Hydroxyapatite characterization

Aryal, S., Bahadour, K.C.R., Bhattarai, J.R., Prabu, P. and Kim, H.Y. (2006) Immobilization of collagen on gold nanoparticles, preparation, characterization and hydroxyapatite growth, foumal of Materials Chemistry, 16, 4642-4648. 

Chen, C.-W., Oakes, C.S., Byrappa, K., Riman, R.E., Brown, K., TenHuisen, K. S. and Janas, V.F. (2004) Synthesis, characterization, and dispersion properties of hydroxyapatite prepared by mechanochemical-hydrothermal... 

In order to achieve the firm fixation of the artificial cornea to host tissues, composites of collagen-immobilized poly(vinyl alcohol) hydrogel with hydroxyapatite were synthesized by a hydroxyapatite particles kneading method. The preparation method, characterization, and the results of corneal cell adhesion and proliferation on the composite material were studied. PVA-COL-HAp composites were successfully synthesized. A micro-porous structure of the PVA-COL-HAp could be introduced by hydrochloric acid treatment and the porosity could be controlled by the pH of the hydrochloric acid solution, the treatment time, and the crystallinity of the HAp particles. Chick embryonic keratocyto-like cells were well attached and proliferated on the PVA-COL-HAp composites. This material showed potential for keratoprosthesis application. Further study such as a long-term animal study is now required [241]. 

S. Ben Abdelkader, I. Khattech, C. Rey, M. Jemal, Synthesis, characterization and thermochemistry of calcium-magnesium hydroxyapatite and fluorapatite, Thermochim. Acta 376 (2001) 25-36. 

Apatite surface properties have been characterized with respect to their role as sorptive surfaces (Wu et al. 1991 Somasundaran Wang 1984 Chander Fuerstenau 1984 Leyva et al. 2001). The point of zero charge (PZC), as measured by titration, electrophoresis, or streaming potential varies from pH values of 7 to 10 for hydroxyapatite and from 4 to 12 for fluoroapatite, and is a function of (1) the presence of C02, (2) ionic strength, and (3) time/aging of the mineral. 

Leyva et al. (2001) studied Sb(III) adsorption to hydroxyapatite. They conducted adsorption isotherms in closed vessels at Sb concentrations of 0.05-50 mg/L, constant I (0.01 m), constant solid phase concentrations of 10g/dm3 at pH values between 5 and 8. The hydroxyapatite was characterized by X-ray diffraction (XRD), SF.M-F.DS, X-ray photoelectron spectroscopy (XPS), and infrared (IR) spectroscopy. Langmuir adsorptions models revealed Fmax of 6.7 x 10 xmol/m2 and Xads = 1.5 x 103dm3/mol. As Sb adsorption occurred, the isoelectric point (pHicp) of the hydroxyapatite changed from 4.0 to 12.0. The decline in the pHjep during sorption as well as the absence of... 

Laperche Traina (1998) studied Pb uptake on hydroxyapatite at low initial solution concentration of Pb (103 mg/L). For this, EXAFS was used to characterize the local coordination environment of Pb on the apatite. The baseline corrected, Fourier-transformed EXAFS spectra revealed fc-values at >3 A, suggesting that Pb was not randomly sorbed. Radial structure functions (RSF) showed three intense peaks, characteristic of pyromorphite. 

The most common and widely distributed phosphate minerals are the apatite group, with the general formula Ca10(PO4)6(X)2. The apatite is designated as fluorapatite, hydroxyapatite, or chlorapatite, when X = F, OH, or Cl, respectively. The most abundant sedimentary apatite is carbonate fluorapatite (ffancolite). Relative to pure fluorapatite, francolite is characterized by the substitution of Na and Mg for Ca and of carbonate and fluoride for phosphate. An empirical formula for francolite... 

Fluorine (F) and its metabolites are of importance in protecting teeth from caries. Fluorine is included in calcium hydroxyapatite, and it promotes the precipitation of calcium phosphate Ca(P03)2 and accelerates the remineralization. The necessary concentration of Fluorine added to drinking water to prevent caries is approximately 1 mg/L. Application of higher Fluorine concentrations (above 8 mg/L) leads to fluorosis. This is a disease that is characterized by a disturbance in the function of the thyroid gland. A long-term application of fluorine leads to intensive mineralization (possible precipitation of calcium sulfate), deformation of bones with possible accretion, and calcification of the connections. 

Recently, PCL containing bovine bone hydroxyapatite (HA) and hydroxyapa-tite/Ag (HA-Ag) composite nanoflbers were prepared via an electrospinning process [43]. The morphology, structure and thermal properties of the PCL, PCL/HA, and PCL/HA-Ag composite nanoflbers before and after immersion in SBF were characterized. SEM images revealed that the nanoflbers were well-oriented and incorporated the HA-Ag nanoparticles well. Mechanical study revealed that the yield stress of PCL/HA-Ag composite nanoflbers showed a higher value than that of PCL/HA composite, possibly due to the addition of metallic Ag nanoparticles [43]. 

