Structural Characterization of Low-Sr-Doped Hydroxyapatite Obtained by Solid-State Synthesis

Abstract

Strontium-substituted Ca10(PO4)6(OH)2 hydroxyapatite (HAp) powders, with Sr wt% concentrations of 2.5, 5.6 and 10%, were prepared by a solid-state synthesis method. The chemical composition of the samples was accurately evaluated by using inductively coupled plasma (ICP) spectroscopy. The morphology of the samples was analyzed via optical microscopy, while structural characterization was achieved through powder X-ray diffraction (PXRD) and infrared (FTIR) and Raman spectroscopy. The PXRD structural characterization showed the presence of the Sr dopant in the Ca1 structural site for HAp with a lower Sr concentration and in the Ca2 site for the sample with a higher Sr concentration. FTIR and Raman spectra showed slight band shifts and minor modifications of the (PO4) bands with increasing the Sr doping rate.

Preparation and Application of Apatite–TiO2 Composite Opacifier: Preventing Titanium Glaze Yellowing through Pre-Combination

“…In the infrared spectrum of TiO 2 in Figure 3 a, the characteristic peak of the surface hydroxyl group appears at 3299 cm −1 [ 13 ], and the wide absorption band generated by the bending vibration of Ti-O-Ti is located in the range of 500–800 cm −1 [ 14 ]. In the infrared spectrum of HAP, the characteristic peaks at 567, 607, 963, 1041, and 1097 cm −1 belong to the vibration of the hydroxyapatite PO 4 3− tetrahedron [ 24 , 25 , 26 , 27 , 28 ]. The absorption peak at 3569 cm −1 is related to -OH in HAP, and the absorption peak at 1649 cm −1 is related to the adsorbed H 2 O [ 29 ].…”

Electrochemical and Structural Characterization of Lanthanum-Doped Hydroxyapatite: A Promising Material for Sensing Applications

“…The typical hexagonal unit cell of HAp [ 5 , 8 ] was identified for our HAp samples. Qualitative analysis revealed the presence of some diffraction peaks, attributed to Ca 3 (PO 4 ) 3 tricalcium phosphate (TCP) and CaCO 3 calcium carbonate phases.…”

“…The wide distribution in biological systems and intrinsic features of HAp (acid-base features, ion-exchange capability, biocompatibility, and adsorption capacity) attracted the interest of materials scientists promoting the research and development of synthetic analogues with customizable properties. The possibility of introducing cationic and anionic substitutions within the HAp framework [ 3 ] enables the production of materials with novel characteristics (increased biocompatibility, bioactivity, osteoconductivity, and reduced toxicity and inflammatory nature compared to natural Hap), paving the way to applications in different research fields including, among others, biomedicine, regenerative medicine, and imaging [ 4 , 5 , 6 , 7 , 8 ]. As an example, our previous studies demonstrated the capability of Sr-substituted HAp nanoparticles to regulate molecular and metabolic processes, and to control the spatial and temporal distribution of novel HAp deposits during differentiation of mature stem cells, strengthening a useful function as new drugs for bone healing [ 9 , 10 , 11 ].…”

Synthesis of a new potassium-substituted lead fluorapatite and its structural characterization

“…), and X is a monovalent anion (F − , OH − , Cl − ). [13][14][15] The most known crystallization arrangements for apatite compounds correspond to the hexagonal P6 3 /m space group (no. 176), or, in rare cases, monoclinic settings.…”