Osteogenic Differentiation Activity Research Articles

(aS)-Glucosciadopitysin, a New Biflavonoid Glycoside from the Leaves of Ginkgo biloba and Osteogenic Activity of Bioflavonoids.

The leaves of Ginkgo biloba have been used in treating freckles and effectively reducing cough and sputum in folk medicines. Recently, investigations into the correlation between ginkgo leaves and the proliferative activity of osteogenic differentiation have been conducted. However, bioactive compounds that enhance osteogenesis or exhibit osteoporosis prevention from G. biloba have not been fully identified. Phytochemical investigation of the MeOH extract of G. biloba leaves led to the isolation and identification of a new biflavonoid glycoside, (aS)-glucosciadopitysin (1), along with five flavonoids (2-6), through LC/MS-guided isolation approach. The structure of the new compound 1 was elucidated by the spectroscopic methods, including 1D and 2D NMR analysis, as well as HR-ESIMS. The absolute configuration of sugar moiety was established through acid hydrolysis, followed by chemical derivatization reaction and the axial chirality arising from the biaryl system with substituents was determined by electronic circular dichroism (ECD) calculations. The isolated flavonoids (1-6) were tested for their effects on mesenchymal stem cell (MSC) differentiation at 20 μM using Oil Red O and alkaline phosphatase (ALP) staining. Ginkgetin (2) was further evaluated for osteogenic activity on C3H10T1/2 cells at concentrations of 1, 2.5, 5, and 10 μM for 10 days. ALP staining and RT-PCR assessed the gene expression of osteogenic markers ALP and osteopontin (OPN). Ginkgetin (2) demonstrated the strongest osteogenic activity, significantly increasing the expression of ALP (12.5-fold) and OPN (4.0-fold) at 10 μM, comparable to the positive control, oryzativol A. Ginkgetin (2) shows potential as a therapeutic agent for osteopenia by promoting osteogenesis in MSCs, suggesting its promising role in treating osteoporosis.

Enhancing bone graft efficacy: Antibacterial and osteogenic effects of cerium‐doped biphasic calcium phosphate scaffolds

AbstractBiphasic calcium phosphate powders, composed of hydroxyapatite and β‐tricalcium phosphate, have gained significant interest as excellent substitutes because of their similarity to natural bone mineral and biocompatibility. The objective was to enhance the biological efficacy of biphasic calcium phosphate powder‐based bone graft materials by incorporating trace elements, such as cerium, into the material. In the context of this investigation, a simple wet chemical precipitation technique was established for the purpose of fabricating microporous biphasic calcium phosphate powders scaffolds of cerium followed by gel casting. The 10% Ce in biphasic calcium phosphate powders scaffolds displayed a network of linked microporous structures characterized by consistent micropore size having 250 ± 25 swelling value. There were no observable alterations in the phase composition and microstructure of the scaffolds when cerium was doped. Further, Staphylococcus aureus was used in the polarization‐induced in vitro antibacterial investigation while the survival of bacteria was greatly reduced on polarized surfaces. The biological activity studies revealed that the 10% cerium‐doped biphasic calcium phosphate powders scaffold exhibited superior efficacy in promoting osteogenic differentiation and antibacterial activities compared to its counterpart. Additionally, polarization improves the antibacterial capabilities of these synthetic scaffolds. The stored charge was found to be 4.02 µC.cm−2 at 550°C.

Proinflammatory Cytokines Enhance the Mineralization, Proliferation, and Metabolic Activity of Primary Human Osteoblast-like Cells.

