Matrix Mineralization Research Articles

Transforming Mining Tailings into Green Steel and Rare Earth Elements

As critical components for energy and defense technologies, the U.S. rare earth element (REE) ore reserves are estimated at ~13 million tons, but domestic production is currently limited to one operational mine residing on high-grade ore deposits in Mountain Pass, CA. While low-grade REE deposits are abundant, high-grade American REE deposits are sparse. Meanwhile, hazardous REE-containing tailings pile up at the economic and environmental cost, and it is estimated that REE value locked within e.g., red mud, is $796 per ton. However, such low-grade deposits or mining tailings are challenging to access because REEs are usually locked within a mineral matrix, typically iron oxide, that renders the ore intractable to mechanical or chemical separation. Here, we propose a process for recovering REEs from low-grade deposits and tailings by electro-metallurgically removing iron oxide, hydro-metallurgically removing aluminum salt, and subsequent separating insoluble rare earth oxides. Our strategy produces not only refinable REEs concentrates but also emissions-free iron metal and supplementary cementitious materials as co-products for decarbonizing steel and cement industries, respectively. By addressing the economic and environmental challenges associated with low-grade REE deposits and mining tailings, our electrochemical approach offers a sustainable pathway for unlocking the potential of domestic rare earth resources.

Mechanical properties and biological behavior of refractory TiZrNbTa medium-entropy and TiZrHfNbTa high-entropy alloy nanofilms on AISI 316L for bone implants

To investigate the feasibility of high-entropy alloys as the coating materials for the application of bone implants, TiZrNbTa refractory medium-entropy alloy (RMEA) and TiZrHfNbTa refractory high-entropy alloy (RHEA) nanofilms were prepared on AISI 316L stainless steel by DC magnetron sputtering and post-annealing treatment. Then, the microstructure, mechanical properties, wear resistance, corrosion resistance, biocompatibility and osteogenic activity of the nanofilms were systematically studied. The results showed that both the films exhibited uniform and dense nanostructures. Post-annealing treatment not only improved the adhesion strength, but also formed an oxidized layer. Notably, owing to the enhanced high-entropy and lattice distortion effects, the RHEA nanofilm showed finer grain sizes, higher hardness (14 GPa), H/E, H3/E2 and better wear resistance. The in vitro experiments proved that RHEA nanofilm had the highest Ecorr (−0.127 V), with the Icorr value was two orders of magnitude lower than substrate. Its osteoblast proliferative capacity was 1.5 times higher than substrate (after culturing for 5 days), and the collagen secretion and extracellular matrix mineralization reached an optimal level, showing excellent osteogenic activity. Therefore, RHEA nanofilm coated biomaterials can be a more attractive candidate for bone replacement.

Mandible development under gestational protein restriction: cellular and molecular mechanisms.

Insufficient evidence regarding how maternal undernutrition affects craniofacial bone development persists. With its unique focus on the impact of gestational protein restriction on calvaria and mandible osteogenesis, this study aims to fill, at least in part, this gap. Female mice were mated and randomized into NP (normal protein) or LP (low protein) groups. On the 18th gestational day (GD), male embryos were collected and submitted to microtomography (µCT), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), PCR, and autophagy dynamic analyses. The study shows that the LP offspring exhibited lower body mass than the NP group, with µCT analysis revealing no volumetric differences in fetus's head. EDS analysis showed lower calcium and higher phosphorus percentages in mandibles and calvaria. SEM assessment evidenced higher hydroxyapatite crystal-like (HC) deposition on the calvaria surface in LP fetus. Conversely, lower HC deposition was observed on the mandible surface, suggesting delayed matrix mineralization in LP fetuses with a higher percentage of collagen fibers in the mandible bone. The autophagy process was reduced in the mesenchyme of LP fetuses. PCR array analysis of 84 genes revealed 27 genes with differential expression in the LP progeny-moreover, increased mRNA levels of Akt1, Mtor, Nfkb, and Smad1 in the LP offspring. In conclusion, the results suggest that gestational protein restriction anticipated bone differentiation in utero, before 18GD, where this process is reduced compared to the control, leading to the reduction in bone area at 15 postnatal day previously observed. These findings provide insights into the molecular and cellular mechanisms of mandible development and suggest potential implications for the Developmental Origins of Health and Disease (DOHaD).

