Osteoblastic Cells Research Articles

Recombinant human secretory leukocyte protease inhibitor (rhSLPI) coated titanium enhanced human osteoblast adhesion and differentiation

Osseointegration is vital to success in orthopedic and dental reconstructions with implanted materials. The bone matrix or cells—particularly osteoblasts—are required to achieve functional contact on the implant surface. Osteoblast induction is therefore essential for osteogenesis to occur. Enhancement of osteoblast adhesion, proliferation, and differentiation, particularly by implant surface modifications, have been found challenging to develop. Secretory Leukocyte Protease Inhibitor (SLPI), a cation ionic protein with anti-inflammatory and anti-bacterial activities, showed activation in osteoblast proliferation and differentiation. However, the effects of coating recombinant human (rh) SLPI on a titanium alloy surface on human osteoblast adhesion, proliferation, and differentiation has never been investigated. In this study, titanium alloys (Ti–6Al–4V) were coated with rhSLPI, while human osteoblast adhesion, proliferation, differentiation, actin cytoskeletal organization, and gene expressions involved in cell adhesion and differentiation were investigated. The results indicate that coating titanium with 10–100 µg/ml rhSLPI enhanced the physical properties of the Ti surface and enhanced human osteoblast (hFOB 1.19) cell adhesion, activated actin dynamic, enhanced adhesive forces, upregulated integrins α1, α2, and α5, enhanced cell proliferation, mineralization, alkaline phosphatase activity, and upregulated ALP, OCN, and Runx2. This is the first study to demonstrate that coating SLPI on titanium surfaces enhances osseointegration and could be a candidate molecule for surface modification in medical implants.

3D Printed SiO2-Tricalcium Phosphate Scaffolds Loaded with Carvacrol Nanoparticles for Bone Tissue Engineering Application.

Bone damage resulting from trauma or aging poses challenges in clinical settings that need to be addressed using bone tissue engineering (BTE). Carvacrol (CA) possesses anti-inflammatory, anticancer, and antibacterial properties. Limited solubility and physicochemical stability restrict its biological activity, requiring a stable carrier system for delivery. Here, we investigate the utilization of a three-dimensional printed (3DP) SiO2-doped tricalcium phosphate (TCP) scaffold functionalized with carvacrol-loaded lipid nanoparticles (CA-LNPs) to improve bone health. It exhibits a negative surface charge with an entrapment efficiency of ∼97% and size ∼129 nm with polydispersity index (PDI) and zeta potential values of 0.18 and -16 mV, respectively. CA-LNPs exhibit higher and long-term release over 35 days. The CA-LNP loaded SiO2-doped TCP scaffold demonstrates improved antibacterial properties against Staphylococcus aureus and Pseudomonas aeruginosa by >90% reduction in bacterial growth. Functionalized scaffolds result in 3-fold decrease and 2-fold increase in osteosarcoma and osteoblast cell viability, respectively. These findings highlight the therapeutic potential of the CA-LNP loaded SiO2-doped TCP scaffold for bone defect treatment.

TNF-α-induced Inhibition of Protein Myristoylation Via Binding Between NMT1 and Sorbs2 in Osteoblasts.

Bone resolution due to tumor invasion often occurs on the surface of the jaw and is important for clinical prognosis. Although cytokines, such as TNF-α are known to impair osteoblasts, the underlying mechanism remains unclear. Protein myristoylation, a post-translational modification, plays an important role in the development of immune responses and cancerization of cells. A clear understanding of the mechanisms underlying this involvement will provide insights into molecular-targeted therapies. N-myristoyltransferase1 (NMT1), a specific enzyme involved in myristoylation, is expressed in cancer cells and in other normal cells, suggesting that changes in myristoylation may result from the regulation of NMT1 in cancer cells. Using newly emerging state-of-the-art techniques such as the Click-it assay, RNA interference, mass spectrometry, immunoprecipitation, immunocytochemistry, and western blotting, the expression of myristoylated proteins and the role of TNF-α stimulation on NMT1 and Sorbs2 binding were evaluated in a murine osteoblastic cell line (MC3T3-E1). The expression of myristoylated proteins was detected; however, TNF-α stimulation resulted in their inhibition in MC3T3-E1 cells. The expression of NMT1 also increased. Immunoprecipitation and mass spectrometry identified Sorbs2 as a novel binding protein of NMT1, which upon TNF-α stimulation, inhibited myristoylation. The binding between NMT1 and Sorbs2 can regulate myristoylation, and NMT1 can be considered as a potential target molecule for tumor invasion.