Osteoporosis is a progressive metabolic bone disease characterized by decreased bone density and microarchitectural deterioration, leading to an increased risk of fracture, particularly in postmenopausal women and the elderly. Increasing evidence suggests that inflammatory processes play a key role in the pathogenesis of osteoporosis and are strongly associated with the activation of osteoclasts, the cells responsible for bone resorption. In the present study, we investigated, for the first time, the influence of proinflammatory cytokines on the osteogenic differentiation, proliferation, and metabolic activity of primary human osteoblast-like cells (OBs) derived from the femoral heads of elderly patients. We found that all the proinflammatory cytokines, IL-1β, TNF-α, IL-6, and IL-8, enhanced the extracellular matrix mineralization of OBs under differentiation-induced cell culture conditions. In the cases of IL-1β and TNF-α, increased mineralization was correlated with increased osteoblast proliferation. Additionally, IL-1β- and TNF-α-increased osteogenesis was accompanied by a rise in energy metabolism due to improved glycolysis or mitochondrial respiration. In conclusion, we show here, for the first time, that, in contrast to findings obtained with cell lines, mesenchymal stem cells, or animal models, human OBs obtained from patients exhibited significantly enhanced osteogenesis upon exposure to proinflammatory cytokines, probably in part via a mechanism involving enhanced cellular energy metabolism. This study significantly contributes to the field of osteoimmunology by examining a clinically relevant cell model that can help to develop treatments for inflammation-related metabolic bone diseases.

The Viability of Osteoblasts against SHED Metabolites and EGCG for Biomaterial Osteogenesis

Background: EGCG, the principal flavonoid found in green tea, exhibits numerous advantageous properties, notably promoting bone regeneration by enhancing the activity of osteoblasts and osteogenic differentiation. Cell-free therapy is an alternative to avoiding the side effects of cell-based therapy. By harnessing the potential of metabolites, SHED combined with EGCG can be a biomaterial to increase osteogenesis. Objectives: This study aims to assess the viability of osteoblast cells when exposed to the combination of SHED metabolites and two concentrations of EGCG, namely 10μM and 50μM. Methods: Osteoblast viability is examined with the 3-(4.5-dimethylthiazole-2-yl)2.5-diphenyl tetrazolium bromide (MTT) assays using an ELISA reader 570nm, and the absorbance value is converted to per cent form. CD50 is a parameter that indicates non-toxicity when the percentage value of living cells is more than 50%. Results: The percentage of living cells exceeded 50%, and statistically significant distinctions were observed among the control media, control cell groups, and the groups exposed to the combination of SHED metabolites and EGCG (p = 0.031). Conclusions: The viability of osteoblast cells exposed to the combination of SHED metabolites and EGCG 10µM, as well as the combination of SHED metabolites and EGCG 50µM, showed no toxicity. The combination of 10µM SHED metabolites and EGCG showed a higher osteoblast cell viability value than the combination of SHED metabolites and EGCG 50 µM.

Cold exposure-induced plasma exosomes impair bone mass by inhibiting autophagy

Recently, environmental temperature has been shown to regulate bone homeostasis. However, the mechanisms by which cold exposure affects bone mass remain unclear. In our present study, we observed that exposure to cold temperature (CT) decreased bone mass and quality in mice. Furthermore, a transplant of exosomes derived from the plasma of mice exposed to cold temperature (CT-EXO) can also impair the osteogenic differentiation of BMSCs and decrease bone mass by inhibiting autophagic activity. Rapamycin, a potent inducer of autophagy, can reverse cold exposure or CT-EXO-induced bone loss. Microarray sequencing revealed that cold exposure increases the miR-25-3p level in CT-EXO. Mechanistic studies showed that miR-25-3p can inhibit the osteogenic differentiation and autophagic activity of BMSCs. It is shown that inhibition of exosomes release or downregulation of miR-25-3p level can suppress CT-induced bone loss. This study identifies that CT-EXO mediates CT-induced osteoporotic effects through miR-25-3p by inhibiting autophagy via targeting SATB2, presenting a novel mechanism underlying the effect of cold temperature on bone mass.

