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Project description:Tantalum (Ta) metal is well known for its ideal corrosion resistance and biological effects as endosseous implants. However, the metal has a elastic modulus as high as 186GPa which is not comparable to the natural bone (10-40GPa), and it also has a relative high cost. Here, to fully exploit the advantages of Ta as endosseous implants, a small amount of Ta (as low as 3 at.%) was successfully added into a zirconium-based metallic glass (MG) to generate an advanced functional endosseous implant, Zr58Cu25Al14Ta3 MG, with superior comprehensive properties. Upon carefully dissecting the surface chemistry and atomic structure, the results show that amorphization of Ta enable the uniform distribution in material surface, leading to a significantly improved chemical stability and extensive material-cell contact regulation. Systematical analyses on the immunological, angiogenesis and osteogenesis capability of the material is carried out by utilizing the next-generation sequencing, revealing that Zr58Cu25Al14Ta3 MG can regulate angiogenesis through VEFG signaling pathway and osteogenesis via BMP signaling pathway. Animal experiment further confirms a sound osseointegration of Zr58Cu25Al14Ta3 MG in achieving better bone-implant-contact and inducing faster peri-implant bone formation.
2024-05-29 | GSE252669 | GEO
Project description:Tantalum (Ta) metal is well known for its ideal corrosion resistance and biological effects as endosseous implants. However, the metal has a elastic modulus as high as 186GPa which is not comparable to the natural bone (10-40GPa), and it also has a relative high cost. Here, to fully exploit the advantages of Ta as endosseous implants, a small amount of Ta (as low as 3 at.%) was successfully added into a zirconium-based metallic glass (MG) to generate an advanced functional endosseous implant, Zr58Cu25Al14Ta3 MG, with superior comprehensive properties. Upon carefully dissecting the surface chemistry and atomic structure, the results show that amorphization of Ta enable the uniform distribution in material surface, leading to a significantly improved chemical stability and extensive material-cell contact regulation. Systematical analyses on the immunological, angiogenesis and osteogenesis capability of the material is carried out by utilizing the next-generation sequencing, revealing that Zr58Cu25Al14Ta3 MG can regulate angiogenesis through VEFG signaling pathway and osteogenesis via BMP signaling pathway. Animal experiment further confirms a sound osseointegration of Zr58Cu25Al14Ta3 MG in achieving better bone-implant-contact and inducing faster peri-implant bone formation.
2024-05-29 | GSE252618 | GEO
Project description:Tantalum (Ta) metal is well known for its ideal corrosion resistance and biological effects as endosseous implants. However, the metal has a elastic modulus as high as 186GPa which is not comparable to the natural bone (10-40GPa), and it also has a relative high cost. Here, to fully exploit the advantages of Ta as endosseous implants, a small amount of Ta (as low as 3 at.%) was successfully added into a zirconium-based metallic glass (MG) to generate an advanced functional endosseous implant, Zr58Cu25Al14Ta3 MG, with superior comprehensive properties. Upon carefully dissecting the surface chemistry and atomic structure, the results show that amorphization of Ta enable the uniform distribution in material surface, leading to a significantly improved chemical stability and extensive material-cell contact regulation. Systematical analyses on the immunological, angiogenesis and osteogenesis capability of the material is carried out by utilizing the next-generation sequencing, revealing that Zr58Cu25Al14Ta3 MG can regulate angiogenesis through VEFG signaling pathway and osteogenesis via BMP signaling pathway. Animal experiment further confirms a sound osseointegration of Zr58Cu25Al14Ta3 MG in achieving better bone-implant-contact and inducing faster peri-implant bone formation.
