growth occurs mainly during the last step of sintering, when the relative bulk density reaches 95% of the maximum value. Though often considered very advantageous, most assisted sintering techniques do not appear very superior to conventional pressureless sintering. Sintering of tricalcium phosphate or biphasic calcium phosphates is also discussed. The chemical composition of calcium phosphate influences the behaviour. Similarly, ionic substitutions in hydroxyapatite or in tricalcium phosphate create lattice defects that modify the sintering rate. Depending on their nature, they can either accelerate or slow down the sintering rate. The thermal stability of compounds at the sintering temperature must also be taken into account. Controlled atmospheres may be required to prevent thermal decomposition, and flash sintering techniques, which allow consolidation at low temperature, can be helpful. PMID:23212081

  7. 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...

  8. 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.

  9. Effects of Nickel on Calcium Phosphate Formation

    Science.gov (United States)

    Guerra-López, J.; González, R.; Gómez, A.; Pomés, R.; Punte, G.; Della Védova, C. O.

    2000-05-01

    We have investigated the effect of nickel on calcium phosphate formation from aqueous solutions. The calcium phosphates prepared under different reaction conditions (pH, temperature, and nickel concentration) were characterized by X-ray diffraction, FTIR spectroscopy, and chemical analysis. The apatite compounds were also studied thermogravimetrically. From the combined results of the techniques employed we have determined that nickel favors the formation of brushite and amorphous calcium phosphate. We have found, as well, that the presence of nickel in the solution inhibits calcium hydroxyapatite (CaHAP) and octacalcium phosphate formation. However in the synthesis performed at basic pH and 95°C the apatitic phase (HAP) could be obtained. The present results suggest that the presence of nickel may modify the precipitation of oral calcium phosphate.

  10. 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.

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

    OpenAIRE

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

    2010-01-01

    International audience 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 biomat...

  12. 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....

  13. 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....

  14. 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.

  15. 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

  16. Hybrid calcium phosphate coatings for implants

    Science.gov (United States)

    Malchikhina, Alena I.; Shesterikov, Evgeny V.; Bolbasov, Evgeny N.; Ignatov, Viktor P.; Tverdokhlebov, Sergei I.

    2016-08-01

    Monophasic biomaterials cannot provide all the necessary functions of bones or other calcined tissues. It is necessary to create for cancer patients the multiphase materials with the structure and composition simulating the natural bone. Such materials are classified as hybrid, obtained by a combination of chemically different components. The paper presents the physical, chemical and biological studies of coatings produced by hybrid technologies (HT), which combine primer layer and calcium phosphate (CaP) coating. The first HT type combines the method of vacuum arc titanium primer layer deposition on a stainless steel substrate with the following micro-arc oxidation (MAO) in phosphoric acid solution with addition of calcium compounds to achieve high supersaturated state. MAO CaP coatings feature high porosity (2-8%, pore size 5-7 µm) and surface morphology with the thickness greater than 5 µm. The thickness of Ti primer layer is 5-40 µm. Amorphous MAO CaP coating micro-hardness was measured at maximum normal load Fmax = 300 mN. It was 3.1 ± 0.8 GPa, surface layer elasticity modulus E = 110 ± 20 GPa, roughness Ra = 0.9 ± 0.1 µm, Rz = 7.5 ± 0.2 µm, which is less than the titanium primer layer roughness. Hybrid MAO CaP coating is biocompatible, able to form calcium phosphates from supersaturated body fluid (SBF) solution and also stimulates osteoinduction processes. The second HT type includes the oxide layer formation by thermal oxidation and then CaP target radio frequency magnetron sputtering (RFMS). Oxide-RFMS CaP coating is a thin dense coating with good adhesion to the substrate material, which can be used for metal implants. The RFMS CaP coating has thickness 1.6 ± 0.1 µm and consists of main target elements calcium and phosphorus and Ca/P ratio 2.4. The second HT type can form calcium phosphates from SBF solution. In vivo study shows that hybrid RFMS CaP coating is biocompatible and produces fibrointegration processes.

  17. 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.

  18. 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

  19. 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...

  20. 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).

  1. 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.

  2. 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.

  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. 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 ...

  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. 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.

  7. 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.

  8. 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)

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

    Science.gov (United States)

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

    2010-06-01

    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, the particles settle down. The engineering sciences have long been interested in models describing the settling (or sedimentation) of particles in viscous fluids. Our work is dedicated to the comprehension of the effect of the formulation on the stability of calcium phosphate suspension before and after steam sterilization. The rheological characterization revealed the macromolecular behavior of the suspending medium. The investigations of settling kinetics showed the influence of the BCP particle size and the HPMC concentration on the settling velocity and sediment compactness before and after sterilization. To decrease the sedimentation process, the granule size has to be smaller and the polymer concentration has to increase. A much lower sedimentation velocity, as compared to Stokes law, is observed and interpreted in terms of interactions between the polymer network in solution and the particles. This experimentation highlights the granules spacer property of hydrophilic macromolecules that is a key issue for interconnection control, one of the better ways to improve osteoconduction and bioactivity. PMID:20229185

  10. 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.

  11. Renal control of calcium, phosphate, and magnesium homeostasis.

    Science.gov (United States)

    Blaine, Judith; Chonchol, Michel; Levi, Moshe

    2015-07-01

    Calcium, phosphate, and magnesium are multivalent cations that are important for many biologic and cellular functions. The kidneys play a central role in the homeostasis of these ions. Gastrointestinal absorption is balanced by renal excretion. When body stores of these ions decline significantly, gastrointestinal absorption, bone resorption, and renal tubular reabsorption increase to normalize their levels. Renal regulation of these ions occurs through glomerular filtration and tubular reabsorption and/or secretion and is therefore an important determinant of plasma ion concentration. Under physiologic conditions, the whole body balance of calcium, phosphate, and magnesium is maintained by fine adjustments of urinary excretion to equal the net intake. This review discusses how calcium, phosphate, and magnesium are handled by the kidneys.

  12. Biodegradable magnetic calcium phosphate nanoformulation for cancer therapy.

    Science.gov (United States)

    Tang, Zhaomin; Zhou, Yangbo; Sun, Huili; Li, Dan; Zhou, Shaobing

    2014-05-01

    We fabricated a magnetic calcium phosphate nanoformulation by the biomineralization of calcium phosphate on the surface of magnetic nanoparticles with abundant amino groups, and thus the inorganic layer of calcium phosphate can improve the biocompatibility and simultaneously the magnetic iron oxide can maintain the magnetic targeting function. Two types of anticancer drug models, doxorubicin hydrochloride and DNA, were entrapped in these nanocarriers, respectively. This delivery system displayed high pH sensitivity in drug-controlled release profile as the dissolution of CaP under acid pH condition. Magnetofection was performed to investigate the intracellular uptake and the anti-proliferative effect of tumor cells in the presence of an external magnet. The transfection of the DNA-loaded magnetic system in A549 and HepG2 tumor cells demonstrated that the magnetic nanoformulation could enhance the transfection efficiency to 30% with an applied external magnetic field. PMID:24462792

  13. 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.

  14. 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 ...

  15. 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)

  16. 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

  17. Molecular mechanisms of crystallization impacting calcium phosphate cements

    Science.gov (United States)

    Giocondi, Jennifer L.; El-Dasher, Bassem S.; Nancollas, George H.; Orme, Christine A.

    2010-01-01

    The biomineral calcium hydrogen phosphate dihydrate (CaHPO4·2H2O), known as brushite, is a malleable material that both grows and dissolves faster than most other calcium minerals, including other calcium phosphate phases, calcium carbonates and calcium oxalates. Within the body, this ready formation and dissolution can play a role in certain diseases, such as kidney stone and plaque formation. However, these same properties, along with brushite’s excellent biocompatibility, can be used to great benefit in making resorbable biomedical cements. To optimize cements, additives are commonly used to control crystallization kinetics and phase transformation. This paper describes the use of in situ scanning probe microscopy to investigate the role of several solution parameters and additives in brushite atomic step motion. Surprisingly, this work demonstrates that the activation barrier for phosphate (rather than calcium) incorporation limits growth kinetics and that additives such as magnesium, citrate and bisphosphonates each influence step motion in distinctly different ways. Our findings provide details of how, and where, molecules inhibit or accelerate kinetics. These insights have the potential to aid in designing molecules to target specific steps and to guide synergistic combinations of additives. PMID:20308110

  18. Atomic structure of intracellular amorphous calcium phosphate deposits.

    Science.gov (United States)

    Betts, F; Blumenthal, N C; Posner, A S; Becker, G L; Lehninger, A L

    1975-06-01

    The radial distribution function calculated from x-ray diffraction of mineralized cytoplasmic structures isolated from the hepatopancreas of the blue crab (Callinectes sapidus) is very similar to that previously found for synthetic amorphous calcium phosphate. Both types of mineral apparently have only short-range atomic order, represented as a neutral ion cluster of about 10 A in longest dimension, whose probable composition is expressed by the formula Ca9(PO4)6. The minor differences observed are attributed to the presence in the biological mineral of significant amounts of Mg-2+ and ATP. Synthetic amorphous calcium phosphate in contact with a solution containing an amount of ATP equivalent to that of the biological mineral failed to undergo conversion to the thermodynamically more stable hydroxyapatite. The amorphous calcium phosphate of the cytoplasmic mineral granules is similarly stable, and does not undergo conversion to hydroxyapatite, presumably owing to the presence of ATP and Mg-2+, known in inhibitors of the conversion process. The physiological implications of mineral deposits consisting of stabilized calcium phosphate ion clusters are discussed.

  19. 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.

  20. 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

  1. 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(

  2. 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.

  3. Magnetic properties study on Fe-doped calcium phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Silva, C C; Valente, M A [Physics Department (I3N), Aveiro University (Portugal); Vasconcelos, I F [Metallurgical and Materials Engineering Department, Federal University of Ceara, Campus do Pici, 714 Block, 60455-760, Fortaleza, Ceara (Brazil); Sombra, A S B [Telecommunications and Materials Science and Engineering Laboratory (LOCEM), Department of Physics, Federal University of Ceara, Campus do Pici, Postal Code 6030, 60455-760, Fortaleza, Ceara (Brazil)], E-mail: ccsilva@ua.pt, E-mail: ccsilva@fisica.ufc.br

    2009-11-15

    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 [Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}-HAP] was prepared by high-energy dry milling (20 h) and mixed with iron oxide (5 wt.%). The mixture was calcinated at 900 deg. C for 5 h with a heating rate of 3 deg. C min{sup -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 {sup 57}Fe-Moessbauer spectra of the calcium phosphate oxides were also measured, revealing the presence of iron in three different phases: Ca{sub 2}Fe{sub 2}O{sub 5}, Fe{sub 2}O{sub 3} and hydroxyapatite.

  4. 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 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......H always remained above 5.5. Hence, calcium-phosphate-osteopontin particles show potential for applications in caries control....

  5. 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......-phosphate-osteopontin particles are a new promising therapeutic approach to caries control. They are designed to bind to dental biofilms and interfere with biofilm build-up, lowering the bacterial burden on the tooth surface without affecting bacterial viability in the oral cavity. Moreover, they dissolve when pH in the biofilm...... 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....

  6. 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.

  7. Diagnosis and clinical manifestations of calcium pyrophosphate and basic calcium phosphate crystal deposition diseases.

    Science.gov (United States)

    Ea, Hang-Korng; Lioté, Frédéric

    2014-05-01

    Basic calcium phosphate and pyrophosphate calcium crystals are the 2 main calcium-containing crystals that can deposit in all skeletal tissues. These calcium crystals give rise to numerous manifestations, including acute inflammatory attacks that can mimic alarming and threatening differential diagnoses, osteoarthritis-like lesions, destructive arthropathies, and calcific tendinitis. Awareness of uncommon localizations and manifestations such as intraspinal deposition (eg, crowned dens syndrome, tendinitis of longus colli muscle, massive cervical myelopathy compression) prevents inappropriate procedures and cares. Coupling plain radiography, ultrasonography, computed tomography, and synovial fluid analysis allow accurate diagnosis by directly or indirectly identifying the GRAAL of microcrystal-related symptoms.

  8. 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.

  9. 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

  10. 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...

  11. 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)

  12. 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

  13. 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)

  14. Calcium Phosphate Coating over Silk Fibroin Film by Biomimetic Methods

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    To investigate the biomineralization behavior of silk fibroin and to valuate the biodegradation and biocompatibility of the hybrid biomaterial, the calcium phosphate deposits were identified with SEM, EDX,XRD and FTIR. The results reveal that supersaturated calcification solution is an effective method for the mineralization of fibroin film. Enzymatic degradation experiment demonstrates the biodegradability of the composites. Osteoblasts incubation shows an excellent cytocompatibility on the mineralized fibroin films.

  15. 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...

  16. 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

  17. Single Step Sintered Calcium Phosphate Fibers from Avian EGG Shell

    Science.gov (United States)

    Dadhich, Prabhash; Das, Bodhisatwa; Dhara, Santanu

    2013-11-01

    Different forms of calcium-phosphate (Hydoxyapatite, α-TCP, β-TCP, CDHA) minerals are found to be major component of bone tissue. Development of calcium-phosphate (CaP) based fibrous microstructures is of significant research interest worldwide owing to its improved mechanical properties and higher interconnectivity. Here we represent a method for single step sintered wet-spun Fibers of calcium phosphate from avian egg shells for biomedical applications. Raw egg shell powder was mixed with chitosan solution and Phosphoric acid. The mixture is milled in a ball mill overnight and then filtered. The slurry was de-aired using 100 microliter 1-octanol per 100 ml of slurry as antifoaming and wet spun in coagulation bath. Fiber was dried overnight and sintered at different temperatures for microstructure and phase analysis. Both green and sintered Fibers were physico-chemical characterized by SEM, EDX, XRD, TGA, DSC, FTIR, and stereo-zoom microscopy. The fibers obtained in this procedure are found to have highly porous interconnected structures which can provide good cell adhesion and therefore can be used for bioactive scaffold making.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. Effects of calcium phosphate bioceramics on skeletal muscle cells.

    Science.gov (United States)

    Sun, J S; Tsuang, Y H; Yao, C H; Liu, H C; Lin, F H; Hang, Y S

    1997-02-01

    With advances in ceramics technology, calcium phosphate bioceramics have been applied as bone substitutes. The effects of implants on bony tissue have been investigated. The effects upon adjacent skeletal muscles have not been determined. The focus of this work is to elucidate the biological effects of various calcium phosphate bioceramics on skeletal muscles. Four different kinds of powder of calcium phosphate biomaterials including beta-tricalcium phosphate (beta-TCP), hydroxyapatite (HA), beta-dicalcium pyrophosphate (beta-DCP) and sintered beta-dicalcium pyrophosphate (SDCP), were tested by myoblast cell cultures. The results were analyzed by cell count, cell morphology and concentration of transforming growth factor beta 1 (TGF-beta 1) in culture medium. The cell population and TGF-beta 1 concentration of the control sample increased persistently as the time of culture increased. The changes in cell population and TGF-beta 1 concentration in culture medium of the beta-TCP and HA were quite low in the first 3 days of culture, then increased gradually toward the seventh day. The changes in cell population and TGF-beta 1 concentration in culture medium of the silica, beta-DCP, and SDCP were quite similar. They were lower during the first day of culture but increased and reached that of the control medium after 7 days' culture. Most cells on B-TCP and HA diminished in size with radially spread, long pseudopods. We conclude that HA and beta-TCP are thought to have an inhibitory effect on growth of the myoblasts. The HA and beta-TCP may interfere with the repair and regeneration of injured skeletal muscle after orthopedic surgery.

  3. 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

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

    Science.gov (United States)

    Lee, Goonhee

    Two technologies, Solid Freeform Fabrication (SFF) and bioceramics are combined in this work to prepare bone replacement implants with complex geometry. SFF has emerged as a crucial technique for rapid prototyping in the last decade. Selective Laser Sintering (SLS) is one of the established SFF manufacturing processes that can build three-dimensional objects directly from computer models without part-specific tooling or human intervention. Meanwhile, there have been great efforts to develop implantable materials that can assist in regeneration of bone defects and injuries. However, little attention has been focused in shaping bones from these materials. The main thrust of this research was to develop a process that can combine those two separate efforts. The specific objective of this research is to develop a process that can construct bone replacement material of complex geometry from synthetic calcium phosphate materials by using the SLS process. The achievement of this goal can have a significant impact on the quality of health care in the sense that complete custom-fit bone and tooth structures suitable for implantation can be prepared within 24--48 hours of receipt of geometric information obtained either from patient Computed Tomographic (CT) data, from Computer Aided Design (CAD) software or from other imaging systems such as Magnetic Resonance Imaging (MRI) and Holographic Laser Range Imaging (HLRI). In this research, two different processes have been developed. First is the SLS fabrication of porous bone implants. In this effort, systematic procedures have been established and calcium phosphate implants were successfully fabricated from various sources of geometric information. These efforts include material selection and preparation, SLS process parameter optimization, and development of post-processing techniques within the 48-hour time frame. Post-processing allows accurate control of geometry and of the chemistry of calcium phosphate, as well as

  5. 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 ...

  6. 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.

  7. 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.

  8. 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...

  9. 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

  10. 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.

  11. Nucleation, growth and evolution of calcium phosphate films on calcite.

    Science.gov (United States)

    Naidu, Sonia; Scherer, George W

    2014-12-01

    Marble, a stone composed of the mineral calcite, is subject to chemically induced weathering in nature due to its relatively high dissolution rate in acid rain. To protect monuments and sculpture from corrosion, we are investigating the application of thin layers of hydroxyapatite (HAP) onto marble. The motivation for using HAP is its low dissolution rate and crystal and lattice compatibility with calcite. A mild, wet chemical synthesis route, in which diammonium hydrogen phosphate salt was reacted with marble, alone and with cationic and anionic precursors under different reaction conditions, was used to produce inorganic HAP layers on marble. Nucleation and growth on the calcite substrate was studied, as well as metastable phase evolution, using scanning electron microscopy, grazing incidence X-ray diffraction, and atomic force microscopy. Film nucleation was enhanced by surface roughness. The rate of nucleation and the growth rate of the film increased with cationic (calcium) and anionic (carbonate) precursor additions. Calcium additions also influenced phase formation, introducing a metastable phase (octacalcium phosphate) and a different phase evolution sequence. PMID:25233226

  12. Reinforcement Strategies for Load-Bearing Calcium Phosphate Biocements

    Directory of Open Access Journals (Sweden)

    Martha Geffers

    2015-05-01

    Full Text Available Calcium phosphate biocements based on calcium phosphate chemistry are well-established biomaterials for the repair of non-load bearing bone defects due to the brittle nature and low flexural strength of such cements. This article features reinforcement strategies of biocements based on various intrinsic or extrinsic material modifications to improve their strength and toughness. Altering particle size distribution in conjunction with using liquefiers reduces the amount of cement liquid necessary for cement paste preparation. This in turn decreases cement porosity and increases the mechanical performance, but does not change the brittle nature of the cements. The use of fibers may lead to a reinforcement of the matrix with a toughness increase of up to two orders of magnitude, but restricts at the same time cement injection for minimal invasive application techniques. A novel promising approach is the concept of dual-setting cements, in which a second hydrogel phase is simultaneously formed during setting, leading to more ductile cement–hydrogel composites with largely unaffected application properties.

  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. 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.

  16. Calcium phosphate cements: study of the beta-tricalcium phosphate--monocalcium phosphate system.

    Science.gov (United States)

    Mirtchi, A A; Lemaitre, J; Terao, N

    1989-09-01

    The possibility of making cements based on beta-tricalcium phosphate (beta-TCP), a promising bone graft material, was investigated. Upon admixture with water, beta-TCP/monocalcium phosphate monohydrate (MCPM) mixtures were found to set and harden like conventional hydraulic cements. Beta-TCP powders with larger particle size, obtained by sintering at higher temperatures, increased the ultimate strength of the cement. Results show that setting occurs after dissolution of MCPM, as a result of the precipitation of dicalcium phosphate dihydrate (DCPD) in the paste. The ultimate tensile strength of the hardened cement is proportional to the amount of DCPD formed. Upon ageing above 40 degrees C, DCPD transforms progressively into anhydrous dicalcium phosphate (DCP), thereby decreasing the strength. Ageing of the pastes in 100% r.h. results in a decay of the mechanical properties. This can be ascribed to an intergranular dissolution of the beta-TCP aggregates as a result of the pH lowering brought about by the MCPM to DCPD conversion.

  17. 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.

  18. 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.

  19. 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)

  20. 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

  1. 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

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

    DEFF Research Database (Denmark)

    Bro, S; Rasmussen, R A; Handberg, J;

    1998-01-01

    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 carbonate (US$6.00/d v US$0.65/d). Calcium ketoglutarate may be an effective and safe alternative to treatment with aluminum......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...

  3. Penggunaan batuan fosfat NDCP (natural defluorinated calcium phosphate sebagai pengganti dicalcium phosphate dalam ransom ayam broiler

    Directory of Open Access Journals (Sweden)

    Arnold P. Sinurat

    1995-08-01

    Full Text Available An experiment was conducted to study the utilization of local rock phosphate or natural defluorinated calcium phosphate (NDCP as phosphorus source for broilers by using the imported dicalcium phosphate (DCP as a reference. The study was designed by formulating 6 experimental diets which consist of 2 phosphorus sources (DCP dan NDCP and 3 dietary total P levels (0 .55 ; 0.65 and 0 .75%. Each diet was fed to 60 chickens (10 replicates with 6 birds each from three day old to 6 weeks of age. Parameters observed were feed consumption, body weight gain, mortality, Ca and P retention, and ash content of tibia bones. Results showed that dietary phosphorus levels (0.55 to 0.75% did not significantly affect body weight gain, feed consumption, and mortalities. However, better feed conversion ratio was obtained when dietary phosphorus level was 0.55%. The NDCP treated birds could significantly gain heavier weight compared with those received DCP, although this improvement was also followed by an increase in the feed consumption. The relative biological value of phosphorus in NDCP was 101 `7n. It is concluded that NDCP can he used in broilers diet to replace DCP as phosphorus source.

  4. Osteoregenerative capacities of dicalcium phosphate-rich calcium phosphate bone cement.

    Science.gov (United States)

    Ko, Chia-Ling; Chen, Jian-Chih; Tien, Yin-Chun; Hung, Chun-Cheng; Wang, Jen-Chyan; Chen, Wen-Cheng

    2015-01-01

    Calcium phosphate cement (CPC) is a widely used bone substitute. However, CPC application is limited by poor bioresorption, which is attributed to apatite, the stable product. This study aims to systematically survey the biological performance of dicalcium phosphate (DCP)-rich CPC. DCP-rich CPC exhibited a twofold, surface-modified DCP anhydrous (DCPA)-to-tetracalcium phosphate (TTCP) molar ratio, whereas conventional CPC (c-CPC) showed a onefold, surface unmodified DCPA-to-TTCP molar ratio. Cell adhesion, morphology, viability, and alkaline phosphatase (ALP) activity in the two CPCs were examined with bone cell progenitor D1 cultured in vitro. Microcomputed tomography and histological observation were conducted after CPC implantation in vivo to analyze the residual implant ratio and new bone formation rate. D1 cells cultured on DCP-rich CPC surfaces exhibited higher cell viability, ALP activity, and ALP quantity than c-CPC. Histological evaluation indicated that DCP-rich CPC showed lesser residual implant and higher new bone formation rate than c-CPC. Therefore, DCP-rich CPC can improve bioresorption. The newly developed DCP-rich CPC exhibited potential therapeutic applications for bone reconstruction.

  5. The utilization of rock phosphate (natural defluorinated calcium phosphate or NDCP in laying hens diet to replace dicalcium phosphate

    Directory of Open Access Journals (Sweden)

    A.P Sinurat

    1996-06-01

    Full Text Available An experimentwas conducted to study the utilization of local rock phosphate or natural defluorinated calcium phosphate (NDCP as phosphorus source for layer chickens by using the imported dicalcium phosphate (DCP as a reference. Eight experimental diets consisted of 2 source of phosphorus (DCP and NDCP and 4 dietary total P levels (0.4, 0.5, 0.6 and 0.7% were formulated. Each diet was fed to 24 pullets (6 replicates with 4 birds each from 20 weeks of age to 14 weeks of egg production. Observations were made on feed consumption, egg production, egg weight, mortality, egg quality, Ca and P retention and ash content of tibial bones . Results showed no significant effect of different source and level of phosphorus tested on egg production (% HD, feed consumption, egg weight and mortality rates . Egg shell thickness was depressed in NDCP diet as compared with DCP, however this only occurred at firstmonth of production. It is concluded that the NDCP can be used in layers diet to replace DCP as phosphorus source. The relative biological value of phosphorus inNDCP is 96% for layers.

  6. Structure, properties and animal study of a calcium phosphate/calcium sulfate composite cement.

    Science.gov (United States)

    Chen, Wei-Luen; Chen, Chang-Keng; Lee, Jing-Wei; Lee, Yu-Ling; Ju, Chien-Ping; Lin, Jiin-Huey Chern

    2014-04-01

    In-vitro and in-vivo studies have been conducted on an in-house-developed tetracalcium phosphate (TTCP)/dicalcium phosphate anhydrous (DCPA)/calcium sulfate hemihydrate (CSH)-derived composite cement. Unlike most commercial calcium-based cement pastes, the investigated cement paste can be directly injected into water and harden without dispersion. The viability value of cells incubated with a conditioned medium of cement extraction is >90% that of Al2O3 control and >80% that of blank medium. Histological examination reveals excellent bonding between host bone and cement without interposition of fibrous tissues. At 12 weeks-post implantation, significant remodeling activities are found and a new bone network is developed within the femoral defect. The 26-week samples show that the newly formed bone becomes more mature, while the interface between residual cement and the new bone appears less identifiable. Image analysis indicates that the resorption rate of the present cement is much higher than that of TTCP or TTCP/DCPA-derived cement under similar implantation conditions.

  7. 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

  8. Initial Stability Study of Calcium Phosphate Coated Dental Implants

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Thin film of biodegradable calcium phosphate coated on threaded commercially pure titanium( cp- Ti) dental implants has been investigated as one of alternatives to eliminate the problem of the long-term instability of plasma sprayed HA coated implants. In order to compare in-vivo hone-to-implant response behavior among as-machined, HA coated and CMP coated groups, each group was implanted into New Zealand white mature male rabbits for 2 and 6 weeks, and then in- vivo biological behavior was examined in terms of H&E staining. Initial stability and removable torques of implants were compared among three groups. Measured removable torque of CMP coated specimen at 6 wceks after implantation was significantly higher than that of non-coated group, but slightly lower than that of HA coated group, without any inflammatory response at the surrounding of the implants. The initial stability (ISQ value; implant stability quotient ) of CMP coated specimen at 2 weeks after implantation was slightly lower than that of HA coated group and significantly higher than that of non-coated group. However, after 6 weeks, ISQ value of CMP coated group was slightly higher than that of HA coated group and significantly higher than that of non-coated group.

  9. Degree of vinyl conversion in experimental amorphous calcium phosphate composites

    Science.gov (United States)

    Tarle, Z.; Knežević, A.; Matošević, D.; Škrtić, D.; Ristić, M.; Prskalo, K.; Musić, S.

    2009-04-01

    An experimental dental composite, based on amorphous calcium phosphate (ACP) with the potential to arrest caries development and regenerate mineral-deficient tooth structures has recently been developed. The aim of this study was to assess the degree of vinyl conversion (DVC) attained in experimental composites based on zirconia-modified ACP. Photo-activated resins were based on ethoxylated bisphenol A dimethacrylate (EBPADMA) [ETHM series with varying EBPADMA/triethylene glycol dimethacrylate (TEGDMA) molar ratios assigned 0.5-ETHM I, 0.85-ETHM II and 1.35-ETHM III], or 2,2-bis[p-(2'-hydroxy-3'-methacryloxypropoxy)phenyl]-propane (Bis-GMA) [BTHZ series]. To asses a possible effect of filler particle size on DVC, composites containing 60 mass % resin and 40 mass % of either milled ACP (mACP; median diameter d m = 0.9 μm) or coarse ACP (cACP; d m = 6.0 μm) were prepared, and irradiated with LED curing unit for 40 s. The DVC was calculated as the % change in the ratio of the integrated peak areas between the aliphatic and aromatic absorption bands determined by Fourier transform infrared spectroscopy (FTIR). The highest DVCs values were attained in mACP-BTHZ, cACP-BTHZ and mACP-ETHM III formulations. DVC of tested ACP composites (on average (76.76 ± 4.43)%) compares well with or exceeds DVCs values reported for the majority of commercial materials.

  10. Structure and properties of silver-doped calcium phosphate nanopowders

    Indian Academy of Sciences (India)

    RAVINDER PAL SINGH; UMA BATRA

    2016-09-01

    Stable and antimicrobial silver-doped calcium phosphate nanopowders were synthesized using sol–gel route by setting the atomic ratio of Ag/(Ag +Ca) at 3%and (Ca $+$ Ag)/P at 1.67. Prior to synthesis of nanopowders, influence of time of hydrolyzation on pH and density of precursors were comprehensively studied. Hydrolyzation time was found to have profound influence on pH of constituent precursors. Sufficient hydrolysis resulted in early maturation of sol. Scanning electron microscopy (SEM) showed the heterogeneous and agglomerated state of particles with average size of $3.9\\pm 1.9$ $\\mu$m. Energy dispersive X-ray spectroscopy (EDX) presented uniform distributionof O, Ag, Ca and P elements in nanopowder. Fourier transform infrared spectroscopy (FTIR) confirmed the formation of apatitic structure, whereas X-ray diffraction (XRD) revealed the multiphase constitution of nanopowdersprimarily composed of $\\beta$-TCP, Ag and other hybrid phases. Crystallite size and lattice parameters of $\\beta$-TCP and Ag phases were increased with the rise in calcination temperature. Thermogravimetric analysis (TGA) showed threeregions of weight change and indicated the high thermal stability of nanopowders. Disk diffusion method was used to test the antimicrobial resistance of nanopowders against Escherichia coli and Staphylococcus aureus bacterial strains. All nanopowders exhibited antimicrobial resistance against both E. coli and S. aureus bacteria.

  11. Hardness and microplasticity of nanocrystalline and amorphous calcium phosphate coatings

    Science.gov (United States)

    Ievlev, V. M.; Kostyuchenko, A. V.; Darinskii, B. M.; Barinov, S. M.

    2014-02-01

    The hardness of thin (1.0-4.0 μm) hydroxyapatite coatings with different structures (nanocrystalline, amorphous-crystalline, and amorphous) grown by rf magnetron sputtering on Ti and Si plates has been studied using the nanoindentation method. All the grown structures are characterized by the strain which has reversible and irreversible components. The hardness of nanocrystalline coatings (about 10 GPa) corresponds to the average hardness of hydroxyapatite single crystals. The structure of nanocrystalline coatings in the indentation zone and outside it has been investigated and changes in the structure under the indenter have been revealed using high-resolution transmission electron microscopy. From a comparison of the hardnesses of coatings with different structures and based on an analysis of the intragranular structure, it has been assumed that the plastic deformation occurs according to a dislocation-free mechanism. The plastic deformation is interpreted in terms of the cluster representation of the hydroxyapatite structure and amorphous calcium phosphates of the same elemental composition and cluster-boundary sliding during the deformation.

  12. 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.

  13. Towards understanding biomineralization:calcium phosphate in a biomimetic minerallzation process

    Institute of Scientific and Technical Information of China (English)

    Yu-rong CAI; Rui-kang TANG

    2009-01-01

    Biomineralization processes result in organic/inorganic hybrid materials with complex shapes,hiemrchi-cal structures.and superior matefial properties. Recent developments in biominemlization and biomatarials have demonstrated that calcium phosphate particles play an important role in the formation of hard tissues in nature. In this paper,current concepts in biominemlization,such as nano assembly,biomimetic shell structure,and their applications are introduced. It is confirmed experimentally that enamel-or bone-liked apatita can be achieved by oriented aggregations using nano calcium phosphates as starting matarials. The assembly of calcium phosphate can be either promoted or inhibited by diflerent biomolecules so that the kinetics can he regulated biologically.In this paper,the role of nano calcium phosphate in tissue repair is highligllted Furthermore,a new,interesting result on biomimetie mineralization 1s Introduced,which can offer an artificial shell for living cells via a biomimatic method .

  14. 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.

  15. Gelation and biocompatibility of injectable alginate-calcium phosphate gels for bone regeneration

    NARCIS (Netherlands)

    Cardoso, D.A.; Beucken, J.J.J.P van den; Both, L.L.; Bender, J.; Jansen, J.A.; Leeuwenburgh, S.C.G.

    2014-01-01

    An emerging approach toward development of injectable, self-setting, and fully biodegradable bone substitutes involves the combination of injectable hydrogel matrices with a dispersed phase consisting of nanosized calcium phosphate particles. Here, novel injectable composites for bone regeneration h

  16. 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.

  17. 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.

  18. Simplified estimates of ion-activity products of calcium oxalate and calcium phosphate in mouse urine.

    Science.gov (United States)

    Tiselius, Hans-Göran; Ferraz, Renato Ribeiro Nogueira; Heilberg, Ita Pfeferman

    2012-08-01

    This study aimed at formulating simplified estimates of ion-activity products of calcium oxalate (AP(CaOx)) and calcium phosphate (AP(CaP)) in mouse urineto find the most important determinants in order to limit the analytical work-up. Literature data on mouse urine composition was used to determine the relative effect of each urine variable on the two ion-activity products. AP(CaOx) and AP(CaP) were calculated by iterative approximation with the EQUIL2 computerized program. The most important determinants for AP(CaOx) were calcium, oxalate and citrate and for AP(CaP) calcium, phosphate, citrate, magnesium and pH. Urine concentrations of the variables were used. A simplified estimate of AP(CaOx) (AP(CaOx)-index(MOUSE)) that numerically approximately corresponded to 10(8) × AP(CaOx) was given the following expression:[Formula: see text]For a series of urine samples with various composition the coefficient of correlation between AP(CaOx)-index(MOUSE) and 10(8) × AP(CaOx) was 0.99 (p = 0.00000). A similar estimate of AP(CaP) (AP(CaP)-index(MOUSE)) was formulated so that it approximately would correspond numerically to 10(14) × AP(CaP) taking the following form:[Formula: see text]For a series of variations in urine composition the coefficient of correlation was 0.95 (p = 0.00000). The two approximate estimates shown in this article are simplified expressions of AP(CaOx) and AP(CaP). The intention of these theoretical calculations was not to get methods for accurate information on the saturation levels in urine, but to have mathematical tools useful for rough conclusions on the outcome of different experimental situations in mice. It needs to be emphasized that the accuracy will be negatively influenced if urine variables not included in the formulas differ very much from basic concentrations.

  19. 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.

  20. 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

  1. Calcium phosphate coating on titanium using laser and plasma spray

    Science.gov (United States)

    Roy, Mangal

    Though calcium phosphate (CaP) coated implants are commercially available, its acceptance is still not wide spread due to challenges related to weaker interfacial bonding between metal and ceramic, and low crystallinity of hydroxyapatite (HA). The objectives of this research are to improve interfacial strength, crystallinity, phase purity and bioactivity of CaP coated metallic implants for orthopaedic applications. The rationale is that forming a diffuse and gradient metal-ceramic interface will improve the interfacial strength. Moreover, reducing CaP particles exposure to high temperature during coating preparation, can lead to improvement in both crystallinity and phase purity of CaP. In this study, laser engineered net shaping (LENS(TM)) was used to coat Ti metal with CaP. LENS(TM) processing enabled generation of Ti+TCP (tricalcium phosphate) composite coating with diffused interface, that also increased the coating hardness to 1049+/-112 Hv compared to a substrate hardness of 200+/-15 Hv. In vitro bone cell-material interaction studies confirmed the bioactivity of TCP coatings. Antimicrobial properties of the TCP coatings were improved by silver (Ag) electrodeposition. Along with LENS(TM), radio frequency induction plasma spray, equipped with supersonic plasma nozzle, was used to prepare HA coatings on Ti with improved crystallinity and phase purity. The coating was made of multigrain HA particles of ˜200 nm in size, which consisted of 15--20 nm HA grains. In vitro bone cell-material interaction and in vivo rat model studies confirmed the HA coatings to be bioactive. Furthermore, incorporation of Sr2+ improved bone cell of HA coatings interaction. A combination of LENS(TM) and plasma spray was used to fabricate a compositionally graded HA coatings on Ti where the microstructure varied from pure HA at the surface to pure Ti substrate with a diffused Ti+TCP composite region in between. The plasma spray system was used to synthesize spherical HA nano powder from

  2. Enzymatic pH control for biomimetic deposition of calcium phosphate coatings

    NARCIS (Netherlands)

    Nijhuis, A.W.G.; Nejadnik, M.R.; Nudelman, F.; Walboomers, X.F.; Riet, J. te; Habibovic, P.; Tahmasebi Birgani, Z.; Li, Y.; Bomans, P.H.; Jansen, J.A.; Sommerdijk, N.A.; Leeuwenburgh, S.C.G.

    2014-01-01

    The current study examines the enzymatic decomposition of urea into carbon dioxide and ammonia as a means to increase the pH during biomimetic deposition of calcium phosphate (CaP) onto implant surfaces. The kinetics of the enzymatically induced pH increase were studied by monitoring pH, calcium con

  3. 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

  4. Calcium carbonate-calcium phosphate mixed cement compositions for bone reconstruction.

    Science.gov (United States)

    Combes, C; Bareille, R; Rey, C

    2006-11-01

    The feasibility of making calcium carbonate-calcium phosphate (CaCO(3)-CaP) mixed cements, comprising at least 40% (w/w) CaCO(3) in the dry powder ingredients, has been demonstrated. Several original cement compositions were obtained by mixing metastable crystalline CaCO(3) phases with metastable amorphous or crystalline CaP powders in aqueous medium. The cements set within at most 1 h at 37 degrees C in atmosphere saturated with water. The hardened cement is microporous and exhibits weak compressive strength. The setting reaction appeared to be essentially related to the formation of a highly carbonated nanocrystalline apatite phase by reaction of the metastable CaP phase with part or almost all of the metastable CaCO(3) phase. The recrystallization of metastable CaP varieties led to a final cement consisting of a highly carbonated poorly crystalline apatite analogous to bone mineral associated with various amounts of vaterite and/or aragonite. The presence of controlled amounts of CaCO(3) with a higher solubility than that of the apatite formed in the well-developed CaP cements might be of interest to increase resorption rates in biomedical cement and favors its replacement by bone tissue. Cytotoxicity testing revealed excellent cytocompatibility of CaCO(3)-CaP mixed cement compositions.

  5. 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.

  6. 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.

  7. 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.

  8. Biomimetic chitosan-calcium phosphate composites with potential applications as bone substitutes: preparation and characterization.

    Science.gov (United States)

    Tanase, Constantin E; Popa, Marcel I; Verestiuc, Liliana

    2012-04-01

    A novel biomimetic technique for obtaining chitosan-calcium phosphates (Cs-CP) scaffolds are presented: calcium phosphates are precipitated from its precursors, CaCl(2) and NaH(2) PO(4) on the Cs matrix, under physiological conditions (human body temperature and body fluid pH; 37°C and pH = 7.2, respectively). Materials composition and structure have been confirmed by various techniques: elemental analysis, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM). FTIR and SEM data have shown the arrangement of the calcium phosphates-hydroxyapatite (CP-Hap) onto Cs matrix. In this case the polymer is acting as glue, bonding the calcium phosphates crystals. Behavior in biological simulated fluids (phosphate buffer solution-PBS and PBS-albumin) revealed an important contribution of the chelation between -NH3(+) and Ca(2+) on the scaffold interaction with aqueous mediums; increased quantities of chitosan in composites permit the interaction with human albumin and improve the retention of fluid. The composites are slightly degraded by the lysozyme which facilitates an in vivo degradation control of bone substitutes. Modulus of elasticity is strongly dependent of the ratio chitosan/calcium phosphates and recommends the obtained biomimetic composites as promising materials for a prospective bone application. PMID:22121073

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. Preparation and mechanical property of core-shell type chitosan/calcium phosphate composite fiber

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Atsushi [Japan Society for the Promotion of Science, Ikenohata1-1-1, Daitou-ku, Tokyo 110-0008 (Japan) and Creative Research Initiative ' Sousei' , Hokkaido University, Sapporo, Hokkaido 001-0021 (Japan)]. E-mail: MATSUDA.Atsushi@nims.go.jp; Ikoma, Toshiyuki [Biomaterials Research Center, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan); Kobayashi, Hisatoshi [Biomaterials Research Center, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan)]. E-mail: Kobayashi.Hisatoshi@nims.go.jp; Tanaka, Junzo [Creative Research Initiative ' Sousei' , Hokkaido University, Sapporo, Hokkaido 001-0021 (Japan); Biomaterials Research Center, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan)

    2004-12-01

    Core-shell type chitosan/calcium phosphate composite fibers were prepared by a facile wet spinning method; the chitosan aqueous solution with PO{sub 4} ions was dropped and coagulated in the ethanol/calcium hydroxide solutions at different mixed ratio. X-ray diffraction (XRD) patterns indicated that the crystal phases of calcium phosphates in the composite fibers were a low-crystalline hydroxyapatite (HAp; Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2})or the low-crystalline hydroxyapatite/brushite mixture depended on the ratio of ethanol/calcium hydroxide solutions. The inorganic contents were ca. 60 wt.% by using the TG-DTA analysis. The energy-dispersive X-ray spectroscopy (EDS) analysis indicated that Ca and P atoms were mainly distributed on the outer layer of the composite fiber to grow calcium phosphate crystals; however, a little amount of P atom still remained at the inside of the fiber. This indicated that the composite fibers formed a unique core-shell structure with shell of calcium phosphate and core of chitosan. The mechanical property of the fibers was reinforced by the initial concentration of chitosan solution.

