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Journal of Materials Chemistry. B Nov 2022Bone replacement using porous and solid metallic implants, such as Ti-alloy implants, is regarded as one of the most practical therapeutic approaches in biomedical... (Review)
Review
Bone replacement using porous and solid metallic implants, such as Ti-alloy implants, is regarded as one of the most practical therapeutic approaches in biomedical engineering. The bone is a complex tissue with various mechanical properties based on the site of action. Patient-specific Ti-6Al-4V constructs may address the key needs in bone treatment for having customized implants that mimic the complex structure of the natural tissue and diminish the risk of implant failure. This review focuses on the most promising methods of fabricating such patient-specific Ti-6Al-4V implants using additive manufacturing (AM) with a specific emphasis on the popular subcategory, which is powder bed fusion (PBF). Characteristics of the ideal implant to promote optimized tissue-implant interactions, as well as physical, mechanical/chemical treatments and modifications will be discussed. Accordingly, such investigations will be classified into 3B-based approaches (Biofunctionality, Bioactivity, and Biostability), which mainly govern native body response and ultimately the success in implantation.
Topics: Humans; Alloys; Titanium; Porosity; Prostheses and Implants
PubMed: 36305245
DOI: 10.1039/d2tb01616h -
Nature Materials Feb 2022Despite the importance of glass forming ability as a major alloy characteristic, it is poorly understood and its quantification has been experimentally laborious and...
Despite the importance of glass forming ability as a major alloy characteristic, it is poorly understood and its quantification has been experimentally laborious and computationally challenging. Here, we uncover that the glass forming ability of an alloy is represented in its amorphous structure far away from equilibrium, which can be exposed by conventional X-ray diffraction. Specifically, we fabricated roughly 5,700 alloys from 12 alloy systems and characterized the full-width at half-maximum, Δq, of the first diffraction peak in the X-ray diffraction pattern. A strong correlation between high glass forming ability and a large Δq was found. This correlation indicates that a large dispersion of structural units comprising the amorphous structure is the universal indicator for high metallic glass formation. When paired with combinatorial synthesis, the correlation enhances throughput by up to 100 times compared to today's state-of-the-art combinatorial methods and will facilitate the discovery of bulk metallic glasses.
Topics: Alloys; Glass; X-Ray Diffraction
PubMed: 34737454
DOI: 10.1038/s41563-021-01129-6 -
Odontology Oct 2023Titanium and its alloys are the preferred materials for medical implants. However, easy infection is a fatal shortcoming of Ti implants. Fortunately, the ongoing... (Review)
Review
Titanium and its alloys are the preferred materials for medical implants. However, easy infection is a fatal shortcoming of Ti implants. Fortunately, the ongoing development of antibacterial implant materials is a promising solution, and Ti alloys with antibacterial properties hold immense potential for medical applications. In this review, we briefly outline the mechanisms of bacterial colonization and biofilm formation on implants; discuss and classify the major antimicrobials currently in use and development, including inorganic and organic antimicrobials; and describe the important role of antimicrobials in the development of implant materials for clinical applications. Strategies and challenges related to improving the antimicrobial properties of implant materials as well as the prospects of antibacterial Ti alloys in the medical field are also discussed.
Topics: Titanium; Alloys; Materials Testing; Staphylococcus aureus; Dental Implants; Anti-Bacterial Agents; Dental Materials; Surface Properties
PubMed: 37402971
DOI: 10.1007/s10266-023-00832-x -
Journal of Biomedical Materials... Mar 2022The effect of unidirectional and cross rolling on the corrosion rate, texture, tensile properties and hemolysis of the Mg-0.375Ga and Mg-0.750Ga alloys was evaluated....