Metabolically healthy obesity in adults with X-linked hypophosphatemia.

X-linked hypophosphatemia (XLH) is characterized by increased concentrations of circulating fibroblast growth factor 23 (FGF-23) resulting in phosphate wasting, hypophosphatemia, atypical growth plate and bone matrix mineralization. Epidemiologic studies suggest a relationship between FGF-23, obesity, and metabolic dysfunction. The prevalence of overweight and obesity is high in children with XLH. We aimed to evaluate the prevalence of obesity and metabolic complications in adults with XLH. We conducted a prospective cohort study in adult XLH patients from a single tertiary referral center. The proportion of patients with a BMI >25 kg/m2 was the main outcome measure. Body fat mass percentage (FM%) and adipose tissue surfaces were secondary outcome measures. Glucose homeostasis (plasma glucose and insulin concentrations after fasting and 2 hours after an oral glucose tolerance test) was explored in a subgroup of patients and compared with age-, sex-, and BMI-matched healthy controls. Among 113 evaluated patients, 85 (75%) were female and 110 (97%) carried a PHEX mutation. Sixty-three (56%) patients were overweight or obese, with a median BMI of 25.3 [IQR, 22.7; 29.2] kg/m2. BMI was correlated with FM%, abdominal and thigh subcutaneous and intra-abdominal adipose tissue surfaces. The prevalence of impaired fasting glucose, impaired glucose tolerance, and diabetes was not different between XLH patients and matched controls. The prevalence of overweight and obesity is high among XLH patients and is associated with excess fat mass. However, the prevalence of glucose homeostasis abnormalities is not increased in patients compared to healthy controls, suggesting that metabolically healthy overweight or obesity predominates.

Fibrin-konjac glucomannan-black phosphorus hydrogel scaffolds loaded with nasal ectodermal mesenchymal stem cells accelerated alveolar bone regeneration

BackgroundEffective treatments for the alveolar bone defect remain a major concern in dental therapy. The objectives of this study were to develop a fibrin and konjac glucomannan (KGM) composite hydrogel as scaffolds for the osteogenesis of nasal mucosa-derived ectodermal mesenchymal stem cells (EMSCs) for the regeneration of alveolar bone defect, and to investigate the osteogenesis-accelerating effects of black phosphorus nanoparticles (BPNs) embedded in the hydrogels.MethodsPrimary EMSCs were isolated from rat nasal mucosa and used for the alveolar bone recovery. Fibrin and KGM were prepared in different ratios for osteomimetic hydrogel scaffolds, and the optimal ratio was determined by mechanical properties and biocompatibility analysis. Then, the optimal hydrogels were integrated with BPNs to obtain BPNs/fibrin-KGM hydrogels, and the effects on osteogenic EMSCs in vitro were evaluated. To explore the osteogenesis-enhancing effects of hydrogels in vivo, the BPNs/fibrin-KGM scaffolds combined with EMSCs were implanted to a rat model of alveolar bone defect. Micro-computed tomography (CT), histological examination, real-time quantitative polymerase chain reaction (RT-qPCR) and western blot were conducted to evaluate the bone morphology and expression of osteogenesis-related genes of the bone regeneration.ResultsThe addition of KGM improved the mechanical properties and biodegradation characteristics of the fibrin hydrogels. In vitro, the BPNs-containing compound hydrogel was proved to be biocompatible and capable of enhancing the osteogenesis of EMSCs by upregulating the mineralization and the activity of alkaline phosphatase. In vivo, the micro-CT analysis and histological evaluation demonstrated that rats implanted EMSCs-BPNs/fibrin-KGM hydrogels exhibited the best bone reconstruction. And compared to the model group, the expression of osteogenesis genes including osteopontin (Opn, p < 0.0001), osteocalcin (Ocn, p < 0.0001), type collagen (Col , p < 0.0001), bone morphogenetic protein-2 (Bmp2, p < 0.0001), Smad1 (p = 0.0006), and runt-related transcription factor 2 (Runx2, p < 0.0001) were all significantly upregulated.ConclusionsEMSCs/BPNs-containing fibrin-KGM hydrogels accelerated the recovery of the alveolar bone defect in rats by effectively up-regulating the expression of osteogenesis-related genes, promoting the formation and mineralisation of bone matrix.

