Effect of yttrium ion on the proliferation, differentiation and mineralization function of primary mouse osteoblasts in vitro

Metal Ion-Doped Hydroxyapatite-Based Materials for Bone Defect Restoration

Hydroxyapatite (HA)-based materials are widely used in the bone defect restoration field due to their stable physical properties, good biocompatibility, and bone induction potential. To further improve their performance with extra functions such as antibacterial activity, various kinds of metal ion-doped HA-based materials have been proposed and synthesized. This paper offered a comprehensive review of metal ion-doped HA-based materials for bone defect restoration based on the introduction of the physicochemical characteristics of HA followed by the synthesis methods, properties, and applications of different kinds of metal ion (Ag+, Zn2+, Mg2+, Sr2+, Sm3+, and Ce3+)-doped HA-based materials. In addition, the underlying challenges for bone defect restoration using these materials and potential solutions were discussed.

Lanthanides-Substituted Hydroxyapatite for Biomedical Applications

Lately, there has been an increasing demand for materials that could improve tissue regenerative therapies and provide antimicrobial effects. Similarly, there is a growing need to develop or modify biomaterials for the diagnosis and treatment of different pathologies. In this scenario, hydroxyapatite (HAp) appears as a bioceramic with extended functionalities. Nevertheless, there are certain disadvantages related to the mechanical properties and lack of antimicrobial capacity. To circumvent them, the doping of HAp with a variety of cationic ions is emerging as a good alterative due to the different biological roles of each ion. Among many elements, lanthanides are understudied despite their great potential in the biomedical field. For this reason, the present review focuses on the biological benefits of lanthanides and how their incorporation into HAp can alter its morphology and physical properties. A comprehensive section of the applications of lanthanides-substituted HAp nanoparticles (HAp NPs) is presented to unveil the potential biomedical uses of these systems. Finally, the need to study the tolerable and non-toxic percentages of substitution with these elements is highlighted.

Effects of Different Rare Earth Elements on the Degradation and Mechanical Properties of the ECAP Extruded Mg Alloys

Effects of different rare earth elements on the degradation and mechanical properties of the ECAP (equal channel angular pressing) extruded Mg alloys were investigated in this work. Microstructural characterization, thermodynamic calculation, a tensile test, an electrochemical test, an immersion test, a hydrogen evolution test and a cytotoxicity test were carried out. The results showed that yttrium addition was beneficial to the improvement of the alloy's strength, and the ultimate tensile strength (UTS) and yield strength (YS) values of the ECAPed Mg-2Zn-0.5Y-0.5Zr alloy reached 315 MPa and 295 MPa, respectively. In addition, Nd was beneficial to the corrosion resistance, for which, the corrosion rate of the ECAPed Mg-2Zn-0.5Nd-0.5Zr alloy was observed to be 0.42 ± 0.04 mm/year in Hank's solution after 14 days of immersion. Gd was moderate in improving both the corrosion resistance and mechanical properties. Moreover, after co-culturing with murine calvarial preosteoblasts (MC3T3-E1) cells, the ECAPed Mg-2Zn-0.5RE (Nd, Gd, Y)-0.5Zr alloys exhibited good cytocompatibility with a grade 1 cytotoxicity. Consequently, the ECAPed Mg-2Zn-0.5Nd-0.5Zr alloy showed the best application prospect in the field of orthopedics.

Adult stem cell response to doped bioactive borate glass

Bioactive glasses have transformed healthcare due to their versatility. Bioactive borate glass, in particular, has shown remarkable healing properties for both hard and soft tissues. Incorporating dopants into the composition of bioactive glass helps to control mechanical properties, and it increases their usefulness for clinical applications. Using a bioactive borate glass, 13-93B3 (B3), we investigated eleven dopants on the viability and migration potential of adipose stem cells (ASCs), a therapeutic source of cells used in tissue engineering and cell therapy. Our results show that under standard cell culture conditions, only Cu-doped B3 decreased cell viability, while only Y-doped B3 attracted ASCs as it dissolved in cell culture media. Using a transwell invasion assay, priming ASCs with Co, Fe, Ga, I, Sr, or Zn-doped B3 increased their homing capacity. Because there is widespread interest in optimizing and enhancing the homing efficiency of ASCs and other therapeutic cells, we then tested if priming bone marrow mesenchymal stem cells (BMSCs) with dopants also increased their homing capacity. In the case of BMSCs, there was a significant increase in invasion when cells were primed with any of the doped-B3 glasses. This work shows that incorporating dopants into borate glasses can provide a platform for a safe and efficient method that stimulates endogenous cells and healing mechanisms.

Investigation on the in vitro cytocompatibility of Mg-Zn-Y-Nd-Zr alloys as degradable orthopaedic implant materials

Mg-Zn-Y-Nd-Zr alloy has been developed as a new type of biodegradable orthopaedic implant material by the authors' research group with its excellent mechanical properties and controllable degradation rate. In this study, the cytocompatibility of Mg-Zn-Y-Nd-Zr alloy was systematically evaluated through in vitro cell culture method. MTT assay was applied to evaluate the cytotoxicity of Mg-Zn-Y-Nd-Zr alloy and no toxic effect was observed on L929 and MC3T3-E1 cells followed the protocol of ISO 10993 standard. Considering the potential ion accumulation in the bony environment, this study further investigated the cytotoxic effect of accumulated metallic ions during the alloy degradation by extending the extract preparation time. When the extract preparation time was prolonged to 1440 h, the accumulated metallic ions leaded to severe cell apoptosis, of which the combined ion concentration was determined as 39.5-65.8 µM of Mg²⁺, 3.5-5.9 µM of Zn²⁺, 0.44-0.74 µM of Y³⁺, 0.3-0.52 µM of Nd³⁺ and 0.11-0.18 µM of Zr⁴⁺ for L929, and 65.8-92.2 µM of Mg²⁺, 5.9-8.3 µM of Zn²⁺, 0.74-1.04 µM of Y³⁺, 0.52-0.73 µM of Nd³⁺ and 0.18-0.25 µM of Zr⁴⁺ for MC3T3-E1 cells. Besides the cell viability assessment, high expression of ALP activity and calcified nodules implied that metal elements in Mg-Zn-Y-Nd-Zr alloys can promote the osteogenic differentiation. Hence, excellent cytocompatibility has equipped Mg-Zn-Y-Nd-Zr alloy as a promising candidate for orthopaedic implant application, which can remarkably guide the magnesium-based alloy design and provide scientific evidence for clinical practice in future.