  15. Silver-doped calcium phosphate nanoparticles: synthesis, characterization, and toxic effects toward mammalian and prokaryotic cells.

    Science.gov (United States)

    Peetsch, Alexander; Greulich, Christina; Braun, Dieter; Stroetges, Christian; Rehage, Heinz; Siebers, Bettina; Köller, Manfred; Epple, Matthias

    2013-02-01

    Spherical silver-doped calcium phosphate nanoparticles were synthesized in a co-precipitation route from calcium nitrate/silver nitrate and ammonium phosphate in a continuous process and colloidally stabilized by carboxymethyl cellulose. Nanoparticles with 0.39 wt% silver content and a diameter of about 50-60 nm were obtained. The toxic effects toward mammalian and prokaryotic cells were determined by viability tests and determination of the minimal inhibitory and minimal bactericidal concentrations (MIC and MBC). Three mammalian cells lines, i.e. human mesenchymal stem cells (hMSC) and blood peripheral mononuclear cells (PBMC, monocytes and T-lymphocytes), and two prokaryotic strains, i.e. Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were used. Silver-doped calcium phosphate nanoparticles and silver acetate showed similar effect toward mammalian and prokaryotic cells with toxic silver concentrations in the range of 1-3 μg mL(-1).

  16. Calcium phosphate nanocoatings and nanocomposites, part 2: thin films for slow drug delivery and osteomyelitis.

    Science.gov (United States)

    Ben-Nissan, Besim; Macha, Innocent; Cazalbou, Sophie; Choi, Andy H

    2016-01-01

    During the last two decades although many calcium phosphate based nanomaterials have been proposed for both drug delivery, and bone regeneration, their coating applications have been somehow slow due to the problems related to their complicated synthesis methods. In order to control the efficiency of local drug delivery of a biomaterial the critical pore sizes as well as good control of the chemical composition is pertinent. A variety of calcium phosphate based nanocoated composite drug delivery systems are currently being investigated. This review aims to give an update into the advancements of calcium phosphate nanocoatings and thin film nanolaminates. In particular recent research on PLA/hydroxyapatite composite thin films and coatings into the slow drug delivery for the possible treatment of osteomyelitis is covered. PMID:26891748

  17. 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 ...

  18. 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.

  19. 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.

  20. Serum Proteins Stabilized Calcium Phosphate Nanoparticles and Its Effect on Bel-7402 Cells

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Hydroxyapatite has a high affinity to biological macromolecules, especially to proteins. Bovine serum proteins were extracted to be used as stablizer to prepare calcium phosphate nanoparticles. 167.7 am and87.7 nm particles were respectively prepared by using bovine serum protein fractions at the concentration of 0.5mg/mL and 1.0 mg/mL. As the polysaccharide stabilized hydroxyapatite nanoparticles, the protein-stablized nanoparticles also inhibited the proliferation rate of Bel-7402 cells. It suggested that proteins could be applied to prepare calcium phosphate nanoparticles and it also has the anticancer effect.

  1. 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)

  2. 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...

  3. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Enlow, Drew Lenzen [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    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 ~40 nm, and agglomerates of these particles (on the order of 0.5 μm) 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.

  5. 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, ...

  6. 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

  7. Chemical immobilization of Pb, Cu, and Cd by phosphate materials and calcium carbonate in contaminated soils.

    Science.gov (United States)

    Huang, Guoyong; Su, Xiaojuan; Rizwan, Muhammad Shahid; Zhu, Yifei; Hu, Hongqing

    2016-08-01

    Soil contamination with toxic metals has increasingly become a global concern over the past few decades. Phosphate and carbonate compounds are good passivation materials for Pb immobilization, while the effect of phosphate and carbonate on the immobilization of multiple heavy metals (Pb, Cu, and Cd) in contaminated soils was seldom investigated. In this study, bone meal (BM), phosphate rock (PR), oxalic acid-activated phosphate rock (APR), super phosphate (SP), and calcium carbonate (CC) were added to the contaminated soils to evaluate the effect of phosphate materials and calcium carbonate on the immobilization of Pb, Cu, and Cd. The results showed that the pH of the treated soils increased 1.3-2.7, except SP which decreased 0.5 at most. Compared to the control treatment, all phosphates and calcium carbonate added to the polluted soils increased the fraction of residual metals, and the application of APR, PR, BM, and CC significantly reduced exchangeable and carbonate-bound fraction metals. PR and APR were the most effective for the immobilization of Pb, Cu, and Cd in the soils among these materials. Moreover, the concentrations of all metals in the toxicity characteristic leaching procedure (TCLP) leachate decreased with increasing amounts of amendments, and the concentrations of Pb in the TCLP leachate for soils treated with PR and APR were below the nonhazardous regulatory limit of 5 mg L(-1) (US Environmental Protection Agency). Based on our results, phosphate rock and oxalic acid-activated phosphate rock are effective in the immobilization of multiple metals by reducing their mobility in the co-contaminated soils. PMID:27197655

  8. Effect of calcium phosphate crystals induced by uremic serum on calcification of human aortic smooth muscle cells

    Institute of Scientific and Technical Information of China (English)

    刘曜蓉

    2013-01-01

    Objective To investigate the impact of calcium phosphate crystals induced by uremic serum on calcification of human aortic smooth muscle cells (HASMCs) .Methods Uremic serum was incubated at 37℃for 3days.Calcium phosphate crystals and uremic supernatant were isolated from uremic serum by ultracentrifugation.

  9. Mapping calcium phosphate activated gene networks as a strategy for targeted osteoinduction of human progenitors.

    Science.gov (United States)

    Eyckmans, Jeroen; Roberts, Scott J; Bolander, Johanna; Schrooten, Jan; Chen, Christopher S; Luyten, Frank P

    2013-06-01

    Although calcium phosphate-containing biomaterials are promising scaffolds for bone regenerative strategies, the osteoinductive capacity of such materials is poorly understood. In this study, we investigated whether endogenous mechanisms of in vivo calcium phosphate-driven, ectopic bone formation could be identified and used to induce enhanced differentiation in vitro of the same progenitor population. To accomplish this, human periosteum derived cells (hPDCs) were seeded on hydroxyapatite/collagen scaffolds (calcium phosphate rich matrix or CPRM), or on decalcified scaffolds (calcium phosphate depleted matrix or CPDM), followed by subcutaneous implantation in nude mice to trigger ectopic bone formation. In this system, osteoblast differentiation occurred in CPRM scaffolds, but not in CPDM scaffolds. Gene expression was assessed by human full-genome microarray at 20 h after seeding, and 2, 8 and 18 days after implantation. In both matrices, implantation of the cell constructs triggered a similar gene expression cascade, however, gene expression dynamics progressed faster in CPRM scaffolds than in CPDM scaffolds. The difference in gene expression dynamics was associated with differential activation of hub genes and molecular signaling pathways related to calcium signaling (CREB), inflammation (TNFα, NFkB, and IL6) and bone development (TGFβ, β-catenin, BMP, EGF, and ERK signaling). Starting from this set of pathways, a growth factor cocktail was developed that robustly enhanced osteogenesis in vitro and in vivo. Taken together, our data demonstrate that through the identification and subsequent stimulation of genes, proteins and signaling pathways associated with calcium phosphate mediated osteoinduction, a focused approach to develop targeted differentiation protocols in adult progenitor cells can be achieved.

  10. 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 ...

  11. 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.

  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. Influence of surface microstructure and chemistry on osteoinduction and osteoclastogenesis by biphasic calcium phosphate discs.

    NARCIS (Netherlands)

    Davison, N.L.; Su, J.; Yuan, H.; Beucken, J.J.J.P van den; Bruijn, J.D. de; rrere-de Groot, F. Ba

    2015-01-01

    It has been reported that surface microstructural dimensions can influence the osteoinductivity of calcium phosphates (CaPs), and osteoclasts may play a role in this process. We hypothesised that surface structural dimensions of

  14. 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 ...

  15. 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.

  16. 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

  17. Novel tea polyphenol-modified calcium phosphate nanoparticle and its remineralization potential

    NARCIS (Netherlands)

    L. He; D. Deng; X. Zhou; L. Cheng; J.M. ten Cate; J. Li; X. Li; W. Crielaard

    2015-01-01

    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 part

  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. 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.

  20. 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.

  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. 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.

  3. 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.

  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. The effects of inorganic additives to calcium phosphate on in vitro behavior of osteoblasts and osteoclasts

    NARCIS (Netherlands)

    Yang, Liang; Perez-Amodio, Soledad; Barrere-de Groot, Florence Y.F.; Everts, Vincent; Blitterswijk, van Clemens A.; Habibovic, Pamela

    2010-01-01

    This study describes a medium-throughput system based on deposition of calcium phosphate films in multi-well tissue culture plates that can be used to study the effect of inorganic additives on the behavior of osteoblasts and osteoclasts in a standardized manner. All tested elements, copper, zinc, s

  6. Biocompatibility and degradation of poly(DL-lactic-co-glycolic acid)/calcium phosphate cement composites

    NARCIS (Netherlands)

    Ruhe, P.Q.; Hedberg, E.L.; Padron, N.T.; Spauwen, P.H.M.; Jansen, J.A.; Mikos, A.G.

    2005-01-01

    Injectable calcium phosphate (Ca-P) cement materials exhibit favorable osteocompatible behavior but are resorbed slowly because of a lack of a bone ingrowth-enabling macroporosity. In this study, poly(DL-lactic-co-glycolic acid) (PLGA) microparticles (average size 66 +/- 25 microm) were incorporated

  7. 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

  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. Chitosan-coated electrospun PLA fibers for rapid mineralization of calcium phosphate.

    Science.gov (United States)

    Lin, Chi-Chang; Fu, Shu-Juan; Lin, Yu-Ching; Yang, I-Kuan; Gu, Yesong

    2014-07-01

    In this work, hydroxyapatite (HA) mineralized on chitosan (CS)-coated poly(lactic acid) (PLA) nanofiber mat was prepared and compared in terms of mineralization characteristics. Significant calcium phosphate crystals formed on various concentrations of CS-coated PLA fiber mat with better uniformity after 2h of incubation in 10 times simulated body fluid (10× SBF). X-ray diffraction results further indicated that the composition of the deposited mineral was a mixture of dicalcium phosphate dehydrates and apatite. Chitosan, a cationic polysaccharide, can promote more nucleation and growth of calcium phosphate under conditions of 0.4% chitosan concentrations. These results indicated that HA-mineralized on CS-coated PLA fiber mat can be prepared directly via simply using CS coating followed by SBF immersion, and the results also suggest that this composite can mimic structural, compositional, and biological functions of native bone and can serve as a good candidate for bone tissue engineering (BTE). PMID:24768970

  10. 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

  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. 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

  13. 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.

  14. 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.

  15. 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.

  16. Kinetic study of the setting reaction of a calcium phosphate bone cement.

    Science.gov (United States)

    Fernández, E; Ginebra, M P; Boltong, M G; Driessens, F C; Ginebra, J; De Maeyer, E A; Verbeeck, R M; Planell, J A

    1996-11-01

    The setting reaction of a calcium phosphate bone cement consisting of a mixture of 63.2 wt % alpha-tertiary calcium phosphate (TCP)[alpha-Ca3(PO4)2], 27.7 wt % dicalcium phosphate (DCP) (CaHPO4), and 9.1 wt % of precipitated hydroxyapatite [(PHA) used as seed material] was investigated. The cement samples were prepared at a liquid-to-powder ratio of: L/P = 0.30 ml/g. Bi-distilled water was used as liquid solution. After mixing the powder and liquid, some samples were molded and aged in Ringer's solution at 37 degrees C. At fixed time intervals they were unmolded and then immediately frozen in liquid nitrogen at a temperature of TN = -196 degrees C, lyofilized, and examined by X-ray diffraction as powder samples. The compressive strength versus time was also measured in setting samples of this calcium phosphate bone cement. The crystal entanglement morphology was examined by scanning electron microscopy. The results showed that: 1) alpha-TCP reacted to a calcium-deficient hydroxyapatite (CDHA), Ca9(HPO4)(PO4)5O H, whereas DCP did not react significantly; 2) the reaction was nearly finished within 32 h, during which both the reaction percentage and the compressive strength increased versus time, with a strong correlation between them; and 3) the calcium phosphate bone cement showed in general a structure of groups of interconnected large plates distributed among agglomerations of small crystal plates arranged in very dense packings.

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

    Energy Technology Data Exchange (ETDEWEB)

    Drevet, Richard, E-mail: richard.drevet@univ-reims.fr; Benhayoune, Hicham

    2013-10-15

    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 1 h 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 (H{sub 2}O{sub 2}) 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. - Highlights: • Strontium-substituted calcium phosphate coatings are successfully electrodeposited. • The strontium is homogeneously distributed in the synthesized prosthetic coating. • This divalent cation modifies the calcium phosphate structure. • H{sub 2}O{sub 2} addition in the electrolyte allows to control the coating's stoichiometry. • This implies a control of the strontium release in the physiological environment.

  18. 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

  19. 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.

  20. In vitro aging of a calcium phosphate cement.

    Science.gov (United States)

    Bohner, M; Merkle, H P; Lemaître, J

    2000-03-01

    Cement samples made of beta-tricalcium phoshate (beta-TCP), phosphoric acid (PA) and water mixtures were incubated in several aqueous solutions to determine their stability over time. The effects of the cement composition and the incubating temperature were investigated in more detail. The cement samples contained mostly dicalcium phosphate dihydrate (DCPD) and remnants of beta-TCP crystals. Depending on the initial cement composition, a certain amount of dicalcium phosphate (DCP) crystals were formed. The larger the initial PA concentration, the larger the DCP amount. After setting, the cement composition was stable for at least 16 days up to 60 degrees C. Above that temperature, the DCPD crystals decomposed into DCP crystals. The latter reaction provoked a decrease of the pH of the incubation solution, phenomenon expected for a cement sample containing an excess of PA. As the cement samples contained an excess of beta-TCP, it was postulated that beta-TCP crystals became so covered by DCP or DCPD crystals during setting that the setting reaction was stopped prematurely. The latter phenomenon gave a good explanation for the low pH values measured in the incubation solutions.

  1. 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

  2. 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.

  3. 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.

  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. ATR-FTIR measurements of albumin and fibrinogen adsorption: Inert versus calcium phosphate ceramics.

    Science.gov (United States)

    Boix, Marcel; Eslava, Salvador; Costa Machado, Gil; Gosselin, Emmanuel; Ni, Na; Saiz, Eduardo; De Coninck, Joël

    2015-11-01

    Arthritis, bone fracture, bone tumors and other musculoskeletal diseases affect millions of people across the world. Nowadays, inert and bioactive ceramics are used as bone substitutes or for bone regeneration. Their bioactivity is very much dictated by the way proteins adsorb on their surface. In this work, we compared the adsorption of albumin and fibrinogen on inert and calcium phosphates ceramics (CaPs) using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) to follow in situ protein adsorption on these materials. To this effect, we developed a sol-gel technique to control the surface chemistry of an ATR-FTIR detector. Hydroxyapatite adsorbed more albumin and β-tricalcium phosphate adsorbed more fibrinogen. Biphasic calcium phosphate presented the lowest adsorption among CaP for both proteins, illustrating the effect of surface heterogeneities. Inert ceramics adsorbed a lower amount of both proteins compared with bioactive ceramics. A significant change was observed in the conformation of the adsorbed protein versus the surface chemistry. Hydroxyapatite produced a larger loss of α-helix structure on albumin and biphasic calcium phosphate reduced β-sheet percentage on fibrinogen. Inert ceramics produced large α-helix loss on albumin and presented weak interaction with fibrinogen. Zirconia did not adsorb albumin and titanium dioxide promoted huge denaturalization of fibrinogen.

  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. 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.

  8. 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.

  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. 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

  11. Study of calcium phosphate (DCPD electrodeposition process on a Mg-3Al-1Zn magnesium alloy surface

    Directory of Open Access Journals (Sweden)

    Filip Pastorek

    2013-02-01

    Full Text Available Evaluation of calcium phosphating process realized on Mg-3Al-1Zn alloy surface after grinding was investigated by electrochemical tests supported by photodocumentation. The electrodeposition treatment was performed by electrochemical method in water solution of Ca(NO32.4H2O, (NH42HPO4 and H2O2. The formation of calcium phosphate was divided into several stages and described using light microscopy. The progress in corrosion protection of created calcium phosphate layer in 0.9% NaCl after particular electrodeposition steps was evaluated by electrochemical impedance spectroscopy. The results in the form of Nyquist plots were analyzed using equivalent circuits.

  12. 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

  13. 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

  14. 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.)

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

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

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

  16. 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.

  17. Preparation and Properties of Nanoparticles of Calcium Phosphates With Various Ca/P Ratios.

    Science.gov (United States)

    Sun, Limin; Chow, Laurence C; Frukhtbeyn, Stanislav A; Bonevich, John E

    2010-01-01

    This study aimed at preparing and studying the properties of nanoparticles of calcium phosphate (nCaP) with Ca/P ratios ranging from 1.0 to 1.67 using a spray-drying technique. Micro-structural analyses suggested that the nCaPs with Ca/P ratios of 1.67 to 1.33 were nano-sized amorphous calcium phosphate (ACP) containing varying amounts of acid phosphate and carbonate. The nCaP with Ca/P ratio of 1 contained only nano-sized low crystalline dicalcium phosphate (DCP). BET measurements of the nCaPs showed specific surface areas of (12 ± 2 to 50 ± 1) m(2)/g, corresponding to estimated equivalent spherical diameters of (38 to 172) nm. However, dynamic light scattering measurements revealed much larger particles of (380 ± 49 to 768 ± 111) nm, owing to agglomeration of the smaller primary nano particles as revealed by Scanning Electron Microscopy (SEM). Thermodynamic solubility measurements showed that the nCaPs with Ca/P ratio of 1.33 - 1.67 all have similar solubility behavior. The materials were more soluble than the crystalline hydroxyapatite (HA) at pH greater than about 4.7, and more soluble than β-tricalcium phosphate (β-TCP), octacalcium phosphate (OCP) and DCP at pH above 5.5. Their solubility approached that of α-tricalcium phosphate (α-TCP) at about pH 7. These nCaPs, which cannot be readily prepared by other currently available methods for nanoparticle preparation, have potential biomedical applications.

  18. 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)

  19. Crystallized nano-sized alpha-tricalcium phosphate from amorphous calcium phosphate: microstructure, cementation and cell response.

    Science.gov (United States)

    Vecbiskena, Linda; Gross, Karlis Agris; Riekstina, Una; Yang, Thomas Chung-Kuang

    2015-04-01

    New insight on the conversion of amorphous calcium phosphate (ACP) to nano-sized alpha tricalcium phosphate (α-TCP) provides a faster pathway to calcium phosphate bone cements. In this work, synthesized ACP powders were treated with either water or ethanol, dried, crystallized between 700 and 800 °C, and then cooled at different cooling rates. Particle size was measured in a scanning electron microscope, but crystallite size calculated by Rietveld analysis. Phase composition and bonding in the crystallized powder was assessed by x-ray diffraction and Fourier-transform infrared spectroscopy. Results showed that 50 nm sized α-TCP formed after crystallization of lyophilized powders. Water treated ACP retained an unstable state that may allow ordering to nanoapatite, and further transition to β-TCP after crystallization and subsequent decomposition. Powders treated with ethanol, favoured the formation of pure α-TCP. Faster cooling limited the growth of β-TCP. Both the initial contact with water and the cooling rate after crystallization dictated β-TCP formation. Nano-sized α-TCP reacted faster with water to an apatite bone cement than conventionally prepared α-TCP. Water treated and freeze-dried powders showed faster apatite cement formation compared to ethanol treated powders. Good biocompatibility was found in pure α-TCP nanoparticles made from ethanol treatment and with a larger crystallite size. This is the first report of pure α-TCP nanoparticles with a reactivity that has not required additional milling to cause cementation. PMID:25886478

  20. 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.

  1. Crystallization at the polymer/calcium-phosphate interface in a sterilized injectable bone substitute IBS.

    Science.gov (United States)

    Schmitt, M; Weiss, P; Bourges, X; Amador del Valle, G; Daculsi, G

    2002-07-01

    Calcium phosphate (CaP) ceramics are the main raw materials used to elaborate blocks or granules for bone substitutes. In this study, injectable bone substitutes (IBS) were developed for applications in orthopedic or dental surgery. Sterile, ready-to-use composite containing CaP granules (biphasic calcium phosphate, BCP) and polymer (hydroxypropylmethylcellulose, HPMC) was prepared. Steam sterilization produced new phenomena at the CaP/polymer interface, resulting in crystal growth. These phenomena may constitute a model for the biomineralization study. Scanning electron microscopy showed that the formed crystallites organize themselves into a three-dimensional structure. Currently, the mechanisms of crystal growth are unknown and have been observed with only one combination of polymer/BCP ceramics after steam sterilization. PMID:12059030

  2. Ultraviolet transmission characteristics of calcium meta phosphate glass; Metarinsan karushiumu garasu no shigaiko toka tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Takenaka, T.; Kawamoto, Y. [Kobe University, Hyogo (Japan). Division of Molecular Scinece

    2000-02-01

    The ultraviolet transmission characteristics of a calcium meta phosphate glass is reported. A calcium meta phosphate glass was prepared using high-purity reagents and taking care in avoiding contamination during glass preparation. This glass exhibited an excellent transmittance in the wavelength range from 250 to 1500 nm (10 mm thick) and an ultraviolet absorption-edge wavelength of 178 nm (3 mm thick). The absorption-edge value was about 60 nm shorter than that reported by Kordes et al. Irradiation of 248-nm excimer laser light to the glass induced strong absorption at <300 nm and weak absorption in the 350-550 nm range. The weak absorption consists of two bands, which are considered to be due to P-O{sup (+)} and Ca{sup 2+(-)}. (author)

  3. Investigation on the biomimetic influence of biopolymers on calcium phosphate precipitation-Part 1: Alginate

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira de Lima, Daniel; Gomes Aimoli, Cassiano [Faculdade de Engenharia Quimica, Unicamp, CP6066 CEP13083-970, Campinas, SP (Brazil); Beppu, Marisa Masumi, E-mail: beppu@feq.unicamp.br [Faculdade de Engenharia Quimica, Unicamp, CP6066 CEP13083-970, Campinas, SP (Brazil)

    2009-05-05

    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.

  4. 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....... The intervention period was 4 weeks and the endpoints were quantitative light-induced fluorescence (QLF) on buccal surfaces of the upper incisors, cuspids and first premolars and visual scoring from digital photos. The attrition rate was 15%, mostly due to technical errors, and 327 lesions were included...... findings were largely reflected by the clinical scores. No side effects were reported. Topical treatment of white spot lesions after debonding of orthodontic appliances with a casein phosphopeptide-stabilised amorphous calcium phosphate agent resulted in significantly reduced fluorescence and a reduced...

  5. 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.

  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. 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.

  8. Calcium phosphate nanocoatings and nanocomposites, part I: recent developments and advancements in tissue engineering and bioimaging.

    Science.gov (United States)

    Choi, Andy H; Ben-Nissan, Besim

    2015-07-01

    A number of materials have been applied as implant coatings and as tissue regeneration materials. Calcium phosphate holds a special consideration, due to its chemical similarity to human bone and, most importantly, its dissolution characteristics, which allow for bone growth and regeneration. The applications of molecular and nanoscale-based biological materials have been and will continue to play an ever increasing role in enhancing and improving the osseointegration of dental and orthopedic implants. More recently, extensive research efforts have been focused on the development and applications of fluorescent nanoparticles and nanocoatings for in vivo imaging and diagnostics as well as devising methods of adding luminescent or fluorescent capabilities to enhance the in vivo functionality of calcium phosphate-based biomedical materials. PMID:26119630

  9. Early resorption of an artificial bone graft made of calcium phosphate for cranioplasty: case report

    Directory of Open Access Journals (Sweden)

    Monaco BA

    2013-11-01

    Full Text Available Bernardo Assumpção de Monaco, Erich Talamoni Fonoff, Manoel Jacobsen TeixeiraDivision of Functional Neurosurgery, Department of Neurology, Hospital das Clinicas, University of São Paulo Medical School, São Paulo, BrazilAbstract: The treatment of uncomplicated osteoma consists of an en bloc resection, or curettage, of the tumor, followed by cranioplasty. Here, we present a case report of a patient treated for a parietal osteoma, followed by a calcium phosphate cranioplasty, with early resorption after 3 months, which was presented by a sinking flap above the resection area. This case suggests that synthetic cranioplasty should be preferred, even in small skull-gap areas.Keywords: cranioplasty, bone cement, osteoma, calcium phosphate, resorption

  10. 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.

  11. Calcium salts of keto-amino acids, a phosphate binder alternative for patients on CAPD.

    Science.gov (United States)

    Macia, M; Coronel, F; Navarro, J F; Gallego, E; Herrero, J A; Méndez, M L; Chahin, J; García, J

    1997-09-01

    Control of hyperphosphoremia is crucial to the prevention of secondary hyperparathyroidism. Calcium salts of keto-amino acids (KAA) were employed as phosphate binders in hemodialysis patients. We wanted to assess the efficacy of these substances as quelating agents in patients under continuous ambulatory peritoneal dialysis (CAPD). Also, as an amino acid supplement, we determined their possible effect on some parameters related to nutritional status. We studied 13 patients (7 M; 6 F) with a mean age of 45.2 +/- 17 years and a mean time on CAPD of 18.4 +/- 11.4 months. None had severe secondary hyperparathyroidism and/or clinically relevant aluminium intoxication. They were not receiving calcitriol and none were using low-calcium peritoneal dialysis fluids. All were under aluminum hydroxide (AlOH3) treatment and 8 patients also received calcium carbonate. These quelating agents were withdrawn and after 21 days (wash-out period) KAA were initiated. We analyzed serum levels of bone metabolism parameters (calcium, phosphate, osteocalcin [OC], intact parathyroid hormone [iPTH], alkaline phosphatase [AP]) and nutritional parameters (total protein, albumin, pre-albumin, transferrin) in four periods: (A) during AlOH3; (B) immediately after the washout period; (C) after 1.5 months; and (D) after 3 months of KAA therapy. In 5 patients serum aluminum level was also measured in periods (A) and (D). The serum phosphate level at period (B) was significantly higher than in other periods. After 3 months of treatment phosphate levels decreased significantly (A = 1.77 +/- 0.3 mmol/l vs D = 1.48 +/- 0.2; p < 0.05). Serum calcium levels increased, while iPTH and OC decreased (p = ns). AP remained stable during the study. All nutritional parameters increased at the end of the study (p = ns). Calcium salts of keto-amino acids showed to be an effective alternative to aluminum-containing phosphate binders. They were well tolerated, without relevant side-effects. These compounds could also

  12. 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.

  13. 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.

  14. 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.

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. Calcium gluconate in phosphate buffered saline increases gene delivery with adenovirus type 5.

    Directory of Open Access Journals (Sweden)

    Marko T Ahonen

    Full Text Available BACKGROUND: Adenoviruses are attractive vectors for gene therapy because of their stability in vivo and the possibility of production at high titers. Despite exciting preclinical data with various approaches, there are only a few examples of clear efficacy in clinical trials. Effective gene delivery to target cells remains the key variable determining efficacy and thus enhanced transduction methods are important. METHODS/RESULTS: We found that heated serum could enhance adenovirus 5 mediated gene delivery up to twentyfold. A new protein-level interaction was found between fiber knob and serum transthyretin, but this was not responsible for the observed effect. Instead, we found that heating caused the calcium and phosphate present in the serum mix to precipitate, and this was responsible for enhanced gene delivery. This finding could have relevance for designing preclinical experiments with adenoviruses, since calcium and phosphate are present in many solutions. To translate this into an approach potentially testable in patients, we used calcium gluconate in phosphate buffered saline, both of which are clinically approved, to increase adenoviral gene transfer up to 300-fold in vitro. Gene transfer was increased with or without heating and in a manner independent from the coxsackie-adenovirus receptor. In vivo, in mouse studies, gene delivery was increased 2-, 110-, 12- and 13-fold to tumors, lungs, heart and liver and did not result in increased pro-inflammatory cytokine induction. Antitumor efficacy of a replication competent virus was also increased significantly. CONCLUSION: In summary, adenoviral gene transfer and antitumor efficacy can be enhanced by calcium gluconate in phosphate buffered saline.

  1. Calcium Gluconate in Phosphate Buffered Saline Increases Gene Delivery with Adenovirus Type 5

    Science.gov (United States)

    Ahonen, Marko T.; Diaconu, Iulia; Pesonen, Sari; Kanerva, Anna; Baumann, Marc; Parviainen, Suvi T.; Spiller, Brad

    2010-01-01

    Background Adenoviruses are attractive vectors for gene therapy because of their stability in vivo and the possibility of production at high titers. Despite exciting preclinical data with various approaches, there are only a few examples of clear efficacy in clinical trials. Effective gene delivery to target cells remains the key variable determining efficacy and thus enhanced transduction methods are important. Methods/Results We found that heated serum could enhance adenovirus 5 mediated gene delivery up to twentyfold. A new protein-level interaction was found between fiber knob and serum transthyretin, but this was not responsible for the observed effect. Instead, we found that heating caused the calcium and phosphate present in the serum mix to precipitate, and this was responsible for enhanced gene delivery. This finding could have relevance for designing preclinical experiments with adenoviruses, since calcium and phosphate are present in many solutions. To translate this into an approach potentially testable in patients, we used calcium gluconate in phosphate buffered saline, both of which are clinically approved, to increase adenoviral gene transfer up to 300-fold in vitro. Gene transfer was increased with or without heating and in a manner independent from the coxsackie-adenovirus receptor. In vivo, in mouse studies, gene delivery was increased 2-, 110-, 12- and 13-fold to tumors, lungs, heart and liver and did not result in increased pro-inflammatory cytokine induction. Antitumor efficacy of a replication competent virus was also increased significantly. Conclusion In summary, adenoviral gene transfer and antitumor efficacy can be enhanced by calcium gluconate in phosphate buffered saline. PMID:20927353

  2. 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

  3. 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 ...

  4. 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

  5. External bone remodeling after injectable calcium-phosphate cement in benign bone tumor: two cases in the hand.

    Science.gov (United States)

    Ichihara, S; Vaiss, L; Acciaro, A L; Facca, S; Liverneaux, P

    2015-12-01

    Bone remodeling commonly occurred after fracture and curettage benign bone tumor. A lot of previous articles reported "internal" trabecular bone remodeling. There were no previous clinical reports about "external" cortical bone remodeling. We present here 2 clinical cases of "external" bone remodeling after injectable calcium-phosphate in benign bone tumor in the hand. In two cases of benign bone tumor, we performed complete removal of the tumor and immediate filling of the metacarpal bone with injectable calcium-phosphate cement Arexbone(®) from the mechanical viewpoint. With respect to the shape of the calcium-phosphate, by using an injection-type, calcium-phosphate is adhered uniformly to the bone cortex by injecting, remodeling has been promoted. After 5 and 8years, both cases were no recurrences, and the shape of the metacarpal looked close to the contralateral side. These findings supposed to be concerned with potential self-healing and self-protection mechanism in human body.

  6. 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.)

  7. 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

  8. 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.

  9. 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

  10. 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.

  11. Physicochemical and Microstructural Characterization of Injectable Load-Bearing Calcium Phosphate Scaffold

    Directory of Open Access Journals (Sweden)

    Mazen Alshaaer

    2013-01-01

    Full Text Available Injectable load-bearing calcium phosphate scaffolds are synthesized using rod-like mannitol grains as porogen. These degradable injectable strong porous scaffolds, prepared by calcium phosphate cement, could represent a valid solution to achieve adequate porosity requirements while providing adequate support in load-bearing applications. The proposed process for preparing porous injectable scaffolds is as quick and versatile as conventional technologies. Using this method, porous CDHA-based calcium phosphate scaffolds with macropores sizes ranging from 70 to 300 μm, micropores ranging from 5 to 30 μm, and 30% open macroporosity were prepared. The setting time of the prepared scaffolds was 15 minutes. Also their compressive strength and e-modulus, 4.9 MPa and 400 MPa, respectively, were comparable with those of the cancellous bone. Finally, the bioactivity of the scaffolds was confirmed by cell growth with cytoplasmic extensions in the scaffolds in culture, demonstrating that the scaffold has a potential for MSC seeding and growth architecture. This combination of an interconnected macroporous structure with pore size suitable for the promotion of cell seeding and proliferation, plus adequate mechanical features, represents a porous scaffold which is a promising candidate for bone tissue engineering.

  12. 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

  13. 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)

  14. 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.

  15. 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.

  16. 3D printing of composite calcium phosphate and collagen scaffolds for bone regeneration.

    Science.gov (United States)

    Inzana, Jason A; Olvera, Diana; Fuller, Seth M; Kelly, James P; Graeve, Olivia A; Schwarz, Edward M; Kates, Stephen L; Awad, Hani A

    2014-04-01

    Low temperature 3D printing of calcium phosphate scaffolds holds great promise for fabricating synthetic bone graft substitutes with enhanced performance over traditional techniques. Many design parameters, such as the binder solution properties, have yet to be optimized to ensure maximal biocompatibility and osteoconductivity with sufficient mechanical properties. This study tailored the phosphoric acid-based binder solution concentration to 8.75 wt% to maximize cytocompatibility and mechanical strength, with a supplementation of Tween 80 to improve printing. To further enhance the formulation, collagen was dissolved into the binder solution to fabricate collagen-calcium phosphate composites. Reducing the viscosity and surface tension through a physiologic heat treatment and Tween 80, respectively, enabled reliable thermal inkjet printing of the collagen solutions. Supplementing the binder solution with 1-2 wt% collagen significantly improved maximum flexural strength and cell viability. To assess the bone healing performance, we implanted 3D printed scaffolds into a critically sized murine femoral defect for 9 weeks. The implants were confirmed to be osteoconductive, with new bone growth incorporating the degrading scaffold materials. In conclusion, this study demonstrates optimization of material parameters for 3D printed calcium phosphate scaffolds and enhancement of material properties by volumetric collagen incorporation via inkjet printing.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. Incorporation of a controlled-release glass into a calcium phosphate cement.

    Science.gov (United States)

    Khairoun, I; Boltong, M G; Gil, F J; Driessens, F C; Planell, J A; Seijas, M M; Martínez, S

    1999-04-01

    A so-called controlled-release glass was synthesized occurring in the system CaO-Na2O-P2O5. A certain sieve fraction of this glass was incorporated in a calcium phosphate cement, of which the powder contained alpha-tricalcium phosphate (alpha-TCP), dicalcium phosphate (DCP) and precipitated hydroxyapatite (HA). The glass appeared to retard the cement setting slightly and it reduced considerably the compressive strength after aging in aqueous solutions which were continuously refreshed. Scanning electron microscope (SEM) pictures and X-ray diffraction (XRD) patterns of the samples after 5 weeks of aging showed that the glass was not dissolved but that large brushite crystals were formed. Thereby, aging in CaCl2 solutions resulted in more brushite formation than aging in NaCl solutions. The brushite crystals did not reinforce the cement. Neither was the aged glass-containing cement weaker than it was before the brushite formation right after complete setting. In conclusion, the incorporation of controlled-release glasses into a calcium phosphate cement and subsequent aging in aqueous solutions did not result in the formation of macropores in the cement structure, but that of brushite crystals. This incorporation reduced the compressive strength of the cement considerably.

  2. 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

  3. 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

    In summary, SPM data has shown that (1) Mg inhibits growth on all steps but relatively high Mg/Ca ratios are needed. Extracting the mechanism of interaction requires more modeling of the kinetic data, but step morphology is consistent with incorporation. (2) Citrate has several effects depending on the citrate/Ca ratio. At the lowest concentrations, citrate increases the step free energy without altering the step kinetics; at higher concentrations, the polar step is slowed. (3) Oxalate also slows the polar step but additionally stabilizes a new facet, with a [100]{sub Cc} step. (4) Etidronate has the greatest kinetic impact of the molecules studied. At 7{micro}M concentrations, the polar step slows by 60% and a new polar step appears. However, at the same time the [10-1]{sub Cc} increases by 67%. It should be noted that all of these molecules complex calcium and can effect kinetics by altering the solution supersaturation or the Ca to HPO{sub 4}{sup 2-} ratio. For the SPM data shown, this effect was corrected for to distinguish the effect of the molecule at the crystal surface from the effect of the molecule on the solution speciation. The goal of this paper is to draw connections between fundamental studies of atomic step motion and potential strategies for materials processing. It is not our intent to promote the utility of SPM for investigating processes in cement dynamics. The conditions are spectacularly different in many ways. The data shown in this paper are fairly close to equilibrium (S=1.6) whereas the nucleation of cements is initiated at supersaturation ratios in the thousands to millions. Of course, after the initial nucleation phase, the growth will occur at more modest supersaturations and as the cement evolves towards equilibrium certainly some of the growth will occur in regimes such as shown here. In addition to the difference in supersaturation, cements tend to have lower additive to calcium ratios. As an example, the additive to Ca ratio is

  4. 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.

  5. Calcium phosphate flocs and the clarification of sugar cane juice from whole of crop harvesting.

    Science.gov (United States)

    Thai, Caroline C D; Moghaddam, Lalehvash; Doherty, William O S

    2015-02-11

    Sugar cane biomass is one of the most viable feedstocks for the production of renewable fuels and chemicals. Therefore, processing the whole of crop (WC) (i.e., stalk and trash, instead of stalk only) will increase the amount of available biomass for this purpose. However, effective clarification of juice expressed from WC for raw sugar manufacture is a major challenge because of the amounts and types of non-sucrose impurities (e.g., polysaccharides, inorganics, proteins, etc.) present. Calcium phosphate flocs are important during sugar cane juice clarification because they are responsible for the removal of impurities. Therefore, to gain a better understanding of the role of calcium phosphate flocs during the juice clarification process, the effects of impurities on the physicochemical properties of calcium phosphate flocs were examined using small-angle laser light scattering technique, attenuated total reflectance Fourier transformed infrared spectroscopy, and X-ray powder diffraction. Results on synthetic sugar juice solutions showed that the presence of SiO2 and Na(+) ions affected floc size and floc structure. Starch and phosphate ions did not affect the floc structure; however, the former reduced the floc size, whereas the latter increased the floc size. The study revealed that high levels of Na(+) ions would negatively affect the clarification process the most, as they would reduce the amount of suspended particles trapped by the flocs. A complementary study on prepared WC juice using cold and cold/intermediate liming techniques was conducted. The study demonstrated that, in comparison to the one-stage (i.e., conventional) clarification process, a two-stage clarification process using cold liming removed more polysaccharides (≤19%), proteins (≤82%), phosphorus (≤53%), and SiO2 (≤23%) in WC juice but increased Ca(2+) (≤136%) and sulfur (≤200%).

  6. The effects of calcium phosphate particles on the growth of osteoblasts.

    Science.gov (United States)

    Sun, J S; Tsuang, Y H; Liao, C J; Liu, H C; Hang, Y S; Lin, F H

    1997-12-01

    With advances in ceramics technology, calcium phosphate bioceramics have been applied as bone substitutes for several decades. The focus of this work is to elucidate the biocompatibility of the particulates of various calcium phosphate cytotoxicities. Four different kinds of calcium phosphate powders, including beta-tricalcium phosphate (beta-TCP), hydroxyapatite (HA), beta-dicalcium pyrophosphate (beta-DCP), and sintered beta-dicalcium pyrophosphate (SDCP), were tested by osteoblast cell culture. The results were analyzed by cell count, concentration of transforming growth factor-beta 1 (TGF-beta 1), alkaline phosphatase (ALP), and prostaglandin E2 (PGE2) in culture media. The changes were most significant when osteoblasts were cultured with beta-TCP and HA bioceramics. The changes in cell population of the beta-TCP and HA were quite low in the first 3 days, then increased gradually toward the seventh day. The changes in TGF-beta 1 concentration in culture medium inversely related to the changes in cell population. The ALP titer in the culture media of the beta-TCP and HA were quite high in the first 3 days, then decreased rapidly between the third and seventh days. The concentrations of PGE2 in the culture media tested were quite high on the first day, decreased rapidly to the third day, and then gradually until the seventh day. The changes in the beta-DCP and SDCP were quite similar to those of HA and beta-TCP but much less significant. We conclude that HA and beta-TCP have an inhibitory effect on the growth of osteoblasts. The inhibitins effects of the HA and beta-TCP powders on the osteoblast cell cultures possibly are mediated by the increased synthesis of PGE2.