2024-05-29 | GSE252670 | GEO
Project description:Over centuries, structural glasses have been deemed as a strong yet inherently 'brittle' material due to their lack of tensile ductility. However, here we report bulk metallic glasses exhibiting both a high strength of ~2 GPa and an unprecedented tensile elongation of 2-4% at room temperature. Our experiments have demonstrated that intense structural evolution can be triggered in theses glasses by the carefully controlled surface mechanical attrition treatment, leading to the formation of gradient amorphous microstructures across the sample thickness. As a result, the engineered amorphous microstructures effectively promote multiple shear banding while delay cavitation in the bulk metallic glass, thus resulting in superior tensile ductility. The outcome of our research uncovers an unusual work-hardening mechanism in monolithic bulk metallic glasses and demonstrates a promising yet low-cost strategy suitable for producing large-sized, ultra-strong and stretchable structural glasses.
| S-EPMC3996486 | biostudies-literature
Project description:Quantitatively correlating the amorphous structure in metallic glasses (MGs) with their physical properties has been a long-sought goal. Here we introduce 'flexibility volume' as a universal indicator, to bridge the structural state the MG is in with its properties, on both atomic and macroscopic levels. The flexibility volume combines static atomic volume with dynamics information via atomic vibrations that probe local configurational space and interaction between neighbouring atoms. We demonstrate that flexibility volume is a physically appropriate parameter that can quantitatively predict the shear modulus, which is at the heart of many key properties of MGs. Moreover, the new parameter correlates strongly with atomic packing topology, and also with the activation energy for thermally activated relaxation and the propensity for stress-driven shear transformations. These correlations are expected to be robust across a very wide range of MG compositions, processing conditions and length scales.
| S-EPMC5159863 | biostudies-literature
Project description:Polarization of macrophages by chemical, topographical and mechanical cues presents a robust strategy for designing immunomodulatory biomaterials. Here, we studied the ability of nanopatterned bulk metallic glasses (BMGs), a new class of metallic biomaterials, to modulate murine macrophage polarization. Cytokine/chemokine analysis of IL-4 or IFN?/LPS-stimulated macrophages showed that the secretion of TNF-?, IL-1?, IL-12, CCL-2 and CXCL1 was significantly reduced after 24-hour culture on BMGs with 55?nm nanorod arrays (BMG-55). Additionally, under these conditions, macrophages increased phagocytic potential and exhibited decreased cell area with multiple actin protrusions. These in vitro findings suggest that nanopatterning can modulate biochemical cues such as IFN?/LPS. In vivo evaluation of the subcutaneous host response at 2?weeks demonstrated that the ratio of Arg-1 to iNOS increased in macrophages adjacent to BMG-55 implants, suggesting modulation of polarization. In addition, macrophage fusion and fibrous capsule thickness decreased and the number and size of blood vessels increased, which is consistent with changes in macrophage responses. Our study demonstrates that nanopatterning of BMG implants is a promising technique to selectively polarize macrophages to modulate the immune response, and also presents an effective tool to study mechanisms of macrophage polarization and function. STATEMENT OF SIGNIFICANCE:Implanted biomaterials elicit a complex series of tissue and cellular responses, termed the foreign body response (FBR), that can be influenced by the polarization state of macrophages. Surface topography can influence polarization, which is broadly characterized as either inflammatory or repair-like. The latter has been linked to improved outcomes of the FBR. However, the impact of topography on macrophage polarization is not fully understood, in part, due to a lack of high moduli biomaterials that can be reproducibly processed at the nanoscale. Here, we studied macrophage interactions with nanopatterned bulk metallic glasses (BMGs), a class of metallic alloys with amorphous microstructure and formability like polymers. We show that nanopatterned BMGs modulate macrophage polarization and transiently induce less fibrotic and more angiogenic responses. Overall, we demonstrate nanopatterning of BMG implants as a technique to polarize macrophages and modulate the FBR.
| S-EPMC6119487 | biostudies-literature
Project description:Nanosurfaces have improved clinical osseointegration by increasing bone/implant contact. Neovascularization is considered an essential prerequisite to osteogenesis, but no previous reports to our knowledge have examined the effect of surface topography on the spatio-temporal pattern of neovascularization during peri-implant healing. We have developed a cranial window model to study peri-implant healing intravitally over clinically relevant time scales as a function of implant topography. Quantitative intravital confocal imaging reveals that changing the topography (but not chemical composition) of an implant profoundly affects the pattern of peri-implant neovascularization. New vessels develop proximal to the implant and the vascular network matures sooner in the presence of an implant nanosurface. Accelerated angiogenesis can lead to earlier osseointegration through the delivery of osteogenic precursors to, and direct formation of bone on, the implant surface. This study highlights a critical aspect of peri-implant healing, but also informs the biological rationale for the surface design of putative endosseous implant materials.