3D-printed titanium scaffolds loaded with gelatin hydrogel containing strontium-doped silver nanoparticles promote osteoblast differentiation and antibacterial activity for bone tissue engineering.

Bone tissue engineering offers a promising alternative to stimulate the regeneration of damaged tissue, overcoming the limitations of conventional autografts and allografts. Recently, titanium alloy (Ti) implants have garnered significant attention for treating critical-sized bone defects, especially with the advancement of 3D printing technology. Although Ti alloys have impressive versatility, their lack of cellular adhesion, osteogenic and antibacterial properties are significant factors that contribute to their failure. Hence, to overcome these obstacles, this study aimed to incorporate osteoinductive and antibacterial cue-loaded hydrogels into 3D-printed Ti (3D-Ti) scaffolds. 3D-Ti scaffolds were synthesized using the direct metal laser sintering method and loaded with a gelatin (Gel) hydrogel containing strontium-doped silver nanoparticles (Sr-Ag NPs). Compared with Ag NPs, Sr-doped Ag NPs increased the expression of Runx2 mRNA, which is a key bone transcription factor. We subjected the bioactive 3D-hybrid scaffolds (3D-Ti/Gel/Sr-Ag NPs) to physicochemical and material characterization, followed by cytocompatibility and osteogenic evaluation. The microporous and macroporous topographies of the scaffolds with Sr-Ag NPs showed increased Runx2 expression and matrix mineralization, with potent antibacterial properties. Therefore, the 3D-Ti scaffolds incorporated with Sr-Ag NP-loaded Gel hydrogels favored osteoblast differentiation and antibacterial activity, indicating their potential for orthopedic applications.

Black Phosphorus and E7-Functionalized Sulfonated Polyetheretherketone with Effective Osteogenicity and Antibacterial Activity

Given its excellent biological properties and the matching of its elastic modulus with that of human bone tissue, medical polyetheretherketone (PEEK) is considered a desirable candidate for bone-implant materials. However, its poor osseointegrative and antibacterial properties greatly limit its clinical application. To address these concerns, a functional PEEK implant is needed. Herein, a novel photo-responsive multifunctional PEEK-based implant material (sPEEK/BP/E7) with both effective osteogenesis and good disinfection properties was constructed via the self-assembly of black phosphorus (BP) nanosheets, mussel-inspired polydopamine (PDA), and bioactive short peptide E7 on sulfonated PEEK (sPEEK). The versatile micro-/nano-structured PEEK surface provides superior hydrophilicity, a favorable osteogenic microenvironment, and excellent photothermal effects under near-infrared (NIR) irradiation. The in vitro results showed that sPEEK/BP/E7 displays enhanced cytocompatibility and osteogenicity in terms of cell adhesion, proliferation, alkaline phosphatase (ALP) activity, matrix mineralization, and osteogenesis-related gene expression, superior to those of the sPEEK and sPEEK/BP samples. In addition to osteogenesis, the multifunctional coating exhibited strong antibacterial activity against both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Furthermore, it was confirmed in a rat femoral infection model that sPEEK/BP/E7 effectively resisted infection caused by S. aureus under NIR light irradiation and promoted osseointegration in vivo. Thus, this work presents a facile strategy to realize improvement of the “functional integration” of new polymer bone-implant materials and provide new ideas for their clinical application.

Effects of photobiomodulation on different phases of in vitro osteogenesis.