  7. Glucose-6-phosphate reduces calcium accumulation in rat brain endoplasmic reticulum

    Directory of Open Access Journals (Sweden)

    Jeffrey Thomas Cole

    2012-04-01

    Full Text Available Brain cells expend large amounts of energy sequestering calcium (Ca2+, while loss of Ca2+ compartmentalization leads to cell damage or death. Upon cell entry, glucose is converted to glucose-6-phosphate (G6P, a parent substrate to several metabolic major pathways, including glycolysis. In several tissues, G6P alters the ability of the endoplasmic reticulum to sequester Ca2+. This led to the hypothesis that G6P regulates Ca2+ accumulation by acting as an endogenous ligand for sarco-endoplasmic reticulum calcium ATPase (SERCA. Whole brain ER microsomes were pooled from adult male Sprague-Dawley rats. Using radio-isotopic assays, 45Ca2+ accumulation was quantified following incubation with increasing amounts of G6P, in the presence or absence of thapsigargin, a potent SERCA inhibitor. To qualitatively assess SERCA activity, the simultaneous release of inorganic phosphate (Pi coupled with Ca2+ accumulation was quantified. Addition of G6P significantly and decreased Ca2+ accumulation in a dose-dependent fashion (1-10 mM. The reduction in Ca2+ accumulation was not significantly different that seen with addition of thapsigargin. Addition of glucose-1-phosphate or fructose-6-phosphate, or other glucose metabolic pathway intermediates, had no effect on Ca2+ accumulation. Further, the release of Pi was markedly decreased, indicating G6P-mediated SERCA inhibition as the responsible mechanism for reduced Ca2+ uptake. Simultaneous addition of thapsigargin and G6P did decrease inorganic phosphate in comparison to either treatment alone, which suggests that the two treatments have different mechanisms of action. Therefore, G6P may be a novel, endogenous regulator of SERCA activity. Additionally, pathological conditions observed during disease states that disrupt glucose homeostasis, may be attributable to Ca2+ dystasis caused by altered G6P regulation of SERCA activity

  8. 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.

  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. Synthesis and characterization of the aluminium phosphates modified with ammonium, calcium and molybdenum by hydrothermal method

    Directory of Open Access Journals (Sweden)

    Łuczka Kinga

    2016-06-01

    Full Text Available Synthesis and characterization of the aluminum phosphates modified with ammonium, calcium and molybdenum were conducted. The influence of process parameters (reactive pressure and molar ratios in the reaction mixture were studied. The contents of the individual components in the products were in the range of: 10.97–17.31 wt% Al, 2.65–13.32 wt% Ca, 0.70–3.11 wt% Mo, 4.36–8.38 wt% NH3, and 35.12–50.54 wt% P2O5. The materials obtained in the experiments were characterized by various physicochemical parameters. The absorption oil number was in the range from 67 to 89 of oil/100 g of product, the surface area was within the range of 4–76 m2/g, whereas the average particle size of products reached 282–370 nm. The Tafel tests revealed comparable anticorrosive properties of aluminum phosphates modified with ammonium, calcium, molybdenum in comparison with commercial phosphate.

  11. In Situ Laser Coating of Calcium Phosphate on TC4 Surface for Enhancing Bioactivity

    Institute of Scientific and Technical Information of China (English)

    DENG Chi; WANG Yong; ZHANG Ya-ping; GAO Jia-cheng

    2007-01-01

    Titanium alloy has been a successful implant material owing to its excellent ratio of strength to weight,toughness, and bio-inert oxide surface. Significant progress has been made in improving the bioactivity of titanium alloy by coating its oxide surface with calcium phosphates. In the present study, in situ coating was reported on Ti6Al4V(TC4) surface with calcium phosphate (Ca-P) bioceramics synthesized and synchronously cladded by laser beam. This coating was grown by first preplacing directly the raw powders, which contain 80% of CaHPO4 ·2H2O, 20% of CaCO3, and dram of rare earth (RE), on the TC4 surfaces, and then exposing the surfaces to the laser beam with a power density of 12. 73-15.27 MW · m-2 and a scanning velocity of 10. 5 m/s. The resultant coating was characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis and Different-thermal Scanning (TG-DSC), and Energy Dispersive X-ray Detection (EDX). The results show that these laser ceramics include hydroxyapatite (HA), tricalcium phosphate (TCP), Ca2P2O7, and other Ca-P phases, and the interface between the coating and the TC4 substrate has tighter fixation, in which the chemical bonding is approved. These laser hybrid coatings are useful in enhancing the bioactivity of titanium alloy surfaces.

  12. Composition of calcium phosphates precipitated from aqueous solutions at different pH values

    Energy Technology Data Exchange (ETDEWEB)

    Salahi, E.; Moztarzadeh, F. [Ceramics Div., Teheran (Iran). Materials and Energy Research Center

    2001-03-01

    During the preparation of calcium phosphate compounds by precipitation from aqueous solutions, several phases, namely dicalcium hydrogen phosphate (DCP, CaHPO{sub 4}), dicalcium hydrogen phosphate dihydrate DCPD, CaHPO{sub 4} (2 H{sub 2}O), hydrated calcium phosphate Ca{sub 3}(PO){sub 4} 2(H{sub 2}O) and hydroxyapatite (HAp, Ca10(PO{sub 4})6(OH){sub 2}), can be formed at different pH values. In the research work presented here, Ca(NO{sub 3})2(4H{sub 2}O) and (NH{sub 4})2HPO{sub 4} were used as starting materials The two solutions with an initial molar ratio of Ca/P=1,67 were mixed at 20 C at 0calcium phosphate are formed. A structural transition was observed at 8phosphate ({beta}-TCP,Ca{sub 3}(PO{sub 4}){sub 2}) developed. Between pH 8 and 9, this phase could be observed clearly. At pH 9..10, there is a transitional state, and at pH >10,5, the hydroxyapatite was developed completely. (orig.)

  13. Porous bioceramic bead prepared by calcium phosphate with sodium alginate gel and PE powder

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Y.C. [Department of Orthopaedic Surgery, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China); Ho, M.L.; Wu, S.C. [Department of Physiology, Kaohsiung Medical University, 100, Shih-Chuan 1st Rd, Kaohsiung 807, Taiwan (China); Hsieh, H.S. [Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100, Shih-Chuan 1st Rd, Kaohsiung 807, Taiwan (China); Wang, C.K. [Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100, Shih-Chuan 1st Rd, Kaohsiung 807, Taiwan (China)], E-mail: ckwang@kmu.edu.tw

    2008-08-01

    The porous calcium phosphate beads were made by an alginate-interacting Ca ions mechanism on addition of a pore-forming polyethylene (PE) powder at 1250 deg. C sintering. The nature of the powders and porous beads were analyzed through X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR) and heavy metal analysis by inductively coupled plasma-optical emission spectroscopy (ICP-OES). The porous beads size and the pore microstructure characteristics were determined using scanning electron microscopy (SEM). Beside, the porosity analysis was evaluated out using an Archimedes' principle and mercury porosimetry. Then, the sodium ampicillin was penetrated/adsorbed onto calcium-deficient hydroxyapatite porous beads, and was subsequently released in PBS. No matter whether the raw material was HAp, TCP or biphase, the Ca{sub 9}(HPO{sub 4})(PO{sub 4}){sub 5}OH phase (CDHA) was formed only after sintering. Porous beads of various calcium phosphates with different sizes (0.9-1.1 mm) and pore size groups (60-120 {mu}m and lower than 10 {mu}m) were appeared. The release kinetics of sodium ampicillin from these porous beads have indicated the possibility of using these materials as possible carriers for drug delivery.

  14. 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.

  15. 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

  16. Reactive calcium-phosphate-containing poly(ester-co-ether) methacrylate bone adhesives: chemical, mechanical and biological considerations.

    Science.gov (United States)

    Zhao, Xin; Olsen, Irwin; Li, Haoying; Gellynck, Kris; Buxton, Paul G; Knowles, Jonathan C; Salih, Vehid; Young, Anne M

    2010-03-01

    A poly(propylene glycol-co-lactide) dimethacrylate adhesive with monocalcium phosphate monohydrate (MCPM)/beta-tricalcium phosphate (beta-TCP) fillers in various levels has been investigated. Water sorption by the photo-polymerized materials catalyzed varying filler conversion to dicalcium phosphate (DCP). Polymer modulus was found to be enhanced upon raising total calcium phosphate content. With greater DCP levels, faster release of phosphate and calcium ions and improved buffering of polymer degradation products were observed. This could reduce the likelihood of pH-catalyzed bulk degradation and localized acid production and thereby may prevent adverse biological responses. Bone-like MG-63 cells were found to attach, spread and have normal morphology on both the polymer and composite surfaces. Moreover, composites implanted into chick embryo femurs became closely apposed to the host tissue and did not appear to induce adverse immunological reaction. The above results suggest that the new composite materials hold promise as clinical effective bone adhesives.

  17. 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

  18. 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.

  19. In situ synthesis of calcium phosphate-polycaprolactone nanocomposites with high ceramic volume fractions.

    Science.gov (United States)

    Makarov, C; Gotman, I; Jiang, X; Fuchs, S; Kirkpatrick, C J; Gutmanas, E Y

    2010-06-01

    Biodegradable calcium phosphate-PCL nanocomposite powders with unusually high ceramic volume fractions (80-95%) and uniform PCL distribution were synthesized by a non-aqueous chemical reaction in the presence of the dissolved polymer. No visible polymer separation occurred during processing. Depending on the reagents combination, either dicalcium phosphate (DCP) or Ca-deficient HA (CDHA) was obtained. CDHA-PCL composite powders were high pressure consolidated at room temperature yielding dense materials with high compressive strengths. Such densification route provides the possibility of incorporating drug and proteins without damaging their biological activity. The CDHA-PCL composites were tested in osteoblastic and endothelial cell line cultures and were found to support the attachment and proliferation of both cell types.

  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. Microwave assisted synthesis & properties of nano HA-TCP biphasic calcium phosphate

    Science.gov (United States)

    Ghomash Pasand, E.; Nemati, A.; Solati-Hashjin, M.; Arzani, K.; Farzadi, A.

    2012-05-01

    Biphasic calcium phosphate (BCP) nanopowders were synthesized by using microwave and non-microwave irradiation assisted processes. The synthesized powders were pressed under a pressure of 90 MPa, and then were sintered at 1000-1200°C for 1 h. The mechanical properties of the samples were investigated. The formed phases and microstructures were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the synthesis time was shorter, along with a more homogeneous microstructure, when the microwave irradiation assisted method was applied. The compression strength and the Young's modulus of the samples synthesized with microwave irradiation were about 60 MPa and 3 GPa, but those of the samples synthesized without microwave irradiation were about 30 MPa and 2 GPa, respectively. XRD patterns of the microwave irradiation assisted and non-microwave irradiation assisted nanopowders showed the coexistence of hydroxyapatite (HA) and tricalcium phosphate (TCP) phases in the system.

  2. 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)

  3. 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

  4. 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)

  5. 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.

  6. Direct 3D powder printing of biphasic calcium phosphate scaffolds for substitution of complex bone defects.

    Science.gov (United States)

    Castilho, Miguel; Moseke, Claus; Ewald, Andrea; Gbureck, Uwe; Groll, Jürgen; Pires, Inês; Teßmar, Jörg; Vorndran, Elke

    2014-03-01

    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.

  7. 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

  8. 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.

  9. Polymeric-Calcium Phosphate Cement Composites-Material Properties: In Vitro and In Vivo Investigations

    Science.gov (United States)

    Khashaba, Rania M.; Moussa, Mervet M.; Mettenburg, Donald J.; Rueggeberg, Frederick A.; Chutkan, Norman B.; Borke, James L.

    2010-01-01

    New polymeric calcium phosphate cement composites (CPCs) were developed. Cement powder consisting of 60 wt% tetracalcium phosphate, 30 wt% dicalcium phosphate dihydrate, and 10 wt% tricalcium phosphate was combined with either 35% w/w poly methyl vinyl ether maleic acid or polyacrylic acid to obtain CPC-1 and CPC-2. The setting time and compressive and diametral tensile strength of the CPCs were evaluated and compared with that of a commercial hydroxyapatite cement. In vitro cytotoxicity and in vivo biocompatibility of the two CPCs and hydroxyapatite cement were assessed. The setting time of the cements was 5–15 min. CPC-1 and CPC-2 showed significantly higher compressive and diametral strength values compared to hydroxyapatite cement. CPC-1 and CPC-2 were equivalent to Teflon controls after 1 week. CPC-1, CPC-2, and hydroxyapatite cement elicited a moderate to intense inflammatory reaction at 7 days which decreased over time. CPC-1 and CPC-2 show promise for orthopedic applications. PMID:20811498

  10. 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.

  11. 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

  12. 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.

  13. 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

  14. 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.

  15. 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...

  16. Importance of FTIR Spectra Deconvolution for the Analysis of Amorphous Calcium Phosphates

    OpenAIRE

    Brangule, A; Gross, K.

    2015-01-01

    This work will consider Fourier transform infrared spectroscopy – diffuse reflectance infrared reflection (FTIR-DRIFT) for collecting the spectra and deconvolution to identify changes in bonding as a means of more powerful detection. Spectra were recorded from amorphous calcium phosphate synthesized by wet precipitation, and from bone. FTIR-DRIFT was used to study the chemical environments of PO4, CO3 and amide. Deconvolution of spectra separated overlapping bands in the ʋ4PO4, ʋ2CO3, ʋ3CO...

  17. 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

  18. 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.

  19. Elucidating the individual effects of calcium and phosphate ions on hMSCs by using composite materials.

    Science.gov (United States)

    Danoux, Charlène B S S; Bassett, David C; Othman, Ziryan; Rodrigues, Ana I; Reis, Rui L; Barralet, Jake E; van Blitterswijk, Clemens A; Habibovic, Pamela

    2015-04-01

    The biological performance of bone graft substitutes based on calcium phosphate bioceramics is dependent on a number of properties including chemical composition, porosity and surface micro- and nanoscale structure. However, in contemporary bioceramics these properties are interlinked, therefore making it difficult to investigate the individual effects of each property on cell behavior. In this study we have attempted to investigate the effects of calcium and inorganic phosphate ions independent from one another by preparing composite materials with polylactic acid (PLA) as a polymeric matrix and calcium carbonate or sodium phosphate salts as fillers. Clinically relevant bone marrow derived human mesenchymal stromal cells (hMSCs) were cultured on these composites and proliferation, osteogenic differentiation and ECM mineralization were investigated with time and were compared to plain PLA control particles. In parallel, cells were also cultured on conventional cell culture plates in media supplemented with calcium or inorganic phosphate to study the effect of these ions independent of the 3D environment created by the particles. Calcium was shown to increase proliferation of cells, whereas both calcium and phosphate positively affected alkaline phosphatase enzyme production. QPCR analysis revealed positive effects of calcium and of inorganic phosphate on the expression of osteogenic markers, in particular bone morphogenetic protein-2 and osteopontin. Higher levels of mineralization were also observed upon exposure to either ion. Effects were similar for cells cultured on composite materials and those cultured in supplemented media, although ion concentrations in the composite cultures were lower. The approach presented here may be a valuable tool for studying the individual effects of a variety of soluble compounds, including bioinorganics, without interference from other material properties. PMID:25676583

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. Osteogenic activity of cyclodextrin-encapsulated doxycycline in a calcium phosphate PCL and PLGA composite.

    Science.gov (United States)

    Trajano, V C C; Costa, K J R; Lanza, C R M; Sinisterra, R D; Cortés, M E

    2016-07-01

    Composites of biodegradable polymers and calcium phosphate are bioactive and flexible, and have been proposed for use in tissue engineering and bone regeneration. When associated with the broad-spectrum antibiotic doxycycline (DOX), they could favor antimicrobial action and enhance the action of osteogenic composites. Composites of polycaprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA), and a bioceramic of biphasic calcium phosphate Osteosynt® (BCP) were loaded with DOX encapsulated in β-cyclodextrin (βCD) and were evaluated for effects on osteoblastic cell cultures. The DOX/βCD composite was prepared with a double mixing method. Osteoblast viability was assessed with methyl tetrazolium (MTT) assays after 1day, 7day, and 14days of composite exposure; alkaline phosphatase (AP) activity and collagen production were evaluated after 7days and 14days, and mineral nodule formation after 14days. Composite structures were evaluated by scanning electron microscopy (SEM). Osteoblasts exposed to the composite containing 25μg/mL DOX/βCD had increased cell proliferation (pcomposite (pcomposite material revealed a surface topography with pore sizes suitable for growing osteoblasts. Together, these results suggest that osteoblasts are viable, proliferative, and osteogenic in the presence of a DOX/βCD-containing BCP ceramic composite.

  6. 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.

  7. 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.

  8. Association of calcium and phosphate ions with collagen in the mineralization of vertebrate tissues.

    Science.gov (United States)

    Landis, William J; Jacquet, Robin

    2013-10-01

    Among the vertebrate species, collagen is the most abundant protein and is associated with mineralization of their skeleton and dentition in all tissues except enamel. In such tissues, bones, calcifying tendon, dentin, and cementum are comprised principally of type I collagen, which has been proposed as a template for apatite mineral formation. Recent considerations of the interaction between type I collagen and calcium and phosphate ions as the major constituents of apatite have suggested that collagen polypeptide stereochemistry underlies binding of these ions at sites within collagen hole and overlap regions and leads to nucleation of crystals. The concept is fundamental to understanding both normal and abnormal mineralization, and it is reviewed in this article. Given this background, avenues for additional research studies in vertebrate mineralization will also be described. The latter include, for instance, how mineralization events subsequent to nucleation, that is, crystal growth and development, occur and whether they, too, are directed by collagen stereochemical parameters; whether mineralization can be expected in all spaces between collagen molecules; whether the side chains of charged amino acid residues actually point toward and into the hole and overlap collagen spaces to provide putative binding sites for calcium and phosphate ions; and what phenomena may be responsible for mineralization beyond hole and overlap zones and into extracellular tissue regions between collagen structural units. These questions will be discussed to provide a broader understanding of collagen contributions to potential mechanisms of vertebrate mineralization.

  9. 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.

  10. 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.

  11. Bone morphogenetic protein Smads signaling in mesenchymal stem cells affected by osteoinductive calcium phosphate ceramics.

    Science.gov (United States)

    Tang, Zhurong; Wang, Zhe; Qing, Fangzhu; Ni, Yilu; Fan, Yujiang; Tan, Yanfei; Zhang, Xingdong

    2015-03-01

    Porous calcium phosphate ceramics (CaP ceramics) could induce ectopic bone formation which was regulated by various signal molecules. In this work, bone marrow mesenchymal stem cells (MSCs) were cultured on the surface of osteoinductive hydroxyapatite (HA) and biphasic calcium phosphate (BCP) ceramics in comparison with control (culture plate) for up to 14 days to detect the signal molecules which might be affected by the CaP ceramics. Without adding osteogenic factors, MSCs cultured on HA and BCP both expressed higher Runx2, Osterix, collagen type I, osteopontin, bone sialoprotein, and osteocalcin at various stages compared with control, thus confirmed the osteoblastic differentiation of MSCs. Later study demonstrated the messenger RNA level of bone morphogenetic protein 2 (BMP2) and BMP4 were also significantly enhanced by HA and BCP. Furthermore, Smad1, 4, 5, and Dlx5, the main molecules in the BMP/Smads signaling pathway, were upregulated by HA and BCP. Moreover, the higher expression of Smads and BMP2, 4 in BCP over HA, corresponded to the better performance of BCP in stimulating in vitro osteoblastic differentiation of MSCs. This was in accordance with the better osteoinductivity of BCP over HA in vivo. Altogether, these results implied that the CaP ceramics may initiate the osteoblastic differentiation of MSCs by influencing the expression of molecules in BMP/Smads pathway.

  12. 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

  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. 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

  15. Importance of FTIR Spectra Deconvolution for the Analysis of Amorphous Calcium Phosphates

    Science.gov (United States)

    Brangule, Agnese; Agris Gross, Karlis

    2015-03-01

    This work will consider Fourier transform infrared spectroscopy - diffuse reflectance infrared reflection (FTIR-DRIFT) for collecting the spectra and deconvolution to identify changes in bonding as a means of more powerful detection. Spectra were recorded from amorphous calcium phosphate synthesized by wet precipitation, and from bone. FTIR-DRIFT was used to study the chemical environments of PO4, CO3 and amide. Deconvolution of spectra separated overlapping bands in the ʋ4PO4, ʋ2CO3, ʋ3CO3 and amide region allowing a more detailed analysis of changes at the atomic level. Amorphous calcium phosphate dried at 80 oC, despite showing an X-ray diffraction amorphous structure, displayed carbonate in positions resembling a carbonated hydroxyapatite. Additional peaks were designated as A1 type, A2 type or B type. Deconvolution allowed the separation of CO3 positions in bone from amide peaks. FTIR-DRIFT spectrometry in combination with deconvolution offers an advanced tool for qualitative and quantitative determination of CO3, PO4 and HPO4 and shows promise to measure the degree of order.

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. Preparation, Physical-Chemical Characterization, and Cytocompatibility of Polymeric Calcium Phosphate Cements

    Science.gov (United States)

    Khashaba, Rania M.; Moussa, Mervet; Koch, Christopher; Jurgensen, Arthur R.; Missimer, David M.; Rutherford, Ronny L.; Chutkan, Norman B.; Borke, James L.

    2011-01-01

    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. PMID:21941551

  1. Calcium-phosphate deposits on a hydrophilic acrylic intraocular lens after silicon oil tamponade

    Directory of Open Access Journals (Sweden)

    Rashid Alsaeidi

    2008-01-01

    Full Text Available We report a 52-year-old man who underwent uncomplicated cataract operation and posterior chamber lens implantation (hydrophilic acrylic lens in his left eye 5 years prior to presentation. Two years after surgery he developed pseudophakic retinal detachment which was successfully treated with pars plana vitrectomy and silicon oil tamponade. The silicon oil was removed one year after surgery. A year later he complained of increasing blurred vision in the left eye. Clinical examination revealed vesicular alterations located superficially on the intraocular lens (IOL, which could not be removed by perflourocarbon-perflourohexloctane lavage. As the patient complained about increasing visual impairment, the IOL was removed. The IOL was investigated by electronmicroscopy and biochemical analysis. During electron microscopy and following biochemical analysis the observed alterations were identified as calcium-phosphate particles located on the superficial aspect of the IOL. The occurrence of calcium-phosphate deposits on a posterior chamber IOL after silicon oil tamponade is a rare complication and has not been described so far. As these deposits interfere with visual acuity, removal of the lens has to be considered.

  2. 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.

  3. 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

  4. Biomimetic calcium phosphate coating on Ti-7.5Mo alloy for dental application.

    Science.gov (United States)

    Escada, A L A; Machado, J P B; Schneider, S G; Rezende, M C R Alves; Claro, A P R Alves

    2011-11-01

    Titanium and its alloys have been used as bone-replacement implants due to their excellent corrosion resistance and biocompatibility. However, a titanium coating is a bioinert material and cannot bond chemically to bone tissue. The objective of this work was to evaluate the influence of alkaline treatment and heat treatment on the formation of calcium phosphate layer on the surface of a Ti-7.5Mo alloy after soaking in simulated body fluid (SBF). Thirty six titanium alloy plates were assigned into two groups. For group I, samples were immersed in a 5.0-M NaOH aqueous solution at 80°C for 72 h, washed with distilled water and dried at 40°C for 24 h. For group II, after the alkaline treatment, samples were heat-treated at 600°C for 1 h in an electrical furnace in air. Then, all samples were immersed in SBF for 7 or 14 days to allow the formation of a calcium phosphate coating on the surface. The surfaces were characterized using SEM, EDS, AFM and contact angle measurements.

  5. 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.

  6. 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.

  7. 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

  8. The size of surface microstructures as an osteogenic factor in calcium phosphate ceramics.

    Science.gov (United States)

    Zhang, Jingwei; Luo, Xiaoman; Barbieri, Davide; Barradas, Ana M C; de Bruijn, Joost D; van Blitterswijk, Clemens A; Yuan, Huipin

    2014-07-01

    The microporosity of calcium phosphate (CaP) ceramics has been shown to have an essential role in osteoinduction by CaP ceramics after ectopic implantation. Here we show that it is not the microporosity but the size of surface microstructural features that is the most likely osteogenic factor. Two tricalcium phosphate (TCP) ceramics, namely TCP-S and TCP-B, were fabricated with equivalent chemistry and similar microporosity but different sizes of surface microstructural features. TCP-S has a grain size of 0.99 ± 0.20 μm and a micropore size of 0.65 ± 0.25 μm, while TCP-B displays a grain size of 3.08 ± 0.52 μm and a micropore size of 1.58 ± 0.65 μm. In vitro, both cell proliferation and osteogenic differentiation were significantly enhanced when human bone marrow stromal cells were cultured on TCP-S without any osteogenic growth factors, compared to TCP-B ceramic granules. The possible involvement of direct contact between cells and the TCP ceramic surface in osteogenic differentiation is also shown with a trans-well culture model. When the ceramic granules were implanted in paraspinal muscle of dogs for 12 weeks, abundant bone was formed in TCP-S (21 ± 10% bone in the available space), whereas no bone was formed in any of the TCP-B implants. The current in vitro and in vivo data reveal that the readily controllable cue, i.e. the size of the surface microstructure, could be sufficient to induce osteogenic differentiation of mesenchymal stem cells, ultimately leading to ectopic bone formation in calcium phosphate ceramics.

  9. 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.

  10. Basic properties of calcium phosphate cement containing different concentrations of citric acid solution

    Institute of Scientific and Technical Information of China (English)

    戴红莲; 闫玉华; 冯凌云; 李世普; 贺建华

    2002-01-01

    The properties of calcium phosphate cement consisting of α-tricalcium phosphate (α-TCP) and tetracalcium phosphate (TTCP) have been investigated by using a cement liquid that contained citric acid with concentration of 0.05 mol/L or higher. The relationship between the setting time of the system cement and the concentration of citric acid solution shows concave type curve. When solution concentration was 0.2 mol/L, the setting time was 8 min, which was the shortest. While the relationship between 24 h compressive strength of the cement and the citric acid concentration shows convex type curve. When solution concentration was 0.2 mol/L, the compressive strength was 39.0 MPa, which was the highest. Afterwards, the microstructure of the hardening product was observed by SEM, the effect of citric acid on the exothermic rate of hydrate reaction was studied by microcalorimeter, and the crushed specimens were subjected to X-ray diffraction. The results verified that the low citric acid concentration can accelerate the hydrate reaction rate of the α-TCP/TTCP system. However, the high citric acid concentration inhibited hydroxyapatite formation and retarded the rate of hydrate reaction of the α-TCP/TTCP cement.

  11. 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.

  12. Calcium phosphates and glass composite coatings on zirconia for enhanced biocompatibility.

    Science.gov (United States)

    Kim, Hae-Won; Georgiou, George; Knowles, Jonathan C; Koh, Young-Hag; Kim, Hyoun-Ee

    2004-08-01

    Calcium phosphates (CaP) and phosphate-based glass (P-glass, xCaO-(0.55-x) Na(2)O-0.45P(2)O(5) composition) composite coatings were obtained on a strong ZrO(2) to improve biocompatibility, the mechanical strength and biological activity. Hydroxyapatite (HA) and P-glass mixed powder slurries were coated on the ZrO(2) substrate, and subsequently heat-treated to obtain CaP- and P-glass composite coatings. The effects of glass composition (x=0.3, 0.4, 0.5 mol), mixing ratio of glass to HA (30%, 40%, 50% wt/wt), and heat treatment temperature (800 degrees C, 900 degrees C, 1000 degrees C) on the coating properties were investigated. After heat treatment, additional calcium phosphates, i.e., dicalcium phosphate (DCP) and tricalcium phosphate (TCP), were crystallized, resulting in the formation of triphasic calcium phosphates (HA-TCP-DCP) surrounded by a glass phase. The relative amounts of the crystalline phases varied with coating variables. The higher heat treatment temperature and glass amount, and the lower CaO content in the glass composition rendered the composite coatings to retain the higher amounts of TCP and DCP while the initial HA decreased. These appearance of additional crystalline phases and reduction of HA amount were attributed to the combined effects, i.e., the melting-crystallization of P-glass and the reaction between glass liquid phase and HA powder during thermal treatment. As a result of the glass phase in the composite coatings, their microstructures became much denser when compared to the pure HA coating. In particular, a completely dense structure was obtained at coating conditions with large amount of glass addition (50 wt%) at the glass composition of lower CaO content (0.3 mol CaO), and the following heat treatment above 800 degrees C for 2h. As a result, the adhesion strengths of the composite coating layers were significantly improved when compared to the pure HA coating. The highest strength of the composite coating was approximately 40

  13. 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...

  14. 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.

  15. 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.

  16. 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.)

  17. 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...

  18. 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...

  19. Gelation and biocompatibility of injectable alginate-calcium phosphate gels for bone regeneration.

    Science.gov (United States)

    Cardoso, D Alves; van den Beucken, J J J P; Both, L L H; Bender, J; Jansen, J A; Leeuwenburgh, S C G

    2014-03-01

    An emerging approach toward development of injectable, self-setting, and fully biodegradable bone substitutes involves the combination of injectable hydrogel matrices with a dispersed phase consisting of nanosized calcium phosphate particles. Here, novel injectable composites for bone regeneration have been developed based on the combination of ultrapure alginate as the matrix phase, crystalline CaP [monetite and poorly crystalline hydroxyapatite (HA)] powders as both a dispersed mineral phase and a source of calcium for cross-linking alginate, glucono-delta-lactone (GDL) as acidifier and glycerol as both plasticizer and temporary sequestrant. The composites were maximized with respect to CaP content to obtain the highest amount of osteoconductive filler. The viscoelastic and physicochemical properties of the precursor compounds and composites were analyzed using rheometry, elemental analysis (for calcium release and uptake), acidity [by measuring pH in simulated body fluid (SBF)], general biocompatibility (subcutaneous implantation in rabbits), and osteocompatibility (implantation in femoral condyle bone defect of rabbits). The gelation of the resulting composites could be controlled from seconds to tens of minutes by varying the solubility of the CaP phase (HA vs. monetite) or amount of GDL. All composites mineralized extensively in SBF for up to 11 days. In vivo, the composites also disintegrated upon implantation in subcutaneous or bone tissue, leaving behind less degradable but osteoconductive CaP particles. Although the composites need to be optimized with respect to the available amount of calcium for cross-linking of alginate, the beneficial bone response as observed in the in vivo studies render these gels promising for minimally invasive applications as bone-filling material.

  20. 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

  1. 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

  2. The calcium phosphate coating of soy lecithin nanoemulsion with performance in stability and as an oxygen carrier

    Science.gov (United States)

    Han, Kyu B.

    This work studied the relationship between surfactant, oil, and water, by building ternary phase diagrams, the goal of which was to identify the oil-in-water phase composition. The resulting nano-sized emulsion was coated with dicalcium phosphate by utilizing the ionic affinity between calcium ions and the emulsion surface. Since the desired function of the particle is as an oxygen carrier, the particle stability, oxygen capacity, and oxygen release rate were investigated. The first step in the process was to construct ternary phase diagrams with 1,2-dioleoyl-sn-glycero-3-phosphate (DOPA) and soy derived lecithin. The results showed that the lecithin surfactant formed an oil-in-water phase region that was 36 times greater than that of DOPA. With the desired phase composition set, the lecithin emulsion was extruded, resulting in a well-dispersed nanosized particle. A pH titration study of the emulsion found an optimized calcium phosphate coating condition at pH 8.8, at which, the calcium ion had a greater affinity for the emulsion surface than phosphate. A Hill plot was used to show calcium cooperativeness on the emulsion surface which suggested one calcium ion binds to one lecithin molecule. The lecithin emulsion particles were then coated with calcium phosphate using a layering technique that allowed for careful control of the coating thickness. The overall particle hydrodynamic radius was consistent with the growth of the calcium phosphate coating, from 8 nm to 28 nm. This observation was further supported with cryo-TEM measurements. The stability of the coated emulsion was tested in conditions that simulate practical thermal, physical, and time-dependent conditions. Throughout the tests, the coated emulsion exhibited a constant mono-dispersed particle size, while the uncoated emulsion size fluctuated greatly and exhibited increased polydispersion. The fast mixing method with the stopped-flow apparatus was employed to test the product as an oxygen carrier, and it

  3. 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

  4. 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.

  5. 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

  6. 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

  7. Influence of colloidal calcium phosphate level on the microstructure and rheological properties of rennet-induced skim milk gels

    DEFF Research Database (Denmark)

    Koutina, Glykeria; Knudsen, Jes Christian; Andersen, Ulf;

    2015-01-01

    lactose, to obtain varying levels of micellar calcium and phosphorus but constant value of pH, serum and free calcium, and serum phosphorus. Bovine chymosin was added to the skim milk samples after dialysis and microstructural and rheological properties during gel formation were recorded at 30°C. Samples......Colloidal calcium phosphate is an essential part of casein micelles and being responsible for their stability. Different mineralization of casein micelles was obtained by acidification of skim milk to pH 6.5, 6.0 or 5.5, followed by a dialysis method, using simulated milk ultrafiltrate without...

  8. 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.)

  9. 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)

  10. 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)

  11. 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.

  12. UV and X radiation effects on the stability of calcium halide phosphate phosphors. 1

    International Nuclear Information System (INIS)

    Intensity losses of several calcium halide phosphate phosphors have been investigated as a function of the time of irradiation with near UV and X radiation. The results show that antimony-containing foreign phases increase such losses. The directly excited manganese centre emission is much more lowered than the sensitized one. Detrimental effects of the 185 nm UV radiation are observable not only in the first minutes of irradiation but also over considerably extended periods. The sensitization effect caused by irradiation in different gases depends on the phosphor, especially on the content of antimony, and can be explained by the sorption of gaseous impurities at the phosphor surface so that the diffusion of photochemical reaction products from the surface is inhibited

  13. Thermally stimulated luminescence and electron paramagnetic resonance studies of actinide doped calcium chloro phosphate

    International Nuclear Information System (INIS)

    Thermally stimulated luminescence (TSL) and electron paramagnetic resonance (EPR) studies were carried out on samples of calcium chloro phosphate doped individually with UO2+2 and 239Pu4+. TSL glow peak Tmax around 135, 176, 190, 210, 435 and 490 K are observed with samples gamma-irradiated at 77 K. The trap depth and frequency factor for the prominent peaks are determined. EPR studies have revealed the formation of paramagnetic radicals PO2-4; O-; O-2; (ClO)2- and H0 under different conditions. From the spectral characteristics of the TSL glows and the thermal stabilities of the radical ions monitored using EPR the possible mechanism of the TSL glows are proposed. (author). 7 refs., 2 figs., 1 tab

  14. 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...

  15. 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.

  16. 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

  17. 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.

  18. Influence of calcium phosphate nanoparticles, Piriformospora indica and Glomus mosseae on growth of Zea mays

    Science.gov (United States)

    Rane, Mansi; Bawskar, Manisha; Rathod, Dnyaneshwar; Nagaonkar, Dipali; Rai, Mahendra

    2015-12-01

    In this study, the arbuscular mycorrhizal fungus (G. mosseae) and endosymbiont (P. indica) colonized Zea mays were treated with calcium phosphate nanoparticles (CaPNPs) and evaluated for their plant growth promotion efficiency. It was observed that CaPNPs in combination with both G. mosseae and P. indica are more potent plant growth promoter than independent combinations of CaPNPs + G. mosseae, CaPNPs + P. indica or CaPNPs alone. The fluorimetric studies of treated plants revealed that CaPNPs alone and in combination with P. indica can enhance vitality of Zea mays by improving chlorophyll a content and performance index of treated plants. Hence, we conclude that CaPNPs exhibit synergistic growth promotion, root proliferation and vitality improvement properties along with endosymbiotic and arbuscular mycorrhizal fungi, which after further field trials can be developed as a cost-effective nanofertilizer with pronounced efficiency.

  19. Current and Future Theranostic Applications of the Lipid-Calcium-Phosphate Nanoparticle Platform

    Science.gov (United States)

    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 the current theranostic applications for LCP using SPECT and PET, and discusses potential future uses of the platform by comparing it with both systemically and locally delivered clinical radiotherapy options as well as introducing its applications as an MRI contrast agent. Strengths and weaknesses of LCP and of nanoparticles in general are discussed, as well as caveats regarding the use of fluorescence to determine the accumulation or biodistribution of a probe. PMID:27217828

  20. 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

  1. Quantitative microradiographic analysis of remineralization of enamel lesions promoted by casein phosphopeptide amorphous calcium phosphate and fluoride

    International Nuclear Information System (INIS)

    Objective: To evaluate the remineralization effect of casein phosphopeptide amorphous calcium phosphate (CPP-ACP) and fluoride complex on artificial enamel subsurface white spot lesions in vitro in order to provide a new method to treat the postorthodontic enamel demineralization. Methods: Extracted premolar teeth for orthodontic reason were immersed into lactic acid gel to prepare artificial white spot lesions. Then the specimens were randomly assigned to seven groups: 5.0% CPP-ACFP group, 1.0% CPP-ACP group, 0.1% CPP-ACPgroup, calcium phosphate saturated solution group, calcium phosphate saturated solution plus fluorid group, deionized water group. Lesion depths and mineral loss were quantitatively determined by microradiography in various groups. Results: The lesion depths and mineral loss after remineralization in each group were significantly reduced (P0.05), but the lesion depths and mineral loss in these three groups were significantly lower than those in deionized water group (P<0.05, P<0.01). Conclusion: CPP-ACP has the ability of promoting remineralization of enamel artificial white spot lesions which can be enhanced by fluorid. The remineralization ability depends on the concentration of calcium phosphate stabilized by CPP-ACP. (authors)

  2. Long-term survival of calcium phosphate-coated dental implants: a meta-analytical approach to the clinical literature

    NARCIS (Netherlands)

    Oirschot, B.A. van; Bronkhorst, E.M.; Beucken, J.J.J.P van den; Meijer, G.J.; Jansen, J.B.M.J.; Junker, R.

    2013-01-01

    BACKGROUND: Calcium phosphate ceramic coatings have the potential to compensate for challenging bone conditions such as delayed or impaired bone healing and low bone quantity or density. Thus, the increasing universal prevalence of subjects with such challenging bone conditions might be paralleled b

  3. Microstructure and Mechanical Properties of Calcium Phosphate Cement/Gelatine Composite Scaffold with Oriented Pore Structure for Bone Tissue Engineering

    Institute of Scientific and Technical Information of China (English)

    QI Xiaopeng; HE Fupo; YE Jiandong

    2012-01-01

    The macroporous calcium phosphate(CPC) cement with oriented pore structure was prepared by freeze casting.SEM observation showed that the macropores in the porous calcium phosphate cement were interconnected aligned along the ice growth direction.The porosity of the as-prepared porous CPC was measured to be 87.6% by Archimede's principle.XRD patterns of specimens showed that poorly crystallized hydroxyapatite was the main phase present in the hydrated porous calcium phosphate cement.To improve the mechanical properties of the CPC scaffold,the 15% gelatine solution was infiltrated into the pores under vacuum and then the samples were freeze dried to form the CPC/gelatine composite scaffolds.After reinforced with gelatine,the compressive strength of CPC/gelatine composite increased to 5.12 MPa,around fifty times greater than that of the unreinforced macroporous CPC scaffold,which was only 0.1 MPa.And the toughness of the scaffold has been greatly improved via the gelatine reinforcement with a much greater fracture strain.SEM examination of the specimens indicated good bonding between the cement and gelatine.Participating the external load by the deformable gelatine,patching the defects of the CPC pores wall,and crack deflection were supposed to be the reinforcement mechanisms.In conclusion,the calcium phosphate cement/gelatine composite with oriented pore structure prepared in this work might be a potential scaffold for bone tissue engineering.

  4. Calcium-Phosphate-Osteopontin Particles Reduce Biofilm Formation and pH Drops in in situ-Grown Dental Biofilms

    DEFF Research Database (Denmark)

    Schlafer, Sebastian; Ibsen, Casper Jon Steenberg; Birkedal, Henrik;

    2016-01-01

    calcium-phosphate-osteopontin particles or sterile saline. After growth, the amount of biofilm formed was determined by confocal microscopy, and pH drops upon exposure to glucose were monitored using confocal-microscopy-based pH ratiometry. A total of 160 biofilms were analysed. No adverse effects...

  5. Porous poly(DL-lactic-co-glycolic acid)/calcium phosphate cement composite for reconstruction of bone defects.

    NARCIS (Netherlands)

    Ruhe, P.Q.; Hedberg, E.L.; Padron, N.T.; Spauwen, P.H.M.; Jansen, J.A.; Mikos, A.G.

