Theranostic Applications of Nanostructured Silicate-Substituted Hydroxyapatite Codoped with Eu³⁺ and Bi³⁺ Ions—A Novel Strategy for Bone Regeneration

Abstract

In this paper, nanocrystalline silicate-substituted hydroxyapatites (nSi-HAps) codoped with Eu3+ were functionalized with Bi3+ ions. Biomaterials were synthesized using a microwave-assisted hydrothermal method and heat-treated at 700 °C. The concentration of Eu3+ ions was established at 1 mol %, and the concentration of Bi3+ was in the range of 0.5–2 mol %. The physicochemical properties of the obtained biomaterials were determined using previously established methods, including X-ray powder diffraction, scanning electron microscopy techniques, and IR spectroscopy. Particle sizes obtained in this study were in the range of 22–65 nm, which was established by the Rietveld method. The luminescence properties of the Eu3+ ion-doped silicate-substituted apatite were recorded depending on the bismuth­(III) concentration. The cytocompatibility of obtained biomaterials was tested using the model of mouse pre-osteoblasts cell line, that is, MC3T3-E1. We showed that the obtained biomaterials exerted anti-apoptotic effect, reducing the number of early and late apoptotic cells and decreasing caspase activity and reactive oxygen species accumulation. The transcripts levels of genes associated with apoptosis confirmed the anti-apoptotic effect of the biomaterials. Increased metabolic activity of MC3T3-E1 in cultures with biomaterials functionalized with Bi3+ ions has been observed. Moreover, the determined profile of osteogenic markers indicates that the obtained matrices, that is, Eu3+:nSi-HAp functionalized with Bi3+ ions, exert pro-osteogenic properties. The biological features of Eu3+:nSi-HAp modified with Bi3+ ions are highly desired in terms of functional tissue restoration and further efficient osteointegration.

Nanohydroxyapatite (nHAp) Doped with Iron Oxide Nanoparticles (IO), miR-21 and miR-124 Under Magnetic Field Conditions Modulates Osteoblast Viability, Reduces Inflammation and Inhibits the Growth of Osteoclast – A Novel Concept for Osteoporosis Treatment: Part 1

“…The protocol was performed accordingly to manufacturers’ instruction, and it was shown in our previous studies. 35 , 36 After incubations with provided reagents, the samples were analysed using Muse TM Cell Analyzer (Merck/Sigma-Aldrich, Munich, Germany). Each measurement was performed in triplicate.…”

“…The procedure was carried out using the conditions described previously in detail. 36 , 39 The concentration of protein level loaded per well was equal to 20 µg. The primary antibody for RUNX-2 (F-2: sc-390351, Santa Cruz Biotechnology, Dallas, Texas, USA) detection was diluted at the ratio of 1:100 and for OPN (ab8448, Abcam, Cambridge, UK) at the ratio of 1:1000.…”

“…The procedures were performed accordingly to our previous studies. 33 , 35 , 36 Briefly, to isolate the RNA, cultures were homogenized by the addition of Extrazol ® (Blirt DNA, Gdańsk, Poland). The purity and the quantity of obtained RNA were measured by a spectrophotometer at 260 and 280 nm wavelength (Epoch, BioTek Instruments, Vermont, USA).…”

Bone marrow stromal cells (BMSCs CD45‐/CD44+/CD73+/CD90+) isolated from osteoporotic mice SAM/P6 as a novel model for osteoporosis investigation

“…The gating procedure of cells’ populations was based on the positive and negative controls. 32 , 33 , 34 …”

“…The staining procedure was performed accordingly to producer's protocol and described previously. 32 Briefly, after trypsinisation 10 µL of cells were added to 190 µL of Muse Oxidative Stress Working Solution and incubated 30 minutes in 37°C. The staining reagent was provided by manufacturer and based on dihydroethidium (DHE), which is widely used for ROS detection in many cell cultures.…”