The effect of unidirectional and cross rolling on the corrosion rate, texture, tensile properties and hemolysis of the Mg-0.375Ga and Mg-0.750Ga alloys was evaluated. Pure Mg and as-cast alloys were processed by unidirectional and cross rolling at 400°C to obtain a total thickness reduction of 50%. The corrosion rate was measured by the weight loss method in simulated body fluid. Determination of the hemolysis percentage was carried out by direct contact of specimens with diluted blood. After hot rolling, the mechanical properties of the alloys were improved. The cross-rolled Mg-0.750Ga alloy showed the highest grain refinement (55 μm) and the highest ultimate tensile strength (240 MPa), however, lower elongation (13.9%) than the rolled Mg-0.375Ga alloy. While unidirectional rolling creates a strong basal texture, cross rolling weakens considerably this texture. The Ga addition weakens the basal texture. Corrosion rate of the Mg-Ga alloys was significantly reduced (<1 mm/yr) after heat treatment and hot rolling due the homogenization of the microstructure and the presence of gallium as alloying element. The cross-rolled samples showed higher corrosion than the heat-treated and unidirectionally rolled samples. After rolling, alloys showed hemolysis percentages between 7.1 and 9.3%, values lower than those presented by pure magnesium (>22.7%) and as-cast alloys (>24.2%); however, the alloys are still hemolytic (>5%).
Topics: Alloys; Biocompatible Materials; Corrosion; Magnesium; Materials Testing; Tensile Strength
PubMed: 34618398
DOI: 10.1002/jbm.b.34943 -
The Journal of Prosthetic Dentistry Mar 2022Although several manufacturers market soft metal milling blanks and systems, comprehensive comparative studies of differences in properties across commercially...
STATEMENT OF PROBLEM
Although several manufacturers market soft metal milling blanks and systems, comprehensive comparative studies of differences in properties across commercially available soft metal milling alloys are lacking.
PURPOSE
The purpose of this in vitro study was to compare the microstructures and mechanical properties of 3 soft metal milling cobalt-chromium (Co-Cr) alloys (Ceramill Sintron, Soft Metal, and Sintermetall).
MATERIAL AND METHODS
Disk-shaped specimens (for surface characterization and hardness test) and dumbbell-shaped specimens (for tensile test as per International Organization for Standardization (ISO) 22674) were prepared by following each soft metal milling manufacturer's instructions. The crystal structures and microstructures of the 3 alloys were evaluated with optical microscopy, X-ray diffractometry (XRD), and scanning electron microscopy with electron backscattered diffraction (EBSD). The mechanical properties were investigated with a tensile test and Vickers hardness test (n=6). The results of the mechanical (tensile and hardness) tests were analyzed with 1-way ANOVA and the post hoc Tukey multiple comparison test (α=.05).
RESULTS
The Sintermetall specimen showed a finer microstructure and more porosity than the other 2 alloys. The XRD and EBSD analyses showed that the γ (face-centered cubic, fcc) matrix phase was predominant in the Ceramill Sintron alloy and the ε (hexagonal close-packed, hcp) matrix phase was predominant in the Soft Metal alloy. The Sintermetall alloy showed a slightly higher amount of ε phase than γ phase, with more chromium carbide formation than the other 2 alloys. The Ceramill Sintron alloy showed a significantly higher tensile strength than the other 2 alloys (P<.05), but a significantly lower 2% offset yield strength than the other 2 alloys (P<.05). The highest elongation was found in the Ceramill Sintron alloy, followed by the Sintermetall and Soft Metal alloys. The elastic modulus was the highest in the Sintermetall alloy, followed by the Soft Metal and Ceramill Sintron alloys. No significant differences in Vickers hardness values were detected among the 3 alloys (P=.263).
CONCLUSIONS
The different commercially available soft metal milling blanks and systems produced dissimilar alloys in terms of crystal structures and microstructures and, as a result, different mechanical properties.
Topics: Alloys; Chromium Alloys; Materials Testing; Metal Ceramic Alloys; Surface Properties; Technology; Tensile Strength
PubMed: 33303192
DOI: 10.1016/j.prosdent.2020.07.037 -
Advanced Science (Weinheim,... Apr 2024Zinc (Zn)-dysprosium (Dy) binary alloys are promising biodegradable bone fracture fixation implants owing to their attractive biodegradability and mechanical properties....