    2006-01-01

    Calcium phosphate (Ca-P) cements are injectable, self-setting ceramic pastes generally known for their favorable bone response. Ingrowth of bone and subsequent degradation rates can be enhanced by the inclusion of macropores. Initial porosity can be induced by CO(2) foaming during setting of the cem

  6. 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

  7. Characterization of nickel-doped biphasic calcium phosphate/graphene nanoplatelet composites for biomedical application

    Energy Technology Data Exchange (ETDEWEB)

    Baradaran, S., E-mail: saeid_baradaran@yahoo.com [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Moghaddam, E. [Tropical Infectious Diseases Research and Education Centre, Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur (Malaysia); Nasiri-Tabrizi, Bahman, E-mail: bahman_nasiri@hotmail.com [Advanced Materials Research Center, Materials Engineering Department, Najafabad Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Basirun, W.J. [Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Institute of Nanotechnology& Catalysis Research (NanoCat), University Malaya, 50603 Kuala Lumpur (Malaysia); Mehrali, M. [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Sookhakian, M. [Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Hamdi, M. [Center of Advanced Manufacturing and Material Processing, University of Malaya, 50603 Kuala Lumpur (Malaysia); Alias, Y. [Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia)

    2015-04-01

    The effect of the addition of an ionic dopant to calcium phosphates for biomedical applications requires specific research due to the essential roles played in such processes. In the present study, the mechanical and biological properties of Ni-doped hydroxyapatite (HA) and Ni-doped HA mixed with graphene nanoplatelets (GNPs) were evaluated. Ni (3 wt.% and 6 wt.%)-doped HA was synthesized using a continuous precipitation method and calcined at 900 °C for 1 h. The GNP (0.5–2 wt.%)-reinforced 6% Ni-doped HA (Ni6) composite was prepared using rotary ball milling for 15 h. The sintering process was performed using hot isostatic pressing at processing conditions of 1150 °C and 160 MPa with a 1-h holding time. The results indicated that the phase compositions and structural features of the products were noticeably affected by the Ni and GNPs. The mechanical properties of Ni6 and 1.5Ni6 were increased by 55% and 75% in hardness, 59% and 163% in fracture toughness and 120% and 85% in elastic modulus compared with monolithic HA, respectively. The in-vitro biological behavior was investigated using h-FOB osteoblast cells in 1, 3 and 5 days of culture. Based on the osteoblast results, the cytotoxicity of the products was indeed affected by the Ni doping. In addition, the effect of GNPs on the growth and proliferation of osteoblast cells was investigated in Ni6 composites containing different ratios of GNPs, where 1.5 wt.% was the optimum value. - Highlights: • Ni doped biphasic calcium phosphate/graphene nanoplatelets composite was investigated. • Mechanical and biological properties were evaluated. • Phase compositions and structural features were influenced noticeably by the Ni and GNPs. • The cytotoxicity of the Ni was improved with the addition of GNPs.

  8. Characterization of nickel-doped biphasic calcium phosphate/graphene nanoplatelet composites for biomedical application

    International Nuclear Information System (INIS)

    The effect of the addition of an ionic dopant to calcium phosphates for biomedical applications requires specific research due to the essential roles played in such processes. In the present study, the mechanical and biological properties of Ni-doped hydroxyapatite (HA) and Ni-doped HA mixed with graphene nanoplatelets (GNPs) were evaluated. Ni (3 wt.% and 6 wt.%)-doped HA was synthesized using a continuous precipitation method and calcined at 900 °C for 1 h. The GNP (0.5–2 wt.%)-reinforced 6% Ni-doped HA (Ni6) composite was prepared using rotary ball milling for 15 h. The sintering process was performed using hot isostatic pressing at processing conditions of 1150 °C and 160 MPa with a 1-h holding time. The results indicated that the phase compositions and structural features of the products were noticeably affected by the Ni and GNPs. The mechanical properties of Ni6 and 1.5Ni6 were increased by 55% and 75% in hardness, 59% and 163% in fracture toughness and 120% and 85% in elastic modulus compared with monolithic HA, respectively. The in-vitro biological behavior was investigated using h-FOB osteoblast cells in 1, 3 and 5 days of culture. Based on the osteoblast results, the cytotoxicity of the products was indeed affected by the Ni doping. In addition, the effect of GNPs on the growth and proliferation of osteoblast cells was investigated in Ni6 composites containing different ratios of GNPs, where 1.5 wt.% was the optimum value. - Highlights: • Ni doped biphasic calcium phosphate/graphene nanoplatelets composite was investigated. • Mechanical and biological properties were evaluated. • Phase compositions and structural features were influenced noticeably by the Ni and GNPs. • The cytotoxicity of the Ni was improved with the addition of GNPs

  9. Development of macroporous calcium phosphate scaffold processed via microwave rapid drying

    International Nuclear Information System (INIS)

    Porous hydroxyapatite (HA) scaffold has great potential in bone tissue engineering applications. A new method to fabricate macroporous calcium phosphate (CP) scaffold via microwave irradiation, followed by conventional sintering to form HA scaffold was developed. Incorporation of trisodium citrate dihydrate and citric acid in the CP mixture gave macroporous scaffolds upon microwave rapid drying. In this work, a mixture of β-tricalcium phosphate (β-TCP), calcium carbonate (CaCO3), trisodium citrate dihydrate, citric acid and double distilled de-ionised water (DDI) was exposed to microwave radiation to form a macroporous structure. Based on gross eye examinations, addition of trisodium citrate at 30 and 40 wt.% in the CP mixture (β-TCP and CaCO3) without citric acid indicates increasing order of pore volume where the highest porosity yield was observed at 40 wt.% of trisodium citrate addition and the pore size was detected at several millimeters. Therefore, optimization of pore size was performed by adding 3-7 wt.% of citric acid in the CP mixture which was separately mixed with 30 and 40 wt.% of trisodium citrate for comparison purposes. Fabricated scaffolds were calcined at 600 deg. C and washed with DDI water to remove the sodium hydroxycarbonate and sintered at 1250 deg. C to form HA phase as confirmed in the X-ray diffraction (XRD) results. Based on Archimedes method, HA scaffolds prepared from 40 wt.% of trisodium citrate with 3-7 wt.% of citric acid added CP mixture have an open and interconnected porous structure ranging from 51 to 53 vol.% and observation using Scanning electron microscope (SEM) showed the pore size distribution between 100 and 500 μm. The cytotoxicity tests revealed that the porous HA scaffolds have no cytotoxic potential on MG63 osteoblast-like cells which might allow for their use as biomaterials.

  10. Mechanical and acid neutralizing properties and bacteria inhibition of amorphous calcium phosphate dental nanocomposite.

    Science.gov (United States)

    Moreau, Jennifer L; Sun, Limin; Chow, Laurence C; Xu, Hockin H K

    2011-07-01

    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 were synthesized via a spray-drying technique and incorporated into a resin. Flexural strength of nanocomposite with 10 to 30% NACP fillers matched the strength of a commercial hybrid composite (p > 0.1). Nanocomposite with 40% NACP matched the strength of a microfill composite, which was 2-fold that of a resin-modified glass ionomer. Nanocomposite with 40% NACP neutralized a lactic acid solution of pH 4 by rapidly increasing the pH to 5.69 in 10 min. In contrast, the commercial controls had pH staying at near 4. Using Streptoccocus mutans, an agar disk-diffusion test showed no inhibition zone for commercial controls. In contrast, the inhibition zone was (2.5 ± 0.7) mm for nanocomposite with 40% NACP. Crystal violet staining showed that S. mutans coverage on nanocomposite was 1/4 that on commercial composite. In conclusion, novel calcium-phosphate nanocomposite matched the mechanical properties of commercial composite and rapidly neutralized lactic acid of pH 4. The nanocomposite appeared to moderately reduce the S. mutans growth, and further study is needed to obtain strong antimicrobial properties. The new nanocomposite may have potential to reduce secondary caries and restoration fracture, two main challenges facing tooth cavity restorations. PMID:21504057

  11. Osteogenic activity of cyclodextrin-encapsulated doxycycline in a calcium phosphate PCL and PLGA composite.

    Science.gov (United States)

    Trajano, V C C; Costa, K J R; Lanza, C R M; Sinisterra, R D; Cortés, M E

    2016-07-01

    Composites of biodegradable polymers and calcium phosphate are bioactive and flexible, and have been proposed for use in tissue engineering and bone regeneration. When associated with the broad-spectrum antibiotic doxycycline (DOX), they could favor antimicrobial action and enhance the action of osteogenic composites. Composites of polycaprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA), and a bioceramic of biphasic calcium phosphate Osteosynt® (BCP) were loaded with DOX encapsulated in β-cyclodextrin (βCD) and were evaluated for effects on osteoblastic cell cultures. The DOX/βCD composite was prepared with a double mixing method. Osteoblast viability was assessed with methyl tetrazolium (MTT) assays after 1day, 7day, and 14days of composite exposure; alkaline phosphatase (AP) activity and collagen production were evaluated after 7days and 14days, and mineral nodule formation after 14days. Composite structures were evaluated by scanning electron microscopy (SEM). Osteoblasts exposed to the composite containing 25μg/mL DOX/βCD had increased cell proliferation (p<0.05) compared to control osteoblast cultures at all experimental time points, reaching a maximum in the second week. AP activity and collagen secretion levels were also elevated in osteoblasts exposed to the DOX/βCD composite (p<0.05 vs. controls) and reached a maximum after 14days. These results were corroborated by Von Kossa test results, which showed strong formation of mineralization nodules during the same time period. SEM of the composite material revealed a surface topography with pore sizes suitable for growing osteoblasts. Together, these results suggest that osteoblasts are viable, proliferative, and osteogenic in the presence of a DOX/βCD-containing BCP ceramic composite. PMID:27127066

  12. Structure-Composition-Property Relationships in Polymeric Amorphous Calcium Phosphate-Based Dental Composites

    Directory of Open Access Journals (Sweden)

    Drago Skrtic

    2009-11-01

    Full Text Available Our studies of amorphous calcium phosphate (ACP-based materials over the last decade have yielded bioactive polymeric composites capable of protecting teeth from demineralization or even regenerating lost tooth mineral. The anti-cariogenic/remineralizing potential of these ACP composites originates from their propensity, when exposed to the oral environment, to release in a sustained manner sufficient levels of mineral-forming calcium and phosphate ions to promote formation of stable apatitic tooth mineral. However, the less than optimal ACP filler/resin matrix cohesion, excessive polymerization shrinkage and water sorption of these experimental materials can adversely affect their physicochemical and mechanical properties, and, ultimately, limit their lifespan. This study demonstrates the effects of chemical structure and composition of the methacrylate monomers used to form the matrix phase of composites on degree of vinyl conversion (DVC and water sorption of both copolymers and composites and the release of mineral ions from the composites. Modification of ACP surface via introducing cations and/or polymers ab initio during filler synthesis failed to yield mechanically improved composites. However, moderate improvement in composite’s mechanical stability without compromising its remineralization potential was achieved by silanization and/or milling of ACP filler. Using ethoxylated bisphenol A dimethacrylate or urethane dimethacrylate as base monomers and adding moderate amounts of hydrophilic 2-hydroxyethyl methacrylate or its isomer ethyl-α-hydroxymethacrylate appears to be a promising route to maximize the remineralizing ability of the filler while maintaining high DVC. Exploration of the structure/composition/property relationships of ACP fillers and polymer matrices is complex but essential for achieving a better understanding of the fundamental mechanisms that govern dissolution/re-precipitation of bioactive ACP fillers, and

  13. VEGF incorporated into calcium phosphate ceramics promotes vascularisation and bone formation in vivo

    Directory of Open Access Journals (Sweden)

    E Wernike

    2010-02-01

    Full Text Available Bone formation and osseointegration of biomaterials are dependent on angiogenesis and vascularization. Angiogenic growth factors such as vascular endothelial growth factor (VEGF were shown to promote biomaterial vascularization and enhance bone formation. However, high local concentrations of VEGF induce the formation of malformed, nonfunctional vessels. We hypothesized that a continuous delivery of low concentrations of VEGF from calcium phosphate ceramics may increase the efficacy of VEGF administration.VEGF was co-precipitated onto biphasic calcium phosphate (BCP ceramics to achieve a sustained release of the growth factor. The co-precipitation efficacy and the release kinetics of the protein were investigated in vitro. For in vivo investigations BCP ceramics were implanted into critical size cranial defects in Balb/c mice. Angiogenesis and microvascularization were investigated over 28 days by means of intravital microscopy. The formation of new bone was determined histomorphometrically. Co-precipitation reduced the burst release of VEGF. Furthermore, a sustained, cell-mediated release of low concentrations of VEGF from BCP ceramics was mediated by resorbing osteoclasts. In vivo, sustained delivery of VEGF achieved by protein co-precipitation promoted biomaterial vascularization, osseointegration, and bone formation. Short-term release of VEGF following superficial adsorption resulted in a temporally restricted promotion of angiogenesis and did not enhance bone formation. The release kinetics of VEGF appears to be an important factor in the promotion of biomaterial vascularization and bone formation. Sustained release of VEGF increased the efficacy of VEGF delivery demonstrating that a prolonged bioavailability of low concentrations of VEGF is beneficial for bone regeneration.

  14. A Comprehensive Study of Osteogenic Calcium Phosphate Silicate Cement: Material Characterization and In Vitro/In Vivo Testing.

    Science.gov (United States)

    Gong, Tianxing; Wang, Zhiqin; Zhang, Yixi; Zhang, Yubiao; Hou, Mingxiao; Liu, Xinwei; Wang, Yu; Zhao, Lejun; Ruse, N Dorin; Troczynski, Tom; Häfeli, Urs O

    2016-02-18

    Vertebral compression fractures can be successfully restored by injectable bone cements. Here the as-yet unexplored in vitro cytotoxicity, in vivo biodegradation, and osteoconductivity of a new calcium phosphate silicate cements (CPSC) are studied, where monocalcium phosphate (MCP; 5, 10, and 15 wt%) is added to calcium silicate cement (CSC). Setting rate and compressive strength of CPSC decrease with the addition of MCP. The crystallinity, microstructure, and porosity of hardened CPSC are evaluated by X-ray diffractometer, Fourier transform infrared spectroscopy, and microcomputed tomography (CT). It is found that MCP reacts with calcium hydroxide, one of CSC hydration products, to precipitate apatite. While the reaction accelerates the hydration of CSC, the formation of calcium silicate hydrate gel is disturbed and highly porous microstructures form, resulting in weaker compressive strength. In vitro studies demonstrate that CPSC is noncytotoxic to osteoblast cells and promotes their proliferation. In the rabbit tibia implantation model, clinical X-ray and CT scans demonstrate that CPSC biodegrades slower and osseointegrates better than clinically used calcium phosphate cement (CPC). Histological studies demonstrate that CPSC is osteoconductive and induces higher bone formation than CPC, a finding that might warrant future clinical studies. PMID:26677175

  15. 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.

  16. Immobilization of heavy metals in sludge using phosphoric acid and monobasic calcium phosphate

    Institute of Scientific and Technical Information of China (English)

    Ping TANG; Yong-chao ZHOU; Zhen-miao XIE

    2013-01-01

    The purpose of this research is to investigate the potential ofpre-treatment with phosphoric acid (PA) and monobasic calcium phosphate (MCP) for the stabilization of heavy metals in sludge and its bottom ash.The tannery sludge samples were collected in Wenzhou,China and heavily contaminated with heavy metals,such as Pb,Cr and so on.The samples were pre-treated with PA or MCP.Then XRD and TCLP tests were adopted as the evaluating methods to characterize the Pb,Cr,Cu,Zn and Cd immobilization in the pre-treated sludge and its bottom ash.The results showed that this treatment effectively immobilized Pb and Cd in the sludge,lightly stabilized the metal Cu,and adversely,enhanced the leachability of Zn.After incineration at 900 ℃,Pb and Cr in the bottom ash of pre-treated sludge were significantly stabilized due to the formation of their highly thermostable phosphates and pyromorphite-like minerals during the incineration process.However,an increase of Cu and Zn solubility was observed which might be attributable to the acidification of sludge due to the addition of PA or MCP.

  17. 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

  18. In situ synthesis of silicon-substituted biphasic calcium phosphate and their performance in vitro

    Science.gov (United States)

    Song, Chang-Weon; Kim, Tae-Wan; Kim, Dong-Hyun; Jin, Hyeong-Ho; Hwang, Kyu-Hong; Lee, Jong Kook; Park, Hong-Chae; Yoon, Seog-Young

    2012-01-01

    In situ preparation of silicon (Si) substituted biphasic calcium phosphate (BCP) of hydroxyapatite (HAp)/ β-tricalcium phosphate (β-TCP) were carried out through aqueous co-precipitation method. The concentrations of added silicon were varied with the phosphor in order to obtain constant Ca/(P+Si) ratios of 1.602. X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy were used to characterize the structure of synthesized silicon substituted BCP powders. The characterization revealed that the formation of biphasic mixtures of different HAp/ β-TCP ratios was dependent on the content of silicon. After immersing in Hanks' balanced salt solution (HBSS) for 1 week, 3 wt% silicon substituted BCP powders were degraded and precipitation started to be formed with small granules consisting of number of flake-like crystal onto the surface of synthesized powders. In the case of 1 wt% silicon substituted BCP powders, the degradation behavior was detected after immersion in HBSS for 3 weeks. On the other hand, silicon unsubtituted BCP powders were not degraded even after that duration. On the basis of these results, silicon substituted BCP is able to develop a new apatite phase on the surface in contact with physiological fluids faster than BCP does. This enhanced reactivity resulted in reduction for the stability of the β-TCP structure due to SiO4 tetrahedral distortion and disorder at the hydroxyl site when silicon incorporates into BCP.

  19. Insights on the properties of levofloxacin-adsorbed Sr- and Mg-doped calcium phosphate powders.

    Science.gov (United States)

    Marques, Catarina F; Matos, Ana C; Ribeiro, Isabel A C; Gonçalves, Lídia M; Bettencourt, Ana; Ferreira, José M F

    2016-07-01

    Several types of biodegradable materials have been investigated for the treatment of osteomyelitis. Calcium phosphate (CaP) ceramics are among the most performing materials due to their resemblance to human hard tissues in terms of mineralogical composition, and proven ability to adsorb and deliver a number of drugs. This research work was intended to study the suitability of modified CaP powders loaded with a fluoroquinolone as drug delivery systems for osteomyelitis treatment. Levofloxacin (LEV) was chosen due to the well-recognized anti-staphylococcal activity and adequate penetration into osteoarticular tissues. Substituted CaP powders (5 mol% Sr(2+) or 5 mol% Mg(2+)) were synthesised through aqueous precipitation. The obtained powders were characterised by X-ray diffraction, SEM and FTIR analysis. The X-ray diffraction patterns confirmed the presence of HA and β-tricalcium phosphates (β-TCP) phases in doped compositions, especially in the case of Mg-doped system. The fixation of LEV at the surface of the particles occurred only by physisorption. Both the in vitro microbiological susceptibility, against Staphylococcus spp, and biocompatibility of LEV-loaded CaP powders have not been compromised. PMID:27300006

  20. Synthesis, characterization, and in-vitro cytocompatibility of amorphous β-tri-calcium magnesium phosphate ceramics.

    Science.gov (United States)

    Singh, Satish S; Roy, Abhijit; Lee, Boeun; Banerjee, Ipsita; Kumta, Prashant N

    2016-10-01

    Biphasic mixtures of crystalline β-tricalcium magnesium phosphate (β-TCMP) and an amorphous calcium magnesium phosphate have been synthesized and reported to support enhanced hMSC differentiation in comparison to β-tricalcium phosphate (β-TCP) due to the release of increased amounts of bioactive ions. In the current study, completely amorphous β-TCMP has been synthesized which is capable of releasing increased amounts of Mg(2+) and PO4(3-) ions, rather than a biphasic mixture as earlier reported. The amorphous phase formed was observed to crystallize between temperatures of 400-600°C. The scaffolds prepared with amorphous β-TCMP were capable of supporting enhanced hMSC proliferation and differentiation in comparison to commercially available β-TCP. However, a similar gene expression of mature osteoblast markers, OCN and COL-1, in comparison to biphasic β-TCMP was observed. To further study the role of Mg(2+) and PO4(3-) ions in regulating hMSC osteogenic differentiation, the capability of hMSCs to mineralize in growth media supplemented with Mg(2+) and PO4(3-) ions was studied. Interestingly, 5mM PO4(3-) supported mineralization while the addition of 5mM Mg(2+) to 5mM PO4(3-) inhibited mineralization. It was therefore concluded that the release of Ca(2+) ions from β-TCMP scaffolds also plays a role in regulating osteogenic differentiation on these scaffolds and it is noted that further work is required to more accurately determine the exact role of Mg(2+) in regulating hMSC osteogenic differentiation. PMID:27287163

  1. Micro-analytical determination of pH, calcium, and phosphate in plaque fluid.

    Science.gov (United States)

    Rankine, C A; Moreno, E C; Vogel, G L; Margolis, H C

    1985-11-01

    Micro-analytical techniques for the determination of calcium, phosphate, and pH in a small volume (less than 0.25 microliter) of plaque fluid are described and evaluated. The accuracy and the precision of the techniques were compared with those for standard macrotechniques applied to a large pooled plaque fluid sample. The results obtained for the micro-analysis of pooled plaque fluid were in excellent agreement with those obtained by macromethods. The described techniques were also used to analyze plaque fluid obtained from single quadrants of the oral cavities of five individuals. In this fashion, it was determined that, although a significant variation in plaque fluid composition exists between the quadrants, a greater variation exists between subjects. Analyses of plaque fluid obtained from six individuals, following sucrose exposure, were also conducted. The pH value of the fluid changed with time, following a typical Stephan curve, with a minimum value occurring between 15 and 30 minutes; following this, the pH increased to a value near that for resting plaque. An inverse relationship between pH and calcium and phosphorus concentrations was observed. It is noted that the described techniques are sensitive enough to carry out the above analyses both accurately and precisely using plaque obtained from a single quadrant. PMID:3867684

  2. Development of calcium phosphate based apatite from hen’s eggshell

    Indian Academy of Sciences (India)

    K Prabakaran; A Balamurugan; S Rajeswari

    2005-04-01

    Stoichiometric hydroxyapatite with Ca/P molar ratio, 1.67, was synthesized using hen’s eggshell as calcium source and phosphoric acid by precipitation method. Conventional EDTA titration and gravimetric methods were adopted to estimate the amount of calcium and phosphorous, respectively. Fourier-transform infrared (FT–IR) and X-ray diffraction (XRD) techniques were employed to investigate the formation of the HAP phase. Thermal analysis (TG–DTA) was carried out to investigate the thermal stability of HAP powder. FT–IR spectra show the characteristic peaks for phosphate and hydroxyl groups. XRD results reveal that the major characteristic peaks of HAP appear in the region of approximately 26°, 28°, 29°, 30–35°, 39°, 46°, 49° and 50° (2) and also indicate that there are no occurrences of secondary phases during HAP formation. TG–DTA result depicts that the synthesized HAP was stable up to 1300°C.

  3. In Vitro Properties of Orthodontic Adhesives with Fluoride or Amorphous Calcium Phosphate

    Directory of Open Access Journals (Sweden)

    Clara Ka Wai Chow

    2011-01-01

    Full Text Available This in vitro study evaluated the efficacy of orthodontic adhesives with fluoride or amorphous calcium phosphate (ACP in reducing bacterial adhesion and enamel demineralization. Forty human premolars each sectioned buccolingually into three parts were bracketed with control resin (Transbond XT or adhesives containing ACP (Aegis Ortho or fluoride (QuickCure. Artificial lesions induced by pH cycling were examined by X-ray photoelectron spectrophotometry (XPS and polarized light microscopy (PLM. After 28 days, Aegis Ortho demonstrated the lowest calcium and phosphorous content by XPS analysis. After 42 days, reductions in lesion depth areas were 23.6% for Quick Cure and 20.3% for Aegis Ortho (P<0.05. In the presence of 1% sucrose, adhesion of Streptococcus mutans to Aegis Ortho and Quick Cure was reduced by 41.8% and 37.7% (P<0.05 as compared to Transbond XT. Composites containing ACP or fluoride reduced bacterial adherence and lesion formation as compared to a composite without ACP or fluoride.

  4. Shear-mediated crystallization from amorphous calcium phosphate to bone apatite.

    Science.gov (United States)

    Niu, Xufeng; Wang, Liyang; Tian, Feng; Wang, Lizhen; Li, Ping; Feng, Qingling; Fan, Yubo

    2016-02-01

    The contribution of fluid shear stress (FSS) on the conversion of amorphous calcium phosphate (ACP) to bone apatite is investigated. The ACP precursors are prepared by using a wet-chemistry method and further exposed to the constant FSS environment with values of 0.5, 1.0, 1.5, and 2.0Pa. At the designated time points, the apatites are characterized by transmission electron microscopy, X-ray diffraction, and inductively coupled plasma-mass spectroscopy. The results show that, the low FSS (≤1.0Pa) has positive effects on the transition of ACP, characterized by the accelerated crystallization velocity and the well-organized calcium-deficient hydroxyapatite (CDHA) structure, whereas the high FSS (>1.0Pa) has negative effects on this conversion process, characterized by the poor CDHA crystal morphologies and the destroyed structures. The bioactivity evaluations further reveal that, compared with the FSS-free group, the CDHA prepared under 1.0Pa FSS for 9h presents the more biocompatible features with pre-osteoblast cells. These results are helpful for understanding the mechanism of apatite deposition in natural bone tissue.

  5. In-situ observation of the transformation of amorphous calcium phosphate to crystalline hydroxyapatite

    Science.gov (United States)

    Stammeier, Jessica; Hippler, Dorothee; Mavromatis, Vasileios; Sacher, Stephan; Dietzel, Martin

    2016-04-01

    Amorphous calcium phosphate (Ca3(PO4)2*nH2O; ACP) is often a precursor phase of the mineral (hydroxy-) apatite (Ca5(PO4)3(OH)) that can be formed in natural settings during both authigenic and biogenic mineral formation. Particularly, in the biomineralization process of fish tissue, ACP has shown to be an important transient phase. In solution ACP rapidly transforms into the crystalline phase. The transformation rate highly depends on the physico-chemical conditions of the solution: Ca & P availability, pH and temperature. In natural settings Ca can be provided by different sources: from (1) seawater, (2) porewater, or (3) diagenetically-altered carbonates, whereas local supersaturation of P can be induced by microbial activity. In this study, we performed phosphate precipitation experiments in order to monitor the transformation process of the ACP to crystalline hydroxyapatite (HAP) using in-situ Raman spectroscopy. During the experiments the temperature was kept constant at 20.0 ± 0.01 ° C and pH at 9 ± 0.1. 50 ml of 0.3 CaCl 2H2O was titrated at a rate of 5 ml/min to an equal volume of 0.2 M Na2HPO4. The pH was kept constant by titration of 1 M NaOH. During the experiment samples were taken from the solution and instantly filtered. The obtained solid samples were lyophilized and analyzed with XRD, ATR and SEM. The respective solution samples were analyzed using ion chromatography and ICP OES, coupling the spectroscopic data with detailed solution chemistry data. We observed transformation of ACP to HAP to occur within 14 hours, illustrated in a clear peak shift in Raman spectra from 950 cm-1 to 960 cm-1. The obtained results are discussed in the aspects of distribution of major elements during the formation of phosphates and/or the diagenetic alteration of carbonates to phosphates in geologic settings. Financial support by DFG-FG 736 and NAWI Graz is kindly acknowledged.

  6. Difference in surface reactions between titanium and zirconium in Hanks' solution to elucidate mechanism of calcium phosphate formation on titanium using XPS and cathodic polarization

    Energy Technology Data Exchange (ETDEWEB)

    Tsutsumi, Y.; Nishimura, D.; Doi, H.; Nomura, N. [Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-surugadai, Chiyoda-ku, Tokyo 101-0062 (Japan); Hanawa, T., E-mail: hanawa.met@tmd.ac.jp [Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-surugadai, Chiyoda-ku, Tokyo 101-0062 (Japan)

    2009-06-01

    Titanium and zirconium were immersed in Hanks' solution with and without calcium and phosphate ions, and the surfaces were characterized with X-ray photoelectron spectroscopy (XPS) to determine the mechanism of calcium phosphate formation on titanium in simulated body fluids and in a living body. In addition, they were cathodically polarized in the above solutions. XPS characterization and cathodic polarization revealed differences in the surface properties in the ability of calcium phosphate formation between titanium and zirconium. The surface oxide film on titanium is not completely oxidized and is relatively reactive; that on zirconium is more passive and protective than that on titanium. Neither calcium nor phosphate stably exists alone on titanium, and calcium phosphate is naturally formed on it; calcium phosphate formed on titanium is stable and protective. On the other hand, calcium is never incorporated on zirconium, while zirconium phosphate, which is easily formed on zirconium, is highly stable and protective. Our study presents new information regarding the surface property of titanium and demonstrates that the characteristics of titanium and zirconium may be applied to various medical devices and new surface modification techniques.

  7. Difference in surface reactions between titanium and zirconium in Hanks' solution to elucidate mechanism of calcium phosphate formation on titanium using XPS and cathodic polarization

    International Nuclear Information System (INIS)

    Titanium and zirconium were immersed in Hanks' solution with and without calcium and phosphate ions, and the surfaces were characterized with X-ray photoelectron spectroscopy (XPS) to determine the mechanism of calcium phosphate formation on titanium in simulated body fluids and in a living body. In addition, they were cathodically polarized in the above solutions. XPS characterization and cathodic polarization revealed differences in the surface properties in the ability of calcium phosphate formation between titanium and zirconium. The surface oxide film on titanium is not completely oxidized and is relatively reactive; that on zirconium is more passive and protective than that on titanium. Neither calcium nor phosphate stably exists alone on titanium, and calcium phosphate is naturally formed on it; calcium phosphate formed on titanium is stable and protective. On the other hand, calcium is never incorporated on zirconium, while zirconium phosphate, which is easily formed on zirconium, is highly stable and protective. Our study presents new information regarding the surface property of titanium and demonstrates that the characteristics of titanium and zirconium may be applied to various medical devices and new surface modification techniques.

  8. Effect of hydroxyapatite, octacalcium phosphate and calcium phosphate on the auto-flocculation of the microalgae in a high-rate algal pond.

    Science.gov (United States)

    Baya, D T; Effebi, K R; Tangou, T T; Keffala, C; Vasel, J L

    2013-01-01

    Recovering microalgae is one of the main technological and economic concerns in a high-rate algal pond (HRAP) because of their small size and their low density. This paper emphasizes the characterization (identification and assessment of potential flocculation) of chemical compounds involved in microalgae auto-flocculation in a HRAP. First, thermodynamic simulations were performed, using two models (i.e. Visual Minteq and a simplified thermodynamic model) in order to determine the chemical compounds of interest. Experimental tests were then carried out with these compounds for assessing their flocculation ability. Both models revealed that precipitates of calcium phosphates and their substituted forms were the compounds involved in the auto-flocculation. Moreover, experimental tests showed that the stoichiometric neutralization of algal charges by calcium phosphates (i.e. hydroxyapatite (Ca5(PO4)3OH), octacalcium phosphate (Ca4H(PO4)3) and amorphous calcium phosphate (Ca3(PO4)2)), at a pH within the range 7-10 yields 70-82% recovered algal biomass. The optimum ratio required for algae auto-flocculation was 0.33 Ca5(PO4)3OH/g DM(algae) at pH 10, 0.11 Ca4H(PO4)3/g DM(algae) at pH 7 and 0.23 g Ca3(PO4)2/g DM(algae) at pH 9. Auto-flocculation appears as a simple, sustainable and promising method for efficient harvesting of microalgae in a HRAP. PMID:24350497

  9. Development of strong and bioactive calcium phosphate cement as a light-cure organic-inorganic hybrid.

    Science.gov (United States)

    Barounian, M; Hesaraki, S; Kazemzadeh, A

    2012-07-01

    In this research, light cured calcium phosphate cements (LCCPCs) were developed by mixing a powder phase (P) consisting of tetracalcium phosphate and dicalcium phosphate and a photo-curable resin phase (L), mixture of hydroxyethylmethacrylate (HEMA)/poly acrylic-maleic acid at various P/L ratios of 2.0, 2.4 and 2.8 g/mL. Mechanical strength, phase composition, chemical groups and microstructure of the cured cements were evaluated at pre-set times, i.e. before and after soaking in simulated body fluid (SBF). The proliferation of Rat-derived osteoblastic cells onto the LCCPCs as well as cytotoxicity of cement extracts were determined by cell counting and 3-{4,5-dimethylthiazol-2yl}-2,5-diphenyl-2H-tetrazolium bromide assay after different culture times. It was estimated from Fourier transforming infrared spectra of cured cements that the setting process is ruled by polymerization of HEMA monomers as well as formation of calcium poly-carboxylate salts. Microstructure of the cured cements consisted of calcium phosphate particles surrounded by polymerized resin phase. Formation of nano-sized needlelike calcium phosphate phase on surfaces of cements with P/L ratios of 2.4 and 2.8 g/mL was confirmed by scanning electron microscope images and X-ray diffractometry (XRD) of the cured specimen soaked in SBF for 21 days. Also, XRD patterns revealed that the formed calcium phosphate layer was apatite phase in a poor crystalline form. Biodegradation of the cements was confirmed by weight loss, change in molecular weight of polymer and morphology of the samples after different soaking periods. The maximum compressive strength of LCCPCs governed by resin polymerization and calcium polycarboxylate salts formation was about 80 MPa for cement with P/L ratio of 2.8 g/mL, after incubation for 24 h. The strength of all cements decreased by decreasing P/L ratio as well as increasing soaking time. The preliminary cell studies revealed that LCCPCs could support proliferation of

  10. Effect of pH and phosphate on calcium carbonate polymorphs precipitated at near-freezing temperature

    OpenAIRE

    Hu, Yu-Bin; Wolthers, Mariëtte; Wolf-Gladrow, Dieter A.; Nehrke, Gernot

    2015-01-01

    The effects of pH and phosphate on the precipitation of calcium carbonate polymorphs from aqueous solution were investigated. Experiments were carried out at near-freezing temperature and two different pH conditions (pH 13.4 and 9.0). At each pH condition, solutions having different concentrations of CaCl2 and NaHCO3 were mixed to achieve Ca/CO3 ratios of 1:1 and 10:1 at different pumping rates with and without phosphate. Results showed that, at pH 13.4, only ikaite wa...

  11. Formation of Calcium-Deficient Hydroxyapatite via Hydrolysis of Nano-Sized Pure Α-Tricalcium Phosphate

    OpenAIRE

    Vecbiškena, L; Gross, K.; Riekstina, U; CK Yang, T

    2015-01-01

    Nano-sized pure α-tricalcium phosphate (α-TCP) fabricated by a novel synthesis approach shows great potential for a faster transformation into calcium-deficient hydroxyapatite (CDHA) than conventionally prepared α-TCP. In this work, amorphous tricalcium phosphate precursors were precipitated and treated with a solvent (water or ethanol), and dried (freeze-dried and oven-dried) before heating at 775 °C. Nano-sized α-TCP powders were investigated for their phase composition and crystallinity...

  12. 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

  13. In vitro surface reaction layer formation and dissolution of calcium phosphate cement-bioactive glass composites

    Energy Technology Data Exchange (ETDEWEB)

    Liu Changsheng [Key Laboratory for Ultrafine Materials of Ministry of Education, and Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Chen, C.-W.; Ducheyne, Paul [Center for Bioactive Materials and Tissue Engineering, Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104 (United States)], E-mail: liucs@ecust.edu.cn, E-mail: ducheyne@seas.upenn.edu

    2008-09-01

    Composites of hydrated calcium phosphate cement (CPC) and bioactive glass (BG) containing Si were immersed in vitro to study the effect of chemical composition on surface reaction layer formation and dissolution/precipitation behavior. The solutions used were 0.05 M tris hydroxymethyl aminomethane/HCl (tris buffer), tris buffer supplemented with plasma electrolyte (TE) with pH 7.4 at 37 deg. C, and this solution complemented with 10% newborn bovine serum (TES). The post-immersion solutions were analyzed for changes in Ca, PO{sub 4} and Si concentrations. The reacted surfaces were analyzed using Fourier transform infrared (FTIR), and scanning electron microscopy with energy dispersive x-ray analysis. The sample weight variations after immersion were also determined. The results showed that the composition of the bioactive composite CPCs greatly affected their behavior in solution and the formation of apatite bioactive surface reaction layers. After immersion in the TE solution, Ca ions were taken up by all samples during the entire immersion duration. Initially, the P ion concentration increased sharply, and then decreased. This reaction pattern reveals the formation of an amorphous calcium phosphate layer on the surface of these composite CPCs. FTIR revealed that the layer was, in fact, poorly crystallized Ca-deficient carbonate apatite. The thickness of the layer was 12-14 {mu}m and it was composed of rod-like apatite with directional arrangement. For immersion in the TES solution, the Ca and Si ion concentrations showed a similar behavior to that in TE, but the release rate of Si ions was higher. FTIR revealed that after TES immersion, not only did the typical, poorly crystallized, Ca-deficient carbonated apatite form, as it did in TE, but also the serum proteins co-adsorbed on the surface and thereby affected the surface reaction layer formation. A thinner apatite layer was formed and was composed of a micro-porous layer comprising rounded particles in a glue

  14. Wollastonite nanofiber–doped self-setting calcium phosphate bioactive cement for bone tissue regeneration

    Directory of Open Access Journals (Sweden)

    Guo H

    2012-07-01

    Full Text Available Han Guo,1,2 Jie Wei,2 Wenhua Song,2 Shan Zhang,2 Yonggang Yan,3 Changsheng Liu,2 Tiqiao Xiao11Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, People's Republic of China; 2Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai, People's Republic of China; 3School of Physical Science and Technology, Sichuan University, Chengdu, People's Republic of ChinaAbstract: The purpose of this study was to synthesize a self-setting bioactive cement by incorporation of wollastonite nanofibers (WNFs into calcium phosphate cement (CPC. The composition, morphology, setting time, compressive strength, hydrophilicity, and degradation of WNF-doped CPC (wnf-CPC were investigated. Scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and inductively coupled plasma atomic emission spectroscopy were utilized. Additionally, methyl-thiazolyl-tetrazolium bromide assay, scanning electron microscopy, inductively coupled plasma atomic emission spectroscopy, and histological evaluation were used to study the cell and tissue responses to wnf-CPC, both in vitro and in vivo. The results confirmed that the addition of WNFs into CPC had no obvious effect on the setting time or the compressive strength of wnf-CPC, provided the WNF amount was not more than 10 wt%. However, the hydrophilicity and degradability of wnf-CPC were significantly improved by the addition of WNFs – this was because of the change of microstructure caused by the WNFs. The preferred dissolution of WNFs caused the formation of microporosity in wnf-CPC when soaked in tris hydrochloride solution. The microporosity enlarged the surface area of the wnf-CPC and so promoted degradation of the wnf-CPC when in contact with liquid. In addition, MG-63 cell attachment and proliferation on the wnf-CPC were superior to that on the CPC, indicating that

  15. The development and characterization of a primarily mineral calcium phosphate - poly(epsilon-caprolactone) biocomposite

    Science.gov (United States)

    Dunkley, Ian Robert

    Orthopaedic reconstruction often involves the surgical introduction of structural implants that provide for rigid fixation, skeletal stabilization, and bone integration. The high stresses incurred by these implanted devices have historically limited material choices to metallic and select polymeric formulations. While mechanical requirements are achieved, these non-degradable materials do not participate actively in the remodeling of the skeleton and present the possibility of long-term failure or rejection. This is particularly relevant in cervical fusion, an orthopaedic procedure to treat damaged, degenerative or diseased intervertebral discs. A significant improvement on the available synthetic bone replacement/regeneration options for implants to treat these conditions in the cervical spine may be achieved with the development of primarily mineral biocomposites comprised of a bioactive ceramic matrix reinforced with a biodegradable polymer. Such a biocomposite may be engineered to possess the clinically required mechanical properties of a particular application, while maintaining the ability to be remodeled completely by the body. A biocomposite of Si-doped calcium phosphate (Si-CaP) and poly(epsilon-caprolactone) (PCL) was developed for application as such a synthetic bone material for potential use as a fusion device in the cervical spine. In this thesis, a method by which high mineral content Si-CaP/PCL biocomposites with interpenetrating matrices of mineral and polymer phases may be prepared will be demonstrated, in addition to the effects of the various preparation parameters on the biocomposite density, porosity and mechanical properties. This new technique by which dense, primarily ceramic Si-CaP/PCL biocomposites were prepared, allowed for the incorporation of mineral contents ranging between 45-97vol%. Polymer infiltration, accomplished solely by passive capillary uptake over several days, was found to be capable of fully infiltrating the microporosity

  16. Dual mode antibacterial activity of ion substituted calcium phosphate nanocarriers for bone infections

    Directory of Open Access Journals (Sweden)

    Sampath Kumar eT.S.

    2015-05-01

    Full Text Available Nanotechnology has tremendous potential for the management of infectious diseases caused by multi-drug resistant (MDR bacteria, through the development of newer antibacterial materials and efficient modes of antibiotic delivery. Calcium phosphate (CaP bioceramics are commonly used as bone substitutes due to their similarity to bone mineral and are widely researched upon for the treatment of bone infections associated with bone loss. CaPs can be used as local antibiotic delivery agents for bone infections and can be substituted with antibacterial ions in their crystal structure to have a wide spectrum, sustained antibacterial activity even against drug resistant bacteria. In the present work, a dual mode antibiotic delivery system with antibacterial ion substituted calcium deficient hydroxyapatite (CDHA nanoparticles has been developed. Antibacterial ions such as zinc, silver and strontium have been incorporated into CDHA at concentrations of 6 at. %, 0.25-0.75 at. % and 2.5-7.5 at. % respectively. The samples were found to be phase pure, acicular nanoparticles of length 40-50 nm and width 5-6 nm approximately. The loading and release profile of doxycycline, a commonly used antibiotic, was studied from the nanocarriers. The drug release was studied for five days and the release profile was influenced by the ion concentrations. The release of antibacterial ions was studied over a period of 21 days. The ion substituted CDHA samples were tested for antibacterial efficacy on S.aureus and E.coli by MIC/MBC studies and time-kill assay. AgCDHA and ZnCDHA showed high antibacterial activity against both bacteria while SrCDHA was weakly active against S.aureus. Present study shows that the antibiotic release can provide the initial high antibacterial activity and the sustained ion release can provide a long-term antibacterial activity. Such dual mode antibiotic and antibacterial ion release offers an efficient and potent way to treat an incumbent drug

  17. CITRIC ACID AS A SET RETARDER FOR CALCIUM ALUMINATE PHOSPHATE CEMENTS.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.; BROTHERS, L.E.