Biocompatible Germanium-Doped Hydroxyapatite Nanoparticles for Promoting Osteogenic Differentiation and Antimicrobial Activity

Biocompatible Germanium-Doped Hydroxyapatite Nanoparticles for Promoting Osteogenic Differentiation and Antimicrobial Activity

Fibrous periosteum repairs bone fracture and maintains the healed bone throughout mouse adulthood

Bone is regarded as one of few tissues that heals without fibrous scar. The outer layer of the periosteum is covered with fibrous tissue, whose function in bone formation is unknown. We herein developed a system to distinguish the fate of fibrous-layer periosteal cells (FL-PCs) from the skeletal stem/progenitor cells (SSPCs) in the cambium-layer periosteum and bone marrow in mice. We showed that FL-PCs did not participate in steady-state osteogenesis, but formed the main body of fibrocartilaginous callus during fracture healing. Moreover, FL-PCs invaded the cambium-layer periosteum and bone marrow after fracture, forming neo-SSPCs that continued to maintain the healed bones throughout adulthood. The FL-PC-derived neo-SSPCs expressed lower levels of osteogenic signature genes and displayed lower osteogenic differentiation activity than the preexisting SSPCs. Consistent with this, healed bones were thinner and formed more slowly than normal bones. Thus, the fibrous periosteum becomes the cellular origin of bones after fracture and alters bone properties permanently.

Structure and properties of cerium-doped TiO2 coatings on Ti40Nb alloy by micro-arc oxidation

Peri-implantitis and insufficient osseointegration are major challenges currently facing dental implants. Therefore, enhancing the antibacterial and bioactive properties of implants is crucial. This study developed a novel Ce-doped porous coating on low-modulus Ti40Nb alloy by micro-arc oxidation to improve antibacterial and bioactive properties. We systematically investigated the microstructure, phase composition, adhesion to the substrate, hydrophilicity, antibacterial and cell compatibility of the coatings, and the effect of Ce content on the coating formation was discussed. The increase in the concentration of Ce3+ ions in the coating significantly enhances its antibacterial properties. The introduction of the porous structure endows the coating with excellent osteogenic differentiation activity, indicating that the cerium-doped MAO coating on the Ti40Nb alloy has great potential in dental applications.

Engineered Metallic Ion-Based Hydrogel for Tendon-Bone Reconstruction.

Rotator cuff regeneration is hindered by compromised vascular architecture, inflammation, and instability of the reconstructed tendon-bone interface. Herein, inspired by the phenomenon of magnetic clasps being connected together by a specific structure, an engineered metallic ion-based hydrogel scaffold was constructed through a bioorthogonal click reaction between (DOPA)4-PEG5-N3 and DBCO-BMP-2 peptides and a photopolymerization process in the hydrogel matrix, exhibiting the potential for angiogenesis, bone regeneration, and modulation of the inflammatory milieu, which aimed at facilitating rotator cuff regeneration. In vitro studies showed that the composite hydrogel scaffold stimulated the angiogenic activity of human umbilical vein endothelial cells and osteogenic differentiation of bone marrow mesenchymal stem cells, transforming macrophages from M1 to M2. Moreover, imaging and immunohistochemical analysis of a rat rotator cuff injury models demonstrated that the composite hydrogel could effectively promote regeneration and exhibit remarkable biocompatibility. In summary, this composite hydrogel material established an effective platform for the release of metal ions and clickable peptides, which accelerated the regeneration of rotator cuff injuries and had broad prospects for application in rotator cuff therapy.

Surface characteristics and in vitro biocompatibility of titanium preserved in a vitamin C-containing saline storage solution