Zinc (Zn)-dysprosium (Dy) binary alloys are promising biodegradable bone fracture fixation implants owing to their attractive biodegradability and mechanical properties. However, their clinical application is a challenge for bone fracture healing, due to the lack of Zn-Dy alloys with tailored proper bio-mechanical and osteointegration properties for bone regeneration. A Zn-5Dy alloy with high strength and ductility and a degradation rate aligned with the bone remodeling cycle is developed. Here, mechanical stability is further confirmed, proving that Zn-5Dy alloy can resist aging in the degradation process, thus meeting the mechanical requirements of fracture fixation. In vitro cellular experiments reveal that the Zn-5Dy alloy enhances osteogenesis and angiogenesis by elevating SIRT4-mediated mitochondrial function. In vivo Micro-CT, SEM-EDS, and immunohistochemistry analyses further indicate good biosafety, suitable biodegradation rate, and great osteointegration of Zn-5Dy alloy during bone healing, which also depends on the upregulation of SIRT4-mediated mitochondrial events. Overall, the study is the first to report a Zn-5Dy alloy that exerts remarkable osteointegration properties and has a strong potential to promote bone healing. Furthermore, the results highlight the importance of mitochondrial modulation and shall guide the future development of mitochondria-targeting materials in enhancing bone fracture healing.
Topics: Absorbable Implants; Alloys; Materials Testing; Mitochondria; Zinc; Dysprosium; Osteogenesis; Sirtuins; Humans; Fractures, Bone
PubMed: 38243646
DOI: 10.1002/advs.202307812 -
Chemosphere Feb 2022Recently, the design and biosynthesis of metallic nanoparticles (NPs) have drawn immense interest, but their very specific function and secondary toxic effects are major...
Recently, the design and biosynthesis of metallic nanoparticles (NPs) have drawn immense interest, but their very specific function and secondary toxic effects are major concern towards commercial application of NPs. That's why environment-friendly (nontoxic) NPs having multiple functions are extremely important. Herein, we report the mechanism of biosynthesis of mono and bimetallic (Au-Ag) alloy NPs and study their multifunctional (antioxidant, antifungal and catalytic) activity and ecotoxicological property. AgNPs exhibit phytotoxicity (at 100 μg/ml) on morphological characteristics of Lentil (during germination), while alloy and AuNPs are non-toxic (up to 100 μg/ml). In-vitro antioxidant response using DPPH methods reveals that alloy NPs (IC = 55.8 μg/ml) possesses better antioxidant activity compared to the monometallic NPs (IC = 73.6-82.6 μg/ml). In addition, alloy NPs displayed appreciable antifungal efficacy against a plant pathogenic fungus Gloeosporium musarum by structural damage to hyphae and conidia of the fungus. The catalytic performance of NPs for degradation of chlorpyriphos (CP) pesticide reveals that alloy NPs is more efficient in terms of rate constant (k = 0.405 d) and half-life (T = 1.71 d) compared to the monometallic counterparts (k = 0.115-0.178 d; T = 3.89-6.04 d). Degradation products of CP (3,5,6-trichloropyridinol and diethyl thiophosphate) are confirmed using mass spectrometry and based on that a degradation pathway has been suggested. Thus, these sustainable and ecological safe biogenic (Au-Ag) alloy NPs promise multiple applications as an antioxidant in the pharmaceutical sector, as a fungicide for disease control in agriculture, as a catalyst for remediation of toxic pollutants and in other pertinent areas.
Topics: Alloys; Catalysis; Gold; Metal Nanoparticles
PubMed: 34656625
DOI: 10.1016/j.chemosphere.2021.132585 -
Journal of Biomedical Materials... Jul 2020Wear and corrosion at taper junctions of orthopaedic endoprostheses remain of great concern and are associated with adverse clinical reactions. Whereas tribocorrosion of...