The influence of radiation-induced bystander effect in osteoblasts mediated by plasma-derived extracellular vesicles (EVs)

ObjectivesHead and neck tumor patients may develop post-radiotherapy diseases after radiotherapy treatment. And radiotherapy can elicit radiation-induced bystander effect, wherein extracellular vesicles (EVs) play a crucial role. For normal parts of the body that have not been directly irradiated, the effect of EVs on them needs to be further explored. This study aims to investigate the functions of plasma-derived EVs in regulating normal osteoblasts during radiation-induced bystander effects. Methods and materialsRat plasma-derived EVs were isolated and identified firstly, followed by an evaluation of their intracellular biological effects on normal osteoblasts in vitro. Transcriptome sequencing analysis and confirmations were performed to identify potential mechanisms. ResultsIrradiated plasma-derived EVs were found to enhance osteoblast proliferation, migration, and cell cycle progression, concurrently suppressing the expression of osteogenesis-related genes and proteins. Furthermore, these EVs attenuated the expression of osteogenesis and oxidative stress resistance related genes, while upregulating the PI3K-AKT pathway and intracellular reactive oxygen species in osteoblasts. ConclusionsIrradiated plasma-derived EVs could alter the biological effects in osteoblasts, which is closely associated with the levels of GPX1 and the PI3K-AKT signaling pathway. This suggests that plasma-derived EVs serve as a crucial factor contributing to radiation-induced bystander effect in osteoblasts.

Lipolysis products from triglyceride-rich lipoproteins induce stress protein ATF3 in osteoblasts.

High fat diets overwhelm the physiological mechanisms for absorption, storage, and utilization of triglycerides (TG); consequently TG, TG-rich lipoproteins (TGRL), and TGRL remnants accumulate, circulate systemically, producing dyslipidemia. This associates with, or is causative for increased atherosclerotic cardiovascular risk, ischemic stroke, fatty liver disease, and pancreatitis. TGRL hydrolysis by endothelial surface-bound lipoprotein lipase (LPL) generates metabolites like free fatty acids which have proinflammatory properties. While osteoblasts utilize fatty acids as an energy source, dyslipidemia is associated with negative effects on the skeleton. In this study we investigated the effects of TGRL lipolysis products (TGRL-LP) on expression of a stress responsive transcription factor, termed activating transcription factor 3 (ATF3), reactive oxygen species (ROS), ATF3 target genes, and angiopoietin-like 4 (Angptl4) in osteoblasts. As ATF3 negatively associates with osteoblast differentiation, we also investigated the skeletal effects of global ATF3 deletion in mice. TGRL-LPincreased expression of Atf3, proinflammatory proteins Ptgs2 and IL-6, and induced ROS in MC3T3-E1 osteoblastic cells. Angptl4 is an endogenous inhibitor of LPL which was transcriptionally induced by TGRL-LP, while recombinant Angptl4 prevented TG-driven Atf3 induction. Atf3 global knockout male mice demonstrated increased trabecular and cortical microarchitectural parameters. In summary, we find that TGRL-LP induce osteoblastic cell stress as evidenced by expression of ATF3, which may contribute to the negative impact of dyslipidemia in the skeleton. Further, concomitant induction of Angptl4 in osteoblasts might play a protective role by reducing local lipolysis.