    2005-01-01

    Citric acid added as set retarder significantly contributed to enhancing the setting temperature and to extending the thickening time of a calcium aluminate phosphate (CaP) geothermal cement slurry consisting of calcium aluminate cement (CAC) as the base reactant and sodium polyphosphate (NaP) solution as the acid reactant. The set-retarding activity of citric acid was due to the uptake of Ca{sup 2+} ions from the CAC by carboxylic acid groups within the citric acid. This uptake led to the precipitation of a Ca-complexed carboxylate compound as a set-retarding barrier layer on the CAC grains' surfaces. However, this barrier layer was vulnerable to disintegration by the attack of free Ca{sup 2+} ions from CAC, and also to degradation at elevated temperature, thereby promoting the generation of exothermic energy from acid-base reactions between the CAC and NaP after the barrier was broken. The exothermic reaction energy that was promoted in this way minimized the loss in strength of the citric acid-retarded cement. The phase composition assembled in both retarded and non-retarded cements after autoclaving at 180 C encompassed three reaction products, hydroxyapatite (HOAp), hydrogrossular and boehmite, which are responsible for strengthening the autoclaved cement. The first two reaction products were susceptible to reactions with sulfuric acid and sodium sulfate to form crystalline bassanite scale as the corrosion product. The boehmite phase possessed a great resistance to acid and sulfate. Although the bassanite scales clinging to the cement's surfaces were the major factor governing the loss in weight, they served in protecting the cement from further acid- and sulfate-corrosion until their spallation eventually occurred. Nevertheless, the repetitive processes of HOAp and hydrogrossular {yields} bassanite {yields} spallation played an important role in extending the useful lifetime of CaP cement in a low pH environment at 180 C.

  18. Why Basic Calcium Phosphate Crystals Should Be Targeted In the Treatment of Osteoarthritis

    Directory of Open Access Journals (Sweden)

    Claire-Louise Murphy

    2014-07-01

    Full Text Available Osteoarthritis (OA is the most common form of arthritis and results in significant social, psychological, and economic costs. It is characterised by progressive cartilage loss, bone remodelling, osteophyte formation, and synovial inflammation with resultant joint pain and disability. Since OA affects the entire joint, it is not surprising that there has been difficulty developing an effective targeted treatment. Treatments available for structural disease modification are limited. Current options appear to mostly reduce symptoms. Basic calcium phosphate (BCP crystals represent a potential therapeutic target in OA; they have been found in 100% of knee and hip cartilages removed at joint replacement. Intra-articular BCP crystals are associated with large joint effusions and dissolution of intra-articular structures, synovial proliferation, and marked degeneration as assessed by diagnostic imaging. While BCP deposition has been considered by many to be simply a consequence of advanced OA, there is substantial evidence to support BCP crystal deposition as an active pathogenic mediator of OA. BCP crystals exhibit a multiplicity of biologic effects in vitro including the ability to stimulate mitogenesis and prostaglandin, cytokine, and matrix metalloproteinase (MMP synthesis in a number of cell types including macrophages, synovial fibroblasts, and chondrocytes. BCP crystals also contribute to inflammation in OA through direct interaction with the innate immune system. Intra-articular BCP crystals can elicit synovial inflammation and cartilage degradation in mice in vivo . Although intra-articular BCP crystals are difficult to detect at the bedside, advances in modern technology should allow improved identification and quantitation of BCP crystals. Our article focuses on why basic calcium crystals are important in the pathogenesis of OA. There is ample evidence that BCP crystals should be explored as a therapeutic target in OA.

  19. Molecular dynamics simulation on the interaction mechanism between polymer inhibitors and calcium phosphate

    Indian Academy of Sciences (India)

    Jian-Ping Zeng; Xiao-Rong Qian; Feng-He Wang; Jing-Ling Shao; Yun-Shan Bai

    2014-05-01

    Investigation on the microscopic interaction between polymer inhibitors and calcium phosphate contributes to the understanding of their scale inhibition mechanism. The results obtained may provide a theoretical guidance to developing new scale inhibitors. In this study, molecular dynamics simulations have been performed to simulate the interaction between hydrolyzed polymaleic anhydride (HPMA), polyaspartic acid (PASP), polyepoxysuccinic acid (PESA), polyacrylic acid (PAA) and the (001) and (110) surfaces of hydroxyapatite (HA) crystal with and without water. Results show that the simulations of polymer inhibitors and the (001) surface of HA with water is closer to the actual situation. On the same HA (001), binding energy of four polymer inhibitors with water has the order of HPMA > PASP > PESA > PAA. On the different surface of HA, the binding energy does not vary much between the same polymer and the two surfaces of HA. But, deformation energies of the same polymer with and without water vary widely. Pair correlation function of Ca (HA)-O (-C=O) implies that the Ca-O bonds formed between the calcium atoms of HA crystal and oxygen atoms of the carboxyl groups in polymers, and water molecules change the distances between polymer inhibitors and HA crystal. The system of polymer-HA is mainly contributed by the non-bond interaction. Polymer inhibitors do not interact directly with HA crystal, but indirectly through the interactions between inhibitor-H2O and H2O-HA. Water molecules cannot be ignored when the interaction models are constructed, i.e., solvent effect must be considered.

  20. Postprandial effects of calcium phosphate supplementation on plasma concentration-double-blind, placebo-controlled cross-over human study

    OpenAIRE

    Trautvetter, Ulrike; Kiehntopf, Michael; Jahreis, Gerhard

    2013-01-01

    Background The aim of the present study was to examine the postprandial calcium and phosphate concentrations after supplementation with pentacalcium hydroxy-triphosphate (CaP). Methods Ten men participated in this double-blind, placebo-controlled, cross-over study. The participants were divided into two groups. One group consumed bread enriched with CaP (plus 1 g calcium/d) and the other group a placebo product for three weeks. After a two week wash-out, the intervention was switched between ...

  1. Atomic-scale compositional mapping reveals Mg-rich amorphous calcium phosphate in human dental enamel.

    Science.gov (United States)

    La Fontaine, Alexandre; Zavgorodniy, Alexander; Liu, Howgwei; Zheng, Rongkun; Swain, Michael; Cairney, Julie

    2016-09-01

    Human dental enamel, the hardest tissue in the body, plays a vital role in protecting teeth from wear as a result of daily grinding and chewing as well as from chemical attack. It is well established that the mechanical strength and fatigue resistance of dental enamel are derived from its hierarchical structure, which consists of periodically arranged bundles of hydroxyapatite (HAP) nanowires. However, we do not yet have a full understanding of the in vivo HAP crystallization process that leads to this structure. Mg(2+) ions, which are present in many biological systems, regulate HAP crystallization by stabilizing its precursor, amorphous calcium phosphate (ACP), but their atomic-scale distribution within HAP is unknown. We use atom probe tomography to provide the first direct observations of an intergranular Mg-rich ACP phase between the HAP nanowires in mature human dental enamel. We also observe Mg-rich elongated precipitates and pockets of organic material among the HAP nanowires. These observations support the postclassical theory of amelogenesis (that is, enamel formation) and suggest that decay occurs via dissolution of the intergranular phase. This information is also useful for the development of more accurate models to describe the mechanical behavior of teeth. PMID:27617291

  2. Novel porous calcium aluminate/phosphate nanocomposites: in situ synthesis, microstructure and permeability

    Science.gov (United States)

    Yang, Jingzhou; Hu, Xiaozhi; Huang, Juntong; Chen, Kai; Huang, Zhaohui; Liu, Yangai; Fang, Minghao; Sun, Xudong

    2016-02-01

    Permeable porous nanomaterials have extensive applications in engineering fields. Here, we report a novel system of porous calcium aluminate/phosphate (CaAl-CaP) nanocomposites fabricated by pore generator free processing. The CaAl rich samples have close micropores and are not permeable. Interestingly, the CaP rich composites have a unique three-dimensional nanosieve structure with interconnected nanopores and exhibit excellent liquid permeability and adsorbability. The pore size has a narrow distribution of 200-500 nm. The CaAl nanoplatelets in the CaP rich composite have a thickness of 202 nm, a diameter of 1600 nm and an aspect ratio of 8. The porosity is from 19% to 40%. The bending strength and compressive strength are 40.3 MPa and 195 MPa, respectively. The CaP rich nanocomposite is highly permeable so that a water droplet can completely penetrate in 10 seconds (1 mm thick disk). The blue dye can be desorbed in 45 min by ultrasonic vibration. Given the nanosieve porous structure, good permeability/adsorbability and high mechanical properties, the CaP rich nanocomposite has big potential in applications for chemical engineering, biomedical engineering and energy/environmental engineering.

  3. Axially aligned organic fibers and amorphous calcium phosphate form the claws of a terrestrial isopod (Crustacea).

    Science.gov (United States)

    Vittori, Miloš; Srot, Vesna; Žagar, Kristina; Bussmann, Birgit; van Aken, Peter A; Čeh, Miran; Štrus, Jasna

    2016-08-01

    Skeletal elements that are exposed to heavy mechanical loads may provide important insights into the evolutionary solutions to mechanical challenges. We analyzed the microscopic architecture of dactylus claws in the woodlice Porcellio scaber and correlated these observations with analyses of the claws' mineral composition with energy dispersive X-ray spectrometry (EDX), electron energy loss spectroscopy (EELS) and selected area electron diffraction (SAED). Extraordinarily, amorphous calcium phosphate is the predominant mineral in the claw endocuticle. Unlike the strongly calcified exocuticle of the dactylus base, the claw exocuticle is devoid of mineral and is highly brominated. The architecture of the dactylus claw cuticle is drastically different from that of other parts of the exoskeleton. In contrast to the quasi-isotropic structure with chitin-protein fibers oriented in multiple directions, characteristic of the arthropod exoskeleton, the chitin-protein fibers and mineral components in the endocuticle of P. scaber claws are exclusively axially oriented. Taken together, these characteristics suggest that the claw cuticle is highly structurally anisotropic and fracture resistant and can be explained as adaptations to predominant axial loading of the thin, elongated claws. The nanoscale architecture of the isopod claw may inspire technological solutions in the design of durable machine elements subjected to heavy loading and wear.

  4. Novel porous calcium aluminate/phosphate nanocomposites: in situ synthesis, microstructure and permeability.

    Science.gov (United States)

    Yang, Jingzhou; Hu, Xiaozhi; Huang, Juntong; Chen, Kai; Huang, Zhaohui; Liu, Yangai; Fang, Minghao; Sun, Xudong

    2016-02-14

    Permeable porous nanomaterials have extensive applications in engineering fields. Here, we report a novel system of porous calcium aluminate/phosphate (CaAl-CaP) nanocomposites fabricated by pore generator free processing. The CaAl rich samples have close micropores and are not permeable. Interestingly, the CaP rich composites have a unique three-dimensional nanosieve structure with interconnected nanopores and exhibit excellent liquid permeability and adsorbability. The pore size has a narrow distribution of 200-500 nm. The CaAl nanoplatelets in the CaP rich composite have a thickness of 202 nm, a diameter of 1600 nm and an aspect ratio of 8. The porosity is from 19% to 40%. The bending strength and compressive strength are 40.3 MPa and 195 MPa, respectively. The CaP rich nanocomposite is highly permeable so that a water droplet can completely penetrate in 10 seconds (1 mm thick disk). The blue dye can be desorbed in 45 min by ultrasonic vibration. Given the nanosieve porous structure, good permeability/adsorbability and high mechanical properties, the CaP rich nanocomposite has big potential in applications for chemical engineering, biomedical engineering and energy/environmental engineering. PMID:26805036

  5. Mixed zirconia calcium phosphate coatings for dental implants: tailoring coating stability and bioactivity potential.

    Science.gov (United States)

    Pardun, Karoline; Treccani, Laura; Volkmann, Eike; Streckbein, Philipp; Heiss, Christian; Li Destri, Giovanni; Marletta, Giovanni; Rezwan, Kurosch

    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. PMID:25579931

  6. Solution combustion synthesis of calcium phosphate particles for controlled release of bovine serum albumin

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Junfeng, E-mail: daidai02304@163.com [School of Chemistry and Materials Engineering, Changshu Institute of Technology, Changshu (China); Jiangsu Laboratory of Advanced Functional Materials, Changshu Institute of Technology, Changshu (China); Zhao, Junjie; Qian, Yu; Zhang, Xiali; Zhou, Feifei; Zhang, Hong [School of Chemistry and Materials Engineering, Changshu Institute of Technology, Changshu (China); Lu, Hongbin [National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing (China); Chen, JianHua; Wang, XuHong [School of Chemistry and Materials Engineering, Changshu Institute of Technology, Changshu (China); Jiangsu Laboratory of Advanced Functional Materials, Changshu Institute of Technology, Changshu (China); Yu, Wencong [School of Chemistry and Materials Engineering, Changshu Institute of Technology, Changshu (China)

    2015-05-01

    Four different phase compositions of calcium phosphate (CaP) particles were prepared via a solution combustion method. X-ray diffraction (XRD) and Rietveld analysis results revealed that the variations in the nominal Ca/P (molar) ratios were found to provide a favorable control in the different proportions of CaP materials. Bovine serum albumin (BSA) was used as a model protein to study the loading and release behavior. The release profile indicated that the BSA release rates depended on the phase compositions of the CaP particles, and showed an order of TCP-BSA > BCP-1-BSA > BCP-2-BSA > HA-BSA. The results suggested that the BSA protein release rate can be controlled by varying the phase compositions of CaP carriers. Moreover, the release process involved two stages: firstly surface diffusion via ion exchange and secondly intraparticle diffusion. - Highlights: • Solution combustion method was an efficient way to produced CaP powders. • Ca/P (molar) ratios provided a favorable control in the different proportions of phase composition. • BSA release rate varied depending on the phase composition of the CaP particles. • Two kinetic models were chosen to simulate the release kinetics of the drugs from CaP carriers.

  7. 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

  8. Influence of Calcium Phosphate and Apatite Containing Products on Enamel Erosion

    Directory of Open Access Journals (Sweden)

    A. Kensche

    2016-01-01

    Full Text Available For the purpose of erosion prevention the present study aimed to compare the efficacy of two biomimetic products and a fluoride solution to optimize the protective properties of the pellicle. After 1 min of in situ pellicle formation on bovine enamel slabs, 8 subjects adopted CPP-ACP (GC Tooth Mousse, a mouthwash with hydroxyapatite microclusters (Biorepair, or a fluoride based mouthwash (elmex Kariesschutz for 1 min each. Afterwards, samples were exposed in the oral cavity for 28 min. Native enamel slabs and slabs exposed to the oral cavity for 30 min without any rinse served as controls. After oral exposure, slabs were incubated in HCl (pH values 2, 2.3, and 3 for 120 s and kinetics of calcium and phosphate release were measured photometrically; representative samples were evaluated by SEM and TEM. The physiological pellicle reduced demineralization at all pH values; the protective effect was enhanced by fluoride. The biomimetic materials also reduced ion release but their effect was less pronounced. SEM indicated no layer formation after use of the different products. However, TEM confirmed the potential accumulation of mineral components at the pellicle surface. The tested products improve the protective properties of the in situ pellicle but not as effectively as fluorides.

  9. Microwave assisted synthesis and characterization of magnesium substituted calcium phosphate bioceramics

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Nida Iqbal [Interdisciplinary Research Centre in Biomedical Materials, COMSATS Institute of Information Technology, M. A. Jinnah Campus, Defence Road, Off Raiwind Road, Lahore (Pakistan); Medical Implant Technology Group (MEDITEG), Faculty of Bioscience and Medical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim (Malaysia); Ijaz, Kashif; Zahid, Muniza; Khan, Abdul S. [Interdisciplinary Research Centre in Biomedical Materials, COMSATS Institute of Information Technology, M. A. Jinnah Campus, Defence Road, Off Raiwind Road, Lahore (Pakistan); Abdul Kadir, Mohammed Rafiq [Medical Implant Technology Group (MEDITEG), Faculty of Bioscience and Medical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim (Malaysia); Hussain, Rafaqat [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Skudai, Johore (Malaysia); Anis-ur-Rehman [Department of Physics, COMSATS Institute of Information Technology, Chakshahzad Campus, Islamabad (Pakistan); Darr, Jawwad A. [Clean Materials Technology Group, Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London WC1H 0AJ (United Kingdom); Ihtesham-ur-Rehman [The Kroto Research Institute, North Campus, University of Sheffield, Broad Lane, Sheffield S3 7HQ (United Kingdom); Chaudhry, Aqif A., E-mail: aqifanwar@ciitlahore.edu.pk [Interdisciplinary Research Centre in Biomedical Materials, COMSATS Institute of Information Technology, M. A. Jinnah Campus, Defence Road, Off Raiwind Road, Lahore (Pakistan)

    2015-11-01

    Hydroxyapatite is used extensively in hard tissue repair due to its biocompatibility and similarity to biological apatite, the mineral component of bone. It differs subtly in composition from biological apatite which contains other ions such as magnesium, zinc, carbonate and silicon (believed to play biological roles). Traditional methods of hydroxyapatite synthesis are time consuming and require strict reaction parameter control. This paper outlines synthesis of magnesium substituted hydroxyapatite using simple microwave irradiation of precipitated suspensions. Microwave irradiation resulted in a drastic decrease in ageing times of amorphous apatitic phases. Time taken to synthesize hydroxyapatite (which remained stable upon heat treatment at 900 °C for 1 h) reduced twelve folds (to 2 h) as compared to traditionally required times. The effects of increasing magnesium concentration in the precursors on particle size, surface area, phase-purity, agglomeration and thermal stability, were observed using scanning electron microscopy, BET surface area analysis, X-ray diffraction and photo acoustic Fourier transform infra-red spectroscopy. Porous agglomerates were obtained after a brief heat-treatment (1 h) at 900 °C. - Highlights: • Microwave irradiation of suspensions of calcium phosphates accelerated maturation. • Reactions took 2 h to complete as compared to 18 h required traditionally. • Magnesium contents higher than 1 wt.% lead to the presence of non-apatitic phases. • Agglomerates with micron and sub-micron porosity were obtained after heat-treatment.

  10. Atomic-scale compositional mapping reveals Mg-rich amorphous calcium phosphate in human dental enamel.

    Science.gov (United States)

    La Fontaine, Alexandre; Zavgorodniy, Alexander; Liu, Howgwei; Zheng, Rongkun; Swain, Michael; Cairney, Julie

    2016-09-01

    Human dental enamel, the hardest tissue in the body, plays a vital role in protecting teeth from wear as a result of daily grinding and chewing as well as from chemical attack. It is well established that the mechanical strength and fatigue resistance of dental enamel are derived from its hierarchical structure, which consists of periodically arranged bundles of hydroxyapatite (HAP) nanowires. However, we do not yet have a full understanding of the in vivo HAP crystallization process that leads to this structure. Mg(2+) ions, which are present in many biological systems, regulate HAP crystallization by stabilizing its precursor, amorphous calcium phosphate (ACP), but their atomic-scale distribution within HAP is unknown. We use atom probe tomography to provide the first direct observations of an intergranular Mg-rich ACP phase between the HAP nanowires in mature human dental enamel. We also observe Mg-rich elongated precipitates and pockets of organic material among the HAP nanowires. These observations support the postclassical theory of amelogenesis (that is, enamel formation) and suggest that decay occurs via dissolution of the intergranular phase. This information is also useful for the development of more accurate models to describe the mechanical behavior of teeth.

  11. 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.

  12. Structure and properties of La- and Si-incorporated calcium phosphate coatings

    Science.gov (United States)

    Komarova, E. G.; Chaikina, M. V.; Sedelnikova, M. B.; Sharkeev, Yu. P.

    2016-08-01

    The physical and chemical properties of calcium phosphate coatings deposited by means of the microarc oxidation method in electrolytes based on simultaneously La- and Si-substituted hydroxyapatite with various concentrations of the substituents (Ca10-xLax(PO4)6-y(SiO4)y(OH)2, x = y = 0.2 and 0.5) under different oxidation voltages from 150 to 350 V are investigated. It is shown that with increasing oxidation voltage the coating thickness and surface roughness increase linearly from 20 to 130 μm and from 2 to 8 μm, respectively. It is established that coatings deposited under voltages in the range 150-250 V have an amorphous structure and, as a consequence, a high rate of bioresorption. The increase in the process voltage to 300-350 leads to the formation of the crystalline phases CaHPO4 and β-Ca2P2O7 in coatings. With increasing voltage, the La concentration increases in coatings and the Si concentration remains almost unaltered. In this case, the maximum La and Si amounts in coatings are equal to 0.22 and 0.16 at. %, respectively. An oxidation voltage increase leads to the intensification of the Ca2+ ion deposition from the electrolyte, thus the Ca content increases in the coating composition and the Ca/P ratio grows from 0.26 to 0.58.

  13. Axially aligned organic fibers and amorphous calcium phosphate form the claws of a terrestrial isopod (Crustacea).

    Science.gov (United States)

    Vittori, Miloš; Srot, Vesna; Žagar, Kristina; Bussmann, Birgit; van Aken, Peter A; Čeh, Miran; Štrus, Jasna

    2016-08-01

    Skeletal elements that are exposed to heavy mechanical loads may provide important insights into the evolutionary solutions to mechanical challenges. We analyzed the microscopic architecture of dactylus claws in the woodlice Porcellio scaber and correlated these observations with analyses of the claws' mineral composition with energy dispersive X-ray spectrometry (EDX), electron energy loss spectroscopy (EELS) and selected area electron diffraction (SAED). Extraordinarily, amorphous calcium phosphate is the predominant mineral in the claw endocuticle. Unlike the strongly calcified exocuticle of the dactylus base, the claw exocuticle is devoid of mineral and is highly brominated. The architecture of the dactylus claw cuticle is drastically different from that of other parts of the exoskeleton. In contrast to the quasi-isotropic structure with chitin-protein fibers oriented in multiple directions, characteristic of the arthropod exoskeleton, the chitin-protein fibers and mineral components in the endocuticle of P. scaber claws are exclusively axially oriented. Taken together, these characteristics suggest that the claw cuticle is highly structurally anisotropic and fracture resistant and can be explained as adaptations to predominant axial loading of the thin, elongated claws. The nanoscale architecture of the isopod claw may inspire technological solutions in the design of durable machine elements subjected to heavy loading and wear. PMID:27320700

  14. Bone Tissue Engineering by Using Calcium Phosphate Glass Scaffolds and the Avidin-Biotin Binding System.

    Science.gov (United States)

    Kim, Min-Chul; Hong, Min-Ho; Lee, Byung-Hyun; Choi, Heon-Jin; Ko, Yeong-Mu; Lee, Yong-Keun

    2015-12-01

    Highly porous and interconnected scaffolds were fabricated using calcium phosphate glass (CPG) for bone tissue engineering. An avidin-biotin binding system was used to improve osteoblast-like cell adhesion to the scaffold. The scaffolds had open macro- and micro-scale pores, and continuous struts without cracks or defects. Scaffolds prepared using a mixture (amorphous and crystalline CPG) were stronger than amorphous group and crystalline group. Cell adhesion assays showed that more cells adhered, with increasing cell seeding efficiency to the avidin-adsorbed scaffolds, and that cell attachment to the highly porous scaffolds significantly differed between avidin-adsorbed scaffolds and other scaffolds. Proliferation was also significantly higher for avidin-adsorbed scaffolds. Osteoblastic differentiation of MG-63 cells was observed at 3 days, and MG-63 cells in direct contact with avidin-adsorbed scaffolds were positive for type I collagen, osteopontin, and alkaline phosphatase gene expression. Osteocalcin expression was observed in the avidin-adsorbed scaffolds at 7 days, indicating that cell differentiation in avidin-adsorbed scaffolds occurred faster than the other scaffolds. Thus, these CPG scaffolds have excellent biological properties suitable for use in bone tissue engineering.

  15. Bone healing response to an injectable calcium phosphate cement with enhanced radiopacity.

    Science.gov (United States)

    Acarturk, Oguz; Lehmicke, Michael; Aberman, Harold; Toms, Derek; Hollinger, Jeffrey O; Fulmer, Mark

    2008-07-01

    The aim of this study was to determine the impact of barium sulfate on remodeling and regeneration in standard tibial defects in rabbits treated with the Norian skeletal repair system (SRS). Two formulations of SRS (with and without barium sulfate) were injected into the medullary canal of the tibia of New Zealand white rabbits. Animals were sacrificed at 6 weeks, 6 months, 1 year, and 2 years. Over the 2-year duration of the study, standard SRS and SRS with barium sulfate appeared to be biocompatible and osteoconductive with no evidence of either inflammation or fibrous tissue around the implant materials or at the bone-material interfaces. This outcome underscores the osteophilic property of the SRS. A difference we observed between the standard SRS and the SRS with barium sulfate was the appearance of acellular material contiguous to the SRS with barium sulfate. Energy dispersive X-ray spectroscopy (EDX) analysis was conducted and confirmed that the acellular material was barium sulfate. Pathological examination of additional tissues including regional lymph nodes revealed neither dissemination of calcium phosphate nor barium sulfate. We concluded that the residual barium sulfate detected by EDX was localized to the intramedullary canal of the tibia. PMID:18098201

  16. Interaction Of Calcium Phosphate Nanoparticles With Human Chorionic Gonadotropin Modifies Secondary And Tertiary Protein Structure

    Directory of Open Access Journals (Sweden)

    Al-Hakeim Hussein K

    2015-12-01

    Full Text Available Calcium phosphate nanoparticles (CaPNP have good biocompatibility and bioactivity inside human body. In this study, the interaction between CaPNP and human chorionic gonadotropin (hCG was analyzed to determine the changes in the protein structure in the presence of CaPNP and the quantity of protein adsorbed on the CaPNP surface. The results showed a significant adsorption of hCG on the CaPNP nanoparticle surface. The optimal fit was achieved using the Sips isotherm equation with a maximum adsorption capacity of 68.23 µg/mg. The thermodynamic parameters, including ∆H° and ∆G°, of the adsorption process are positive, whereas ∆S° is negative. The circular dichroism results of the adsorption of hCG on CaPNP showed the changes in its secondary structure; such changes include the decomposition of α-helix strand and the increase in β-pleated sheet and random coil percentages. Fluorescence study indicated minimal changes in the tertiary structure near the microenvironment of the aromatic amino acids such as tyrosine and phenyl alanine caused by the interaction forces between the CaPNP and hCG protein. The desorption process showed that the quantity of the hCG desorbed significantly increases as temperature increases, which indicates the weak forces between hCG and the surface.

  17. Injectable nanoamorphous calcium phosphate based in situ gel systems for the treatment of periapical lesions.

    Science.gov (United States)

    Mostafa, Amany A; Zaazou, Mohamed H; Chow, Laurence C; Mahmoud, Azza A; Zaki, Dalia Y; Basha, Mona; Abdel Hamid, Mohamed A; Khallaf, Maram E; Sharaf, Nehal F; Hamdy, Tamer M

    2015-12-01

    Nonsurgical local treatment of a periapical lesion arising from trauma or bacterial infection is a promising innovative approach. The present study investigated the feasibility of developing injectable amorphous calcium phosphate nanoparticles (ACP NPs) and ACP NPs loaded with an anti-inflammatory drug; ibuprofen (IBU-ACP NPs) in the form of thermoreversible in situ gels to treat periapical lesions with the stimulation of bone formation. NPs were produced by a spray-drying technique. Different formulations of Poloxamer 407 were incorporated with/without the produced NPs to form injectable gels. A drug release study was carried out. A 3 month in vivo test on a dog model also was assessed. Results showed successful incorporation of the drug into the NPs of CP during spray drying. The particles had mean diameters varying from 100 to 200 nm with a narrow distribution. A drug release study demonstrated controlled IBU release from IBU-ACP NPs at a pH of 7.4 over 24 h. The gelation temperature of the injectable in situ gels based on Poloxamer 407 was measured to be 30 °C. After 3 months of implantation in dogs, the results clearly demonstrated that the inclusion of ACP NPs loaded with IBU showed high degrees of periapical bone healing and cementum layer deposition around the apical root tip.

  18. Microwave assisted synthesis and characterization of magnesium substituted calcium phosphate bioceramics

    International Nuclear Information System (INIS)

    Hydroxyapatite is used extensively in hard tissue repair due to its biocompatibility and similarity to biological apatite, the mineral component of bone. It differs subtly in composition from biological apatite which contains other ions such as magnesium, zinc, carbonate and silicon (believed to play biological roles). Traditional methods of hydroxyapatite synthesis are time consuming and require strict reaction parameter control. This paper outlines synthesis of magnesium substituted hydroxyapatite using simple microwave irradiation of precipitated suspensions. Microwave irradiation resulted in a drastic decrease in ageing times of amorphous apatitic phases. Time taken to synthesize hydroxyapatite (which remained stable upon heat treatment at 900 °C for 1 h) reduced twelve folds (to 2 h) as compared to traditionally required times. The effects of increasing magnesium concentration in the precursors on particle size, surface area, phase-purity, agglomeration and thermal stability, were observed using scanning electron microscopy, BET surface area analysis, X-ray diffraction and photo acoustic Fourier transform infra-red spectroscopy. Porous agglomerates were obtained after a brief heat-treatment (1 h) at 900 °C. - Highlights: • Microwave irradiation of suspensions of calcium phosphates accelerated maturation. • Reactions took 2 h to complete as compared to 18 h required traditionally. • Magnesium contents higher than 1 wt.% lead to the presence of non-apatitic phases. • Agglomerates with micron and sub-micron porosity were obtained after heat-treatment

  19. Adhesion failure behavior of sputtered calcium phosphate thin film coatings evaluated using microscratch testing.

    Science.gov (United States)

    Toque, J A; Herliansyah, M K; Hamdi, M; Ide-Ektessabi, A; Sopyan, I

    2010-05-01

    It is generally accepted that calcium phosphate (CaP) is one of the most important biomaterials in implant coating applications mainly because of its excellent bioactivity. However, its relatively poor mechanical properties limits its application. This entails that a better understanding of the mechanical properties of a CaP coating is a must especially its behavior and the mechanisms involved when subjected to stresses which eventually lead to failure. The mechanical properties of the coating may be evaluated in terms of its adhesion strength. In this study, a radio frequency-magnetron (RF-MS) sputtering technique was used to deposit CaP thin films on 316L stainless steel (SS). The coatings were subjected to series of microscratch tests, taking careful note of its behavior as the load is applied. The adhesion behavior of the coatings showed varying responses. It was revealed that several coating process-related factors such as thickness, post-heat treatment and deposition parameters, to name a few, affect its scratching behavior. Scratch testing-related factors (i.e. loading rate, scratch speed, scratch load, etc.) were also shown to influence the mechanisms involved in the coating adhesion failure. Evaluation of the load-displacement graph combined with optical inspection of the scratch confirmed that several modes of failure occurred during the scratching process. These include trackside cracking, tensile cracking, radial cracking, buckling, delamination and combinations of one or more modes.

  20. Enhancement of pedicle screw stability using calcium phosphate cement in osteoporotic vertebrae: in vivo biomechanical study.

    Science.gov (United States)

    Taniwaki, Yoshimichi; Takemasa, Ryuichi; Tani, Toshikazu; Mizobuchi, Hiroo; Yamamoto, Hiroshi

    2003-01-01

    We conducted an experimental study using female beagles with and without ovariectomy-induced osteoporosis to determine the effect of calcium phosphate cement (CPC) on the mechanical stability of inserted pedicle screws. A drill hole was created from the base of the transverse process to the vertebral body; CPC was injected into the hole, and then a screw was inserted into the same hole. In the presence of osteoporosis evidenced by dual X-ray absorptiometry, the stability of the inserted screw augmented by CPC against pull-out and cephalocaudal forces were significantly greater by 28% and 54% at 1 week after operation, 48% and 71% at 2 weeks, and 56% and 68% at 4 weeks compared with those without CPC. The pull-out strength increased progressively with time after surgery, probably reflecting new-bone growth from the surrounding cancellous bone, which was in direct contact with the CPC, as shown in the histologic study. At each time point the cephalocaudal rigidity was similar and the pull-out strength greater than that for the screws inserted without CPC in nonporotic dogs. These findings suggest that CPC augments the stability of the inserted pedicle screws and increases the stiffness of fixed osteoporotic motion segments using instrumentation. PMID:12768486

  1. New depowdering-friendly designs for three-dimensional printing of calcium phosphate bone substitutes.

    Science.gov (United States)

    Butscher, A; Bohner, M; Doebelin, N; Hofmann, S; Müller, R

    2013-11-01

    Powder-based three-dimensional printing (3DP) is a versatile method that allows creating synthetic calcium phosphate (CaP) scaffolds of complex shapes and structures. However, one major drawback is the difficulty of removing all remnants of loose powder from the printed scaffolds, the so-called depowdering step. In this study, a new design approach was proposed to solve this problem. Specifically, the design of the printed scaffolds consisted of a cage with windows large enough to enable depowdering while still trapping loose fillers placed inside the cage. To demonstrate the potential of this new approach, two filler geometries were used: sandglass and cheese segment. The distance between the fillers was varied and they were either glued to the cage or free to move after successful depowdering. Depowdering efficiency was quantified by microstructural morphometry. The results showed that the use of mobile fillers significantly improved depowdering. Based on this study, large 3DP scaffolds can be realized, which might be a step towards a broader clinical use of 3D printed CaP scaffolds.

  2. Enhanced photodynamic therapy efficacy of methylene blue-loaded calcium phosphate nanoparticles.

    Science.gov (United States)

    Seong, Da-Young; Kim, Young-Jin

    2015-05-01

    Although methylene blue (MB) is the most inexpensive photosensitizer with promising applications in the photodynamic therapy (PDT) for its high quantum yield of singlet oxygen generation, the clinical use of MB has been limited by its rapid enzymatic reduction in the biological environment. To enhance PDT efficacy of MB by preventing the enzymatic reduction, we have developed a new mineralization method to produce highly biocompatible MB-loaded calcium phosphate (CaP-MB) nanoparticles in the presence of polymer templates. The resulting CaP-MB nanoparticles exhibited spherical shape with a size of under 50 nm. Fourier transform infrared (FT-IR) and zeta-potential analyses confirmed the insertion of MB into the CaP-MB nanoparticles. The encapsulation of MB in CaP nanoparticles could effectively protect MB from the enzymatic reduction. In addition, the CaP-MB nanoparticles exhibited a good biocompatibility in the dark condition and significantly enhanced PDT efficacy due to apoptotic cell death against human breast cancer cells as compared with free MB, implying that CaP-MB nanoparticle system might be potentially applicable in PDT.

  3. A PLA/calcium phosphate degradable composite material for bone tissue engineering: an in vitro study.

    Science.gov (United States)

    Charles-Harris, Montse; Koch, Martin A; Navarro, Melba; Lacroix, Damien; Engel, Elisabeth; Planell, Josep A

    2008-04-01

    Biodegradable polymers reinforced with an inorganic phase such as calcium phosphate glasses may be a promising approach to fulfil the challenging requirements presented by 3D porous scaffolds for tissue engineering. Scaffolds' success depends mainly on their biological behaviour. This work is aimed to the in vitro study of polylactic acid (PLA)/CaP glass 3D porous constructs for bone regeneration. The scaffolds were elaborated using two different techniques, namely solvent-casting and phase-separation. The effect of scaffolds' micro and macrostructure on the biological response of these scaffolds was assayed. Cell proliferation, differentiation and morphology within the scaffolds were studied. Furthermore, polymer/glass scaffolds were seeded under dynamic conditions in a custom-made perfusion bioreactor. Results indicate that the final architecture of the solvent-cast or phase separated scaffolds have a significant effect on cells' behaviour. Solvent-cast scaffolds seem to be the best candidates for bone tissue engineering. Besides, dynamic seeding yielded a higher seeding efficiency in comparison with the static method. PMID:18266084

  4. 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.

  5. HAp granules encapsulated oxidized alginate-gelatin-biphasic calcium phosphate hydrogel for bone regeneration.

    Science.gov (United States)

    Sarker, Avik; Amirian, Jhaleh; Min, Young Ki; Lee, Byong Taek

    2015-11-01

    Bone repair in the critical size defect zone using 3D hydrogel scaffold is still a challenge in tissue engineering field. A novel type of hydrogel scaffold combining ceramic and polymer materials, therefore, was fabricated to meet this challenge. In this study, oxidized alginate-gelatin-biphasic calcium phosphate (OxAlg-Gel-BCP) and spherical hydroxyapatite (HAp) granules encapsulated OxAlg-Gel-BCP hydrogel complex were fabricated using freeze-drying method. Detailed morphological and material characterizations of OxAlg-Gel-BCP hydrogel (OGB00), 25wt% and 35wt% granules encapsulated hydrogel (OGB25 and OGB35) were carried out for micro-structure, porosity, chemical constituents, and compressive stress analysis. Cell viability, cell attachment, proliferation and differentiation behavior of rat bone marrow-derived stem cell (BMSC) on OGB00, OGB25 and OGB35 scaffolds were confirmed by MTT assay, Live-Dead assay, and confocal imaging in vitro experiments. Finally, OGB00 and OGB25 hydrogel scaffolds were implanted in the critical size defect of rabbit femoral chondyle for 4 and 8 weeks. The micro-CT analysis and histological studies conducted by H&E and Masson's trichrome demonstrated that a significantly higher (***phydrogel than in OxAlg-Gel-BCP complex alone. All results taken together, HAp granules encapsulated OxAlg-Gel-BCP system can be a promising 3D hydrogel scaffold for the healing of a critical bone defect.

  6. Influence of Calcium Phosphate and Apatite Containing Products on Enamel Erosion

    Science.gov (United States)

    Kensche, A.; Pötschke, S.; Hannig, C.; Richter, G.; Hoth-Hannig, W.; Hannig, M.

    2016-01-01

    For the purpose of erosion prevention the present study aimed to compare the efficacy of two biomimetic products and a fluoride solution to optimize the protective properties of the pellicle. After 1 min of in situ pellicle formation on bovine enamel slabs, 8 subjects adopted CPP-ACP (GC Tooth Mousse), a mouthwash with hydroxyapatite microclusters (Biorepair), or a fluoride based mouthwash (elmex Kariesschutz) for 1 min each. Afterwards, samples were exposed in the oral cavity for 28 min. Native enamel slabs and slabs exposed to the oral cavity for 30 min without any rinse served as controls. After oral exposure, slabs were incubated in HCl (pH values 2, 2.3, and 3) for 120 s and kinetics of calcium and phosphate release were measured photometrically; representative samples were evaluated by SEM and TEM. The physiological pellicle reduced demineralization at all pH values; the protective effect was enhanced by fluoride. The biomimetic materials also reduced ion release but their effect was less pronounced. SEM indicated no layer formation after use of the different products. However, TEM confirmed the potential accumulation of mineral components at the pellicle surface. The tested products improve the protective properties of the in situ pellicle but not as effectively as fluorides. PMID:27430013

  7. 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.

  8. Selective extraction of calcium on tri-n-butyl phosphate plasticized selective extraction of calcium on tri-n-butyl phosphate plasticized polyurethane foam for its spectrophotometric determination in glass and ceramics.

    Science.gov (United States)

    Mondal, Jayanta K; Kundu, Dipali

    2005-12-01

    The present paper describes the application of a solid phase extraction system in order to separate traces of calcium from glass and ceramics for its spectrophotometric determination. The method is based on the extraction of calcium from sodium hydroxide solution by tri-n-butyl phosphate (TBP) loaded polyurethane foam (PUF), followed by its elution in hydrochloric acid. The spectrophotometric measurement of the absorbance of calcium complex with calconcarboxylic acid (2-hydroxy-1-(2-hydroxy-4-sulfo-1-naphthylazo)-3-naphthoic acid) takes place at pH 12. The following parameters were studied: effects of sodium hydroxide concentration and temperature on the extraction of calcium, time of equilibration for quantitative calcium extraction, effect of TBP concentration, effect of hydrochloric acid concentration for quantitative elution of calcium from PUF, effect of pH and concentration of calconcarboxylic acid for quantitative formation of the complex with calcium, effect of acetone on the stability of calcium-calconcarboxylic acid complex and influence of diverse ions on calcium sorption by TBP-loaded PUF. The results show that calcium traces can be separated onto TBP-loaded PUF from 0.25 mol L(-1) NaOH at 30 +/- 5 degrees C within 30 min. PUF was loaded with TBP in CCl4 (40% v/v). Elution of calcium was done in 1.0 mol l(-1) HCl. The calcium formed a complex with calconcarboxylic acid at pH 12 and absorbance was measured at 560 nm in acetone-water medium. Molar absorptivity was found to be 1.082 x 10(4) l mol(-1) cm(-1). The method obeys Beer's law from 0.10 to 5.0 microg ml(-1) Ca. The validity of the method was established by its successful application in NIST standard reference materials. The method proposed was applied to determine calcium in glass and ceramic materials. The results of the proposed method are comparable with the results of ICP-AES analysis and they are found to be in good agreement. PMID:16379392

  9. The effect of two types chewing gum containing casein phosphopeptide-amorphous calcium phosphate and xylitol on salivary Streptococcus mutans

    OpenAIRE

    Shila Emamieh; Yosra Khaterizadeh; Hossein Goudarzi; Amir Ghasemi; Alireza Akbarzadeh Baghban; Hasan Torabzadeh

    2015-01-01

    Aim: The aim was to evaluate the effect of sugar-free chewing gum containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and xylitol on salivary Streptococcus mutans. Materials and Methods: A total of 60 dental students of 20-25 years old, who volunteered after checking their health condition and signing an informed consent, were randomly allocated to receive one of the following interventions: (A) Chewing gum containing CPP-ACP; (B) containing xylitol. Subjects within the ...