Wear and corrosion at taper junctions of orthopaedic endoprostheses remain of great concern and are associated with adverse clinical reactions. Whereas tribocorrosion of hip tapers was extensively investigated, there is only little knowledge regarding the clinical performance of modular total shoulder prostheses. This retrieval study evaluated 35 modular taper junctions of anatomical shoulder explants using stereomicroscopy, confocal microscopy, as well as optical and scanning electron microscopy to determine the damage modes as well as the effects of taper topography and alloy microstructure. Among all humeral head tapers, 89% exhibited material degradation. Different overlapping wear mechanisms were identified such as plastic deformation, adhesive material transfer, microploughing, and fretting damage. Only CoCrMo cast alloy heads showed a susceptibility to electrochemically dominated fretting in comparison to CoCrMo wrought alloy. Moreover, corundum blasted stem tapers show a significantly increased incidence rate for microploughing. To date, this is the most comprehensive study on the damage types of modular taper junctions of anatomical shoulder arthroplasty proving the existence of fretting even on less weight-bearing implants. This study revealed critical fretting factors, such as the surface finish and the alloy type that are essential for the development of countermeasures that avoid any taper corrosion.
Topics: Adult; Aged; Alloys; Aluminum Oxide; Chromium; Cobalt; Corrosion; Female; Humans; Male; Middle Aged; Molybdenum; Prosthesis Failure; Prosthesis Implantation; Shoulder Joint; Shoulder Prosthesis; Surface Properties
PubMed: 31763747
DOI: 10.1002/jbm.b.34519 -
Nature Nanotechnology Jul 2020
Topics: Alloys; Electrochemical Techniques; Electrodes; Nervous System
PubMed: 32514009
DOI: 10.1038/s41565-020-0702-9 -
Biomaterials Aug 2022Implant-related infections caused by drug-resistant bacteria remain a major challenge faced by orthopedic surgeons. Furthermore, ideal prevention and treatment methods...
Implant-related infections caused by drug-resistant bacteria remain a major challenge faced by orthopedic surgeons. Furthermore, ideal prevention and treatment methods are lacking in clinical practice. Here, based on the antibacterial and osteogenic properties of Zn alloys, Ag and Li were selected as alloying elements to prepare biodegradable Zn-Li-Ag ternary alloys. Li and Ag addition improved the mechanical properties of Zn-Li-Ag alloys. The Zn-0.8Li-0.5Ag alloy exhibited the highest ultimate tensile strength (>530 MPa). Zn-Li-Ag alloys showed strong bactericidal effects on methicillin-resistant Staphylococcus aureus (MRSA) in vitro. RNA sequencing revealed two MRSA-killing mechanisms exhibited by the Zn-0.8Li-0.5Ag alloy: cellular metabolism disturbance and induction of reactive oxygen species production. To verify that the therapeutic potential of the Zn-0.8Li-0.5Ag alloy is greater than that of Ti intramedullary nails, X-ray, micro-computed tomography, microbiological, and histological analyses were conducted in a rat femoral model of MRSA-induced osteomyelitis. Treatment with Zn-0.8Li-0.5Ag alloy implants resulted in remarkable infection control and favorable bone retention. The in vivo safety of this ternary alloy was confirmed by evaluating vital organ functions and pathological morphologies. We suggest that, with its good antibacterial and osteogenic properties, Zn-0.8Li-0.5Ag alloy can serve as an orthopedic implant material to prevent and treat orthopedic implant-related infections.
Topics: Rats; Animals; Methicillin-Resistant Staphylococcus aureus; Materials Testing; Alloys; Zinc; X-Ray Microtomography; Osteomyelitis; Anti-Bacterial Agents; Absorbable Implants; Corrosion; Biocompatible Materials
PubMed: 35810539
DOI: 10.1016/j.biomaterials.2022.121663