The influence of biodegradable magnesium alloys on the osteogenic differentiation of human mesenchymal stem cells

The postdegradation effect of pure Mg, Mg-1Y, Mg-5Al, and Mg-2Ca alloys on the differentiation, proliferation and gene expression of human mesenchymal stem cells (hMSCs) was investigated. It was revealed that that Mg(2+) ions result in an increase in cell proliferation. However, we observed a maximum concentration (approximately 8.0 × 10(-4) M) that was favourable to ATP production, above which ATP production began to decrease. In contrast to proliferation, no maximum concentration for osteogenic differentiation was observed, with increasing concentration of Mg(2+) ions resulting in an increase in osteogenic differentiation across the entire tested range. Interestingly, the Mg-2Ca alloy had minimal effect on osteogenic differentiation, with Mg-1Y and pure Mg having a superior effect on the proliferation and differentiation of hMSCs. This was also observed from gene expression data, where these alloys upregulated TGFβ-1, SMAD4, FGF-2, FGF-10, and BMP-2, while SOX-2, SOX-9, and TNF-α were downregulated. Increased expression of TGFβ-1, SMAD4, BMPs, and COLIA1 protein provided further evidence to support osteogenic differentiation and that the influence of the alloying extracts on differentiation may be via the SMAD signaling pathway.

Samarium doped glass-reinforced hydroxyapatite with enhanced osteoblastic performance and antibacterial properties for bone tissue regeneration

Cell adhesion of MG63 osteoblastic cells seeded over GR-HA_control and Sm doped composites, at day 1 of culture. Low (A) and high (B) CLSM images of cells stained for F-actin cytoskeleton (green) and nuclei (red); (C) SEM images.

The dual-effects of LaCl₃ on the proliferation, osteogenic differentiation, and mineralization of MC3T3-E1 cells

A series of experimental methods including 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide, alkaline phosphatase (ALP) activity measurement, alizarin red S stain and measurement, quantitative real-time reverse transcriptase polymerase chain reaction, and Western blot analysis were employed to assess the effects of LaCl₃ on the proliferation, osteogenic differentiation, and mineralization of a murine preosteoblast cell line MC3T3-E1 at cell and molecular levels. The results indicated that LaCl₃ had dual effects on the proliferation, osteogenic differentiation, and mineralization of MC3T3-E1 cells. First, LaCl₃ promoted the proliferation, osteogenic differentiation, and mineralization of MC3T3-E1 cells at lower concentrations, then had no effects and further turned to inhibit the proliferation, osteogenic differentiation, and mineralization of MC3T3-E1 cells with increasing concentrations. The expression of runt-related transcription factor 2 (Runx2), bone morphogenetic protein 2 (BMP2), ALP, bone sialoprotein (BSP), collagen I (Col I), and osteocalcin (OCN) genes was upregulated in the presence of 0.0001 and 0.1 μM LaCl₃, but these genes were downregulated in the MC3T3-E1 cells treated with 1,000 μM LaCl₃. In addition, the expression of BMP2, Runx2, and OCN proteins was promoted by LaCl₃ at the concentration of 0.0001 μM, but these proteins were downregulated after 1,000 μM LaCl₃ treatment. The results suggest that LaCl₃ likely up- or downregulates the expression of Runx2, which subsequently up- or downregulates osteoblasts marker genes Col I and BMP2 at early stages and ALP and OCN at later stages of differentiation, thus causes to promote or inhibit the proliferation, osteogenic differentiation and mineralization of MC3T3-E1 cells. The results will be helpful for understanding the mechanisms of bone metabolism and application of lanthanum-based compounds in the future.

Effects of niobium ions released from calcium phosphate invert glasses containing Nb2O5 on osteoblast-like cell functions

The effects of niobium ions released from 60CaO-30P(2)O(5)-(10-x)Na(2)O-xNb(2)O(5) (mol %, x = 0-10) glasses on MC3T3-E1 cell functions were evaluated by culture tests with two systems; cell culture on glass plates, or in culture media containing glass extracts. Alkaline phosphatase (ALP) activity in the cells cultured on the glass plates containing 3 and 5 mol % of Nb(2)O(5) was significantly higher than that on the Nb(2)O(5)-free glass, although proliferation was not enhanced on all glasses containing Nb(2)O(5). Cells cultured in the medium containing 3 × 10(-7) M niobium ions showed the highest ALP activity in comparison with other Nb-containing media or normal medium, regardless of the presence of osteogenic factors (ascorbic acid, β-glycerophosphate and dexamethasone) in the media. Calcium deposition by the cells cultured in the medium containing 3 × 10(-7) M niobium ions was twice as high as those cultured in medium containing no niobium ions. The effects of niobium ions were thought to depend on ion concentration, and to enhance differentiation and mineralization of osteogenic cells rather than their initial adhesion or proliferation.