  10. Low-pressure plasma treatment of polylactide fibers for enhanced mechanical performance of fiber-reinforced calcium phosphate cements

    OpenAIRE

    Canal Barnils, Cristina; Gallinetti, Sara; Ginebra Molins, Maria Pau

    2014-01-01

    Calcium phosphate cements (CPCs) are extensively used as synthetic bone grafts, but their poor mechanical properties limit their applicability to non-stress-bearing applications. The aim of the present work is to evaluate the potential of plasma surface modification of polylactide (PLA) fibers for reinforcement of CPCs. Oxygen low-pressure plasma was employed at different treatment times and the surface properties of the untreated and plasma-treated PLA were evaluated. Plasma treatment on the...

  11. Structural studies of calcium phosphate doped with titanium and zirconium obtained by high-energy mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Silva, C C; Sombra, A S B [Telecommunications and Materials Science and Engineering Laboratory (LOCEM), Physics Department, Federal University of Ceara, Campus do Pii, Postal Code 6030, 60455-760, Fortaleza-Ceara (Brazil)], E-mail: sombra@fisica.ufc.br

    2009-12-15

    In this paper, we present a new variation of the solid-state procedure on the synthesis of bioceramics with titanium (CapTi) and zirconium (CapZr), considering that zirconium (ZrO{sub 2}) and titanium oxide (TiO{sub 2}) are strengthening agents, due to their superb force and fracture toughness. The high efficiency of the calcination process opens a new way of producing commercial amounts of nanocrystalline bioceramics. In this work, a new variation of the solid-state procedure method was used to produce nanocrystalline powders of titanium and zirconium, using two different experimental chemical routes: CapTi: Ca(H{sub 2}PO{sub 4}){sub 2}+TiO{sub 2} and CapZr: Ca(H{sub 2}PO{sub 4}){sub 2}+ZrO{sub 2}. The powders were submitted to calcination processes (CapTic and CapZrc) at 800, 900 and 1000 deg. C. The calcium titanium phosphate phase, CaTi{sub 4}P{sub 6}O{sub 24}, was obtained in the CapTic reaction and the calcium zirconium phosphate, CaZr{sub 4}P{sub 6}O{sub 24}, was obtained in the CapZrc reaction. The obtained ceramics were characterized by x-ray powder diffraction (XRD), infrared (IR) spectroscopy, Raman scattering spectroscopy (RSS) and scanning electron microscopy (SEM) analysis. This method was compared with the milling process (CapTim and CapZrm), where in the last process the melting is not necessary and the powder obtained is nanocrystalline. The calcium titanium phosphate phase, CaTi{sub 4}P{sub 6}O{sub 24}, was obtained in the reaction CapTim, but in CapZrm the formation of any calcium phosphate phase even after 15 h of dry mechanical alloying was not observed.

  12. In vitro study on biomineralization of biphasic calcium phosphate biocomposite crosslinked with hydrolysable tannins of Terminalia chebula

    Indian Academy of Sciences (India)

    G Krithiga; Antaryami Jena; P Selvamani; T P Sastry

    2011-06-01

    In this study, we report the preparation of a bone graft material, having cylindrical shape, containing biphasic calcium phosphate (BCP), gelatin (G), chitosan (C) and Terminalia chebula (TC) extract. TC extract was used as a crosslinker that gives stability to bone graft when it is placed in SBF. The graft was stable in the SBF solution for 21 days and FTIR, SEM, EDX and thermogravimetric studies revealed the ossification of the implant.

  13. Effect of casein phosphopeptide - amorphous calcium phosphate containing chewing gum on salivary concentration of calcium and phosphorus: An in-vivo study

    Directory of Open Access Journals (Sweden)

    B P Santhosh

    2012-01-01

    Full Text Available Aim: Caries clinical trials of sugar-free chewing gum have shown that the gum is noncariogenic and in fact has anticariogenic effect through the stimulation of saliva. Sugar-free gums, therefore, may be an excellent delivery vehicle for safe and effective additive, capable of promoting enamel remineralization. Casein phosphopeptide - amorphous calcium phosphate (CPP-ACP nanocomplexes incorporated into sugar-free chewing gum have shown to remineralize enamel subsurface lesions in situ. So this study was conducted to evaluate the effect of CPP-ACP containing sugar-free chewing gum on salivary concentration of calcium and phosphorous. Materials and Methods : Unstimulated saliva from each 24 selected subjects was collected. Then each subject was given two pellets of chewing gum containing CPP-ACP and asked to chew for a period of 20 min, after which saliva samples were collected from each individual. Once all the samples were collected they were assessed for calcium and phosphorous concentration using affiliated reagent kits and photometer. Statistical Analysis Used: Data obtained were analyzed using student′s paired t test. Results: Significant difference was found in the calcium and phosphorus concentration of saliva before and after chewing CPP-ACP containing chewing gum. Conclusions: Chewing of CPP-ACP containing chewing gum showed a significant increase in the salivary concentration of calcium for a prolonged period of time hence it may help in the remineralization of tooth surfaces.

  14. Production and characterization of setting hydraulic cements based on calcium phosphate; Obtencao e caracterizacao de cimentos de fosfato de calcio de pega hidraulica

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Luci C. de; Rigo, Eliana C.S.; Santos, Luis A dos; Boschi, Anselmo Ortega [Sao Carlos Univ., SP (Brazil). Dept. de Engenharia de Materiais; Carrodeguas, Raul G. [Universidad de La Habana, Habana (Cuba). Centro de Biomateriales

    1997-12-31

    Setting hydraulic cements based on calcium phosphate has risen great interest in scientific literature during recent years due to their total bio compatibility and to the fact that they harden `in situ`, providing easy handling and adaptation to the shape and dimensions of the defect which requires correction, differently from the predecessors, the calcium phosphate ceramics (Hydroxy apatite, {beta}-tri calcium phosphate, biphasic, etc) in the shape of dense or porous blocks and grains. In the work, three calcium-phosphate cement compositions were studied. The resulting compositions were characterized according to the following aspects: setting times, pH, mechanical resistance, crystalline phases, microstructure and solubility in SBF (Simulated Body Fluid). The results show a potential use for the compositions. (author) 6 figs., 4 tabs.

  15. Effectiveness of nano-calcium phosphate paste on sensitivity during and after bleaching: a randomized clinical trial

    Directory of Open Access Journals (Sweden)

    Alessandro Dourado LOGUERCIO

    2015-01-01

    Full Text Available The study aimed to evaluate the effectiveness of in-office bleaching and associated tooth sensitivity on application of nano-calcium phosphate paste as desensitizing agent. Bleaching was performed with 35% hydrogen peroxide gel in 40 patients who were randomly divided into placebo and nano-calcium phosphate paste groups. Bleaching efficacy (BE was evaluated using a value-oriented Vita shade guide. Tooth sensitivity was recorded using a numeric rating scale (0–4 during bleaching and up to 48 h after each session. The primary outcome of absolute risk of tooth sensitivity was compared using the Fisher’s exact test (α = 0.05. The intensity of tooth sensitivity and the efficacy of in-office bleaching were also statistically evaluated. No significant differences in absolute risk and intensity of tooth sensitivity were detected between the groups (p = 1.0 and p = 0.53, respectively. BE was also found to be similar between the groups (p = 0.67. Although the use of a nano-calcium phosphate paste associated with fluoride and potassium nitrate did not influence the whitening outcome, but it also did not reduce bleaching-induced tooth sensitivity.

  16. Formation of interconnected macropores in apatitic calcium phosphate bone cement with the use of an effervescent additive.

    Science.gov (United States)

    Hesaraki, S; Moztarzadeh, F; Sharifi, D

    2007-10-01

    Calcium phosphate cements (CPCs) can be considered as good candidate for bone tissue engineering because they can be resorbed and take part in the bone remodeling process. Several efforts have been made into improve the resorption rate of the calcium phosphate cement by introducing macropores to the cement matrix. In this investigation a simple and effective method has been presented based on the addition of various amounts of an effervescent agent to the calcium phosphate cement components. The effervescent agent was a mixture of sodium hydrogen carbonate, NaHCO(3) (that was added to the powder phase), and citric acid monohydrate, C(6)H(8)O(7).H(2)O (that was dissolved in the liquid phase). The obtained macroporous samples were characterized by Fourier transform infrared spectrometer, X-ray diffraction, and scanning electron microscopy techniques at 4 h after setting and 3 days after soaking in a special simulated body fluid solution named Hank's balanced salt solution. Mercury intrusion porosimetry was also employed for characterizing the pore volume and pore size distribution in the cement structure. Results showed that the rate of conversion of staring reactant to the apatite phase and the apatite chemistry were significantly changed by using the additive in the cement components. Also both the pore volume and pore size were changed by varying both the amount of effervescent additive and the powder to liquid ratio. PMID:17380498

  17. Nicotinic acid adenine dinucleotide phosphate-mediated calcium signalling in effector T cells regulates autoimmunity of the central nervous system

    Science.gov (United States)

    Cordiglieri, Chiara; Odoardi, Francesca; Zhang, Bo; Nebel, Merle; Kawakami, Naoto; Klinkert, Wolfgang E. F.; Lodygin, Dimtri; Lühder, Fred; Breunig, Esther; Schild, Detlev; Ulaganathan, Vijay Kumar; Dornmair, Klaus; Dammermann, Werner; Potter, Barry V. L.; Guse, Andreas H.

    2010-01-01

    Nicotinic acid adenine dinucleotide phosphate represents a newly identified second messenger in T cells involved in antigen receptor-mediated calcium signalling. Its function in vivo is, however, unknown due to the lack of biocompatible inhibitors. Using a recently developed inhibitor, we explored the role of nicotinic acid adenine dinucleotide phosphate in autoreactive effector T cells during experimental autoimmune encephalomyelitis, the animal model for multiple sclerosis. We provide in vitro and in vivo evidence that calcium signalling controlled by nicotinic acid adenine dinucleotide phosphate is relevant for the pathogenic potential of autoimmune effector T cells. Live two photon imaging and molecular analyses revealed that nicotinic acid adenine dinucleotide phosphate signalling regulates T cell motility and re-activation upon arrival in the nervous tissues. Treatment with the nicotinic acid adenine dinucleotide phosphate inhibitor significantly reduced both the number of stable arrests of effector T cells and their invasive capacity. The levels of pro-inflammatory cytokines interferon-gamma and interleukin-17 were strongly diminished. Consecutively, the clinical symptoms of experimental autoimmune encephalomyelitis were ameliorated. In vitro, antigen-triggered T cell proliferation and cytokine production were evenly suppressed. These inhibitory effects were reversible: after wash-out of the nicotinic acid adenine dinucleotide phosphate antagonist, the effector T cells fully regained their functions. The nicotinic acid derivative BZ194 induced this transient state of non-responsiveness specifically in post-activated effector T cells. Naïve and long-lived memory T cells, which express lower levels of the putative nicotinic acid adenine dinucleotide phosphate receptor, type 1 ryanodine receptor, were not targeted. T cell priming and recall responses in vivo were not reduced. These data indicate that the nicotinic acid adenine dinucleotide phosphate/calcium

  18. The fabrication of nanocomposites via calcium phosphate formation on gelatin-chitosan network and the gelatin influence on the properties of biphasic composites

    Energy Technology Data Exchange (ETDEWEB)

    Babaei, Zahra [Nanotechnology Research Institute, School of Chemical Engineering, Babol University of Technology, Babol (Iran, Islamic Republic of); Jahanshahi, Mohsen, E-mail: mjahan@nit.ac.ir [Nanotechnology Research Institute, School of Chemical Engineering, Babol University of Technology, Babol (Iran, Islamic Republic of); Rabiee, Sayed Mahmood [Nanotechnology Research Institute, School of Chemical Engineering, Babol University of Technology, Babol (Iran, Islamic Republic of); School of Mechanical Engineering, Babol University of Technology, Babol (Iran, Islamic Republic of)

    2013-01-01

    A novel biodegradable polymer-ceramic nanocomposite which consisted of gelatin (Gel), chitosan (CS), and calcium phosphate (CaP) nanoparticles was prepared based on in situ preparation method. The fabricated biocomposites were characterized by FTIR, X-ray diffraction (XRD), transmission electron microscopy (TEM) as well as scanning electron microscope with X-ray elemental analysis (SEM-EDX). The characterization results confirmed that the crystalline calcium phosphate nanoparticles were mineralized in polymeric matrix and the interaction between Ca2+ in calcium phosphate and functional groups in polymers molecular chains was formed. XRD result showed that in addition to hydroxyapatite (HA), Brushite (BR) and tricalcium phosphate ({beta}-TCP) particles also were formed due to lack of complete penetration of the basic solution into the polymeric matrix. However, SEM image indicated that the polymeric matrix has the controlling role in the particle size of calcium phosphate. The size of particles in three component composites was about 100 nm while in two component composites proved to be more in {mu}m size. TEM observation supported SEM results and showed that the three component composites have calcium phosphate nanoparticles. The elastic modulus and compressive strength of the composites were also improved by the employment of gelatin and chitosan together, which can make them more beneficial for surgical applications. - Highlights: Black-Right-Pointing-Pointer A new type of calcium phosphate nanocomposites consisted chitosan and gelatin as polymeric matrix was obtained via in situ precipitation method. Black-Right-Pointing-Pointer The formed particles into the polymeric matrix are hydroxyapatite, Brushite and {beta}-tricalcium phosphate. Black-Right-Pointing-Pointer The polymer concentration is a predominant factor for inhibiting nucleation and growth of calcium phosphate particles as the particles size was also decreased by increasing the amount of polymeric

  19. 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

  20. Strontium hydroxyapatite and strontium carbonate as templates for the precipitation of calcium-phosphates in the absence and presence of fluoride

    Science.gov (United States)

    Sternitzke, Vanessa; Janousch, Markus; Heeb, Michèle B.; Hering, Janet G.; Johnson, C. Annette

    2014-06-01

    The heterogeneous precipitation of calcium-phosphates on calcium hydroxyapatite (Ca10(PO4)6(OH)2 or HAP) in the presence and absence of fluoride is important in the formation of bone and teeth, protection against tooth decay, dental and skeletal fluorosis and defluoridation of drinking water. Strontium hydroxyapatite (Sr10(PO4)6(OH)2 or SrHAP) and strontium carbonate (SrCO3) were used as calcium-free seed templates in precipitation experiments conducted with varying initial calcium-to-phosphate (Ca/P) or calcium-to-phosphate-to-fluoride (Ca/P/F) ratios. Suspensions of SrHAP or SrCO3 seed templates (which were calcium-limited for both templates and phosphate-limited in the case of SrCO3) were reacted at pH 7.3 (25 °C) over 3 days. The resulting solids were examined with Scanning Transmission Electron Microscopy (STEM), X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR), and X-ray Photoelectron Spectroscopy (XPS), X-ray Absorption Near Edge Structure (XANES), and Extended X-ray Absorption Fine Structure spectroscopy (EXAFS). Calcium apatite was the predominant phase identified by all techniques independent of the added Ca/P ratios and of the presence of fluoride. It was not possible to make an unambiguous distinction between HAP and fluorapatite (Ca10(PO4)6F2, FAP). The apatite was calcium-deficient and probably contained some strontium.

  1. 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.

  2. Synthesis and Enhanced Phosphate Recovery Property of Porous Calcium Silicate Hydrate Using Polyethyleneglycol as Pore-Generation Agent

    Directory of Open Access Journals (Sweden)

    Ling Pei

    2013-07-01

    Full Text Available The primary objective of this paper was to synthesize a porous calcium silicate hydrate (CSH with enhanced phosphate recovery property using polyethyleneglycol (PEG as pore-generation agent. The formation mechanism of porous CSH was proposed. PEG molecules were inserted into the void region of oxygen–silicon tetrahedron chains and the layers of CSH. A steric hindrance layer was generated to prevent the aggregation of solid particles. A porous structure was formed due to the residual space caused by the removal of PEG through incineration. This porous CSH exhibited highly enhanced solubility of Ca2+ and OH− due to the decreased particle size, declined crystalline, and increased specific surface area (SBET and pore volume. Supersaturation was increased in the wastewater with the enhanced solubility, which was beneficial to the formation of hydroxyapatite (HAP crystallization. Thus, phosphate can be recovered from wastewater by producing HAP using porous CSH as crystal seed. In addition, the regenerated phosphate-containing products (HAP can be reused to achieve sustainable utilization of phosphate. The present research could provide an effective approach for the synthesis of porous CSH and the enhancement of phosphate recovery properties for environmental applications.

  3. In vivo resorption behavior of a high strength injectable calcium-phosphate cement

    Energy Technology Data Exchange (ETDEWEB)

    Wolke, J.G.C.; Ooms, E.M.; Jansen, J.A. [Univ. Medical Center, Nijmegen (Netherlands). Dept. Biomaterials

    2001-07-01

    A high strength calcium-phosphate-cement powder was prepared from a composition comprising of {alpha}-TCP, CaHPO{sub 4} (monetite), CaCO{sub 3} and some seeds of precipitated apatite. An aqueous solution of 4% Na{sub 2}HPO{sub 4} was used as liquid to start the setting reaction. The powder was mixed with cement liquid in three different liquid/powder ratios respectively 0.3, 0.35 and 0.4. Observation of the setting reaction versus time revealed that the maximum of compressive strength was achieved after 3 days reaching the value of 81 MPa. The X-ray diffraction pattern of the Ca-P cement measured 3 days after mixing and storage in Ringer's solution at 37 C showed that the {alpha}-TCP was transformed to hydroxylapatite with superposition of the peaks for monetite. XRD showed that after eight weeks of implantation the monetite peaks had disappeared. Further, the clinical handling properties of all three types of Ca-P cement appeared to be excellent. No problems in setting time or cavity filling were met during the application. The histological evaluation after two weeks of implantation showed abundant bone apposition on the cement surface without inflammatory reaction. At later time points the Ca-P cements were totally covered by a thin layer of bone and osteoclast-like cells in remodeling lacunae at the interface were resorbing the cement. At all implantation periods the PMMA controls showed the presence of a thin fibrous membrane. (orig.)

  4. 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.

  5. 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

  6. Effects of adding resorbable chitosan microspheres to calcium phosphate cements for bone regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Dan [Department of Prosthodontics, Beijing Stomatological Hospital, Capital Medical University, Beijing 100050 (China); Dong, Limin [Beijing Key Lab of Fine Ceramics, Institute of Nuclear and New Energy Technology, Tsinghua University, Energy Science Building, Beijing 100084 (China); Wen, Ying [Department of Prosthodontics, Beijing Stomatological Hospital, Capital Medical University, Beijing 100050 (China); Xie, Qiufei, E-mail: xieqiuf@163.com [Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing 100081 (China)

    2015-02-01

    Calcium phosphate cements (CPCs) have been widely used as bone graft substitutes. However, the undesirable osteoinductivity and slow degradability of CPCs greatly hamper their clinical application. The aim of this study was to synthesize a type of injectable, bioactive cement. This was accomplished by incorporating chitosan microspheres into CPC. CPC containing chitosan microspheres was analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). XRD showed that the hardened chitosan microsphere/CPC with different proportions of microspheres contained diffraction peaks of hydroxyapatite and chitosan. Compressive strength and dissolution in simulated body fluid were measured. The chitosan microsphere/CPC containing 10% (w/w) chitosan microspheres had a compressive strength of 14.78 ± 0.67 MPa. Cavity defects were created in both femoral condylar regions of New Zealand White rabbits. Chitosan microsphere/CPC (composite group) and α-TCP/CPC (control group) were implanted separately into the bone defects of both femurs. X-ray analysis was performed to observe the filling of these bone defects 3 days after surgery. The extent of bone substitute degradation and new bone formation were evaluated by SEM and histological examination at 8, 16, and 24 weeks after implantation. These results showed far more new bone formation and degradation of the chitosan microsphere/CPC composite in the bone defects. These data indicate that a chitosan microsphere/CPC composite might be considered as a promising injectable material for the generation of new bone tissue. - Highlights: • We synthesized an injectable, bioactive chitosan microsphere/CPC for the first time. • 100–400 μm chitosan microspheres were incorporated into the cement solid phase. • XRD showed the construct contained diffraction peaks of hydroxyapatite and chitosan. • Compressive strength of the composite was about 15 MPa comparable to cancellous bone. • The new construct shows better bone

  7. Perfusion electrodeposition of calcium phosphate on additive manufactured titanium scaffolds for bone engineering.

    Science.gov (United States)

    Chai, Yoke Chin; Truscello, Silvia; Bael, Simon Van; Luyten, Frank P; Vleugels, Jozef; Schrooten, Jan

    2011-05-01

    A perfusion electrodeposition (P-ELD) system was reported to functionalize additive manufactured Ti6Al4V scaffolds with a calcium phosphate (CaP) coating in a controlled and reproducible manner. The effects and interactions of four main process parameters - current density (I), deposition time (t), flow rate (f) and process temperature (T) - on the properties of the CaP coating were investigated. The results showed a direct relation between the parameters and the deposited CaP mass, with a significant effect for t (P=0.001) and t-f interaction (P=0.019). Computational fluid dynamic analysis showed a relatively low electrolyte velocity within the struts and a high velocity in the open areas within the P-ELD chamber, which were not influenced by a change in f. This is beneficial for promoting a controlled CaP deposition and hydrogen gas removal. Optimization studies showed that a minimum t of 6 h was needed to obtain complete coating of the scaffold regardless of I, and the thickness was increased by increasing I and t. Energy-dispersive X-ray and X-ray diffraction analysis confirmed the deposition of highly crystalline synthetic carbonated hydroxyapatite under all conditions (Ca/P ratio=1.41). High cell viability and cell-material interactions were demonstrated by in vitro culture of human periosteum derived cells on coated scaffolds. This study showed that P-ELD provides a technological tool to functionalize complex scaffold structures with a biocompatible CaP layer that has controlled and reproducible physicochemical properties suitable for bone engineering.

  8. Efficiency of calcium phosphate composite nanoparticles in targeting Ehrlich carcinoma cells transplanted in mice

    Directory of Open Access Journals (Sweden)

    Eman I. Abdel-Gawad

    2016-01-01

    Full Text Available The present study aimed to investigate the mode of action of nano-CaPs in vivo as a therapy for solid tumor in mice. To achieve this goal, Ehrlich Ascites Carcinoma (EAC was transplanted into 85 Swiss male albino mice. After nine days, the mice were divided into 9 groups. Groups 1 and 2 were allocated as the EAC control. Groups 3 and 4 were injected once intratumorally (IT by nano-calcium phosphate (nano-CaP. Groups 5 and 6 received once intraperitoneal injection (IP of nano-CaP. Groups 7, 8, and 9 received nano-CaP (IP weekly. Blood samples and thigh skeletal muscle were collected after three weeks from groups 1, 3, 5, and 7 and after four weeks from groups 2, 4, 6, and 8. On the other hand, group 9 received nano-CaP (IP for four weeks and lasted for three months to follow up the recurrence of tumor and to ensure the safety of muscle by histopathological analysis. Tumor growth was monitored twice a week throughout the experiment. DNA fragmentation of tumor cells was evaluated. In thigh tissue, noradrenaline, dopamine, serotonin (5HT, and gamma-aminobutyric acid (GABA were measured. In serum, 8-Hydroxy-deoxyguanosine (8-OHDG, adenosine triphosphate (ATP, and vascular endothelial growth factor (VEGF were analyzed. Histopathological and biochemical results showed a significant therapeutic effect of nano-CaP on implanted solid tumor and this effect was more pronounced in the animals treated IP for four weeks. This improvement was evident from the repair of fragmented DNA, the significant decrease of caspase-3, 8-OHDG, myosin, and VEGF, and the significant increase of neurotransmitters (NA, DA, 5HT, and GABA. Additionally, histopathological examination showed complete recovery of cancer cells in the thigh muscle after three months.

  9. Calcium phosphate cement delivering zoledronate decreases bone turnover rate and restores bone architecture in ovariectomized rats.

    Science.gov (United States)

    Wu, Chang-Chin; Wang, Chen-Chie; Lu, Dai-Hua; Hsu, Li-Ho; Yang, Kai-Chiang; Lin, Feng-Huei

    2012-06-01

    Patients sustaining bony fractures frequently require the application of bone graft substitutes to fill the bone defects. In the meantime, anti-osteoporosis drugs may be added in bone fillers to treat osteoporosis, especially in postmenopausal women and the elderly. The effects of zoledronate-impregnated calcium phosphate cement (ZLN/CPC) on ovariectomized (OVX) rats were evaluated. OVX rats were implanted with ZLN/CPC, containing 0.025 mg ZLN in the greater omentum. Afterward the clinical sign of toxicity was recorded for eight weeks. The rats were sacrificed and blood samples were collected for hematology and serum bone turnover markers analyses. The four limbs of the rats were harvested and micro-computer tomography (micro-CT) scanning and bone ash analyses were performed. No clinical toxicity was observed in the treated rats. Compared to the OVX rats, levels of bone resorption markers (fragments of C-telopeptides of type I collagen) and bone formation markers (alkaline phosphatase and osteocalcin) decreased significantly in the treated rats. Osteopontin, which mediates the anchoring of osteoclasts to the mineral matrix of bones, also decreased significantly. Micro-CT scanning and histologic examinations of the distal femoral metaphyses showed that the cancellous bone architectures were restored, with a concomitant decrease in bone porosity. The bone mineral content in the bone ashes also increased significantly. This study indicates that ZLN-impregnated CPC reduces bone turnover rate and restores bone architecture in OVX rats. CPC may be an appropriate carrier to deliver drugs to treat osteoporosis, and this approach may also reduce rates of post-dosing symptoms for intravenous ZLN delivery.

  10. Porogen-based solid freeform fabrication of polycaprolactone-calcium phosphate scaffolds for tissue engineering.

    Science.gov (United States)

    Mondrinos, Mark J; Dembzynski, Robert; Lu, Lin; Byrapogu, Venkata K C; Wootton, David M; Lelkes, Peter I; Zhou, Jack

    2006-09-01

    Drop on demand printing (DDP) is a solid freeform fabrication (SFF) technique capable of generating microscale physical features required for tissue engineering scaffolds. Here, we report results toward the development of a reproducible manufacturing process for tissue engineering scaffolds based on injectable porogens fabricated by DDP. Thermoplastic porogens were designed using Pro/Engineer and fabricated with a commercially available DDP machine. Scaffolds composed of either pure polycaprolactone (PCL) or homogeneous composites of PCL and calcium phosphate (CaP, 10% or 20% w/w) were subsequently fabricated by injection molding of molten polymer-ceramic composites, followed by porogen dissolution with ethanol. Scaffold pore sizes, as small as 200 microm, were attainable using the indirect (porogen-based) method. Scaffold structure and porosity were analyzed by scanning electron microscopy (SEM) and microcomputed tomography, respectively. We characterized the compressive strength of 90:10 and 80:20 PCL-CaP composite materials (19.5+/-1.4 and 24.8+/-1.3 Mpa, respectively) according to ASTM standards, as well as pure PCL scaffolds (2.77+/-0.26 MPa) fabricated using our process. Human embryonic palatal mesenchymal (HEPM) cells attached and proliferated on all scaffolds, as evidenced by fluorescent nuclear staining with Hoechst 33258 and the Alamar Blue assay, with increased proliferation observed on 80:20 PCL-CaP scaffolds. SEM revealed multilayer assembly of HEPM cells on 80:20 PCL-CaP composite, but not pure PCL, scaffolds. In summary, we have developed an SFF-based injection molding process for the fabrication of PCL and PCL-CaP scaffolds that display in vitro cytocompatibility and suitable mechanical properties for hard tissue repair. PMID:16678255

  11. Electrospun gelatin/poly(ε-caprolactone) fibrous scaffold modified with calcium phosphate for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Rajzer, Izabella, E-mail: irajzer@ath.bielsko.pl [University of Bielsko-Biala (ATH), Department of Mechanical Engineering Fundamentals, Division of Materials Engineering, Willowa 2 Street, 43-309 Bielsko-Biała (Poland); Menaszek, Elżbieta [Jagiellonian University (UJ), Collegium Medicum, Department of Cytobiology, Medyczna 9 Street, 30-068 Cracow (Poland); Kwiatkowski, Ryszard [University of Bielsko-Biala (ATH), Faculty of Materials and Environmental Sciences, Institute of Textile Engineering and Polymer Materials, Willowa 2 Street, 43-309 Bielsko-Biała (Poland); Planell, Josep A.; Castano, Oscar [Institute for Bioengineering of Catalonia (IBEC), Biomaterials for Regenerative Therapies, Baldiri Reixac 15-21, 08028 Barcelona (Spain); Polytechnic University of Catalonia (UPC), Diagonal 647, 08028 Barcelona (Spain); CIBER-BBN The Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine, Barcelona (Spain)

    2014-11-01

    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), Fourier transform infrared spectroscopy (FTIR) and the wide angle X-ray diffraction (WAXD) measurements confirmed that SG5 nanoparticles were successfully incorporated into the fibrous gelatin matrix. The composite Gel/SG5/PCL scaffold exhibited more enhanced mechanical properties than individual Gel and Gel/SG5 scaffolds. The presence of SG5 nanoparticles accelerated the nucleation and growth of apatite crystals on the surface of the composite Gel/SG5/PCL scaffold in simulated body fluid (SBF). The osteoblast response in vitro to developed electrospun scaffolds (PCL and Gel/SG5/PCL) was investigated by using normal human primary NHOst cell lines. NHOst cell culture studies showed that higher alkaline phosphatase (ALP) activity and better mineralization were obtained in the case of composite materials than in pure PCL scaffolds. The mechanically strong PCL scaffold served as a skeleton, while the Gel/SG5 fibers facilitated cell spreading and mineralization of the scaffold. - Highlights: • Bi-layer scaffolds were produced by electrospinning method. • The addition of nanoparticles enhanced the bioactivity of scaffold. • Bi-layer scaffold enhanced ALP activity and NHOst cell mineralization.

  12. Directed osteogenic differentiation of human mesenchymal stem/precursor cells on silicate substituted calcium phosphate.

    Science.gov (United States)

    Cameron, Kate; Travers, Paul; Chander, Chaman; Buckland, Tom; Campion, Charlie; Noble, Brendon

    2013-01-01

    Insufficient, underactive, or inappropriate osteoblast function results in serious clinical conditions such as osteoporosis, osteogenesis imperfecta and fracture nonunion and therefore the control of osteogenesis is a medical priority. In vitro mesenchymal stem cells (MSCs) can be directed to form osteoblasts through the addition of soluble factors such as β-glycerophosphate, ascorbic acid, and dexamethasone; however this is unlikely to be practical in the clinical setting. An alternative approach would be to use a scaffold or matrix engineered to provide cues for differentiation without the need for soluble factors. Here we describe studies using Silicate-substituted calcium phosphate (Si-CaP) and unmodified hydroxyapatite (HA) to test whether these materials are capable of promoting osteogenic differentiation of MSCs in the absence of soluble factors. Si-CaP supported attachment and proliferation of MSCs and induced osteogenesis to a greater extent than HA, as evidenced through upregulation of the osteoblast-related genes: Runx2 (1.2 fold), Col1a1 (2 fold), Pth1r (1.5 fold), and Bglap (1.7 fold) Dmp1 (1.1 fold), respectively. Osteogenic-associated proteins, alkaline phosphatase (1.4 fold), RUNX2, COL1A1, and BGLAP, were also upregulated and there was an increased production of mineralized bone matrix (1.75 fold), as detected by the Von Kossa Assay. These data indicate that inorganic substrates are capable of directing the differentiation programme of stem cells in the absence of known chemical drivers and therefore may provide the basis for bone repair in the clinical setting.

  13. Calcium phosphate cement delivering zoledronate decreases bone turnover rate and restores bone architecture in ovariectomized rats

    International Nuclear Information System (INIS)

    Patients sustaining bony fractures frequently require the application of bone graft substitutes to fill the bone defects. In the meantime, anti-osteoporosis drugs may be added in bone fillers to treat osteoporosis, especially in postmenopausal women and the elderly. The effects of zoledronate-impregnated calcium phosphate cement (ZLN/CPC) on ovariectomized (OVX) rats were evaluated. OVX rats were implanted with ZLN/CPC, containing 0.025 mg ZLN in the greater omentum. Afterward the clinical sign of toxicity was recorded for eight weeks. The rats were sacrificed and blood samples were collected for hematology and serum bone turnover markers analyses. The four limbs of the rats were harvested and micro-computer tomography (micro-CT) scanning and bone ash analyses were performed. No clinical toxicity was observed in the treated rats. Compared to the OVX rats, levels of bone resorption markers (fragments of C-telopeptides of type I collagen) and bone formation markers (alkaline phosphatase and osteocalcin) decreased significantly in the treated rats. Osteopontin, which mediates the anchoring of osteoclasts to the mineral matrix of bones, also decreased significantly. Micro-CT scanning and histologic examinations of the distal femoral metaphyses showed that the cancellous bone architectures were restored, with a concomitant decrease in bone porosity. The bone mineral content in the bone ashes also increased significantly. This study indicates that ZLN-impregnated CPC reduces bone turnover rate and restores bone architecture in OVX rats. CPC may be an appropriate carrier to deliver drugs to treat osteoporosis, and this approach may also reduce rates of post-dosing symptoms for intravenous ZLN delivery. (paper)

  14. Tissue-engineered calcium phosphate cement in rabbit femoral condylar bone defects

    Institute of Scientific and Technical Information of China (English)

    LIU Chun-rong; MIAO Jun; XIA Qun; HUANG Hong-chao; GONG Chen; YANG Qiang; LI Lan-ying

    2012-01-01

    Background Calcium phosphate cement (CPC) is a favorable bone-graft substitute,with excellent biocompatibility and osteoconductivity.However,its reduced osteoinductive ability may limit the utility of CPC.To increase its osteoinductive potential,this study aimed to prepare tissue-engineered CPC and evaluate its use in the repair of bone defects.The fate of transplanted seed cells in vivo was observed at the same time.Methods Tissue-engineered CPC was prepared by seeding CPC with encapsulated bone mesenchymal stem cells (BMSCs) expressing recombinant human bone morphogenetic protein-2 (rhBMP-2) and green fluorescent protein (GFP).Tissue-engineered CPC and pure CPC were implanted into rabbit femoral condyle bone defects respectively.Twelve weeks later,radiographs,morphological observations,histomorphometrical evaluations,and in vivo tracing were performed.Results The radiographs revealed better absorption and faster new bone formation for tissue-engineered CPC than pure CPC.Morphological and histomorphometrical evaluations indicated that tissue-engineered CPC separated into numerous small blocks,with active absorption and recorstruction noted,whereas the residual CPC area was larger in the group treated with pure CPC.In the tissue-engineered CPC group,in vivo tracing revealed numerous cells expressing both GFP and rhBMP-2 that were distributed in the medullar cavity and on the surface of bony trabeculae.Conclusion Tissue-engineered CPC can effectively repair bone defects,with allogenic seeded cells able to grow and differentiate in vivo after transplantation.

  15. Calcium Phosphate Scaffolds Combined with Bone Morphogenetic Proteins or Mesenchymal Stem Cells in Bone Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Han Sun

    2015-01-01

    Full Text Available Objective: The purpose of this study was to review the current status of calcium phosphate (CaP scaffolds combined with bone morphogenetic proteins (BMPs or mesenchymal stem cells (MSCs in the field of bone tissue engineering (BTE. Date Sources: Data cited in this review were obtained primarily from PubMed and Medline in publications from 1979 to 2014, with highly regarded older publications also included. The terms BTE, CaP, BMPs, and MSC were used for the literature search. Study Selection: Reviews focused on relevant aspects and original articles reporting in vitro and/or in vivo results concerning the efficiency of CaP/BMPs or CaP/MSCs composites were retrieved, reviewed, analyzed, and summarized. Results: An ideal BTE product contains three elements: Scaffold, growth factors, and stem cells. CaP-based scaffolds are popular because of their outstanding biocompatibility, bioactivity, and osteoconductivity. However, they lack stiffness and osteoinductivity. To solve this problem, composite scaffolds of CaP with BMPs have been developed. New bone formation by CaP/BMP composites can reach levels similar to those of autografts. CaP scaffolds are compatible with MSCs and CaP/MSC composites exhibit excellent osteogenesis and stiffness. In addition, a CaP/MSC/BMP scaffold can repair bone defects more effectively than an autograft. Conclusions: Novel BTE products possess remarkable osteoconduction and osteoinduction capacities, and exhibit balanced degradation with osteogenesis. Further work should yield safe, viable, and efficient materials for the repair of bone lesions.

  16. Vascularization of plastic calcium phosphate cement in vivo induced by in-situ-generated hollow channels.

    Science.gov (United States)

    Yu, Tao; Dong, Chao; Shen, Zhonghua; Chen, Yan; Yu, Bo; Shi, Haishan; Zhou, Changren; Ye, Jiandong

    2016-11-01

    Despite calcium phosphate cement (CPC) is promising for bone repair therapy, slow biodegradation and insufficient vascularization in constructs negatively impacts its clinical application. A self-setting CPC composited with gelatin fiber is investigated to test the utility of this tissue engineering strategy to support rapid and extensive vascularization process. The interconnected hollow channels in CPC are formed after dissolution of gelatin fibers in vivo. The CPC-gelatin samples exhibit relatively decent/enhanced mechanical property, compared to the control. When implanted in vivo, the pre-established vascular networks in material anastomose with host vessels and accelerate vascular infiltration throughout the whole tissue construct. Different channel sizes induce different vascularization behaviors in vivo. Results indicate that the channel with the size of 250μm increases the expression of the representative angiogenic factors HIF1α, PLGF and migration factor CXCR4, which benefit the formation of small vessels. On the other hand, the channel with the size of 500μm enhances VEGF-A expression, which benefit the development of large vessels. Notably, the intersection area of channels has high invasive, sprouting and vasculogenesis potential under hypoxic condition, because more HIF1α-positive cells are observed there. Observation of the CD31-positive lumen in the border of scaffold indicates the ingrowth of blood vessels from its host into material through channel, benefited from gradually increased HIF1α expression. This kind of material was suggested to promote the effective application of bone regeneration through the combination of in situ self-setting, plasticity, angiogenesis, and osteoconductivity. PMID:27524007

  17. Calcium Phosphate Scaffolds Combined with Bone Morphogenetic Proteins or Mesenchymal Stem Cells in Bone Tissue Engineering

    Institute of Scientific and Technical Information of China (English)

    Han Sun; Hui-Lin Yang

    2015-01-01

    Objective:The purpose of this study was to review the current status of calcium phosphate (CaP) scaffolds combined with bone morphogenetic proteins (BMPs) or mesenchymal stem cells (MSCs) in the field of bone tissue engineering (BTE).Date Sources:Data cited in this review were obtained primarily from PubMed and Medline in publications from 1979 to 2014,with highly regarded older publications also included.The terms BTE,CaP,BMPs,and MSC were used for the literature search.Study Selection:Reviews focused on relevant aspects and original articles reporting in vitro and/or in vivo results concerning the efficiency of CaP/BMPs or CaP/MSCs composites were retrieved,reviewed,analyzed,and summarized.Results:An ideal BTE product contains three elements:Scaffold,growth factors,and stem cells.CaP-based scaffolds are popular because of their outstanding biocompatibility,bioactivity,and osteoconductivity.However,they lack stiffness and osteoinductivity.To solve this problem,composite scaffolds of CaP with BMPs have been developed.New bone formation by CaP/BMP composites can reach levels similar to those of autografts.CaP scaffolds are compatible with MSCs and CaP/MSC composites exhibit excellent osteogenesis and stiffness.In addition,a CaP/MSC/BMP scaffold can repair bone defects more effectively than an autograft.Conclusions:Novel BTE products possess remarkable osteoconduction and osteoinduction capacities,and exhibit balanced degradation with osteogenesis.Further work should yield safe,viable,and efficient materials for the repair of bone lesions.