Investigating the cryoprotective efficacy of fructans in mammalian cell systems via a structure-functional perspective

Fructans have long been known with their role in protecting organisms against various stress factors due to their ability to induce controlled dehydration and support membrane stability. Considering the vital importance of such features in cryo-technologies, this study aimed to explore the cryoprotective efficacy of fructans in mammalian cell systems where structurally different fructan polymers were examined on in vitro cell models derived from organs such as the liver, frequently used in transplantation, osteoblast, and cord cells, commonly employed in cell banking, as well as human seminal fluids that are of vital importance in assisted reproductive technology. To gain insights into the fructan/membrane interplay, structural differences were linked to rheological properties as well as to lipid membrane interactions where both fluorescein leakage from unilamellar liposomes and membrane integrity of osteoblast cells were monitored. High survival rates obtained with human endothelial, osteoblast and liver cells for up to two months clearly showed that fructans could be considered as effective non-permeating cryoprotectants, especially for extended periods of cryopreservation. In trials with human seminal fluid, short chained levan in combination with human serum albumin and glycerol proved very effective in preserving semen samples across multiple patients without any morphological abnormalities.

Microcrystallization Effects in Borosilicate Bioactive Glasses: Controllable Release of Bioactive Elements and In Vitro Degradation Properties.

Borosilicate bioactive glasses exhibit excellent bioactivity and degradation properties; however, they suffer from the rapid release of bioactive elements at the initial stage of their degradation. Excessive local concentrations (such as those of B) can affect cell proliferation. Moreover, the degradation and mineralization ability of these glasses deteriorate at the later stages. Aiming to balance the release of bioactive elements during the whole process, herein, a borosilicate bioactive glass 18SiO2-6Na2O-8K2O-8MgO-22CaO-2P2O5-36B2O3 (mol%) was prepared using the melting method. Further, the effects of microcrystallization on the release of bioactive elements and in vitro degradation were studied. Results show that after heat treatment at temperatures over 620 °C, multiple microcrystalline phases, including Ca2SiO4, CaB2O4, and CaMgB2O5, form in the glass. The glass samples heat-treated within the range of 620-640 °C undergo appropriate devitrification degrees, decelerating the rate of pH increase of the immersion solution during the initial stage in comparison to those treated at lower temperatures. This results in a more continuous release of all bioactive elements and allows better control of the overall degradation. Contrarily, the more extensive devitrification degrees of glass samples heat-treated at higher temperatures reverse the pH increase and degradation trends. Since bone marrow mesenchymal stem cells and mouse embryonic osteoblast cells are pH-sensitive, inducing a suitable degree of devitrification proved to favor cell viability and enhance the mineralization capacity. Thus, different microcrystallization degrees provide new approaches for controlling the degradation and release of bioactive elements, resulting in the simultaneous enhancement of biosafety and bioactivity.

In vitro biodegradation, blood, and cytocompatibility studies of a bioactive lithium silicate glass-ceramic

This study investigates a novel non-stoichiometric lithia-silica glass-ceramic (Bioactive LD) designed for bone tissue engineering applications. Incorporating SiO2–Li2O–CaO–P2O5–K2O–SrO–ZnO, the glass-ceramic underwent optimized thermal treatments resulting in a composition predominantly of lithium disilicate (Li2Si2O5 - 87 %) with a minor lithium phosphate phase (Li3PO4 - 13 %). Structural analysis using X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed a refined microstructure with Li2Si2O5 crystals in rod form with a high aspect ratio of around 4:1. Expanding on previous work, this study investigates the in vitro osteoblastic response of Bioactive LD compared to a commercial glass-ceramic (E-Max CAD®). The evaluation, employing live/dead assays, resazurin assays, and alkaline phosphatase activity measurements at different time points, demonstrated comparable cell viability and proliferation on both glass-ceramics. The chemical stability of the samples was tested, and the Bioactive LD showed a higher amount of leached ions in the solution, without significant mass loss, consistent with the standardized values for a class 4 material (ISO 6872), with no significant change in its microstructure. The chemical solubility tests were investigated employing SEM and energy dispersive X-ray analysis (EDS), giving insights into the role of leached ions in the microstructure and bioactivity of the materials. Notably, Bioactive LD exhibits higher alkaline phosphatase activity, indicating enhanced stimulation of osteoblastic cells. Additionally, the Bioactive LD promotes mineralization matrix production, as evidenced by alizarin red S staining. The study also employs SEM-EDS to evaluate the formation of apatite mineralized matrix. Bioactive LD exhibits a homogeneous mineralized matrix with increased Calcium and Sulfur signals, suggesting early hydroxyapatite formation after Alizarin Red S assay. In contrast, Commercial LD shows limited reactivity and bioactivity, with no substantial calcium deposition. An indirect cytotoxicity test indicates minimal cytotoxicity for Bioactive LD, while Commercial LD exhibits slight cytotoxicity, consistent with findings from the literature. The results highlight Bioactive LD's potential for bone regeneration, emphasizing its enhanced bioactivity and the formation of a complex mineralized matrix that could contribute to improved bone integration properties.