The purpose of this study is to explore a storage solution for titanium implants and investigate its osteogenic properties. The commercial pure titanium (cp-Ti) surface and double-etched (SLA) titanium surface specimens were preserved in air, saline, 10 mM Vitamin C (VitC)-containing saline and 100 mM VitC-containing saline storage solutions for 2 weeks. The surface microtopography of titanium was observed by scanning electron microscopy (SEM), the surface elemental compositions of the specimens were analyzed by Raman and X-ray photoelectron spectroscopy (XPS), and water contact angle and surface roughness of the specimens were tested. The protein adsorption capacity of two titanium surfaces after storage in different media was examined by BCA kit. The MC3T3-E1 osteoblasts were cultured on two titanium surfaces after storage in different media, and the proliferation, adhesion and osteogenic differentiation activity of osteoblasts were detected by CCK-8, laser confocal microscope (CLSM) and Western blot. The SEM results indicated that the titanium surfaces of the air group were relatively clean while scattered sodium chloride or VitC crystals were seen on the titanium surfaces of the other three groups. There were no significant differences in the micromorphology of the titanium surfaces among the four groups. Raman spectroscopy detected VitC crystals on the titanium surfaces of two experimental groups. The XPS, water contact angle and surface roughness results suggested that cp-Ti and SLA-Ti stored in 0.9% NaCl and two VitC-containing saline storage solutions possessed less carbon contamination and higher surface hydrophilicity. Moreover, the protein adsorption potentials of cp-Ti and SLA-Ti surfaces were significantly improved under preservation in two VitC-containing saline storage solutions. The results of in vitro study showed that the preservation of two titanium surfaces in 100 mM VitC-containing saline storage solution upregulated the cell adhesion, proliferation, osteogenic related protein expressions of MC3T3-E1 osteoblasts. In conclusion, preservation of cp-Ti and SLA-Ti in 100 mM VitC-containing saline storage solution could effectively reduce carbon contamination and enhance surface hydrophilicity, which was conducive to osteogenic differentiation of osteoblasts.Graphical

Piezo1 contributes to alveolar bone remodeling by activating β-catenin under compressive stress

The mechanosensitive ion channel, Piezo1, is responsible for transducing mechanical stimuli into intracellular biochemical signals and has been identified within periodontal ligament cells (PDLCs). Nonetheless, the precise biologic function of Piezo1 in the regulation of alveolar bone remodeling by PDLCs during compressive forces remains unclear. Therefore, this study focused on elucidating the role of the Piezo1 channel in alveolar bone remodeling and uncovering its underlying mechanisms. PDLCs were subjected to compressive force and Piezo1 inhibitors. Piezo1 and β-catenin expressions were quantified by quantitative reverse transcription polymerase chain reaction and Western blot. The intracellular calcium concentration was measured using Fluo-8 AM staining. The osteogenic and osteoclastic activities were assessed using alkaline phosphatase staining, enzyme-linked immunosorbent assay, quantitative reverse transcription polymerase chain reaction, and Western blot. Invivo, orthodontic tooth movement was used to determine the effects of Piezo1 on alveolar bone remodeling. Piezo1 and activated β-catenin expressions were upregulated under compressive force. Piezo1 inhibition reduced β-catenin activation, osteogenic differentiation, and osteoclastic activities. β-catenin knockdown reversed the increased osteogenic differentiation but had little impact on osteoclastic activities. Invivo, Piezo1 inhibition led to decreased tooth movement distance, accompanied by reduced β-catenin activation and expression of osteogenic and osteoclastic markers on the compression side. The Piezo1 channel is a key mechanotransduction component of PDLCs that senses compressive force and activates β-catenin to regulate alveolar bone remodeling.

EXTRACELLULAR VESICLES SECRETED BY OSTEOGENIC-DIFFERENTIATED MESENCHYMAL STEM CELLS PROMOTE BONE FORMATION IN RAT CALVARIAL DEFECT

