Microstructural, mechanical, and osteocompatibility properties of Mg²⁺/F⁻‐doped nanophase hydroxyapatite

Abstract

Pure as well as Mg(2+)- and F(-)-doped nanophase (i.e., grain sizes in the nanometer regime in at least one dimension) hydroxyapatite (HA) samples were synthesized by a precipitation method followed by sintering at 1100 degrees C for 1 h to determine their microstructural, mechanical, and osteoblast (bone-forming cell) adhesion properties pertinent for orthopedic applications. Different amounts of Mg(2+) and F(-) ions (specifically from 0 to 7.5 mol %) were doped into the HA samples. X-ray diffraction was used to identify the presence of crystalline phases, lattice parameters, and crystal volumes of the samples. Fourier transform infrared (FTIR) was further used to chemically characterize HA, and thus FTIR patterns revealed the characteristic absorption bands of HA. Microhardness measurements were also performed to assess mechanical properties of the novel formulations. Results of this study showed an improvement in sample density for some of the samples, which was a consequence of the molar percentage variation of the dopants. Moreover, in most of the samples doped with Mg, beta-tricalcium phosphate was observed as a second phase to HA. In addition, 1% Mg- and 2.5% F-doped HA had the highest microhardness values. Lastly, results demonstrated the highest osteoblast densities when the HA samples were doped with 2.5-7.5% Mg(2+) and F(-). Thus, the results of this study suggest that decreasing the grain size of HA into the nanometer regime and doping HA with Mg(2+) and F(-) can potentially increase the efficacy of HA for orthopedic applications.

High‐Performance Hydroxyapatite Scaffolds for Bone Tissue Engineering Applications

“…Despite these advantages the HA exhibits quite limited mechanical properties, that become scarce when a highly porous sample is considered. 27,28 In this study, we describe the fabrication method and the characterization of a highly porous HA scaffold produced by polymer sponge replica method using a submicrometer HA powder synthesized in our laboratories. Many attempts have been made to improve HA mechanical properties by optimizing the processing, sintering regimes, [17][18][19][20] and by controlling important parameters such as particle size and shape, 21 particle distribution, and agglomeration 22 thereby obtaining high density.…”

Influence of MgO, SrO, and ZnO Dopants on Electro-Thermal Polarization Behavior and In Vitro Biological Properties of Hydroxyapatite Ceramics

“…34 The amount (the wt% fraction) of different phases (i.e., HAp, b-tricalcium phosphate (TCP), tetra tricalcium phosphate (TTCP), CaO) present in the sintered undoped and doped HAp samples was quantitatively determined by using the ratio of the relative intensities of the most prominent or highest diffracted XRD peaks of the respective phases by the the following equation 35 : The bulk densities of the sintered doped and undoped HAp were measured by the Archimedian's method.…”

“…The theoretical densities of the different sintered samples were calculated using rule of mixture based on XRD phase analysis results using the the following equation 34 : The theoretical densities of the different sintered samples were calculated using rule of mixture based on XRD phase analysis results using the the following equation 34 :…”

Mg-Containing Hydroxyapatite Coatings Produced by Plasma Electrolytic Oxidation of Titanium

“…Owing to that, improvements in the biological properties and greater similarity to human bone can be achieved by the incorporation of ionic elements into synthetic HA 36,37 . Magnesium is the fourth most abundant ion present in the human body, where it helps to inhibit crystallization, to reduce crystal size, to decrease the proliferation and activities of osteoblast-like cells [38][39][40][41] . Therefore, magnesium deficiency can affect bone metabolism and growth, reducing osteoplastic activity and resulting in fragile bones [42][43][44][45][46] .…”