Synthesis of magnesium- and manganese-doped hydroxyapatite structures assisted by the simultaneous incorporation of strontium.

Samples of crystalline hydroxyapatite (HA) with and without the addition of individual Mg(2+), Mn(2+) and Sr(2+) ions and samples with the addition of all three ions simultaneously were prepared using the precipitation method in an aqueous medium. Chemical, structural, spectroscopic and thermophysical analyses of the synthesized samples were conducted. The obtained results indicate that Sr(2+) ions were easily incorporated into the HA crystal structure, whereas it was difficult to incorporate Mg(2+) and Mn(2+) ions into the HA lattice when these ions were individually introduced into the samples.

Interlaboratory studies on in vitro test methods for estimating in vivo resorption of calcium phosphate ceramics.

Unlabelled: A potential standard method for measuring the relative dissolution rate to estimate the resorbability of calcium-phosphate-based ceramics is proposed. Tricalcium phosphate (TCP), magnesium-substituted TCP (MgTCP) and zinc-substituted TCP (ZnTCP) were dissolved in a buffer solution free of calcium and phosphate ions at pH 4.0, 5.

A study of the physical, chemical and biological properties of TiO2 coatings produced by micro-arc oxidation in a Ca-P-based electrolyte.

In this work, a porous and homogeneous titanium dioxide layer was grown on commercially pure titanium substrate using a micro-arc oxidation (MAO) process and Ca-P-based electrolyte. The structure and morphology of the TiO2 coatings were characterized by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy, and profilometry. The chemical properties were studied using electron dispersive X-ray spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy.

Biocompatibility of wollastonite-poly(N-butyl-2-cyanoacrylate) composites.

Wollastonite-poly(n-butyl-2-cyanoacrylate) composite (W-BCA) has been proposed to immobilize anatomically bone fragments in order to achieve an optimal healing process. The present study evaluated the in vitro and in vivo behavior of three types of fillers: powdered natural wollastonite (Wn), synthetic pseudowollastonite powder (Ws), and synthetic pseudowollastonite powder coated with 5% acetyl tributyl citrate (Wst). The Wst-BCA composite underwent a higher degradability in the real-time degradation test and a superior cytotoxic effect; whereas the Wn-BCA composite showed a higher degradability in the accelerated test with no cytotoxicity.

Surface-enhanced Raman scattering study of the redox adsorption of p-phenylenediamine on gold or copper surfaces.

The adsorption of the p-phenylenediamine (PPD(+)) radical cation on gold or copper nanoparticle (NP) surfaces was studied through surface-enhanced Raman scattering (SERS) spectroscopy, excited at 1064 nm. The SERS spectra were obtained from gold or copper NPs after exposure to non-oxidized p-phenylenediamine (PPD) aqueous solution, in millimolar concentration. The gold NPs were synthesized as nanoshells involving silica cores (SiO(2)@Au) and the copper NPs were obtained in aqueous medium, undergoing surface oxidation with the formation of Cu(II) oxide nanoshell (Cu@CuO).

Understanding the impact of divalent cation substitution on hydroxyapatite: an in vitro multiparametric study on biocompatibility.

Hydroxyapatite (HA), a stable and biocompatible material for bone tissue therapy, may present a variable stoichiometry and accept a large number of cationic substitutions. Such substitutions may modify the chemical activity of HA surface, with possible impact on biocompatibility. In this work, we assessed the effects of calcium substitution with diverse divalent cations (Pb(2+), Sr(2+), Co(2+), Zn(2+), Fe(2+), Cu(2+), or Mg(2+)) on the biological behavior of HA.

Surface characterization of dental implants coated with hydroxyapatite by plasma spray and biomimetic process.

Purpose: The aim of this study was to characterize implants coated with hydroxyapatite (HA) using 2 different processes.

Materials And Methods: Commercially pure titanium implants were coated with HA using a modified biomimetic process and the plasma spray process. These implants were characterized by scanning electron microscopy, Fourier-transformed infrared spectroscopy, and x-ray photoelectron spectroscopy.

Physicochemical characterization of two deproteinized bovine xenografts.

Calcium phosphate salts, or more specifically hydroxyapatite, are products of great interest in the fields of medical and dental science due to their biocompatibility and osteoconduction property. Deproteinized xenografts are primarily constituted of natural apatites, sintered or not. Variations in the industrial process may affect physicochemical properties and, therefore, the biological outcome.

Hydroxyapatite deposition by electrophoresis on titanium sheets with different surface finishing.

Hydroxyapatite coatings are commonly applied to metallic biomedical implants to accelerate osseointegration. These coatings, usually produced by plasma spray techniques, can be obtained by alternative processes, like biomimetic process, electrolytic deposition, or electrophoretic process as well. Electrophoretic deposition of hydroxyapatite exhibits several advantages like simplicity and low cost.