Skartsila, K. and Spanos, N., Surface characterization of hydroxyapatite Potentiometric titrations coupled with solubihty measurements, 7. Colloid Interf. Sci., 308, 405, 2007. 

Fig. 5 Characterization of crystals formed by isolated MVs in the presence of varying [Pi]/[PPi] ratio [from ref. 77], (a) Minerals formed by MVs in buffer containing 2 mM Ca, 1.42-3.42 mM P, and varying amounts of PPi. (b) Infrared spectra of minerals produced by MVs revealing the presence of hydroxyapatite (HA) or calcium pyrophosphate dihydrate (CPPD) crystals...

Cement is a binder that sets and hardens by itself or binds other materials together. The most widely known application of cements is in construction a second one is the area of bone cements. Cements used in construction are characterized as hydraulic or nonhydraulic and mostly for the production of mortars and concrete. Hydraulic cements set and harden after combining with water. Most construction cements are hydraulic and based on Portland cement, which consists of calcium silicates (at least 2/3 by weight). Nonhydraulic cements include the use of nonhydraulic materials such as lime and gypsum plasters. Bone cements and bone cement composites refer to compounds that have a polymer matrix with a dispersed phase of particles. For instance, polymethylmethacrylate (PMMA) is reinforced with barium sulphate crystals (for radio-opacity) or with hydroxyapatite... 

Heimann, R.B. (2009) Characterization of as-plasma-sprayed and incubated hydroxyapatite coatings with high resolution techniques. Materialwiss. Werkstofftech.,... 

Abrishamchian, A., Hooshmand, T., Mohammadi, M., and Hajafi, F. (2013) Preparation and characterization of multi-walled carbon nanotube/hydroxyapatite nanocomposite film dip coated on Ti-6A1-4V by sol-gel method for biomedical applications an in vitro study. Mater Sci. Eng. C, 33 (4), 2002 -2010. 

Campbell, A.A., Song, L., Li, X., Bottoni, C., Nelson, B.J., Brooks, D.E., and Dejong, E.S. (2000) Development, characterization, and anti-microbial efficacy of hydroxyapatite-chlorhexidine coatings produced by surface induced mineralization. J. Biomed. Mater. Res. (Appl. Biomater.), 53, 400-407. 

Ciobanu, G., Ignat, D., and Luca, C. (2009) Polyurethane-hydroxyapatite bionanocomposites development and characterization. Chem. Bull. Tolitehnika Univ. Timisoara, 54 (68), 1-57. 

Demnati, I., Grossin, D., Errassifi, F., Combes, C., Rey, C., and Le Boley, N. (2014a) Sythesis of fluor-hydroxyapatite powder for plasma sprayed biomedical coatings characterization and improvement of the powder properties. Powder Technol., 255, 23-28. 

Kwok, C.T., Wong, P.K., Cheng, F.T., and Man, H.C. (2009) Characterization and corrosion behaviour of hydroxyapatite coatings on Ti6Al4V fabricated by electrophoretic deposition. Appl Surf. Set,... 

Rath, PC., Besra, L., Singh, B.P, and Bhattacharjee, S. (2012) Tita-nia/hydroxyapatite bi-layer coating on Ti metal by electrophoretic deposition characterization and corrosion studies. Ceram. Int., 38, 3209—3216. 

Rosu, R.A., Bran, I., Popescu, M., and Opris, C. (2012) In vitro characterization of hydroxyapatite layers deposited by APS and HVOF thermal spraying methods. Ceram. Silik., 56, 25—31. 

Salman, S.A., Kuroda, K., and Okido, M. (2013) Preparation and characterization of hydroxyapatite coating on AZ31 Mg alloy for implant application. Bioinorg. Chem. Appl., 2013, Article ID 175756, 6 pp. 

L. (2014) Fabrication, characterization and in.vitro evaluation of nanostructured zirconia/hydroxyapatite composite films on zirconium. Surf. Coat. Technol., 238, 58-67. 

Vasilescu, C., Popa, M., Drob, S.I., Osiceanu, P., Anastasescu, M., and Calderon Moreno, J.M. (2014) Deposition and characterization of bioactive ceramic hydroxyapatite coating on surfaces of Ti-15Zr-5Nb alloy. Ceram. Int. 40 (9 Part B), 14973-14982. 

Wang, C., Lin, J., Ju, C., Ong, H., and Chang, R. (1997) Structural characterization of pulsed-laser deposited hydroxyapatite films on titanium substrate. Biomaterials, 18, 1331-1338. 

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