Drug-Releasing Tannic Acid-Mediated Adhesive PEG Hydrogel for Porous Titanium Implants.

Porous titanium implants are commonly utilized for orthopedic surgery because they can mimic the mechanical properties and porous structure of human bone. However, the bioinertness of titanium (Ti) has been reported to obstruct biointegration processes, resulting in slower bone repair. Here, we propose a localized drug delivery system on Ti surfaces using adhesive hydrogel to enhance biological-Ti interactions. The hydrogel was fabricated from polyethylene glycol (PEG), which was cross-linked by the complex of tannic acid (TA) and 1,4-phenylenediboronic acid (PDBA) and stabilized by bovine serum albumin (BSA). The hydrogel was formed and attached to a Ti plate to investigate stability, biodegradability, controlled drug release, and biocompatibility. The stability and biodegradability of the hydrogel could be tuned by adjusting the concentrations of BSA and TA. The hydrogel lasted and remained adhered to the Ti surface after being submerged in PBS for at least 15 days. The controlled release of strontium ranelate (SrRan) and the release mechanism depended on the amount of TA since it was found to govern the hydrogel integrity and pore size. Additionally, in vitro biocompatibility was validated using L929 fibroblast and MC3T3-E1 osteoblast cells that showed greater than 70% viability. The adhesive hydrogel was further studied by injecting it into a 3D-printed Ti-scaffold that contained a porous structure mimicking natural human bone. The hydrogel completely filled and adhered to the inner porous structure of the scaffold. The biodegradation and drug release of the hydrogel in the scaffold occurred at a slower rate, suggesting sustainable drug release that is suitable for bone cell regeneration. The overall results in biodegradability, controlled drug release, and biocompatibility demonstrate the great potential of the drug-releasing TA-mediated adhesive PEG hydrogel as a Ti-enhancing biomaterial that supports osseointegration.

Microgravity triggers ferroptosis and accelerates senescence in the MG-63 cell model of osteoblastic cells

In space, cells sustain strong modifications of their mechanical environment. Mechanosensitive molecules at the cell membrane regulate mechanotransduction pathways that induce adaptive responses through the regulation of gene expression, post-translational modifications, protein interactions or intracellular trafficking, among others. In the current study, human osteoblastic cells were cultured on the ISS in microgravity and at 1 g in a centrifuge, as onboard controls. RNAseq analyses showed that microgravity inhibits cell proliferation and DNA repair, stimulates inflammatory pathways and induces ferroptosis and senescence, two pathways related to ageing. Morphological hallmarks of senescence, such as reduced nuclear size and changes in chromatin architecture, proliferation marker distribution, tubulin acetylation and lysosomal transport were identified by immunofluorescence microscopy, reinforcing the hypothesis of induction of cell senescence in microgravity during space flight. These processes could be attributed, at least in part, to the regulation of YAP1 and its downstream effectors NUPR1 and CKAP2L.