Growing evidence has suggested that paracrine mechanisms of Mesenchymal stem cell (MSC) may be involved in the underlying mechanism of MSC after transplantation, and extracellular vesicles (EVs) are an important component of this paracrine role. The aim of this study was to investigate the in vitro osteogenic effects of EVs derived from undifferentiated mesenchymal stem cells and from chemically induced to differentiate into osteogenic cells for 7 days. Further, the osteoinductive potential of EVs for bone regeneration in rat calvarial defects was assessed.We could isolate and characterize EVs from naïve and osteogenic-induced MSCs. Proteomic analysis revealed that EVs contained distinct protein profiles, with Osteo-EVs having more differentially expressed proteins with osteogenic properties. EVs were found to enhance the proliferation and migration of cultured MSC. In addition, the study found that Osteo-EVs/MEM combination scaffolds could enhance greater bone formation after 4 weeks as compared to native MEM loaded with serum-free media.The study suggests that EVs derived from chemically osteogenic-induced MSCs for 7 days can significantly enhance both the osteogenic differentiation activity of cultured hMSCs and the osteoinductivity of MEM scaffolds. The results indicate that Osteo-MSC-secreted nanocarriers-EVs combined with MEM scaffolds can be used for repairing bone defects.

Enhancement of properties of a cell-laden GelMA hydrogel-based bioink via calcium phosphate phase transition

To improve the properties of the hydrogel-based bioinks, a calcium phosphate phase transition was applied, and the products were examined. We successfully enhanced the mechanical properties of the hydrogels by adding small amounts (< 0.5 wt%) of alpha-tricalcium phosphate (α-TCP) to photo-crosslinkable gelatin methacrylate (GelMA). As a result of the hydrolyzing calcium phosphate phase transition involving α-TCP, which proceeded for 36 h in the cell culture medium, calcium-deficient hydroxyapatite was produced. Approximately 18 times the compressive modulus was achieved for GelMA with 0.5 wt% α-TCP (20.96 kPa) compared with pure GelMA (1.18 kPa). Although cell proliferation decreased during the early stages of cultivation, both osteogenic differentiation and mineralization activities increased dramatically when the calcium phosphate phase transition was performed with 0.25 wt% α-TCP. The addition of α-TCP improved the printability and fidelity of GelMA, as well as the structural stability and compressive modulus (approximately six times higher) after three weeks of culturing. Therefore, we anticipate that the application of calcium phosphate phase transition to hydrogels may have the potential for hard tissue regeneration.

A chlorogenic acid-chitosan complex bifunctional coating for improving osteogenesis differentiation and bactericidal properties of zirconia implants.

Poor osteogenesis caused by limited bioactivity and peri-implantitis caused by bacterial colonization are the main challenges affecting the use of zirconia-based materials in dental implants. Accordingly, the development of a surface treatment method with an antibacterial effect and that promotes osteogenesis without damage to cells is crucial for yttrium-stabilized tetragonal zirconia (Y-TZP) implants. Herein, we have developed a functional surface modification strategy whereby a poly (ethylene imine)/hyaluronic acid /chitosan-chlorogenic acid (PEI/HA/CGA-CS) conjugate is deposited on a zirconia surface by the layer-by-layer (LBL) technique, enhancing its osteogenic differentiation and antibacterial activities. The results showed that the PEI/HA/CGA-CS coating improved the wettability of the zirconia surface and maintained stable release of CGA. The PEI/HA/CGA-CS functional coating was found to promote early cell adhesion, proliferation, differentiation, and calcification. The results of bacterial adhesion and activity tests showed that the coating effectively inhibits the proliferation and activity of Porphyromonas gingivalis (P. gingivalis) and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) without impairing the biological activity of osteoblasts. In addition, we found that the PEI/HA/CGA-CS coating enhances the osteogenesis of MC3T3-E1 cells by promoting the protein expression of Nephronectin (NPNT) and activating the Wnt/β-catenin signaling pathway. The above results are of profound significance for the practical application of zirconia-based implants. DATA AVAILABILITY: Data will be made available on request.

Exercise improved bone health in aging mice: a role of SIRT1 in regulating autophagy and osteogenic differentiation of BMSCs.