  18. Effects of adding resorbable chitosan microspheres to calcium phosphate cements for bone regeneration

    International Nuclear Information System (INIS)

    Calcium phosphate cements (CPCs) have been widely used as bone graft substitutes. However, the undesirable osteoinductivity and slow degradability of CPCs greatly hamper their clinical application. The aim of this study was to synthesize a type of injectable, bioactive cement. This was accomplished by incorporating chitosan microspheres into CPC. CPC containing chitosan microspheres was analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). XRD showed that the hardened chitosan microsphere/CPC with different proportions of microspheres contained diffraction peaks of hydroxyapatite and chitosan. Compressive strength and dissolution in simulated body fluid were measured. The chitosan microsphere/CPC containing 10% (w/w) chitosan microspheres had a compressive strength of 14.78 ± 0.67 MPa. Cavity defects were created in both femoral condylar regions of New Zealand White rabbits. Chitosan microsphere/CPC (composite group) and α-TCP/CPC (control group) were implanted separately into the bone defects of both femurs. X-ray analysis was performed to observe the filling of these bone defects 3 days after surgery. The extent of bone substitute degradation and new bone formation were evaluated by SEM and histological examination at 8, 16, and 24 weeks after implantation. These results showed far more new bone formation and degradation of the chitosan microsphere/CPC composite in the bone defects. These data indicate that a chitosan microsphere/CPC composite might be considered as a promising injectable material for the generation of new bone tissue. - Highlights: • We synthesized an injectable, bioactive chitosan microsphere/CPC for the first time. • 100–400 μm chitosan microspheres were incorporated into the cement solid phase. • XRD showed the construct contained diffraction peaks of hydroxyapatite and chitosan. • Compressive strength of the composite was about 15 MPa comparable to cancellous bone. • The new construct shows better bone

  19. Induced Pluripotent Stem Cell-derived Mesenchymal Stem Cell Seeding on Biofunctionalized Calcium Phosphate Cements

    Institute of Scientific and Technical Information of China (English)

    WahWah TheinHan; Jun Liu; Minghui Tang; Wenchuan Chen; Linzhao Cheng; Hockin H. K. Xu

    2013-01-01

    Induced pluripotent stem cells (iPSCs) have great potential due to their proliferation and differentiation capability. The objectives of this study were to generate iPSC-derived mesenchymal stem cells (iPSC-MSCs), and investigate iPSC-MSC proliferation and osteogenic differentiation on calcium phosphate cement (CPC) containing biofunctional agents for the first time. Human iPSCs were derived from marrow CD34+ cells which were reprogrammed by a single episomal vector. iPSCs were cultured to form embryoid bodies (EBs), and MSCs migrated out of EBs. Five biofunctional agents were incorporated into CPC:RGD (Arg-Gly-Asp) peptides, fibronectin (Fn), fibronectin-like engineered polymer protein (FEPP), extracellular matrix Geltrex, and platelet concentrate. iPSC-MSCs were seeded on five biofunctionalized CPCs:CPC-RGD, CPC-Fn, CPC-FEPP, CPC-Geltrex, and CPC-Platelets. iPSC-MSCs on biofunctional CPCs had enhanced proliferation, actin fiber expression, osteogenic differentiation and mineralization, compared to control. Cell proliferation was greatly increased on biofunctional CPCs. iPSC-MSCs underwent osteogenic differentiation with increased alkaline phosphatase, Runx2 and collagen-I expressions. Mineral synthesis by iPSC-MSCs on CPC-Platelets was 3-fold that of CPC control. In conclusion, iPSCs showed high potential for bone engineering. iPSC-MSCs on biofunctionalized CPCs had cell proliferation and bone mineralization that were much better than traditional CPC. iPSC-MSC-CPC constructs are promising to promote bone regeneration in craniofacial/orthopedic repairs.

  20. The Remineralization of Enamel Lesions by Casein Phosphopeptide-Amorphous Calcium Fluoride Phosphate

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    目的:探讨2%酪蛋白磷酸多肽钙氟磷复合体(CPP-ACFP)溶液对牙釉质缺损的再矿化作用。方法:从人第3磨牙切取28块釉质块(每片中制备两条釉质缺损),随机平分为4组,每组分别于再矿化液中浸泡1,3,5,10天,测定矿物质含量。结果:再矿化率分别为9.19%,14.27%,29.07%,38.45%。经One-wayScheffe差异多因素分析比较发现每两组间差异皆有显著性。结论:CPP-ACFP作为食物及牙膏添加剂,在龋病预防中将起重要作用。%Objective:To evaluate the remineralizing effect on artificialenamel subsurface lesions in vitro by 2% casein phosphopeptide-amorphous calcium fluoride phosphate complexes(CPP-ACFP).Methods:Twenty-eight enamel blocks were cut from human third molars,and 2 lesions were prepared from each block.Twenty-eight samples were randomly assigned to four groups,each group was incubated in reminera-lization solution for 1,3,5,10 days respectively.The mineral content was determined by microdensitometry.Results:The remineralizing rate was 9.19%,14.27%,29.07,38.45% respectively.Significant differences were found in remineralizing rate between two groups using One-way Scheffe multiple comparison.Conclusion:The CPP-ACFP plays an important role as a food and/or a toothpaste additive for the control of dental caries.

  1. Conditional Deletion of Fgfr1 in the Proximal and Distal Tubule Identifies Distinct Roles in Phosphate and Calcium Transport.

    Directory of Open Access Journals (Sweden)

    Xiaobin Han

    Full Text Available A postnatal role of fibroblast growth factor receptor-1 (FGFR1 in the kidney is suggested by its binding to α-Klotho to form an obligate receptor for the hormone fibroblast growth factor-23 (FGF-23. FGFR1 is expressed in both the proximal and distal renal tubular segments, but its tubular specific functions are unclear. In this study, we crossed Fgfr1flox/flox mice with either gamma-glutamyltransferase-Cre (γGT-Cre or kidney specific-Cre (Ksp-Cre mice to selectively create proximal tubule (PT and distal tubule (DT Fgfr1 conditional knockout mice (designated Fgfr1PT-cKO and Fgfr1DT-cKO, respectively. Fgfr1PT-cKO mice exhibited an increase in sodium-dependent phosphate co-transporter expression, hyperphosphatemia, and refractoriness to the phosphaturic actions of FGF-23, consistent with a direct role of FGFR1 in mediating the proximal tubular phosphate responses to FGF-23. In contrast, Fgfr1DT-cKO mice unexpectedly developed hypercalciuria, secondary elevations of parathyroid hormone (PTH, hypophosphatemia and enhanced urinary phosphate excretion. Fgfr1PT-cKO mice also developed a curly tail/spina bifida-like skeletal phenotype, whereas Fgfr1DT-cKO mice developed renal tubular micro-calcifications and reductions in cortical bone thickness. Thus, FGFR1 has dual functions to directly regulate proximal and distal tubule phosphate and calcium reabsorption, indicating a physiological role of FGFR1 signaling in both phosphate and calcium homeostasis.

  2. Enhanced effect of β-tricalcium phosphate phase on neovascularization of porous calcium phosphate ceramics: in vitro and in vivo evidence.

    Science.gov (United States)

    Chen, Y; Wang, J; Zhu, X D; Tang, Z R; Yang, X; Tan, Y F; Fan, Y J; Zhang, X D

    2015-01-01

    Neovascularization plays a key role in bone repair and regeneration. In the present study, four types of porous calcium phosphate (CaP) ceramics, namely hydroxyapatite (HA), biphasic calcium phosphates (BCP-1 and BCP-2) and β-tricalcium phosphate (β-TCP), with HA to β-TCP ratios of 100/0, 70/30, 30/70 and 2/98, respectively, were investigated in terms of their angiogenic induction. The in vitro cell culture revealed that the ceramics could promote proliferation and angiogenesis of human umbilical vein endothelial cells (HUVECs). This result could be achieved by stimulating CCD-18Co human fibroblasts to secrete angiogenic factors (vascular endothelial growth factor, basic fibroblast growth factor and transforming growth factor-β) as a paracrine effect, as well as by up-regulating HUVECs to express these angiogenic factors and their receptors (KDR, FGFR1 and ACVRL1) and the downstream eNOS as an autocrine effect. These effects were more significant in β-TCP and BCP-2, which had a higher content of β-TCP phase. In the in vivo implantation into the thigh muscles of mice, the process of neovascularization of the ceramics was initiated at 2 weeks and the mature vascular networks were formed at 4 weeks as visualized by hematoxylin and eosin staining and scanning electron microscopy. Microvessel density count confirmed that β-TCP and BCP-2 induced more microvessels to form than HA or BCP-1. This phenomenon was further confirmed by the significantly up-regulated expressions of angiogenesis-related genes in the ingrowth of cells into the inner pores of the two ceramics. All the results confirmed the angiogenic induction of porous CaP ceramics, and a higher content of β-TCP phase had an enhanced effect on the neovascularization of the ceramics. PMID:25246313

  3. Electron diffraction and high resolution transmission electron microscopy in the characterization of calcium phosphate precipitation from aqueous solutions under biomineralization conditions

    Directory of Open Access Journals (Sweden)

    Suvorova E. I.

    2001-01-01

    Full Text Available Calcium phosphate precipitation obtained from aqueous solutions at room and body temperature and pH 5.5-7.5 were investigated by high-resolution transmission electron microscopy (HRTEM, transmission electron diffraction, scanning electron microscopy (SEM and X-ray diffraction (XRD. Supersaturated solutions of calcium phosphates were prepared by different methods of mixing of the stock solutions: diffusion-controlled mixing in space, convection-controlled mixing on earth and forced mixing on earth and with typical physiological parameters (pH and temperature. Concentrations of the stock solutions, rate of solution mixing and duration of precipitation influence very strongly the chemical composition of the precipitation, the phase composition of individual crystals, their sizes, morphology and structure. Microdiffraction and HRTEM techniques showed an incontestable advantage on other techniques like SEM and XRD in the investigation of small particles and mixtures of calcium phosphates (hydroxyapatite and octacalcium phosphate with different proportions.

  4. Mg-doped biphasic calcium phosphate by a solid state reaction route: Characterization and evaluation of cytotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Webler, Geovana D. [Instituto de Física, Universidade Federal de Alagoas, Maceió-AL 57072970 (Brazil); Correia, Ana C.C.; Barreto, Emiliano [Laboratório de Biologia Celular, Universidade Federal de Alagoas, Maceió-AL 57072970 (Brazil); Fonseca, Eduardo J.S., E-mail: eduardo@fis.ufal.br [Instituto de Física, Universidade Federal de Alagoas, Maceió-AL 57072970 (Brazil)

    2015-07-15

    Hydroxyapatite (HAP) and β-tricalcium phosphate (β-TCP) are widely used in tissue engineering because of their chemical similarity to the inorganic bone phase. In this work, we prepare biphasic calcium phosphate (BCP, a mixture of HAP and β-TCP) doped with different concentrations of magnesium to investigate the influence of magnesium on the BCP crystal structure. Magnesium is known to be an important element in the composition of bones and teeth. Recent research has shown that the doping of magnesium into BCP improves its bone metabolism and mechanical properties without affecting its biocompatibility. The samples were prepared by solid-state reaction from calcium carbonate, monobasic ammonium phosphate, and magnesium nitrate hexahydrate. Varying concentrations of magnesium were used and its modifications were examined by different characterization techniques. The phase composition and morphology of the ceramic powders were characterized by X-ray diffraction and scanning electron microscopy, respectively. The functional groups were analyzed using Fourier transform infrared spectroscopy and Raman spectroscopy. Cell viability experiments, using macrophage-like cell lines J774, showed that the synthesized Mg-doped BCP did not exhibit cytotoxicity regardless of the doses assayed or the different concentrations of magnesium used, suggesting it as a good material for potential biological applications. - Highlights: • Simple and fast method for the preparation of the Mg-BCP. • Study of the influence of the incorporation of Mg in the BCP. • Cell viability showed that the synthesized Mg-BCP did not exhibit cytotoxicity.

  5. Staphylococcal biofilm formation on the surface of three different calcium phosphate bone grafts: a qualitative and quantitative in vivo analysis.

    Science.gov (United States)

    Furustrand Tafin, Ulrika; Betrisey, Bertrand; Bohner, Marc; Ilchmann, Thomas; Trampuz, Andrej; Clauss, Martin

    2015-03-01

    Differences in physico-chemical characteristics of bone grafts to fill bone defects have been demonstrated to influence in vitro bacterial biofilm formation. Aim of the study was to investigate in vivo staphylococcal biofilm formation on different calcium phosphate bone substitutes. A foreign-body guinea-pig infection model was used. Teflon cages prefilled with β-tricalcium phosphate, calcium-deficient hydroxyapatite, or dicalcium phosphate (DCP) scaffold were implanted subcutaneously. Scaffolds were infected with 2 × 10(3) colony-forming unit of Staphylococcus aureus (two strains) or S. epidermidis and explanted after 3, 24 or 72 h of biofilm formation. Quantitative and qualitative biofilm analysis was performed by sonication followed by viable counts, and microcalorimetry, respectively. Independently of the material, S. aureus formed increasing amounts of biofilm on the surface of all scaffolds over time as determined by both methods. For S. epidermidis, the biofilm amount decreased over time, and no biofilm was detected by microcalorimetry on the DCP scaffolds after 72 h of infection. However, when using a higher S. epidermidis inoculum, increasing amounts of biofilm were formed on all scaffolds as determined by microcalorimetry. No significant variation in staphylococcal in vivo biofilm formation was observed between the different materials tested. This study highlights the importance of in vivo studies, in addition to in vitro studies, when investigating biofilm formation of bone grafts.

  6. Mg-doped biphasic calcium phosphate by a solid state reaction route: Characterization and evaluation of cytotoxicity

    International Nuclear Information System (INIS)

    Hydroxyapatite (HAP) and β-tricalcium phosphate (β-TCP) are widely used in tissue engineering because of their chemical similarity to the inorganic bone phase. In this work, we prepare biphasic calcium phosphate (BCP, a mixture of HAP and β-TCP) doped with different concentrations of magnesium to investigate the influence of magnesium on the BCP crystal structure. Magnesium is known to be an important element in the composition of bones and teeth. Recent research has shown that the doping of magnesium into BCP improves its bone metabolism and mechanical properties without affecting its biocompatibility. The samples were prepared by solid-state reaction from calcium carbonate, monobasic ammonium phosphate, and magnesium nitrate hexahydrate. Varying concentrations of magnesium were used and its modifications were examined by different characterization techniques. The phase composition and morphology of the ceramic powders were characterized by X-ray diffraction and scanning electron microscopy, respectively. The functional groups were analyzed using Fourier transform infrared spectroscopy and Raman spectroscopy. Cell viability experiments, using macrophage-like cell lines J774, showed that the synthesized Mg-doped BCP did not exhibit cytotoxicity regardless of the doses assayed or the different concentrations of magnesium used, suggesting it as a good material for potential biological applications. - Highlights: • Simple and fast method for the preparation of the Mg-BCP. • Study of the influence of the incorporation of Mg in the BCP. • Cell viability showed that the synthesized Mg-BCP did not exhibit cytotoxicity

  7. Regulatory inhibition of biological tissue mineralization by calcium phosphate through post-nucleation shielding by fetuin-A

    Science.gov (United States)

    Chang, Joshua C.; Miura, Robert M.

    2016-04-01

    In vertebrates, insufficient availability of calcium and inorganic phosphate ions in extracellular fluids leads to loss of bone density and neuronal hyper-excitability. To counteract this problem, calcium ions are usually present at high concentrations throughout bodily fluids—at concentrations exceeding the saturation point. This condition leads to the opposite situation where unwanted mineral sedimentation may occur. Remarkably, ectopic or out-of-place sedimentation into soft tissues is rare, in spite of the thermodynamic driving factors. This fortunate fact is due to the presence of auto-regulatory proteins that are found in abundance in bodily fluids. Yet, many important inflammatory disorders such as atherosclerosis and osteoarthritis are associated with this undesired calcification. Hence, it is important to gain an understanding of the regulatory process and the conditions under which it can go awry. In this manuscript, we extend mean-field continuum classical nucleation theory of the growth of clusters to encompass surface shielding. We use this formulation to study the regulation of sedimentation of calcium phosphate salts in biological tissues through the mechanism of post-nuclear shielding of nascent mineral particles by binding proteins. We develop a mathematical description of this phenomenon using a countable system of hyperbolic partial differential equations. A critical concentration of regulatory protein is identified as a function of the physical parameters that describe the system.

  8. Regulatory inhibition of biological tissue mineralization by calcium phosphate through post-nucleation shielding by fetuin-A.

    Science.gov (United States)

    Chang, Joshua C; Miura, Robert M

    2016-04-21

    In vertebrates, insufficient availability of calcium and inorganic phosphate ions in extracellular fluids leads to loss of bone density and neuronal hyper-excitability. To counteract this problem, calcium ions are usually present at high concentrations throughout bodily fluids-at concentrations exceeding the saturation point. This condition leads to the opposite situation where unwanted mineral sedimentation may occur. Remarkably, ectopic or out-of-place sedimentation into soft tissues is rare, in spite of the thermodynamic driving factors. This fortunate fact is due to the presence of auto-regulatory proteins that are found in abundance in bodily fluids. Yet, many important inflammatory disorders such as atherosclerosis and osteoarthritis are associated with this undesired calcification. Hence, it is important to gain an understanding of the regulatory process and the conditions under which it can go awry. In this manuscript, we extend mean-field continuum classical nucleationtheory of the growth of clusters to encompass surface shielding. We use this formulation to study the regulation of sedimentation of calcium phosphate salts in biological tissues through the mechanism of post-nuclear shielding of nascent mineral particles by binding proteins. We develop a mathematical description of this phenomenon using a countable system of hyperbolic partial differential equations. A critical concentration of regulatory protein is identified as a function of the physical parameters that describe the system. PMID:27389239

  9. Calcium phosphate cements properties with polymers addition; Propriedades do cimento de fosfato de calcio com adicao de polimeros

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, J.M.; Trajano, W.T.; Escobar, C.F.; Santos, L.A., E-mail: julianafernandes2@yahoo.com.br [Universidade Federal do Rio Grande do Sul (UFRGS), RS (Brazil)

    2012-07-01

    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.

  10. A systematic review on the long-term success of calcium phosphate plasma-spray-coated dental implants.

    Science.gov (United States)

    van Oirschot, B A J A; Bronkhorst, E M; van den Beucken, J J J P; Meijer, G J; Jansen, J A; Junker, R

    2016-09-01

    The objectives of the current review were (1) to systematically appraise, and (2) to evaluate long-term success data of calcium phosphate (CaP) plasma-spray-coated dental implants in clinical trials with at least 5 years of follow-up. To describe the long-term efficacy of functional implants, the outcome variables were (a) percentage annual complication rate (ACR) and (b) cumulative success rate (CSR), as presented in the selected articles. The electronic search yielded 645 titles. On the basis of the inclusion criteria, 8 studies were finally included. The percentage of implants in function after the first year was estimated to be 98.4 % in the maxilla and 99.2 % in the mandible. The estimates of the weighted mean ACR-percentage increased over the years up to 2.6 (SE 0.7) during the fifth year of function for the maxilla and to 9.4 (SE 8.4) for the mandible in the tenth year of function. After 10 years, the mean percentage of successful implants was estimated to be 71.1 % in the maxilla and 72.2 % in the mandible. The estimates seem to confirm the proposed, long-term progressive bone loss pattern of CaP-ceramic-coated dental implants. Within the limits of this meta-analytic approach to the literature, we conclude that: (1) published long-term success data for calcium phosphate plasma-spray-coated dental implants are limited, (2) comparison of the data is difficult due to differences in success criteria among the studies, and (3) long-term CSRs demonstrate very weak evidence for progressive complications around calcium phosphate plasma-spray-coated dental implants.

  11. Biocompatible and colloidally stabilized mPEG-PE/calcium phosphate hybrid nanoparticles loaded with siRNAs targeting tumors.

    Science.gov (United States)

    Gao, Pei; Zhang, Xiangyu; Wang, Hongzhi; Zhang, Qinghong; Li, He; Li, Yaogang; Duan, Yourong

    2016-01-19

    Calcium phosphate nanoparticles are safe and effective delivery vehicles for small interfering RNA (siRNA), as a result of their excellent biocompatibility. In this work, mPEG-PE (polyethylene glycol-L-α-phosphatidylethanolamine) was synthesized and used to prepare nanoparticles composed of mPEG-PE and calcium phosphate for siRNA delivery. Calcium phosphate and mPEG-PE formed the stable hybrid nanoparticles through self-assembly resulting from electrostatic interaction in water. The average size of the hybrid nanoparticles was approximately 53.2 nm with a negative charge of approximately -16.7 mV, which was confirmed by dynamic light scattering (DLS) measurements. The nanoparticles exhibited excellent stability in serum and could protect siRNA from ribonuclease (RNase) degradation. The cellular internalization of siRNA-loaded nanoparticles was evaluated in SMMC-7721 cells using a laser scanning confocal microscope (CLSM) and flow cytometry. The hybrid nanoparticles could efficiently deliver siRNA to cells compared with free siRNA. Moreover, the in vivo distribution of Cy5-siRNA-loaded hybrid nanoparticles was observed after being injected into tumor-bearing nude mice. The nanoparticles concentrated in the tumor regions through an enhanced permeability and retention (EPR) effect based on the fluorescence intensities of tissue distribution. A safety evaluation of the nanoparticles was performed both in vitro and in vivo demonstrating that the hybrid nanoparticle delivery system had almost no toxicity. These results indicated that the mPEG-PE/CaP hybrid nanoparticles could be a stable, safe and promising siRNA nanocarrier for anticancer therapy.

  12. Effect of increasing the colloidal calcium phosphate of milk on the texture and microstructure of yogurt.

    Science.gov (United States)

    Ozcan, T; Horne, D; Lucey, J A

    2011-11-01

    The effect of increasing the colloidal calcium phosphate (CCP) content on the physical, rheological, and microstructural properties of yogurt was investigated. The CCP content of heated (85°C for 30 min) milk was increased by increasing the pH by the addition of alkali (NaOH). Alkalized milk was dialyzed against pasteurized skim milk at approximately 4°C for 72 h to attempt to restore the original pH and soluble Ca content. By adjustment of the milk to pH values 7.45, 8.84, 10.06, and 10.73, the CCP content was increased to approximately 107, 116, 123, and 128%, respectively, relative to the concentration in heated milk. During fermentation of milk, the storage modulus (G') and loss tangent values of yogurts were measured using dynamic oscillatory rheology. Large deformation rheological properties were also measured. The microstructure of yogurt was observed using fluorescence microscopy, and whey separation was determined. Acid-base titration was used to evaluate changes in the CCP content in milk. Total Ca and casein-bound Ca increased with an increase in the pH value of alkalization. During acidification, elevated buffering occurred in milk between pH values 6.7 to 5.2 with an increase in the pH of alkalization. When acidified milk was titrated with alkali, elevated buffering occurred in milk between pH values 5.6 to 6.4 with an increase in the pH of alkalization. The high residual pH of milk after dialysis could be responsible for the decreased contents of soluble Ca in these milks. The pH of gelation was higher in all dialyzed samples compared with the heated control milk, and the gelation pH was higher with an increase in CCP content. The sample with highest CCP content (128%) exhibited gelation at very high pH (6.3), which could be due to alkali-induced CN micellar disruption. The G' values at pH 4.6 were similar in gels with CCP levels up to 116%; at higher CCP levels, the G' values at pH 4.6 greatly decreased. Loss tangent values at pH 5.1 were similar

  13. In vitro elution of vancomycin from biodegradable osteoconductive calcium phosphate-polycaprolactone composite beads for treatment of osteomyelitis.

    Science.gov (United States)

    Makarov, C; Cohen, V; Raz-Pasteur, A; Gotman, I

    2014-10-01

    In this work, osteoconductive composite materials comprising a large volume fraction of a bioresorbable calcium phosphate ceramic (CaP) and a smaller amount of a polycaprolactone polymer (PCL) were studied as a degradable antibiotic carrier material for treatment of osteomyelitis. Beads loaded with 1 and 4wt.% vancomycin were prepared by admixing dissolved drug to an in situ synthesized dicalcium phosphate (DCP)-PCL or solution-mixed beta-tricalcium phosphate (βTCP)-PCL composite powder followed by high pressure consolidation of the blend at room temperature. Vancomycin release was measured in phosphate-buffered saline (PBS) at 37°C. All the beads gradually released the drug over the period of 4-11weeks, depending on the composite matrix homogeneity and porosity. Mathematical modeling using the Peppas equation showed that vancomycin elution was diffusion controlled. The stability of the antibiotic after high pressure application at room temperature was demonstrated by high-performance liquid chromatography-mass spectrometry (HPLC-MS) studies and MIC testing. The preservation of the structure and activity of vancomycin during the processing of composite beads and its sustained in vitro release profile suggest that high pressure consolidated CaP-PCL beads may be useful in the treatment of chronic bone infections as resorbable delivery vehicles of vancomycin and even of thermally unstable drug substances.

  14. Local treatment of osteoporosis with alendronate-loaded calcium phosphate cement

    Institute of Scientific and Technical Information of China (English)

    Zhao Jindong; Tang Hai; Wang Jiayang; Li Gang

    2014-01-01

    Background A new treatment strategy is to target specific areas of the skeletal system that are prone to clinically significant osteoporotic fractures.We term this strategy as the "local treatment of osteoporosis".The study was performed to investigate the effect of alendronate-loaded calcium phosphate cement (CPC) as a novel drug delivery system for local treatment of osteoorosis.Methods An in vitro study was performed using CPC fabricated with different concentrations of alendronate (ALE,0,2,5,10 weight percent (wt%)).The microstructure,setting time,infrared spectrum,biomechanics,drug release,and biocompatibility of the composite were measured in order to detect changes when mixing CPC with ALE.An in vivo study was also performed using 30 Sprague-Dawley rats randomly divided into six groups:normal,Sham (ovariectomized (OVX) + Sham),CPC with 2% ALE,5%ALE,and 10% ALE groups.At 4 months after the implantation of the composite,animals were sacrificed and the caudal vertebrae (levels 4-7) were harvested for micro-CT examination and biomechanical testing.Results The setting time and strength of CPC was significantly faster and greater than the other groups.The ALE release was sustained over 21 days,and the composite showed good biocompatibility.In micro-CT analysis,compared with the Sham group,there was a significant increase with regard to volumetric bone mineral density (BMD) and trabecular number (Tb.N) in the treated groups (P <0.05).Trabecular spacing (Tb.Sp) showed a significant increase in the Sham group compared to other groups (P <0.01).However,trabecular thickness (Tb.Th) showed no significant difference among the groups.In biomechanical testing,the maximum compression strength and stiffness of trabecular bone in the Sham group were lower than those in the experimental groups.Conclusions The ALE-loaded CPC displayed satisfactory properties in vitro,which can reverse the OVX rat vertebral trabecular bone microarchitecture and biomechanical

  15. 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

  16. Different Angiogenic Abilities of Self-Setting Calcium Phosphate Cement Scaffolds Consisting of Different Proportions of Fibrin Glue

    OpenAIRE

    Jintao Xiu; Junjun Fan; Jie Li; Geng Cui; Wei Lei

    2014-01-01

    To investigate the different angiogenic abilities of the self-setting calcium phosphate cement (CPC) consisting of different proportions of fibrin glue (FG), the CPC powder and the FG solution were mixed at the powder/liquid (P/L) ratios of 1 : 0.5, 1 : 1, and 1 : 2 (g/mL), respectively, and pure CPC was used as a control. After being implanted into the lumbar dorsal fascia of the rabbit, the angiogenic process was evaluated by histological examination and CD31 immunohistochemistry to detect ...

  17. 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...

  18. Calcium and Inorganic Phosphate Transport in Rat Colon: DISSOCIATED RESPONSE TO 1,25-DIHYDROXYVITAMIN D3

    OpenAIRE

    Lee, D. B. N.; Walling, M. W.; Gafter, U; Silis, V.; Coburn, J W

    1980-01-01

    In the small intestine, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] stimulates both calcium (Ca) and inorganic phosphate (Pi) absorption. This is mediated through an increase in mucosal-to-serosal flux (Jms) whereas the serosal-to-mucosal flux (Jsm) remains unchanged. We now report that in rat proximal colon, 1,25(OH)2D3 produces active Ca absorption without affecting Pi transport, and that this induced active Ca absorption is associated with alterations in kinetics of both Jms and Jsm so that bot...

  19. 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.

  20. Fibronectin-calcium phosphate composite layer on hydroxyapatite to enhance adhesion, cell spread and osteogenic differentiation of human mesenchymal stem cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Sogo, Yu [National Institute of Advanced Industrial Science and Technology (AIST), Institute for Human Science and Biomedical Engineering, Central 6, 1-1-1, Higashi, Tsukuba, Ibaraki 305-8566 (Japan); Ito, Atsuo [National Institute of Advanced Industrial Science and Technology (AIST), Institute for Human Science and Biomedical Engineering, Central 6, 1-1-1, Higashi, Tsukuba, Ibaraki 305-8566 (Japan); Matsuno, Tomonori [Department of Oral and Maxillofacial Surgery, School of Life Dentistry at Tokyo, Nippon Dental University, 1-9-20 Fujimi, Chiyoda-ku, Tokyo 102-8159 (Japan); Oyane, Ayako [National Institute of Advanced Industrial Science and Technology (AIST), Nanotechnology Research Institute, Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan); Tamazawa, Gaku [Department of Oral and Maxillofacial Surgery, School of Life Dentistry at Tokyo, Nippon Dental University, 1-9-20 Fujimi, Chiyoda-ku, Tokyo 102-8159 (Japan); Satoh, Tazuko [Department of Oral and Maxillofacial Surgery, School of Life Dentistry at Tokyo, Nippon Dental University, 1-9-20 Fujimi, Chiyoda-ku, Tokyo 102-8159 (Japan); Yamazaki, Atsushi [Department of Resources and Environmental Engineering, School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 (Japan); Uchimura, Eiji [Department of Resources and Environmental Engineering, School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 (Japan); Ohno, Tadao [Department of Resources and Environmental Engineering, School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 (Japan)

    2007-06-01

    Fibronectin (Fn) and type I collagen (Col) were immobilized on a surface of a hydroxyapatite (HAP) ceramic by coprecipitation with calcium phosphate in a supersaturated calcium phosphate solution prepared by mixing clinically approved infusion fluids. These proteins and the calcium phosphate precipitate formed a composite surface layer. As a result, the proteins were immobilized firmly as not to be released completely for 3 d in a physiological salt solution. When human mesenchymal stem cells (hMSCs) were cultured on a HAP ceramic in a differentiation medium supplemented with dexamethasone, {beta}-glycerophosphate and ascorbic acid, hMSCs spread well within 1 h. The alkaline phosphatase (ALP) activity of hMSCs cultured on the Fn-calcium phosphate composite layer significantly increased compared with that of hMSCs cultured on the untreated HAP ceramic. On the other hand, Col did not increase the ALP activity of hMSCs and no synergy between Fn and Col was observed. Therefore, the Fn-calcium phosphate composite layer formed on the HAP is useful for the enhancement of the spreading and osteogenic differentiation of hMSCs in vitro.

  1. Effects of calcium and phosphate on uranium(IV) oxidation. Comparison between nanoparticulate uraninite and amorphous UIV–phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Latta, Drew E. [Argonne National Lab. (ANL), Argonne, IL (United States); Kemner, Kenneth M. [Argonne National Lab. (ANL), Argonne, IL (United States); Mishra, Bhoopesh [Argonne National Lab. (ANL), Argonne, IL (United States); Illinois Inst. of Technology, Chicago, IL (United States); Boyanov, Maxim I. [Argonne National Lab. (ANL), Argonne, IL (United States); Bulgarian Academy of Sciences, Sofia (Bulgaria)

    2016-02-01

    The mobility of uranium in subsurface environments depends strongly on its redox state, with UIV phases being significantly less soluble than UVI minerals. This study compares the oxidation kinetics and mechanisms of two potential products of UVI reduction in natural systems, a nanoparticulate UO2 phase and an amorphous UIV–Ca–PO4 analog to ningyoite (CaUIV(PO4)2·1–2H2O). The valence of U was tracked by X-ray absorption near-edge spectroscopy (XANES), showing similar oxidation rate constants for UIVO2 and UIV–phosphate in solutions equilibrated with atmospheric O2 and CO2 at pH 7.0 (kobs,UO2 = 0.17 ± 0.075 h-1 vs. kobs,UIVPO4 = 0.30 ± 0.25 h-1). Addition of up to 400 μM Ca and PO4 decreased the oxidation rate constant by an order of magnitude for both UO2 and UIV–phosphate. The intermediates and products of oxidation were tracked by electron microscopy, powder X-ray diffraction (pXRD), and extended X-ray absorption fine-structure spectroscopy (EXAFS). In the absence of Ca or PO4, the product of UO2 oxidation is Na–uranyl oxyhydroxide (under environmentally relevant concentrations of sodium, 15 mM NaClO4 and low carbonate concentration), resulting in low concentrations of dissolved UVI (<2.5 × 10-7 M). Oxidation of UIV–phosphate produced a Na-autunite phase (Na2(UO2)PO4·xH2O), resulting in similarly low dissolved U concentrations (<7.3 × 10-8 M). When Ca and PO4 are present in the solution, the EXAFS data and the solubility of the UVI phase resulting from oxidation of UO2 and UIV–phosphate are consistent with the precipitation of Na-autunite. Bicarbonate extractions and Ca K-edge X-ray absorption spectroscopy of oxidized solids indicate the formation of a Ca–UVI–PO4 layer on the UO2 surface and suggest a passivation layer mechanism for the decreased rate of UO2 oxidation in the presence of Ca and PO4. Interestingly, the extractions were unable to remove all of the oxidized U from partially oxidized UO2 solids, suggesting that oxidized U is

  2. Effects of calcium and phosphate on uranium(IV) oxidation: Comparison between nanoparticulate uraninite and amorphous UIV-phosphate

    Science.gov (United States)

    Latta, Drew E.; Kemner, Kenneth M.; Mishra, Bhoopesh; Boyanov, Maxim I.

    2016-02-01

    The mobility of uranium in subsurface environments depends strongly on its redox state, with UIV phases being significantly less soluble than UVI minerals. This study compares the oxidation kinetics and mechanisms of two potential products of UVI reduction in natural systems, a nanoparticulate UO2 phase and an amorphous UIV-Ca-PO4 analog to ningyoite (CaUIV(PO4)2·1-2H2O). The valence of U was tracked by X-ray absorption near-edge spectroscopy (XANES), showing similar oxidation rate constants for UIVO2 and UIV-phosphate in solutions equilibrated with atmospheric O2 and CO2 at pH 7.0 (kobs,UO2 = 0.17 ± 0.075 h-1 vs. kobs,UIVPO4 = 0.30 ± 0.25 h-1). Addition of up to 400 μM Ca and PO4 decreased the oxidation rate constant by an order of magnitude for both UO2 and UIV-phosphate. The intermediates and products of oxidation were tracked by electron microscopy, powder X-ray diffraction (pXRD), and extended X-ray absorption fine-structure spectroscopy (EXAFS). In the absence of Ca or PO4, the product of UO2 oxidation is Na-uranyl oxyhydroxide (under environmentally relevant concentrations of sodium, 15 mM NaClO4 and low carbonate concentration), resulting in low concentrations of dissolved UVI (<2.5 × 10-7 M). Oxidation of UIV-phosphate produced a Na-autunite phase (Na2(UO2)PO4·xH2O), resulting in similarly low dissolved U concentrations (<7.3 × 10-8 M). When Ca and PO4 are present in the solution, the EXAFS data and the solubility of the UVI phase resulting from oxidation of UO2 and UIV-phosphate are consistent with the precipitation of Na-autunite. Bicarbonate extractions and Ca K-edge X-ray absorption spectroscopy of oxidized solids indicate the formation of a Ca-UVI-PO4 layer on the UO2 surface and suggest a passivation layer mechanism for the decreased rate of UO2 oxidation in the presence of Ca and PO4. Interestingly, the extractions were unable to remove all of the oxidized U from partially oxidized UO2 solids, suggesting that oxidized U is distributed between

  3. Calcium phosphate nanoparticles carrying BMP-7 plasmid DNA induce an osteogenic response in MC3T3-E1 pre-osteoblasts.

    Science.gov (United States)

    Hadjicharalambous, Chrystalleni; Kozlova, Diana; Sokolova, Viktoriya; Epple, Matthias; Chatzinikolaidou, Maria

    2015-12-01

    Functionalized calcium phosphate nanoparticles with osteogenic activity were prepared. Polyethyleneimine-stabilized calcium phosphate nanoparticles were coated with a shell of silica and covalently functionalized by silanization with thiol groups. Between the calcium phosphate surface and the outer silica shell, plasmid DNA which encoded either for bone morphogenetic protein 7 (BMP-7) or for enhanced green fluorescent protein was incorporated as cargo. The plasmid DNA-loaded calcium phosphate nanoparticles were used for the transfection of the pre-osteoblastic MC3T3-E1 cells. The cationic nanoparticles showed high transfection efficiency together with a low cytotoxicity. Their potential to induce an osteogenic response by transfection was demonstrated by measuring the alkaline phosphatase (ALP) activity and calcium deposition with alizarin red staining. The expression of the osteogenic markers Alp, Runx2, ColIa1 and Bsp was investigated by means of real-time quantitative polymerase chain reaction. It was shown that phBMP-7-loaded nanoparticles can provide a means of transient transfection and localized production of BMP-7 in MC3T3-E1 cells, with a subsequent increase of two osteogenic markers, specifically ALP activity and calcium accumulation in the extracellular matrix. Future strategies to stimulate bone regeneration focus into enhancing transfection efficiency and achieving higher levels of BMP-7 produced by the transfected cells.

  4. Scientific Opinion on the safety and efficacy of vitamin C (ascorbic acid, sodium ascorbate, calcium ascorbate, ascorbyl palmitate, sodium calcium ascorbyl phosphate and sodium ascorbyl phosphate) as a feed additive for all animal species based on a dossier submitted by DSM Nutritional Products Ltd

    OpenAIRE

    EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP)

    2013-01-01

    Vitamin C is essential for primates, guinea pigs and fish. Vitamin C, in the form of ascorbic acid and its calcium and sodium salts, ascorbyl palmitate, sodium calcium ascorbyl phosphate and sodium ascorbyl phosphate, is safe for all animal species. Setting a maximum content in feed and water for drinking is not considered necessary. Data on the vitamin C consumption of consumers are based on the levels of vitamin C in foodstuffs, including food of animal origin, produced in accordance with c...

  5. Enzymatic pH Control for Biomimetic Deposition of Calcium Phosphate Coatings

    NARCIS (Netherlands)

    Nijhuis, A.W.; Reza Nejadnik, M.; Nudelman, F.; Walboomers, X.F.; Riet, te J.; Habibovic, P.; Tahmasebi Birgani, Z.; Yubao, L.; Bomans, P.H.H.; Jansen, J.A.; Sommerdijk, N.A.J.M.; Leeuwenburgh, S.C.G.

    2014-01-01

    The current study has focused on enzymatic decomposition of urea into carbon dioxide and ammonia as a means to increase the pH during biomimetic deposition of Calcium Phospate (CaP) onto implant surfaces. The kinetics of the enzymatically induced pH increase were studied by monitoring pH, calcium co

  6. An investigation into the effects of high laser fluence on hydroxyapatite/calcium phosphate films deposited by pulsed laser deposition

    International Nuclear Information System (INIS)

    Pulsed laser deposited mixed hydroxyapatite (HA)/calcium phosphate thin films were prepared at room temperature using KrF laser source with different laser fluence varying between 2.4 J/cm2 and 29.2 J/cm2. Samples deposited at 2.4 J/cm2 were partially amorphous and had rough surfaces with a lot of droplets while higher laser fluences showed higher level of crytallinity and lower roughness of surfaces of obtained samples. Higher laser fluences also decreased ratio Ca/P of as-deposited samples. X-ray photoelectron spectroscopy (XPS) revealed traces of carbonate groups in obtained samples, which were removed after thermal annealing. The decomposition of HA into TCP was observed to start at about 400 deg. C. The formation of new crystalline phase of HA was found after annealing as well. The cracks observed on surface of sample deposited at 29.2 J/cm2 after annealing indicated that the HA/ calcium phosphate films deposited at higher laser energy densities were probably more densed.

  7. Porous calcium phosphate-poly (lactic-co-glycolic) acid composite bone cement: A viable tunable drug delivery system.

    Science.gov (United States)

    Roy, Abhijit; Jhunjhunwala, Siddharth; Bayer, Emily; Fedorchak, Morgan; Little, Steve R; Kumta, Prashant N

    2016-02-01

    Calcium phosphate based cements (CPCs) are frequently used as bone void fillers for non-load bearing segmental bone defects due to their clinically relevant handling characteristics and ability to promote natural bone growth. Macroporous CPC scaffolds with interconnected pores are preferred for their ability to degrade faster and enable accelerated bone regeneration. Herein, a composite CPC scaffold is developed using newly developed resorbable calcium phosphate cement (ReCaPP) formulation containing degradable microspheres of bio-compatible poly (lactic-co-glycolic acid) (PLGA) serving as porogen. The present study is aimed at characterizing the effect of in-vitro degradation of PLGA microspheres on the physical, chemical and structural characteristics of the composite cements. The porosity measurements results reveal the formation of highly interconnected macroporous scaffolds after degradation of PLGA microspheres. The in-vitro characterizations also suggest that the degradation by products of PLGA reduces the pH of the local environment thereby increasing the dissolution rate of the cement. In addition, the in-vitro vancomycin release from the composite CPC scaffold suggests that the drug association with the composite scaffolds can be tuned to achieve control release kinetics. Further, the study demonstrates control release lasting for longer than 10weeks from the composite cements in which vancomycin is encapsulated in PLGA microspheres. PMID:26652353

  8. Biopolymer-induced calcium phosphate scaling in membrane-based water treatment systems: Langmuir model films studies.

    Science.gov (United States)

    Dahdal, Yara N; Oren, Yoram; Schwahn, Dietmar; Pipich, Vitaliy; Herzberg, Moshe; Ying, Wang; Kasher, Roni; Rapaport, Hanna

    2016-07-01

    Biofouling and scaling on reverse osmosis (RO) or nanofiltration (NF) membranes during desalination of secondary and tertiary effluents pose an obstacle that limits the reuse of wastewater. In this study we explored the mineral scaling induced by biopolymers originated from bacterial biofilms: bovine serum albumin (BSA), fibrinogen, lysozyme and alginic acid, as well as an extracts of extracellular polymeric substances (EPS) from bio-fouled RO membranes from wastewater treatment facility. Mineralization studies were performed on Langmuir films of the biopolymers deposited at the interface of a solution simulating RO desalination of secondary-treated wastewater effluents. All studied biopolymers and EPS induced heterogeneous mineralization of mainly calcium phosphate. Using IR spectroscopy coupled with systematic quantitative analysis of the surface pressure versus molecular-area isotherms, we determined the mineralization tendencies of the biopolymers to be in the order of: fibrinogen>lysozyme>BSA>alginic acid. The biopolymers and EPS studied here were found to be accelerators of calcium-phosphate mineralization. This study demonstrates the utilization of Langmuir surface-pressure area isotherms and a model solution in quantitatively assessing the mineralization tendencies of various molecular components of EPS in context of membrane-based water treatment systems. PMID:27015648

  9. 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

  10. Porous calcium phosphate-poly (lactic-co-glycolic) acid composite bone cement: A viable tunable drug delivery system.