Nano apatite growth on demineralized bone matrix capped with curcumin and silver nanoparticles: Dental implant mechanical stability and optimal cell growth analysis

ObjectivesThe prevention of implant-associated infections is becoming increasingly clinically important in the field of dentistry. Extensive investigations into the development of innovative antibacterial materials that interact effectively to reinforce their functionality are currently being conducted in the biomedical sector. In the present study, a novel dental nano putty (D-nP) has been developed using demineralized bone matrix (DBM), calcium sulfate hemihydrate (CSH), curcumin nanoparticles (CU-NPs), and silver nanoparticles (AgNPs). MethodsThe produced D-nP was evaluated using physicochemical, mechanical, and in vitro analyses. Surface characterization, particularly the analysis of calcium and phosphorus content, was performed before and after immersion in the simulated body fluid (SBF). In addition, the impact of surface treatment on biological activity was studied. ResultsThe results showed that the mechanical properties of the D-nP were outstanding and its performance is promising. D-nP exhibited excellent antibacterial activity against Actinomyces naeslundii (5.22 ± 0.07 mm) and Streptococcus oralis (5.41 ± 0.1 mm). The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was conducted using MG-63 osteoblast cells, which exhibited 95 % viability in D-nP. ConclusionsBased on these characterization results, the D-nP developed in this study exhibited excellent performance for tooth tissue in bone repair.

Effects of using collagen and aloe vera grafted fibroin scaffolds on osteogenic differentiation of rat bone marrow mesenchymal stem cells in SBF-enriched cell culture medium

In the study, collagen and aloe vera were grafted onto silk fibroin with two different methods, and 3D-microporous scaffolds (1F5C4A1 and 2F5C4A1) were formed by lyophilization. Three osteogenic cultures were started by seeding rat bone marrow mesenchymal stem cells (MSCs) and pre-induced MSC (osteoblast (OB)) on biopolymeric scaffolds. The osteogenic medium was enriched with 10% (v/v) simulated body fluid (SBF) to promote mineralization and osteogenic differentiation in one of the MSC cultures and the OB culture. X-ray diffraction (XRD), scanning electron microscopy (SEM), scanning electron microscopy- energy dispersive spectrum (SEM-EDS) analyses on cellular samples and histochemical (alizarin red, safranin-O, alcian blue) and immunohistochemical (anti-collagen-1, anti-osteocalcin, anti-osteopontin) staining showed that bone-like mineralization was occurred by both chemically and cellular activity. In addition, pre-osteogenic induction of MSCs in 2D-cultured was found to promote osteogenesis more rapidly when started 3D-cultured. These results indicated that enrichment of the cell culture medium with SBF is sufficient for in vitro mineralization rather than using high concentrations of SBF. The findings showed that OB cells on the 2F5C4A1 scaffold obtained the best osteogenic activity. Still, other culture media with 10% SBF content could be used for bone tissue engineering under osteogenic induction.

Isolation of Pro-Osteogenic Compounds from Euptelea polyandra That Reciprocally Regulate Osteoblast and Osteoclast Differentiation.

Plants contain a large number of small-molecule compounds that are useful for targeting human health and in drug discovery. Healthy bone metabolism depends on the balance between bone-forming osteoblast activity and bone-resorbing osteoclast activity. In an ongoing study searching for 22 plant extracts effective against osteoporosis, we found that the crude extract of Euptelea polyandra Sieb. et Zucc (E. polyandra) had osteogenic bioactivity. In this study, we isolated two compounds, isoquercitrin (1) and astragalin (2), responsible for osteogenic bioactivity in osteoblastic MC3T3-E1 cells from the leaf of E. polyandra using column chromatography and the spectroscopic technique. This is the first report to isolate astragalin from E. polyandra. Compounds (1) and (2) promoted osteoblast differentiation by increasing alkaline phosphatase (ALP) activity and alizarin red S stain-positive calcium deposition, while simultaneously suppressing tartrate-resistant acid phosphatase (TRAP)-positive osteoclast differentiation in RAW264.7 cells at non-cytotoxic concentrations. Isoquercitrin (1) and astragalin (2) increased the expression of osteoblastic differentiation genes, Osterix, ALP, and Osteoprotegerin in the MC3T3-E1 cells, while suppressing osteoclast differentiation genes, TRAP, Cathepsin K, and MMP 9 in the RAW264.7 cells. These compounds may be ideal targets for the treatment of osteoporosis due to their dual function of promoting bone formation and inhibiting bone resorption.