The present study aimed to evaluate the effect of photobiomodulation therapy (PBM) on different stages of osteogenesis in vitro. For this, osteoblastic-like cells (Saos-2 cell lineage) were irradiated in two different periods: during the Proliferation phase (PP; from the second to the fourth day) and during the Differentiation phase (DP; from the seventh to the ninth day). The energy density used in the study was 1.5J/ cm2. The following parameters were evaluated: 1) quantification ofcollagen type 1 (COL 1), osteopontin (OPN), and bone morphogenetic protein 2 (BMP-2); 2) quantification of alkaline phosphatase (ALP) activity; and 3) quantification of extracellular matrix (ECM)mineralization. Non-irradiated cultures were used as controls. The data were analyzed using the Student's t-test or one-way ANOVA, considering a significance level of 5%. The results indicated that COL 1 and BMP-2 quantification was higher in Saos-2 irradiated during the DP in relation to the control group at day 10 (p < 0.05). No differences were observed for other comparisons at this time point(p>0.05).OPN expression was greater in PP compared with the other experimental groups at day 10 (p < 0.05). Irradiation did not affect ALP activity in Saos-2 regardless of the exposure phase and the time point evaluated (p > 0.05). At day 14, ECMmineralization was higher in Saos-2 cultures irradiated during the DP in relation to the PP (p < 0.05). In conclusion, the results suggested that the effects of PBM on osteoblastic cells may be influenced by the stage of cell differentiation.

Cuttlefish Bone-Derived Calcium Phosphate Bioceramics Have Enhanced Osteogenic Properties.

Cuttlefish bones are byproducts of cuttlefish processing and are readily available in the marine food industry. In this study, calcium phosphate bioceramics were prepared from cuttlefish bones using a two-stage hydrothermal calcination process. The results indicated that all bioceramics derived from cuttlefish bones had a higher degradation capacity, better bone-like apatite formation ability, and higher degree of osteogenic differentiation than commercially available hydroxyapatite. Notably, β-tricalcium phosphate, which had the highest degree of Ca2+ and Sr2+ dissolution among the bioceramics extracted, can significantly upregulate osteogenic markers (alkaline phosphatase, osteocalcin) and stimulate bone matrix mineralization. Thus, it is a promising bioceramic material for applications in bone regeneration.

Birc5 and Nudc are screened as candidate reference genes for RT-qPCR studies in mouse cementoblast mineralization using time-series RNA-seq data.

The robustness and credibility of RT-qPCR results are critically dependent on the selection of suitable reference genes. However, the mineralization of the extracellular matrix can alter the intracellular tension and energy metabolism within cells, potentially impacting the expression of traditional reference genes, namely Actb and Gapdh. To methodically identify appropriate reference genes for research focused on mouse cementoblast mineralization. Time-series transcriptomic data of mouse cementoblast mineralization were used. To ensure expression stability and medium to high expression levels, three specific criteria were applied to select potential reference genes. The expression stability of these genes was ranked based on the DI index (1/coefficient of variation) to identify the top six potential reference genes. RT-qPCR validation was performed on these top six candidates, comparing their performance against six previously used reference genes (Rpl22, Ppib, Gusb, Rplp0, Actb, and Gapdh). Cq values of these 12 genes were analyzed by RefFinder to get a stability ranking. A total of 4418 (12.27%) genes met the selection criteria. Among them, Rab5if, Chmp4b, Birc5, Pea15a, Nudc, Supt4a were identified as candidate reference genes. RefFinder analyses revealed that two candidates (Birc5 and Nudc) exhibited superior performance compared to previously used reference genes. RefFinder's stability ranking does not consider the influence of primer efficiency. We propose Birc5 and Nudc as candidate reference genes for RT-qPCR studies investigating mouse cementoblast mineralization and cementum repair.