This study was designed to investigate the effect of running exercise on improving bone health in aging mice and explore the role of the SIRT1 in regulating autophagy and osteogenic differentiation of Bone marrow Mesenchymal Stem Cells (BMSCs). Twelve-month-old male C57BL/6J mice were used in this study as the aging model and were assigned to treadmill running exercise for eight weeks. Non-exercise male C57BL/6J mice of the same old were used as aging control and five-month-old mice were used as young controls. BMSCs were isolated from mice and subjected to mechanical stretching stimulation in vitro. The results showed that aging mice had lower bone mass, bone mineral density (BMD), and autophagy than young mice, while running exercise improved BMD and bone mass as well as upregulated autophagy in bone cells. Mechanical loading increased osteogenic differentiation and autophagy in BMSCs, and knockdown of SIRT1 in BMSCs demonstrated that SIRT1-regulated autophagy involved the mechanical loading activation of osteogenic differentiation. Taken together, this study revealed that exercise improved bone health during aging by activating bone formation, which can be attributed to osteogenic differentiation of BMSCs through the activation of SIRT1-mediated autophagy. The mechanisms underlying this effect may involve mechanical loading.

Bavachinin selectively modulates PPAR γ and maintains bone homeostasis in Type 2 Diabetes.

Full peroxisome proliferator-activated receptor (PPAR) γ agonists, Thiazolidinediones (TZDs), effectively prevent the process of Type 2 Diabetes Mellitus (T2DM), but their side effects have curtailed use in the clinic, including weight gain and bone loss. Here, we identified that a selective PPAR γ modulator, Bavachinin (BVC), isolated from the seeds of Psoralea Corylifolia L., could potently regulate bone homeostasis. MC3T3-E1 pre-osteoblast cells and C3H10T1/2 mesenchymal stem cells were assessed for osteogenic differentiation activities, and receptor activator of NF-κB ligand (RANKL)-induced RAW 264.7 cells were assessed osteoclasts formation. Leptin receptor-deficient mice and diet-induced obesity mice were applied to evaluate the effect of BVC on bone homeostasis in vivo. Compared to full PPAR γ agonist rosiglitazone, BVC significantly increased the osteogenesis differentiation activities under normal and high glucose conditions in MC3T3-E1 cells. Moreover, BVC could alleviate osteoclast differentiation in RANKL-induced RAW 264.7 cells. In vivo, synthesized BVC prodrug (BN) has been applied to improve water solubility, increase the extent of oral absorption of BVC and prolong its residence time in blood circulation. BN could prevent weight gain, ameliorate lipid metabolism disorders, improve insulin sensitivity, and maintain bone mass and bone biomechanical properties. BVC, a unique PPAR γ selective modulator, could maintain bone homeostasis, and its prodrug (BN) exhibits insulin sensitizer activity while circumventing the side effects of the TZDs, including bone loss and undesirable weight gain.

Graphene quantum dots enhance the osteogenic differentiation of PDLSCs in the inflammatory microenvironment

Background and objectiveGraphene quantum dots (GQDs), a type of carbon-based nanomaterial, have remarkable biological, physical, and chemical properties. This study investigated the biological mechanisms of the proliferation and osteogenic differentiation of human periodontal ligament stem cells (PDLSCs) induced by GQDs in an inflammatory microenvironment.Materials and methodsPDLSCs were cultured in osteogenic-induced medium with various concentrations of GQDs in standard medium or medium mimicking a proinflammatory environment. The effects of GQDs on the proliferation and osteogenic differentiation activity of PDLSCs were tested by CCK-8 assay, Alizarin Red S staining, and qRT‒PCR. In addition, Wnt/β-catenin signalling pathway-related gene expression was measured by qRT‒PCR.ResultsCompared with the control group, the mRNA expression levels of ALP, RUNX2, and OCN and the number of mineralized nodules were all increased in PDLSCs after treatment with GQDs. Moreover, during the osteogenic differentiation of PDLSCs, the expression levels of LRP6 and β-catenin, which are Wnt/β-catenin signalling pathway-related genes, were upregulated.ConclusionIn the inflammatory microenvironment, GQDs might promote the osteogenic differentiation ability of PDLSCs by activating the Wnt/β-catenin signalling pathway.