Bone implant substitutes from synthetic polymer and reduced graphene oxide: Current perspective.

In the present work, bone implant materials (BIM) were produced, in sheet form which comprises epoxy resin (synthetic polymer) (ER), calcium carbonate (CaCO3), and reduced graphene oxide (R-GO), by open mold method, for the possibility uses in bone tissue engineering. The developed BIM was analyzed for its physico-chemical, mechanical, bioactivity test, antimicrobial study, and biocompatibility. The BIM had excellent mechanical properties such as tensile strength (194.44 + 0.21 MPa), flexural strength (278.76 + 0.41 MPa), and water absorption (02.61 + 0.24%). A pore size distribution study using the HR-SEM has proved the 180 and 255 μm average pore was observed in the BIM structure. The Bioactivity test of BIM was examined after being immersed in a simulated body fluids (SBF) solution. The result of BIM formed an excellent deposition of bone tube apatite crystals. High-resolution scanning electron microscopy (HR-SEM) morphology of the bone tube apatite crystals revealed the diameter size in the range from 100 ± 159 to 210 ± 188 nm. BIM has excellent antimicrobial characteristics against E. coli (8.75 + 0.06 mm) and S. aureus (9.82 + 0.08 mm). The biocompatibility of the study MTT (3-(4, 5-dimethyl) thiazol-2-yl-2, 5-dimethyl tetrazolium bromide) assay using the MG-63 (human osteoblast cell line) has proven to be the 78% viable cell presence in BIM. After receiving the necessary approval, the scaffold with the required strength and biocompatibility could be tested as a bone implant material in large animals.

Bcl2l1 Deficiency in Osteoblasts Reduces the Trabecular Bone Due to Enhanced Osteoclastogenesis Likely through Osteoblast Apoptosis.

Bcl2l1 (Bcl-XL) belongs to the Bcl-2 family, Bcl2 and Bcl2-XL are major anti-apoptotic proteins, and the apoptosis of osteoblasts is a key event for bone homeostasis. As the functions of Bcl2l1 in osteoblasts and bone homeostasis remain unclear, we generated osteoblast-specific Bcl2l1-deficient (Bcl2l1fl/flCre) mice using 2.3-kb Col1a1 Cre. Trabecular bone volume and the trabecular number were lower in Bcl2l1fl/flCre mice of both sexes than in Bcl2l1fl/fl mice. In bone histomorphometric analysis, osteoclast parameters were increased in Bcl2l1fl/flCre mice, whereas osteoblast parameters and the bone formation rate were similar to those in Bcl2l1fl/fl mice. TUNEL-positive osteoblastic cells and serum TRAP5b levels were increased in Bcl2l1fl/flCre mice. The deletion of Bcl2l1 in osteoblasts induced Tnfsf11 expression, whereas the overexpression of Bcl-XL had no effect. In a co-culture of Bcl2l1-deficient primary osteoblasts and wild-type bone-marrow-derived monocyte/macrophage lineage cells, the numbers of multinucleated TRAP-positive cells and resorption pits increased. Furthermore, serum deprivation or the deletion of Bcl2l1 in primary osteoblasts increased apoptosis and ATP levels in the medium. Therefore, the reduction in trabecular bone in Bcl2l1fl/flCre mice may be due to enhanced bone resorption through osteoblast apoptosis and the release of ATP from apoptotic osteoblasts, and Bcl2l1 may inhibit bone resorption by preventing osteoblast apoptosis.

Enhancing Osteoblastic Cell Cultures with Gelatin Methacryloyl, Bovine Lactoferrin, and Bioactive Mesoporous Glass Scaffolds Loaded with Distinct Parsley Extracts.