An enhanced tri-layer bionic periosteum with gradient structure loaded by mineralized collagen for guided bone regeneration and in-situ repair

Severe fracture non-union often accompanied by damaged or even absent periosteum remains a significant challenge. This paper presents a novel tri-layer bionic periosteum with gradient structure and mineralized collagen (MC) mimics natural periosteum for in-situ repair and bone regeneration. The construct with ultrasonic polylactic acid as the loose outer fibrous layer (UPLA), poly(ε-caprolactone) as the intermediate barrier layer (PCL-M), and poly(ε-caprolactone)/MC as the inner osteoblastic layer (PM) was prepared. The physicochemical properties of layers were investigated. UPLA/PCL-M/PM exhibited a tensile strength (3.55 ± 0.23 MPa) close to that of natural periosteum and excellent adhesion between the layers. In vitro experiments demonstrated that all layers had no toxicity to cells. UPLA promoted inward growth of mouse fibroblasts. PCL-M with a uniform pore size (2.82 ± 0.05 μm) could achieve a barrier effect against fibroblasts according to the live/dead assay. Meanwhile, PM could effectively promote cell migration with high alkaline phosphatase expression and significant mineralization of the extracellular matrix. Besides, in vivo experiments showed that UPLA/PCL-M/PM significantly promoted the regeneration of bone and early angiogenesis. Therefore, this construct with gradient structure developed in this paper would have great application potential in the efficient and high-quality treatment of severe fractures with periosteal defects.

Copper nanoparticles incorporated visible light-curing chitosan-based hydrogel membrane for enhancement of bone repair

Alveolar bone defects caused by tumor, trauma and inflammation can lead to the loss of oral function and complicate denture restoration. Currently, guided bone regeneration (GBR) barrier membranes for repairing bone defect cannot effectively promote bone regeneration due to their unstable degradation rate and poor antibacterial properties. Furthermore, they require additional tailoring before implantation. Therefore, this study developed a visible light-curing hydrogel membrane (CF–Cu) comprising methacrylated carboxymethyl chitosan (CMCS-MA), silk fibroin (SF), and copper nanoparticles (Cu NPs) to address these shortcomings of commercial membranes. The CF-Cu hydrogel, characterized by scanning electron microscopy (SEM), a universal testing machine, and swelling and degradation tests, demonstrated a smooth porous network structure, suitable swelling ratio, biodegradability, and enhanced mechanical strength. Cytotoxicity and hemolysis tests in vitro demonstrated excellent cyto- and hemo-compatibility of the CF-Cu hydrogel extracts. Additionally, evaluation of antibacterial properties in vitro, including colony forming unit (CFU) counts, MTT assays, and live/dead fluorescence staining, showed that the CF-Cu hydrogel exhibited excellent antibacterial properties, inhibiting over 80% of S. aureus, S. mutans, and P. gingivalis with CF-1Cu hydrogel compared to the control group. Moreover, evaluation of osteogenic differentiation of rBMSCs in vitro suggested that the CF-1Cu hydrogel significantly improved alkaline phosphatase (ALP) activity and the mineralization of extracellular matrix, up-regulating the expressions of osteogenesis-related genes (Runx2, ALP, Col-1, OPN and BSP). In summary, these results indicated that CF-1Cu hydrogel exhibited excellent cytocompatibility, antibacterial and osteogenic properties in vitro. Therefore, the CF-1Cu hydrogel holds potential as a viable material for application in GBR procedures aimed at addressing bone defects.

Bone mineral density affects tumor growth by shaping microenvironmental heterogeneity.

Breast cancer bone metastasis is the leading cause of mortality in patients with advanced breast cancer. Although decreased mineral density is a known risk factor for bone metastasis, the underlying mechanisms remain poorly understood because studying the isolated effect of bone mineral density on tumor heterogeneity is challenging with conventional approaches. Here, we investigate how bone mineral content affects tumor growth and microenvironmental complexity in vivo by combining single-cell RNA-sequencing with mineral-containing or mineral-free decellularized bone matrices. We discover that the absence of bone mineral significantly influences fibroblast and immune cell heterogeneity, promoting phenotypes that increase tumor growth and alter the response to injury or disease. Importantly, we observe that the stromal response to matrix mineral content depends on host immunocompetence and the murine tumor model used. Collectively, our findings suggest that bone mineral density affects tumor growth by altering microenvironmental complexity in an organism-dependent manner.