Comparing bio-tribocorrosion of selective laser melted Titanium-25% Niobium and conventionally manufactured Ti-6Al-4 V in inflammatory conditions

The present study aims to evaluate the biocompatibility and bio-tribocorrosion potential of selective laser melted (SLM) Titanium-25% Niobium (Ti-25 Nb) alloy. Further the suitability of the Ti-25 Nb implant was assessed by benchmarking with conventionally manufactured commercial Ti-6Al-4 V implant. Ball-on-plate tests were performed on these alloys while submerging them in an acidic sodium lactate (ASL) medium. Simultaneously, the open circuit potential (OCV) of the two alloys were measured before, during and after sliding the indenter. Characterization of the surface morphology and composition after the test revealed that SLM fabricated Ti-25 Nb exhibits superior wear resistance and hence has greater resistance to depassivation than commercial Ti-6Al-4 V implant. Biocompatibility of the implants, in terms of cell adhesion, cell proliferation, osteogenic differentiation and Alkaline Phosphatase (ALP) activity were also studied on the surfaces of the worn alloys. Results indicate that the worn Ti-25 Nb surface is more conducive for the healthy growth of cells and facilitates more pronounced ALP activity than that of Ti-6Al-4 V, over a duration of 14 days. The superior bio-tribocorrosion performance and biocompatibility of Ti-25 Nb is attributed to SLM induced development of compressive residual stresses, smoother worn surface, higher compactness of the Nb oxides over the alloy surface and negligible toxicity of Nb.

Biological properties of hydroxyapatite coatings on titanium dioxide nanotube surfaces using negative pressure method.

Titanium (Ti) exhibits superior biocompatibility and mechanical properties but is bioinert, while hydroxyapatite (HA) possesses excellent osteogenesis and is widely used for the modification of Ti surface coatings. However, the synthesis of homogeneous and stable HA on metallic materials is still a major challenge. In this study, porous titanium dioxide nanotube arrays were prepared on Ti surface by anodic oxidation, loaded with calcium and phosphorus precursors by negative pressure immersion, and HA coating was formed by in situ crystallization of calcium and phosphorus on the surface by hydrothermal heating. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and bonding strength were conducted to confirm the surface characteristics of each group. The cell proliferation, mineralization degree, and alkaline phosphatase (ALP) activity of MC3T3-E1 cells on samples were calculated and compared in vitro experiments. Cylindrical samples were implanted into rat femurs to evaluate biocompatibility and osteogenesis in vivo. The results showed that HA crystals successfully synthesized in TiO2 nanotubes, enhancing the bonding strength of HA coating and Ti substrate under negative pressure. Moreover, HA coating on Ti substrate remarkably enhanced cell proliferation and osteogenic differentiation activity in vitro, and improved new bone formation as well as osseointegration in vivo.

Bioinspired strontium magnesium phosphate cement prepared utilizing the precursor method for bone tissue engineering.

Bioinspired strontium magnesium phosphate cements for bone tissue engineering were prepared using a new, facile, environmentally friendly and high yielding (98.5%) precursor method. The bioinspired SMPCs have uniform particle distributions, excellent mechanical strengths and high biocompatibilities. The in vitro responses of bone marrow stromal cells to the SMPCs, including viability, osteogenic differentiation and alkaline phosphatase activity, were evaluated. The results show that the SMPC containing 0.5mol of strontium (referred to as SMPC-2) has a higher degradation rate and biological activity than magnesium phosphate cements and the other SMPCs. In addition, the synergistic effect of strontium and magnesium ion release from SMPC-2 creates a conducive environment for cell proliferation, mineralized calcium deposition and new bone formation. These observations demonstrate the feasibility of using the new precursor method to generate SMPCs and the utility of these biologically compatible and highly effective cements for bone tissue engineering.