The increasing interest in innovative solutions for addressing bone defects has driven research into the use of Bioactive Mesoporous Glasses (MBGs). These materials, distinguished by their well-ordered mesoporous structure, possess the capability to accommodate plant extracts with well-established osteogenic properties, including bovine lactoferrin (bLF), as part of their 3D scaffold composition. This harmonizes seamlessly with the ongoing advancements in the field of biomedicine. In this study, we fabricated 3D scaffolds utilizing MBGs loaded with extracts from parsley leaves (PL) and embryogenic cultures (EC), rich in bioactive compounds such as apigenin and kaempferol, which hold potential benefits for bone metabolism. Gelatin Methacryloyl (GelMa) served as the polymer, and bLF was included in the formulation. Cytocompatibility, Runx2 gene expression, ALP enzyme activity, and biomineralization were assessed in preosteoblastic MC3T3-E1 cell cultures. MBGs effectively integrated PL and EC extracts with loadings between 22.6 ± 0.1 and 43.6 ± 0.3 µM for PL and 26.3 ± 0.3 and 46.8 ± 0.4 µM for EC, ensuring cell viability through a release percentage between 28.3% and 59.9%. The incorporation of bLF in the 3D scaffold formulation showed significant differences compared to the control in all assays, even at concentrations below 0.2 µM. Combinations, especially PL + bLF at 0.19 µM, demonstrated additive potential, with superior biomineralization compared to EC. In summary, this study highlights the effectiveness of MBGs in incorporating PL and EC extracts, along with bLF, into 3D scaffolds. The results underscore cytocompatibility, osteogenic activity, and biomineralization, offering exciting potential for future in vivo applications.

Corrosion behaviour of plasma-sprayed baghdadite bioceramic coatings reinforced with carbon nanotubes

Bioceramics have been extensively used for the restoration and replacement of hard tissues, such as bones and teeth due to their physicochemical resemblance to these tissues. This study focuses on enhancing the properties of plasma-sprayed bioceramic coatings with the addition of carbon nanotubes. The coatings deposited include hydroxyapatite, baghdadite, and baghdadite with carbon nanotube reinforcement. The effect of incorporating carbon nanotubes into baghdadite coatings is thoroughly investigated in terms of microstructural, mechanical, and electrochemical properties. Multiple characterization techniques such as scanning electron microscopy, energy dispersive spectroscopy, X-ray diffractometry, and Raman spectroscopy have been employed to reveal microstructural details, elemental composition, and phase constituents of the deposited coatings. The results indicate that baghdadite coatings exhibit higher porosity compared to hydroxyapatite coatings. However, the addition of carbon nanotubes as reinforcement into baghdadite coatings effectively reduces porosity by integrating carbon nanotubes within the inter-lamellae structure and filling voids within the inter-splat regions. This integration also mitigates common post plasma spray defects including porosity, voids, and microcracks. The incorporation of 2 wt% carbon nanotubes into the baghdadite matrix results in a substantial 80% reduction in corrosion current density(Icorr). This reduction is attributed to the combined effects of reduced porosity, and improved structural integrity due to carbon nanotubes. Furthermore, the carbon nanotubes reinforced baghdadite coatings have indicated the healthy development of the MC3T3-E1 osteoblast cell line.

Octacalcium phosphate phase forming cements as an injectable bone substitute materials: Preparation and in vitro structural study