    Science.gov (United States)

    Roy, Abhijit; Jhunjhunwala, Siddharth; Bayer, Emily; Fedorchak, Morgan; Little, Steve R; Kumta, Prashant N

    2016-02-01

    Calcium phosphate based cements (CPCs) are frequently used as bone void fillers for non-load bearing segmental bone defects due to their clinically relevant handling characteristics and ability to promote natural bone growth. Macroporous CPC scaffolds with interconnected pores are preferred for their ability to degrade faster and enable accelerated bone regeneration. Herein, a composite CPC scaffold is developed using newly developed resorbable calcium phosphate cement (ReCaPP) formulation containing degradable microspheres of bio-compatible poly (lactic-co-glycolic acid) (PLGA) serving as porogen. The present study is aimed at characterizing the effect of in-vitro degradation of PLGA microspheres on the physical, chemical and structural characteristics of the composite cements. The porosity measurements results reveal the formation of highly interconnected macroporous scaffolds after degradation of PLGA microspheres. The in-vitro characterizations also suggest that the degradation by products of PLGA reduces the pH of the local environment thereby increasing the dissolution rate of the cement. In addition, the in-vitro vancomycin release from the composite CPC scaffold suggests that the drug association with the composite scaffolds can be tuned to achieve control release kinetics. Further, the study demonstrates control release lasting for longer than 10weeks from the composite cements in which vancomycin is encapsulated in PLGA microspheres.

  11. An ex situ study of the adsorption of calcium phosphate from solution onto TiO2(110) and Al2O3(0001)

    Science.gov (United States)

    Murphy, M.; Walczak, M. S.; Hussain, H.; Acres, M. J.; Muryn, C. A.; Thomas, A. G.; Silikas, N.; Lindsay, R.

    2016-04-01

    Ex situ atomic force microscopy and x-ray photoelectron spectroscopy are employed to characterise the adsorption of calcium phosphate from an aqueous solution of CaCl2.H2O and KH2PO4 onto rutile-TiO2(110) and α-Al2O3(0001). Prior to immersion, the substrates underwent wet chemical preparation to produce well-defined surfaces. Calcium phosphate adsorption is observed on both rutile-TiO2(110) and α-Al2O3(0001), with atomic force microscopy images indicating island-type growth. In contrast to other studies on less well-defined TiO2 and Al2O3 substrates, the induction period for calcium phosphate nucleation appears to be comparable on these two surfaces.

  12. Prostaglandin-E2 Mediated Increase in Calcium and Phosphate Excretion in a Mouse Model of Distal Nephron Salt Wasting.

    Directory of Open Access Journals (Sweden)

    Manoocher Soleimani

    Full Text Available Contribution of salt wasting and volume depletion to the pathogenesis of hypercalciuria and hyperphosphaturia is poorly understood. Pendrin/NCC double KO (pendrin/NCC-dKO mice display severe salt wasting under basal conditions and develop profound volume depletion, prerenal renal failure, and metabolic alkalosis and are growth retarded. Microscopic examination of the kidneys of pendrin/NCC-dKO mice revealed the presence of calcium phosphate deposits in the medullary collecting ducts, along with increased urinary calcium and phosphate excretion. Confirmatory studies revealed decreases in the expression levels of sodium phosphate transporter-2 isoforms a and c, increases in the expression of cytochrome p450 family 4a isotypes 12 a and b, as well as prostaglandin E synthase 1, and cyclooxygenases 1 and 2. Pendrin/NCC-dKO animals also had a significant increase in urinary prostaglandin E2 (PGE-2 and renal content of 20-hydroxyeicosatetraenoic acid (20-HETE levels. Pendrin/NCC-dKO animals exhibit reduced expression levels of the sodium/potassium/2chloride co-transporter 2 (NKCC2 in their medullary thick ascending limb. Further assessment of the renal expression of NKCC2 isoforms by quantitative real time PCR (qRT-PCR reveled that compared to WT mice, the expression of NKCC2 isotype F was significantly reduced in pendrin/NCC-dKO mice. Provision of a high salt diet to rectify volume depletion or inhibition of PGE-2 synthesis by indomethacin, but not inhibition of 20-HETE generation by HET0016, significantly improved hypercalciuria and salt wasting in pendrin/NCC dKO mice. Both high salt diet and indomethacin treatment also corrected the alterations in NKCC2 isotype expression in pendrin/NCC-dKO mice. We propose that severe salt wasting and volume depletion, irrespective of the primary originating nephron segment, can secondarily impair the reabsorption of salt and calcium in the thick ascending limb of Henle and/or proximal tubule, and reabsorption of

  13. 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

  14. Self-Setting Calcium Phosphate Cements with Tunable Antibiotic Release Rates for Advanced Antimicrobial Applications.

    Science.gov (United States)

    Ghosh, Shreya; Wu, Victoria; Pernal, Sebastian; Uskoković, Vuk

    2016-03-01

    Osteomyelitis, an infectious disease predominantly tied to poor sanitary conditions in underdeveloped regions of the world, is in need of inexpensive, easily in situ synthesizable and administrable materials for its treatment. The results of this study stem from the attempt to create one such affordable and minimally invasive therapeutic platform in the form of a self-setting, injectable cement with a tunable drug release profile, composed of only nanoparticulate hydroxyapatite, the synthetic version of the bone mineral. Cements comprised two separately synthesized hydroxyapatite powders, one of which, HAP2, was precipitated abruptly, retaining the amorphous nature longer, and the other one of which, HAP1, was precipitated at a slower rate, more rapidly transitioning to the crystalline structure. Cements were made with four different weight ratios of the two hydroxyapatite components: 100/0, 85/15, 50/50, and 0/100 with respect to HAP1 and HAP2. Both the setting and the release rates measured on two different antibiotics, vancomycin and ciprofloxacin, were controlled using the weight ratio of the two hydroxyapatite components. Various inorganic powder properties were formerly used to control drug release, but here we demonstrate for the first time that the kinetics of the mechanism of formation of a solid compound can be controlled to produce tunable drug release profiles. Specifically, it was found that the longer the precursor calcium phosphate component of the cement retains the amorphous nature of the primary precipitate, the more active it was in terms of speeding up the diffusional release of the adsorbed drug. The setting rate was, in contrast, inversely proportional to the release rate and to the content of this active hydroxyapatite component, HAP2. The empirical release profiles were fitted to a set of equations that could be used to tune the release rate to the therapeutic occasion. All of the cements loaded with vancomycin or ciprofloxacin inhibited the

  15. 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

  16. A new iron calcium phosphate material to improve the osteoconductive properties of a biodegradable ceramic: a study in rabbit calvaria.

    Science.gov (United States)

    Manchón, Angel; Hamdan Alkhraisat, Mohammad; Rueda-Rodriguez, Carmen; Prados-Frutos, Juan Carlos; Torres, Jesús; Lucas-Aparicio, Julia; Ewald, Andrea; Gbureck, Uwe; López-Cabarcos, Enrique

    2015-10-20

    β-tricalcium phosphate (β-TCP) is an osteoconductive and biodegradable material used in bone regeneration procedures, while iron has been suggested as a tool to improve the biological performance of calcium phosphate-based materials. However, the mechanisms of interaction between these materials and human cells are not fully understood. In order to clarify this relationship, we have studied the iron role in β-TCP ceramics. Iron-containing β-TCPs were prepared by replacing CaCO3 with C6H5FeO7 at different molar ratios. X-ray diffraction analysis indicated the occurrence of β-TCP as the sole phase in the pure β-TCP and iron-containing ceramics. The incorporation of iron ions in the β-TCP lattice decreased the specific surface area as the pore size was shifted toward meso- and/or macropores. Furthermore, the human osteoblastlike cell line MG-63 was cultured onto the ceramics to determine cell proliferation and viability, and it was observed that the iron-β-TCP ceramics have better cytocompatibility than pure β-TCP. Finally, in vivo assays were performed using rabbit calvaria as a bone model. The scaffolds were implanted for 8 and 12 weeks in the defects created in the skullcap with pure β-TCP as the control. The in vivo behavior, in terms of new bone formed, degradation, and residual graft material were investigated using sequential histological evaluations and histomorphometric analysis. The in vivo implantation of the ceramics showed enhanced bone tissue formation and scaffold degradation for iron-β-TCPs. Thus, iron appears to be a useful tool to enhance the osteoconductive properties of calcium phosphate ceramics.

  17. Effect of ultrafine poly(ε-caprolactone fibers on calcium phosphate cement: in vitro degradation and in vivo regeneration

    Directory of Open Access Journals (Sweden)

    Yang BY

    2016-01-01

    Full Text Available Boyuan Yang,1 Yi Zuo,1 Qin Zou,1 Limei Li,1 Jidong Li,1 Yi Man,2 Yubao Li1 1Research Center for Nano Biomaterials, Analytical and Testing Center, Sichuan University, Chengdu, People’s Republic of China; 2State Key Laboratory of Oral Disease, West China Hospital of Stomatology, Sichuan University, Chengdu, People’s Republic of China Abstract: We incorporated ultrafine polymer fibers into calcium phosphate cement (CPC to improve the resorption rate of CPC with fiber degradation. Different weight percentages of electrospun poly(ε-caprolactone fibers (0%, 3%, and 7%, named as ultrafine fiber-incorporated CPC0 [UFICPC0], UFICPC3, and UFICPC7 were included into preset CPC specimens for in vitro immersion in lipase phosphate-buffered solution and long-term in vivo implantation in the femoral condyle of rabbits. The effect of the ultrafine poly(ε-caprolactone fibers with a diameter ranging from nanometer to micrometer on CPC degradation was evaluated by measuring the pH of the medium, mass loss, porosity, and physiochemical properties. For the in vivo evaluation, histomorphometrical analysis as well as three-dimensional (3D reconstruction was applied to assess the osteogenic properties of the CPC composite. After in vitro immersion and in vivo implantation, the total porosity and macroporosity as well as the bone formation and ingrowth increased significantly during time in the fiber-incorporated CPC specimens. After 24 weeks of implantation, the degraded space was occupied by newly formed bone, and the UFICPC3 and UFICPC7 composites showed a ~3.5 times higher fraction of bone volume than that of the pristine CPC (UFICPC0. In vitro and in vivo results proved that the introduction of ultrafine degradable fibers within a CPC matrix can be used to improve macroporosity efficiently and enhance CPC degradation and bone ingrowth largely. Keywords: ultrafine fibers, calcium phosphate cement, macroporosity, degraded space, bone ingrowth

  18. Bone formation induced by strontium modified calcium phosphate cement in critical-size metaphyseal fracture defects in ovariectomized rats.

    Science.gov (United States)

    Thormann, Ulrich; Ray, Seemun; Sommer, Ursula; Elkhassawna, Thaqif; Rehling, Tanja; Hundgeburth, Marvin; Henß, Anja; Rohnke, Marcus; Janek, Jürgen; Lips, Katrin S; Heiss, Christian; Schlewitz, Gudrun; Szalay, Gabor; Schumacher, Matthias; Gelinsky, Michael; Schnettler, Reinhard; Alt, Volker

    2013-11-01

    The first objective was to investigate new bone formation in a critical-size metaphyseal defect in the femur of ovariectomized rats filled with a strontium modified calcium phosphate cement (SrCPC) compared to calcium phosphate cement (CPC) and empty defects. Second, detection of strontium release from the materials as well as calcium and collagen mass distribution in the fracture defect should be targeted by time of flight secondary ion mass spectrometry (TOF-SIMS). 45 female Sprague-Dawley rats were randomly assigned to three different treatment groups: (1) SrCPC (n = 15), (2) CPC (n = 15), and (3) empty defect (n = 15). Bilateral ovariectomy was performed and three months after multi-deficient diet, the left femur of all animals underwent a 4 mm wedge-shaped metaphyseal osteotomy that was internally fixed with a T-shaped plate. The defect was then either filled with SrCPC or CPC or was left empty. After 6 weeks, histomorphometric analysis showed a statistically significant increase in bone formation of SrCPC compared to CPC (p = 0.005) and the empty defect (p = 0.002) in the former fracture defect zone. Furthermore, there was a statistically significant higher bone formation at the tissue-implant interface in the SrCPC group compared to the CPC group (p < 0.0001). These data were confirmed by immunohistochemistry revealing an increase in bone-morphogenic protein 2, osteocalcin and osteoprotegerin expression and a statistically significant higher gene expression of alkaline phosphatase, collagen10a1 and osteocalcin in the SrCPC group compared to CPC. TOF-SIMS analysis showed a high release of Sr from the SrCPC into the interface region in this area compared to CPC suggesting that improved bone formation is attributable to the released Sr from the SrCPC.

  19. The immunohistochemical demonstration of parafollicular cells and evaluation of calcium-phosphate balance in patients with thyroid hemiagenesis

    Directory of Open Access Journals (Sweden)

    Jerzy Sowinski

    2011-07-01

    Full Text Available Thyroid hemiagenesis (TH is characterized by the congenital absence of one thyroid lobe. The aim of this study was to evaluate the calcium-phosphate balance in TH. Twenty patients with TH and 20 controls with a bilobed thyroid were studied. Serum concentrations of total calcium, parathormon and calcitonin were measured. Additionally, the immunohistochemical expression of calcitonin, chromogranin A (chA, neuron-specific enolase (NSE and calcitonin gene-related peptide (CGRP was evaluated in surgical specimens from patients with TH and controls. There were no significant differences in biochemical parameters between TH and controls. Positive staining for calcitonin was demonstrated in 3/8 thyroid sections from three patients with TH, but only in 2/33 sections from four controls (p < 0.005. All sections from patients with TH positive for calcitonin also expressed chA, NSE and CGRP. Two sections from controls positive for calcitonin presented an additionally positive reaction for chA, and one of them also for NSE. None presented positive staining for CGRP. Of three TH sections, in one, hyperplasia of C cells of medium grade, and in another hyperplasia of C cells of high grade, could be detected. In the controls, hyperplasia of C cells of low and medium grade was observed. TH was associated with slightly enhanced C cells hyperplasia compared to controls, which might indicate compensatory proliferation. However, the calcium-phosphate balance does not seem to be significantly affected. (Folia Histochemica et Cytobiologica 2011; Vol. 49, No. 2, pp. 299–305

  20. Editorial on the original article entitled "3D printing of composite calcium phosphate and collagen scaffolds for bone regeneration" published in the Biomaterials on February 14, 2014.

    Science.gov (United States)

    Li, Lan; Jiang, Qing

    2015-05-01

    The paper entitled "3D printing of composite calcium phosphate and collagen scaffolds for bone regeneration" published in the Biomaterials recently illuminated the way to make particular scaffolds with calcium phosphate (CaP) powder, phosphoric acid, type I collagen and Tween 80 in low temperature. After the optimal concentration of each component was determined, the scaffolds were evaluated in a critically sized murine femoral defect model and exhibited good material properties. We made some related introduction of materials applied in 3D printing for bone tissue engineering based on this article to demonstrate the current progress in this field of study.

  1. Biocalcite, a multifunctional inorganic polymer: Building block for calcareous sponge spicules and bioseed for the synthesis of calcium phosphate-based bone

    Directory of Open Access Journals (Sweden)

    Xiaohong Wang

    2014-05-01

    Full Text Available Calcium carbonate is the material that builds up the spicules of the calcareous sponges. Recent results revealed that the calcium carbonate/biocalcite-based spicular skeleton of these animals is formed through an enzymatic mechanism, such as the skeleton of the siliceous sponges, evolutionarily the oldest animals that consist of biosilica. The enzyme that mediates the calcium carbonate deposition has been identified as a carbonic anhydrase (CA and has been cloned from the calcareous sponge species Sycon raphanus. Calcium carbonate deposits are also found in vertebrate bones besides the main constituent, calcium phosphate/hydroxyapatite (HA. Evidence has been presented that during the initial phase of HA synthesis poorly crystalline carbonated apatite is deposited. Recent data summarized here indicate that during early bone formation calcium carbonate deposits enzymatically formed by CA, act as potential bioseeds for the precipitation of calcium phosphate mineral onto bone-forming osteoblasts. Two different calcium carbonate phases have been found during CA-driven enzymatic calcium carbonate deposition in in vitro assays: calcite crystals and round-shaped vaterite deposits. The CA provides a new target of potential anabolic agents for treatment of bone diseases; a first CA activator stimulating the CA-driven calcium carbonate deposition has been identified. In addition, the CA-driven calcium carbonate crystal formation can be frozen at the vaterite state in the presence of silintaphin-2, an aspartic acid/glutamic acid-rich sponge-specific protein. The discovery that calcium carbonate crystals act as bioseeds in human bone formation may allow the development of novel biomimetic scaffolds for bone tissue engineering. Na-alginate hydrogels, enriched with biosilica, have recently been demonstrated as a suitable matrix to embed bone forming cells for rapid prototyping bioprinting/3D cell printing applications.

  2. Fluoride-containing nanoporous calcium-silicate MTA cements for endodontics and oral surgery: Early fluorapatite formation in a phosphate-containing solution

    OpenAIRE

    Gandolfi, M.G.; Taddei, P.; Siboni, F.; Modena, E.; Ginebra Molins, Maria Pau; Prati, Claudio

    2011-01-01

    Gandolfi MG, Taddei P, Siboni F, Modena E, Ginebra MP, Prati C. Fluoride-containing nanoporous calcium-silicate MTA cements for endodontics and oral surgery: early fluorapatite formation in a phosphate-containing solution. International Endodontic Journal, 44, 938–949, 2011. Aim To test the chemical–physical properties and apatite-forming ability of experimental fluoride-doped calcium silicate cements designed to create novel bioactive materials for use in endodontics ...

  3. Performance of functionally graded implants of polylactides and calcium phosphate/calcium carbonate in an ovine model for computer assisted craniectomy and cranioplasty.

    Science.gov (United States)

    Eufinger, Harald; Rasche, Christian; Lehmbrock, Jutta; Wehmöller, Michael; Weihe, Stephan; Schmitz, Inge; Schiller, Carsten; Epple, Matthias

    2007-01-01

    Biodegradable functionally graded skull implants on the basis of polylactides and calcium phosphate/calcium carbonate were prepared in an individual mould using a combination of different processing techniques. A geometrically corresponding resection template was designed to enable a craniectomy and cranioplasty with the prepared implant in the same operation. After various preliminary experiments concerning degradation kinetics, pH evolution during degradation, micromorphology, biocompatibility tests in human osteoblast cell cultures and surgery of cadaver heads, a new large-animal model was developed for long-term in vivo studies. In eight 12-months-old sheep, the surgical templates were used to create 4.5 x 5 cm(2) calvarial defects which were then filled with the corresponding degradable implants in the same operation. The animals were sacrificed after 2, 9, 12 and 18 months, and the implants and the surrounding tissues were analysed by computer tomography (CT), macroscopic examination and microscopy. The new animal model proved to be reliable and very suitable for large individual craniectomies and cranioplasties. The formation of new bone from the dural layer of the meninges corresponded well to the degradation of the porous inner layer of the implants whereas the skull contour was stabilised by the compact outer layer over the follow-up period.

  4. Printability of calcium phosphate: calcium sulfate powders for the application of tissue engineered bone scaffolds using the 3D printing technique.

    Science.gov (United States)

    Zhou, Zuoxin; Buchanan, Fraser; Mitchell, Christina; Dunne, Nicholas

    2014-05-01

    In this study, calcium phosphate (CaP) powders were blended with a three-dimensional printing (3DP) calcium sulfate (CaSO4)-based powder and the resulting composite powders were printed with a water-based binder using the 3DP technology. Application of a water-based binder ensured the manufacture of CaP:CaSO4 constructs on a reliable and repeatable basis, without long term damage of the printhead. Printability of CaP:CaSO4 powders was quantitatively assessed by investigating the key 3DP process parameters, i.e. in-process powder bed packing, drop penetration behavior and the quality of printed solid constructs. Effects of particle size, CaP:CaSO4 ratio and CaP powder type on the 3DP process were considered. The drop penetration technique was used to reliably identify powder formulations that could be potentially used for the application of tissue engineered bone scaffolds using the 3DP technique. Significant improvements (pprinted constructs were manufactured, which exhibited appropriate green compressive strength and a high level of printing accuracy.

  5. Enhanced solubilization of iron and calcium phosphates by Aspergillus niger by the addition of alcohols

    Directory of Open Access Journals (Sweden)

    Cinthya Babá Barroso

    2013-04-01

    Full Text Available The present study deals with the effect of increased concentrations of alcohols (methanol and ethanol on the solubilization of FePO4 and CaHPO4 by Aspergillus niger. The efficiency of solubilization (ES of inorganic phosphates, fungal growth, acid production and pH variation were determined. The concentrations of alcohols that most favored the solubilization of phosphates were 4% methanol and 3% ethanol. The ES of phosphates by the fungus in media containing methanol ranged from 11-96% and 0.4-87% for ethanol. The stimulation or inhibition of solubilization was dependent on greater or lesser fungus growth, acid production and decreased pH. These responses were supported by the correlation between the amount of phosphate dissolved and fungal growth (0.630** to 0.831**, the production of acids (0.529* to 0.989** and a decrease in pH (-0.755** to -0.962**. Thus, the addition of alcohols facilitated insoluble phosphates dissolution during the fungus growth.

  6. Effect of several additives and their admixtures on the physico-chemical properties of a calcium phosphate cement.

    Science.gov (United States)

    Bohner, M; Merkle, H P; Landuyt, P V; Trophardy, G; Lemaitre, J

    2000-02-01

    Combinations of citrate (C6H5O(7)3-), pyrophosphate (P2O(7)4-) and sulfate (SO(4)2-) ions were used to modify the physico-chemical properties of a calcium phosphate cement (CPC) composed of beta-tricalcium phosphate (beta-TCP) and phosphoric acid (PA) solution. The results obtained with only one additive at a time are similar to those previously published. New facts are: the positive effect of C6H5O(7)3- ions on cement failure strain and their negative effect on cement pH. The position of the setting time maximum measured at an SO(4)2- concentration of 0.09 M was not displaced by the addition of C6H5O(7)3- and P2O(7)4- ions. However, the effect of SO(4)2- ions on the setting time was depressed by C6H5O(7)3- ions. Moreover, no increase in tensile strength was observed when increasing amounts of SO(4)2- were added into a C6H5O(7)3--containing cement. The latter results suggest a competitive effect of C6H5O(7)3- and SO(4)2- on setting time and tensile strength. Anhydrous dicalcium phosphate (DCP; CaHPO4) appeared in cement samples dried just after setting, but not in cement samples incubated for 24 h in deionized water before the drying step. It is believed that the setting reaction is stopped by the drying step, leaving a low internal pH in the sample, hence providing favorable conditions for the transformation of dicalcium phosphate dihydrate (DCPD) into DCP. Interestingly, even though C6H5O(7)3- ions dramatically lowered the equilibrium pH of the cement with 5 ml of deionized water, they still prevented the occurrence of the transformation of DCPD into DCP.

  7. Combined Percutaneous Iliosacral Screw Fixation With Sacroplasty Using Resorbable Calcium Phosphate Cement for Osteoporotic Pelvic Fractures Requiring Surgery.

    Science.gov (United States)

    Collinge, Cory A; Crist, Brett D

    2016-06-01

    Osteoporotic sacral fractures, including acute and chronic insufficiency fractures, are increasing in frequency and present a number of management problem. Many of these patients are treated nonoperatively with relative immobility (eg, bedrest, wheelchair, or weight-bearing restrictions) and analgesics, which likely make the osteoporotic component worse. Surgery in this patient population may be desirable in some cases with the goals of improving mobility, relieving pain, and healing in an aligned position while minimizing deformity progression. However, internal fixation of the osteoporotic pelvis can be difficult. Large unicortical lag screws are the workhorse of posterior pelvic fixation, and yet fixation in cancellous bone corridors of an osteoporotic sacrum seems unlikely to achieve optimal fixation. As a result, the operative management and clinical results of these difficult injuries may not be uniformly successful. The authors present a technique for treating osteoporotic patients with a sacral fracture when operative treatment is indicated using percutaneous screw fixation combined with screw augmentation using a resorbable calcium phosphate bone substitute or "cement." The guide wire for a 7.3-mm or other large cannulated lag screw is fully inserted along the desired bony sacral corridor as is standard. The lag screw is then inserted over the wire to the depth where cement is desired. The guide wire is removed, and the aqueous calcium phosphate is injected through the screw's cannulation. For acute fractures, cement was applied to the areas distant to the fracture; whereas in insufficiency fractures, the cement was inserted along most of the screw path. The guide wire then can be reinserted and the lag screw fully inserted. The rationale for using these 2 modalities is their synergistic effect: the cannulated screw provides typical screw fixation and also a conduit for cement application. The cement augments the lag screw's purchase in osteoporotic bone

  8. True absorption of phosphorus from di calcium phosphate, mono ammonium phosphate, triple superphosphate and urea-phosphate in bovine by the radio phosphorus dilution technique

    International Nuclear Information System (INIS)

    With the aim to study the utilization of alternative sources of phosphorus by ruminants. Twenty four males steers, with 250 Kg live weight and 18 months of age, were allocated in four groups of six animals each. The animals were housed in individual pens and received a diet containing chopped hay, corn and soybean meal, urea and mineral mixtures. The phosphate sources were added to supply 10 g of phosphorus per animal daily. The animals were injected intravenously and individually with 37 MBq of P-32 (N A2 H P O4) at the 20th day of the experimental trial into the jugular vein. Blood and faces were collected and sampled at 24 hours intervals, for 8 days. Based on the specific activities in plasma and faces, the fecal endogenous loss and true phosphorus absorption were determined. (author)

  9. Comparative study of biphasic calcium phosphate with beta-tricalcium phosphate in rat cranial defects--A molecular-biological and histological study.

    Science.gov (United States)

    Kunert-Keil, Christiane; Scholz, Franziska; Gedrange, Tomasz; Gredes, Tomasz

    2015-05-01

    The aim of this study was to evaluate the in vivo biocompatibility of a biphasic calcium phosphate (BCP) bone graft substitute consisting of 60% hydroxyapatite and 40% β-tricalcium phosphate (β-TCP) in comparison to a pure β-TCP of identical shape and porosity. The materials were evaluated using an established rat cranial defect model in 24 animals. One bone defect with a diameter of 5mm was created per animal. The defects were filled with either BCP or β-TCP and left to heal for 4 weeks. Twelve samples (6 per material) were processed for histological evaluation and immunohistochemistry. The remaining 12 samples were processed for mRNA expression analysis. No signs of inflammation or adverse material reactions were detected. New bone formation in the former defect site did not differ between the two groups (BCP: 49.2%; β-TCP: 52.4%). Osteoblast-like and TRAP-positive osteoclast-like cells were found at the surface of the bone graft substitute granules. The β-TCP group showed significantly higher mRNA levels for the bone resorption marker Acp5 and osteogenic differentiation marker Runx2. The expression of IGF1, IGF2, VEGF, Phex, Alpl, Col1, Col2, Bglap and MMP8 did not differ between the groups. The in vivo biocompatibility of BCP is to a large part identical to those of TCP. Within the limitation of the animal model, the implantation study shows that BCP can be used as bone graft substitute, due to the fact that the material integrates into tissue, remains stable in the implantation bed and serves as an osteoconductive scaffold. PMID:24439994

  10. Modulation of intestinal calcium and phosphate transport in young goats fed a nitrogen- and/or calcium-reduced diet.

    Science.gov (United States)

    Elfers, Kristin; Wilkens, Mirja R; Breves, Gerhard; Muscher-Banse, Alexandra S

    2015-12-28

    Feeding ruminants a reduced N diet is a common approach to reduce N output based on rumino-hepatic circulation. However, a reduction in N intake caused massive changes in Ca and inorganic phosphate (Pi) homoeostasis in goats. Although a single dietary Ca reduction stimulated intestinal Ca absorption in a calcitriol-dependent manner, a concomitant reduction of Ca and N supply led to a decrease in calcitriol, and therefore a modulation of intestinal Ca and Pi absorption. The aim of this study was to examine the potential effects of dietary N or Ca reduction separately on intestinal Ca and Pi transport in young goats. Animals were allocated to a control, N-reduced, Ca-reduced or combined N- and Ca-reduced diet for about 6-8 weeks, whereby N content was reduced by 25 % compared with recommendations. In Ussing chamber experiments, intestinal Ca flux rates significantly decreased in goats fed a reduced N diet, whereas Pi flux rates were unaffected. In contrast, a dietary Ca reduction stimulated Ca flux rates and decreased Pi flux rates. The combined dietary N and Ca reduction withdrew the stimulating effect of dietary Ca reduction on Ca flux rates. The expression of Ca-transporting proteins decreased with a reduced N diet too, whereas Pi-transporting proteins were unaffected. In conclusion, a dietary N reduction decreased intestinal Ca transport by diminishing Ca-transporting proteins, which became clear during simultaneous N and Ca reduction. Therefore, N supply in young ruminant nutrition is of special concern for intestinal Ca transport. PMID:26443238

  11. Fusion of phospholipid vesicles induced by muscle glyceraldehyde-3-phosphate dehydrogenase in the absence of calcium.

    Science.gov (United States)

    Morero, R D; Viñals, A L; Bloj, B; Farías, R N

    1985-04-01

    Ca2+-induced fusion of phospholipid vesicles (phosphatidylcholine/phosphatidic acid, 9:1 mol/mol) prepared by ethanolic injection was followed by five different procedures: resonance energy transfer, light scattering, electron microscopy, intermixing of aqueous content, and gel filtration through Sepharose 4-B. The five methods gave concordant results, showing that vesicles containing only 10% phosphatidic acid can be induced to fuse by millimolar concentrations of Ca2+. When the fusing capability of several soluble proteins was assayed, it was found that concanavalin A, bovine serum albumin, ribonuclease, and protease were inactive. On the other hand, lysozyme, L-lactic dehydrogenase, and muscle and yeast glyceraldehyde-3-phosphate dehydrogenase were capable of inducing vesicle fusion. Glyceraldehyde-3-phosphate dehydrogenase from rabbit muscle, the most extensively studied protein, proved to be very effective: 0.1 microM was enough to induce complete intermixing of bilayer phospholipid vesicles. Under conditions used in this work, fusion was accompanied by leakage of internal contents. The fusing capability of glyceraldehyde-3-phosphate dehydrogenase was not affected by 5 mM ethylenediaminetetraacetic acid. The Ca2+ concentration in the medium, as determined by atomic absorption spectroscopy, was 5 ppm. Heat-denatured enzyme was incapable of inducing fusion. We conclude that glyceraldehyde-3-phosphate dehydrogenase is a soluble protein inherently endowed with the capability of fusing phospholipid vesicles.

  12. 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.

  13. Effect of biphasic calcium phosphate nanocomposite on healing of surgically created alveolar bone defects in beagle dogs

    Science.gov (United States)

    Wang, Lanlei; Guan, Aizhong; Shi, Han; Chen, Yangxi; Liao, Yunmao

    2009-09-01

    The aim of the present study was to investigate the effect of porous biphasic calcium phosphate nanocomposite (nanoBCP) scaffolds bioceramic. Alveolar bone defects were surgically created bilaterally at the buccal aspects of the upper second premolar in fourteen beagle dogs. After root conditioning with ethylenediaminetetraacetate (EDTA), nanoBCP was randomly filled in the defects and nothing was put into the contralaterals as controls. Dogs were killed at the 12th weeks. Histological observations were processed through a light microscopy. The results revealed that a great amount of functional periodontal fissures formed in the defects in the nanoBCP groups while minimal bone took shape in the controls. In this study, nanoBCP has proved to work well as a biocompatible and osteoconductive scaffold material to promote periodontal regeneration effectively.

  14. 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.

  15. 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

  16. Bone healing around nanocrystalline hydroxyapatite, deproteinized bovine bone mineral, biphasic calcium phosphate, and autogenous bone in mandibular bone defects

    DEFF Research Database (Denmark)

    Broggini, Nina; Bosshardt, Dieter D; Jensen, Simon S;

    2015-01-01

    The individual healing profile of a given bone substitute with respect to osteogenic potential and substitution rate must be considered when selecting adjunctive grafting materials for bone regeneration procedures. In this study, standardized mandibular defects in minipigs were filled with nanocr......The individual healing profile of a given bone substitute with respect to osteogenic potential and substitution rate must be considered when selecting adjunctive grafting materials for bone regeneration procedures. In this study, standardized mandibular defects in minipigs were filled...... with nanocrystalline hydroxyapatite (HA-SiO), deproteinized bovine bone mineral (DBBM), biphasic calcium phosphate (BCP) with a 60/40% HA/β-TCP (BCP 60/40) ratio, or particulate autogenous bone (A) for histological and histomorphometric analysis. At 2 weeks, percent filler amongst the test groups (DBBM (35.65%), HA...

  17. Multifunctional nanocrystalline calcium phosphates loaded with Tetracycline antibiotic combined with human adipose derived mesenchymal stromal stem cells (hASCs).

    Science.gov (United States)

    Marycz, K; Pazik, R; Zawisza, K; Wiglusz, K; Maredziak, M; Sobierajska, P; Wiglusz, R J

    2016-12-01

    Osteoconductive drug delivery system composed of nanocrystalline calcium phosphates (Ca10(PO4)6(OH)2/β-Ca3(PO4)2) co-doped with Yb(3+)/Er(3+) ions loaded with Tetracycline antibiotic (TC) was developed. Their effect on human adipose derived mesenchymal stromal stem cells (hASCs) as a potential reconstructive biomaterial for bone tissue regeneration was studied. The XRD and TEM measurements were used in order to determine the crystal structure and morphology of the final products. The characteristics of nanocomposites with the TC and hASCs as potential regenerative materials as well as the antimicrobial activity of the nanoparticles against: Staphylococcus aureus ATCC 25923 as a model of the Gram-positive bacteria, Escherichia coli ATCC 8739 of the Gram-negative bacteria, were shown. These combinations can be a promising material for theranostic due to its regenerative, antimicrobial and fluorescent properties. PMID:27612684

  18. Effect of curing conditions on the dimensional and thermal stability of calcium phosphate cement for elevated temperature applications

    Energy Technology Data Exchange (ETDEWEB)

    Blom, Johan [Vrije Universiteit Brussel, Department of Mechanics of Materials and Constructions, Pleinlaan 2, Brussels 1050 (Belgium); Rahier, Hubert [Vrije Universiteit Brussel, Research Group of Physical Chemistry and Polymer Sciences, Pleinlaan 2, Brussels 1050 (Belgium); Wastiels, Jan, E-mail: Jan.Wastiels@vub.ac.be [Vrije Universiteit Brussel, Department of Mechanics of Materials and Constructions, Pleinlaan 2, Brussels 1050 (Belgium)

    2014-12-15

    Calcium phosphate cements (CPCs) are attractive materials for elevated temperature applications, like moulds to process thermoplastics up to 300 °C. The CPC resulting from the reaction of wollastonite with phosphoric acid cured at room temperature however contains hydrated phases like brushite, and is thus not stable when exposed to temperatures above 200 °C. A non-contact method based on digital image correlation demonstrated that isothermal curing at 60 °C reduces the thermal shrinkage up to 300 °C by 25%. This curing method results in the direct formation of the more stable monetite in a shorter curing time. The correlated results of TGA, pH of the filtration water, and DSC analysis on partially cured material indicate this. XRD diffractograms and SEM images in combination with EDX show the evolution of the transformation of wollastonite into monetite, and the structure and morphology of the formed material.

  19. Adsorption of levofloxacin onto goethite: Effects of pH, calcium and phosphate

    NARCIS (Netherlands)

    Qin, X.P.; Liu, F.; Wang, G.C.; Weng, L.; Li, L.

    2014-01-01

    Adsorption of levofloxacin (LEV), one of the extensively used antibiotics, onto goethite was investigated using batch experiments. The adsorption of LEV on goethite was pH-dependent. A maximum adsorption was reached at pH 6. Above or below pH 6, the adsorption decreased. In the presence of calcium (

  20. 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

  1. 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

  2. The effect of a calcium phosphate mouth rinse on (chemo) radiation induced oral mucositis in head and neck cancer patients : a prospective study

    NARCIS (Netherlands)

    Stokman, M. A.; Burlage, F. R.; Spijkervet, F. K. L.

    2012-01-01

    Objectives: Promising results of a calcium phosphate (CP) mouth rinse on reduced severity of oral mucositis have been reported. The aim of this study was to determine the effect of a CP mouth rinse on the frequency, duration and severity of (chemo) radiation induced oral mucositis in patients with h

  3. Bone reaction adjacent to microplasma-sprayed calcium phosphate-coated oral implants subjected to an occlusal load, an experimental study in the dog

    NARCIS (Netherlands)

    Junker, R.; Manders, P.J.D.; Wolke, J.G.C.; Borisov, Y.; Braceras, I.; Jansen, J.A.

    2011-01-01

    BACKGROUND: A new microplasma spraying equipment (MSE) to deposit calcium phosphate (CaP) ceramic coatings onto titanium substrates has been developed. With this system, it is possible to spray fine particles and to apply textured hydroxylapatite coatings onto titanium surfaces. Moreover, due to the

  4. Post-prandial changes in plasma mineral levels in rainbow trout fed a complete plant ingredient based diet and the effect of supplemental di-calcium phosphate

    NARCIS (Netherlands)

    Antony Jesu Prabhu, P.; Schrama, J.W.; Mariojouls, C.; Godin, S.; Fontagné-Dicharry, S.; Geurden, I.; Surget, A.; Bouyssiere, B.; Kaushik, S.J.

    2014-01-01

    Post-prandial changes in plasma mineral levels and utilisation of minerals in rainbow trout fed complete plant ingredient based diets with or without supplemental di-calcium phosphate (DCP) were studied over an 8 week period. Three diets were used: diet M was FM and fish oil (FO) based diet (control

  5. Tuning the Degradation Rate of Calcium Phosphate Cements by Incorporating Mixtures of Polylactic-co-Glycolic Acid Microspheres and Glucono-Delta-Lactone Microparticles

    NARCIS (Netherlands)

    Sariibrahimoglu, K.; An, J.; Oirschot, B.A.J.A. van; Nijhuis, A.W.G.; Eman, R.M.; Alblas, J.; Wolke, J.G.C.; Beucken, J.J.J.P van den; Leeuwenburgh, S.C.G.; Jansen, J.A.

    2014-01-01

    Calcium phosphate cements (CPCs) are frequently used as synthetic bone graft materials in view of their excellent osteocompatibility and clinical handling behavior. Hydroxyapatite-forming CPCs, however, degrade at very low rates, thereby limiting complete bone regeneration. The current study has inv

  6. Fabrication and materials properties of high-density polyethylene (HDPE)/biphasic calcium phosphate (BCP) hybrid bone plates

    International Nuclear Information System (INIS)

    Biphasic calcium phosphate-reinforced high-density polyethylene (BCP/HDPE) hybrid composite is a new orthopedic biomaterial, which was made to simulate a natural bone composition. Calcium phosphate systems and HDPE hybrid composites have been used in biomedical applications without any inflammatory response. Differences in natural bone of both materials have motivated the use of coupling agents to improve their interfacial interfacial interactions. The composites were prepared using medical grade BCP powder and granular polyethylene. This material was produced by replacing the mineral component and collagen soft tissue of the bone with BCP and HDPE, respectively. As expected, increased volume fraction of either reinforcement type over 0 ∼ 50 vol.% resulted in a increased Vickers hardness and Young's modulus. Thus, BCP particle-reinforced HDPE composites possessed improved material and mechanical properties. BCP particles-reinforced composites were anisotropic due to an alignment of the particles in the matrix during a processing. On the other hand, bending and tensile strength was dramatically changed in the matrix. To change the material and mechanical properties of HDPE/BCP composites, the process of a blending was used, and its effect on the microstructure and mechanical proprieties of HDPE/BCP composites were investigated by means of FT-IR/ATR spectroscopy, XRD, FE-SEM, Vickers Hardness Testing Machine, Universal Testing Machine, Mercury Porosimeter and Ultrasonic Flaw Detector at room temperature. For the evaluation of the cell viability and proliferation onto the external surface of HDPE/BCP hybrid plates with a HaCaT cell line, which is a multipotent cell line able to differentiate towards different phenotypes under the action of biological factors, has been evaluated with in vitro studies and quantified by colormetric assays. These findings indicate that the HDPE/BCP hybrid plates are biocompatible and non-toxic