Enhanced nitrogen and phosphorus removal by iron-manganese mediated autotrophic denitrification in electrochemical system and the underlying mechanisms

At present, the research on Fe/Mn autotrophic denitrification is very limited, and the underlying mechanism in electrochemical system is not clear. In this study, an electrochemical system based on Fe-Mn autotrophic denitrification was constructed for the treatment of low C/N wastewater. The underlying mechanism and electrochemical process of Fe/Mn-mediated autotrophic denitrification were elucidated. The results showed that pyrite and manganese mineral matrix had no significant effect on COD removal, but had significant effect on nitrogen removal. R1 (activated carbon matrix) had the lowest nitrogen removal rate, with an average of 66.06 %. The mean removal rate of R2 (iron matrix) and R3 (manganese matrix) were 93.94 % and 95.89 %, respectively. The coupling of iron/manganese ammoxidation and autotrophic denitrification was the main mechanism to achieve efficient nitrogen removal. ICP and FIRT results showed that strong REDOX reactions of Fe, Mn and sulfur occurred at the anode of MFC. Direct precipitation of iron and manganese and electrochemical flocculation (FeOOH) effectively improved phosphorus removal. The phosphorus removal rates of R2 and R3 reached 93.89 % and 95.85 %, respectively. R3 has high electron transfer efficiency with a maximum voltage of 680 mV. Metagenomic analysis showed that 19 important transcripts associated with nitrogen metabolism pathways and 4 nitrogen metabolism pathways were detected. Enzymes encoded by nap A and nar G genes were abundant in R3 system. Reductase encoded by nrfA and nrfH genes was abundant in R2 system. Iron REDOX genes iroE, iroN, oorA, and manganese REDOX genes moxR, moxA were detected. The results of metabolic pathways and related enzymes further revealed the coupling cycle relationship between metal elements and nitrogen, phosphorus and sulfur in electrochemical systems. This study can not only provide a new method for efficient nitrogen and phosphorus removal of sewage, but also provide scientific basis for improving the geochemical cycle of metal elements and nitrogen elements.

Jaboticaba Peel Extract Attenuates Ovariectomy-Induced Bone Loss by Preserving Osteoblast Activity.

Therapies to prevent osteoporosis are relevant since it is one of the most common non-communicable human diseases in the world and the most prevalent bone disorder in adults. Since jaboticaba peel extract (JPE) added to the culture medium enhanced the osteogenic potential of mesenchymal stem cells (MSCs) derived from osteoporotic rats, we hypothesized that JPE prevents the development of ovariectomy-induced osteoporosis. Ovariectomized rats were treated with either JPE (30 mg/kg of body weight) or its vehicle for 90 days, starting 7 days after the ovariectomy. Then, the femurs were subjected to microcomputed tomography and histological analyses, and the osteoblast and adipocyte differentiation of MSCs was evaluated. JPE attenuated ovariectomy-induced bone loss, as evidenced by higher bone volume/total volume and trabecular number, along with lower trabecular separation and bone marrow adiposity. These protective effects of JPE on bone tissue are due to its ability to prevent the imbalance between osteoblast and adipocyte differentiation of MSCs, since, compared with MSCs derived from ovariectomized rats treated with vehicle, MSCs treated with JPE exhibited higher gene and protein expression of osteogenic markers and extracellular matrix mineralization, as well as lower gene expression of adipogenic markers. These data highlight the potential therapeutic use of JPE to prevent osteoporosis.

Biopsies from patients with sacral insufficiency fracture are characterized by low bone matrix mineralization and high turnover.