In the realm of regenerating damaged or degenerated bones through minimally invasive techniques, injectable materials have emerged as exceptionally promising. Among these, calcium phosphate bone cements (CPCs) have garnered significant interest due to their remarkable bioactivity, setting it apart from non-degradable alternatives such as polymethyl methacrylate cements. α-Tricalcium phosphate (α-TCP) is a widely used solid phase component in CPCs. It can transform into calcium-deficient hydroxyapatite (CDHAp) when it comes in contact with water. In this study, we aimed to create an injectable, self-setting bone cement using low-temperature synthesized α-TCP powder as a single precursor of the powder phase. We found that changes in the pH of the liquid phase (pH 6.0, pH 6.2, pH 7.0 and pH 7.4) significantly altered the cement's setting, handling, and mechanical properties. The formation of the octacalcium phosphate (OCP) phase was identified in our study, which positively affects the osteoblastic cell response. Hardened OCP-forming bone cements prepared using a liquid phase with pH 7.0 and 7.4 showed better osteogenic cell attachment and proliferation than those prepared with pH 6.0 and 6.2. Our study suggests that changes in the pH of the liquid phase can significantly affect the properties of α-TCP-based bone cement, and the presence of the OCP phase is crucial for optimal cement performance.

ZnO and Cu/ZnO-modified Magnesium orthopedic implant with improved osteoblast cellular activity: An in-vitro study

Mg-based biomaterials, due to their desirable mechanical integrity, natural bioabsorbability, and osteopromotive characteristics, are promising candidates for both orthopedic applications, such as the surgical fixation of injured musculoskeletal tissues, and cardiovascular applications like coronary artery stents. In the present study, nano- and micro-sized ZnO and Cu/ZnO bioactive particles were used to fabricate Mg-based biocomposites using friction stir processing (FSP). FSP resulted in significant microstructural modification in terms of grain refinement, uniform redistribution of secondary phase particles and homogenous dispersion of bioactive particles. Long-term biodegradation results through H2 evolution method illustrated that biodegradation rate of the bioabsorbable WE43 alloy was significantly reduced by addition of bioactive particles. In addition, fabricated biocomposites with addition of nano-sized particles resulted in lower biodegradation rate in comparison to those with micro-sized particles. Furthermore, uniform dispersion of bioactive particles resulted in superior in-vitro biocompatibility in contact with MC3T3-E1 mouse osteoblast cells. Mg–ZnO–N and Mg–Cu/ZnO–N biocomposites showed improved cell adhesion with elongated and spread morphology of MC3T3-E1 osteoblast cells. Live/dead staining and MTT assay indicated that number of healthy cells and cell viability after 24 h of incubation increased by uniform distribution of bioactive particles. Moreover, fabricated biocomposites with homogenous distribution of Zn2+ and Cu2+ ions showed higher ALP activity. Our findings propose that Mg–ZnO and Mg–Cu/ZnO biocomposites with homogenous dispersion of bioactive particles can be promising candidates for bone tissue regeneration applications.

In vitro and in vivo study of copper-doped bioactive glass for bone regeneration application

Bioactive glasses (BGs) are being explored in bone regeneration applications with great interest banking on their excellent bioactivity, angiogenesis, osteogenesis, and bone-bonding capacity. In this connection, the designing of metal-doped BG composite with enhanced biological properties is attracting the attention of the scientific community. With this motivation, the present study focuses on the synthesis of copper-doped 70S30C bioactive glass (CuBGs) using a simple precipitation method, wherein rice husk, eggshell, and copper sulfate were used as a precursor for silica, calcium, and copper. The objective of the study is to synthesize acid-free and binder-free CuBGs for bone regeneration application. The structural and textural properties of the CuBG samples were studied using XRD, FTIR, SEM-EDS, and BET techniques. In addition, in vitro bioactivity and degradation studies were performed in simulated body fluid (SBF). The antibacterial activity of the CuBGs shows an inhibitory effect against E. coli and S. aureus bacteria. The in vitro haemolysis study indicates haemo-compatibility and significantly improved angiogenesis after copper doping. The histology study of chick bone demonstrates the growth of osteoblast cells. Further, MG-63 cells were exposed to the CuBGs samples (concentrations up to 10 mg mL−1) to assess biocompatibility and it was observed that it did not exhibit any toxic effects. This is supported by an in vivo biocompatibility study indicating its non-toxic nature. The results reveal that CuBG plays an important role in enhancing bioactivity, antibacterial activity, and angiogenesis, and it is non-toxic making it a promising candidate for bone tissue engineering application.