Characterization of Magnesium‐Doped Hydroxyapatite Prepared by Sol‐Gel Process

Abstract

Pure and doped hydroxyapatite (HA) nanocrystalline powders (Ca10‐xMgx(PO4)6OH2) were synthesized using sol‐gel process. For this, calcium nitrate tetrahydrate, magnesium nitrate hexahydrate, and phosphorous pentoxide were used as precursors for Ca, Mg, and P, respectively. Calculated amounts of magnesium ions (Mg+2) especially from 0 to 10% (molar ratio) were incorporated as dopant into the calcium sol solution. The structure and morphology of the gels obtained after mixing the phosphorous and (calcium + magnesium) sol solution were different, and their condensations in time depend on the quantities of magnesium added. The several powders resulting from the gels dried and sintered at 500°C for 1 h were characterized by thermogravimetry (TG), Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), and inductively coupled plasma (ICP). Additionally, their agglomeration, morphology, and particle size were investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The specific surface area of each sample was measured by the Brunauer–Emmett–Teller (BET) gas adsorption technique. The results of XRD, FTIR, and ICP values ranged between 0.45 and 2.11 mg/L indicated that the magnesium added in the calcium solution was incorporated in the lattice structure of HA so prepared, while those obtained by SEM and TEM confirmed the influence of Mg on their morphology (needle and irregular shape) and crystallite size, which is about 30–60 nm. The as‐prepared powders had a specific surface area ranged between 6.37 and 27.60 m2/g.

Synthesis, characterization, in vitro bioactivity and antimicrobial activity of magnesium and nickel doped silicate hydroxyapatite

“…1) [30]. XRD pattern also showed the broadening of reflections due to the reduction in the crystallite size and increase in the lattice disorder, which were attributed to the Mg 2 þ substitution in the HA lattice (Table 2) [31]. In addition to the standard peaks for HA, two very low intensity peaks were also observed in the XRD pattern of Mg-SiHA and 1Ni-Mg-SiHA at 42.911 and 62.201, which were respectively assigned to the (2 0 0) and (2 2 0) reflection of magnesium oxide (MgO) (JCDPS no.…”

Synthesis of macro and micro porous hydroxyapatite (HA) structure from waste kina ( Evechinus chloroticus ) shells

“…Walsh et al [10] synthesized mineralised red algae and reported XRD results that showed the conversion to hydroxyapatite (HA) at 100 °C for 14 h was successful and the composition of the obtained HA was characterized to be 64% HA, 33% CaCO 3 and 3% TCP, reinforcing that a 100% conversion under these conditions was not achievable. The longer processing time in this study (28 h) may be due to the presence of magnesium, which has an inhibitory effect on the HA crystal growth and increases the lattice disorder [19] . However, maintaining the conversion process at high pH (pH > 10) and longer processing time improves the formation of the HA layer on the shell surface [20] , which appears to be the case in the present study.…”

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

“…Recent studies have shown that HA can be produced by PEO of titanium and its alloys. Usually, however, long process times (>20 min) or two-step procedures are required and the HA produced is of low crystallinity 48,49 . In titanium oxidation using PEO other structures such as anatase, rutile, and phosphates are also produced.…”