Sacral insufficiency fractures are known to occur primarily in older women without adequate trauma. While an association with low bone mineral density (ie, osteoporosis) has been reported, more detailed information on local bone quality properties in affected patients is not available. In the present study, core biopsies were obtained from the S1 sacral ala in patients with a bilateral sacral insufficiency fracture (type IV according to the fragility fractures of the pelvis classification) who required surgical stabilization. Dual energy X-ray absorptiometry (DXA) and laboratory bone metabolism analyses were performed. For comparison, control biopsies were acquired from skeletally intact age- and sex-matched donors during autopsy. A total of 31 biopsies (fracture: n = 19; control: n = 12) were evaluated by micro-computed tomography, histomorphometry on undecalcified sections, and quantitative backscattered electron imaging (qBEI). DXA measurements showed mean T-scores in the range of osteoporosis in the fracture cohort (T-scoremin -2.6 ± 0.8). Biochemical analysis of bone metabolism parameters revealed high serum alkaline phosphatase and urinary deoxypyridinoline/creatinine levels. In the biopsies, a loss of trabecular microstructure along with increased osteoid values were detected in the fracture patients compared with controls (osteoid volume per bone volume 5.9 ± 3.5 vs. 0.9 ± 0.5%, p <.001). We also found evidence of microfractures with chronic healing processes (ie, microcallus) as well as pronounced hypomineralization in the biopsies of the fracture cohort compared with the controls as evidenced by lower CaMean measured by qBEI (22.5 ± 1.6 vs. 24.2 ± 0.5wt%, p =.003). In conclusion, this high-resolution biopsy study provides evidence of local hypomineralization in patients with sacral insufficiency fractures, pointing to reduced fracture resistance but also a distinct phenotype other than the predominant loss of trabeculae as in postmenopausal osteoporosis. Our data highlight the importance of therapies that promote bone mineralization to optimally treat and prevent sacral insufficiency fractures.

Hydroxyapatite-Coated Ti6Al4V ELI Alloy: In Vitro Cell Adhesion.

The high rate of rejection and failure of orthopedic implants is primarily attributed to incomplete osseointegration and stress at the implant-to-bone interface due to significant differences in the mechanical properties of the implant and the surrounding bone. Various surface treatments have been developed to enhance the osteoconductive properties of implants. The aim of this work was the in vitro characterization of titanium alloy modified with a nanocrystalline hydroxyapatite surface layer in relative comparison to unmodified controls. This investigation focused on the behavior of the surface treatment in relation to the physiological environment. Moreover, the osteogenic response of human osteoblasts and adipose stem cells was assessed. Qualitative characterization of cellular interaction was performed via confocal laser scanning microscopy focusing on the cell nuclei and cytoskeletons. Filipodia were assessed using scanning electron microscopy. The results highlight that the HA treatment promotes protein adhesion as well as gene expression of osteoblasts and stem cells, which is relevant for the inorganic and organic components of the extracellular matrix and bone. In particular, cells grown onto HA-modified titanium alloy are able to promote ECM production, leading to a high expression of collagen I and non-collagenous proteins, which are crucial for regulating mineral matrix formation. Moreover, they present an impressive amount of filipodia having long extensions all over the test surface. These findings suggest that the HA surface treatment under investigation effectively enhances the osteoconductive properties of Ti6Al4V ELI.

Biocompatibility, bioactivity and immunomodulatory properties of three calcium silicate-based sealers: an in vitro study on hPDLSCs

ObjectivesTo assess the biocompatibility, bioactivity, and immunomodulatory properties of three new calcium silicate cement-based sealers: Ceraseal (CS), Totalfill BC Sealer (TFbc) and WellRoot ST (WR-ST) on human periodontal ligament stem cells (hPDLSCs).Materials and methodsHPDLSCs were isolated from extracted third molars from healthy patients. Eluates (1:1, 1:2, and 1:4 ratio) and sample discs of CS, TFbc and WR-ST after setting were prepared. A series of assays were performed: cell characterization, cell metabolic activity (MTT assay) cell attachment and morphology (SEM assay), cell migration (wound-healing assay), cytoskeleton organization (phaloidin-based assay); IL-6 and IL-8 release (ELISA); differentiation marker expression (RT-qPCR assay), and cell mineralization (Alizarin Red S staining). HPDLSCs cultured in unconditioned (negative control) or osteogenic (positive control) culture media were used as a comparison. Statistical significance was established at p < 0.05.ResultsAll the tested sealers exhibited similar results in the cytocompatibility assays (cell metabolic activity, migration, attachment, morphology, and cytoskeleton organization) compared with a negative control group. CS and TFbc exhibited an upregulation of at least one osteo/cementogenic marker compared to the negative and positive control groups. CS and TFbc also showed a significantly higher calcified nodule formation than the negative and positive control groups. Both the marker expression and calcified nodule formation were significantly higher in CS-treated cells than TFbc treated cells. WR-ST exhibited similar results to the control group. CS and TFbc-treated cells exhibited a significant downregulation of IL-6 after 72 h of culture compared to the negative control group (p < 0.05).ConclusionAll the tested sealers exhibited an adequate cytocompatibility. CS significantly enhances cell differentiation by upregulating the expression of key genes associated with bone and cementum formation. Additionally, CS was observed to facilitate the mineralization of the extracellular matrix effectively. In contrast, the effects of TFbc and WR-ST on these processes were less pronounced compared to CS. Furthermore, both CS and TFbc exhibited an anti-inflammatory potential, contributing to their potential therapeutic benefits in regenerative endodontics.Clinical relevanceThis is the first study to compare the biological properties and immunomodulatory potential of Ceraseal, Totalfill BC Sealer, and WellRoot ST. The results act as supporting evidence for their use in root canal treatment.

