Structure of Biocompatible Coatings Produced from Hydroxyapatite Nanoparticles by Detonation Spraying

Abstract

Detonation-produced hydroxyapatite coatings were studied by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Raman spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy. The source material for detonation spraying was a B-type carbonated hydroxyapatite powder. The coatings consisted of tetracalcium phosphate and apatite. The ratio depended slightly on the degree of crystallinity of the initial powder and processing parameters of the coating preparation. The tetracalcium phosphate phase was homogeneous; the apatite phase contained defects localized on the sixfold axis and consisted of hydroxyapatite and oxyapatite. Technological factors contributing to the transformation of hydroxyapatite powder structure during coating formation by detonation spraying are discussed.

Structural variations of bioactive glasses obtained by different synthesis routes

“…The band at 1062 and 1073 cm −1 , observed for 45S5_gel and A2_gel materials, respectively, can be assigned to asymmetric stretching mode of PO 4 3-in the apatite-like crystalline phases [49], namely Na 2 Ca 4 (PO 4 ) 2 SiO 4 (silicorhenanite) and Ca 5 (PO 4 ) 3 OH (hydroxyapatite). The band in this spectral region is also characteristic for the asymmetric stretching of Q 4 Si units [45,46].…”

Synthesis and Optimization of Colloidal Hydroxyapatite Nanoparticles by Hydrothermal Processes

“…These peaks can be attributed to tetracalcium phosphate (TTCP) phase or tricalcium phosphate (β-TCP) phase which is usually present in the HA nanoparticles. 31 The crystallite size calculations for the nanoparticles were performed from the Scherrer equation: (1) where L is the crystallite size; K is the proportionality constant (the Scherrer constant, K = 0.9); λ is the wavelength of radiation in the X-rays emission CuKα (λ = 1.5406 Å); β is the peak width in full width at half maximum (FWHM); and θ is Bragg's diffraction angle. 35,36 Table 2 shows crystallite size (L) for different diffraction peaks in each experiment.…”

“…The experimental conditions used were based on the literature. [17][18][19]25,27,31,32 All matrix calculi were carried out using the free software GUI Octave 33 (version 3.6), in Microsoft Windows 10 Home 64 bits System. Two levels, high (+) and low (-), were defined for each factor, as shown in Table 1.…”

“…In this work an empirical model that allows the control of the shape and size of HA nanoparticles due to the control of the initial experimental conditions was proposed. Although studies using factorial design to understand the effect of some experimental conditions on the final properties of colloidal HA nanoparticles have been previously published, 19,21,22,24,25,28,29,31 only a few of them evaluated the statistical significance of the effects. Usually, these studies present models that consider the experimental parameters that affect the size of the particles, which were previously identified in univariate studies, but their statistical significance has been ignored, which is not true in multivariate studies.…”

Electrodeposition of Hydroxyapatite on a Metallic 3D-Woven Bioscaffold

“…These include the presence of amorphous phases resulting from the extremely high process temperatures [26] and the difficulty of coating implants with complex geometrical features due to the line-of-sight nature of the process [27]. Alternative methods include: Sol-gel processing [28,29], biomimetic deposition [30][31][32], hydrothermal processing [33], electrophoresis [34], gas detonation deposition [35][36][37], and electrodeposition [38][39][40]. Among these, electrodeposition is the most promising technique because it can deposit homogeneous HAp coatings on interior and exterior surfaces of metallic scaffolds, regardless of a sample's size or pore geometry.…”