| S-EPMC6123776 | biostudies-literature
Project description:In the past few years, laser powder-bed fusion (LPBF) of bulk metallic glasses (BMGs) has gained significant interest because of the high heating and cooling rates inherent to the process, providing the means to bypass the crystallization threshold. In this study, (for the first time) the tensile and Charpy impact toughness properties of a Zr-based BMG fabricated via LPBF were investigated. The presence of defects and lack of fusion (LoF) in the near-surface region of the samples resulted in low properties. Increasing the laser power at the borders mitigated LoF formation in the near-surface region, leading to an almost 27% increase in tensile yield strength and impact toughness. Comparatively, increasing the core laser power did not have a significant influence. It was therefore confirmed that, for BMGs like for crystalline alloys, near-surface LoFs are more detrimental than core LoFs. Although increasing the border and core laser power resulted in a higher crystallized fraction, detrimental to the mechanical properties, reducing the formation of LoF defects (confirmed using micro-computed tomography, Micro-CT) was comparatively more important.
| S-EPMC8510030 | biostudies-literature
Project description:ZrCu-based bulk metallic glass composites (BMGCs) are well known for their plastic deformability, superior to traditional metallic glasses (MGs), which is attributed to a unique dual-phases structure, namely, the glassy matrix and unstable B2 phase. In the present study, in-situ tensile testing is used to trace the deformation process of a ZrCu-based BMGC. Three deformation stages of the BMGC, i.e., the elastic-elastic stage, the elastic-plastic stage, and the plastic-plastic stage are identified. In the elastic-elastic and elastic-plastic stages, the yield strength and elastic limit are major influenced by the volume fraction of the B2 crystals. In the plastic-plastic stage, the B2 phase stimulates the formation of multiple shear bands and deflects the direction of shear bands by disturbing the stress field in front of the crack tip. The deformation-induced martensitic transformation of the metastable B2 phase contributes to the plasticity and work hardening of the composite. This study highlights the formation and propagation of multiple shear bands and reveals the interactions of shear bands with structural heterogeneities in situ. Especially, the blocking of shear bands by crystals and the martensitic transformation of the B2 phase are critical for the mechanistic deformation process and illustrate the function of the B2 phase in the present BMGCs.
| S-EPMC5854620 | biostudies-literature
Project description:Objective:To compare the elastic modulus, flexural strength, and hardness of an experimental resin based composite (RBC) with and without containing silver nanoparticles (AgNPs) and bioactive glass (BAG) with a commercially available RBC. Methods:This study was conducted, during the period August 2016-May 2018, at the Department of Dental Materials, Peshawar Dental College, Peshawar (Pakistan) and Department of Chemistry, University of Montreal, Canada. Test specimens made in the commercial RBC acted as Group-1 (G1). An experimental RBC containing 70 wt % filler content was synthesized. It was first used as such to prepare test specimens to act as the experimental control group (G2). This RBC was then modified by adding various amounts of BAG (5%, 10% and 15%) and a fixed amount of 0.009% AgNPs to use the so modified RBCs for preparing the test specimens to belong to three groups (G3, G4 & G5). The AgNPs had been synthesized in situ by reduction of salt during photo-polymerization. Flexural strength (FS), elastic modulus (EM) and Vickers hardness were determined using universal testing machine and hardness tester respectively. Data were analyzed using one-way ANOVA and Tukey post-hoc test. Results:Except for G3 restorations showing significantly lower mean FS value, the FS for those in the other groups were not significantly different (p>0.05). Elastic modulus of the experimental RBC restorations was though higher than those of the others but the difference was statistically insignificant (p>0.05). Reduced Vickers hardness values were documented for the restorations in the G4 and G5 compared to those in the G3 but again the difference was insignificant (p>0.05). Flexural strength and hardness values of the test specimens in the experimental RBCs were significantly lower than those made in the commercial hybrid RBC (p<0.05). Conclusion:BAG and AgNPs addition to the experimental RBC in the mentioned concentration adversely affected the tested mechanical properties.
| S-EPMC7260929 | biostudies-literature