Association between host defence peptide IDR-1002 and ciprofloxacin: Effects on human dental pulp cells.

To evaluate the effects of the association of host defence peptide IDR-1002 and ciprofloxacin on human dental pulp cells (hDPSCs). hDPSCs were stimulated with ciprofloxacin and IDR-1002. Cell viability (by MTT assay), migration capacity (by scratch assay), production of inflammatory and anti-inflammatory mediators by hDPSCs (RT-PCR) and osteogenic differentiation (alizarin red staining) were evaluated. Phenotypic profile of hDPSCs demonstrated 97% for positive marked mesenchymal stem cell. Increased pulp cell migration and proliferation were observed after 24 and 48 h of exposure to IDR-1002 with ciprofloxacin. Mineral matrix formation by hDPSCs was observed of the association while its reduction was observed in the presence of peptide. After 24 h, the association between ciprofloxacin and IDR-1002 significantly downregulated TNFRSF-1, IL-1β, IL-8, IL-6 and IL-10 gene expression (p ≤ 0.0001). The association between the IDR-1002 and ciprofloxacin showed favourable immunomodulatory potential, emerging as a promising option for pulp revascularisation processes.

Retrospective Study of Multimodality Imaging Features of Chondroblastoma

PurposeTo evaluate the multimodality imaging features of chondroblastoma.Materials and MethodsRetrospective analysis of imaging features of 52 cases of histopathologically proven chondroblastoma from 2010 to 2022 was performed. Radiographs were evaluated for lesion site, location, morphology, margins, matrix mineralization, cortical breach, periosteal reaction, eccentricity, and subarticular extension. Appearance on T1, T2 weighted and post-contrast T1 was evaluated on MRI, with analysis of peritumoral edema and joint effusion.ResultsMean patient age was 18 years (10–57 years) with male preponderance (M = 39; F = 13). 75% (n = 39) cases involved an unfused skeleton and 25% (n = 13) affected a mature skeleton. Appendicular skeleton was involved in 88.5% (n = 46) cases and axial skeleton was involved in 11.5% (n = 6) cases with all cases involving epiphysis/epiphyseal equivalent. Radiographically, all cases were well-defined geographic osteolytic lesions with a narrow zone of transition, thin sclerotic rim and lobulated [56% (n = 29)] or smooth [44% (n = 23)] margins. Matrix calcification appreciable in 62% (n = 32) cases was ‘fluffy/smudgy’. Chondroblastoma appeared isointense (83%, n = 43) on T1 MRI with characteristically low signal and hyperintense foci within (67%, n = 35) on T2-weighted images and post-contrast enhancement [heterogeneous lobular (88%, n = 46) or septal pattern (12%, n = 6)] with all barring three lesions showing perilesional edema. None of the cases of chondroblastoma in our study developed metastasis till last follow-up (mean: 71 months).ConclusionChondroblastoma has distinctive imaging appearance and is often unlike majority other cartilaginous benign lesions due to characteristic low T2 signal on MRI and associated exuberant perilesional edema.