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1.
Adv Mater ; : e2407040, 2024 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-39104283

RESUMO

Over the decades, the management of osteochondral lesions remains a significant yet unmet medical challenge without curative solutions to date. Owing to the complex nature of osteochondral units with multi-tissues and multicellularity, and inherently divergent cellular turnover capacities, current clinical practices often fall short of robust and satisfactory repair efficacy. Alternative strategies, particularly tissue engineering assisted with biomaterial scaffolds, achieve considerable advances, with the emerging pursuit of a more cost-effective approach of in situ osteochondral regeneration, as evolving toward cell-free modalities. By leveraging endogenous cell sources and innate regenerative potential facilitated with instructive scaffolds, promising results are anticipated and being evidenced. Accordingly, a paradigm shift is occurring in scaffold development, from biodegradable and biocompatible to bioadaptable in spatiotemporal control. Hence, this review summarizes the ongoing progress in deploying bioadaptable criteria for scaffold-based engineering in endogenous osteochondral repair, with emphases on precise control over the scaffolding material, degradation, structure and biomechanics, and surface and biointerfacial characteristics, alongside their distinguished impact on the outcomes. Future outlooks of a highlight on advanced, frontier materials, technologies, and tools tailoring precision medicine and smart healthcare are provided, which potentially paves the path toward the ultimate goal of complete osteochondral regeneration with function restoration.

2.
Nanomicro Lett ; 16(1): 160, 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38512500

RESUMO

MgH2 is a promising high-capacity solid-state hydrogen storage material, while its application is greatly hindered by the high desorption temperature and sluggish kinetics. Herein, intertwined 2D oxygen vacancy-rich V2O5 nanosheets (H-V2O5) are specifically designed and used as catalysts to improve the hydrogen storage properties of MgH2. The as-prepared MgH2-H-V2O5 composites exhibit low desorption temperatures (Tonset = 185 °C) with a hydrogen capacity of 6.54 wt%, fast kinetics (Ea = 84.55 ± 1.37 kJ mol-1 H2 for desorption), and long cycling stability. Impressively, hydrogen absorption can be achieved at a temperature as low as 30 °C with a capacity of 2.38 wt% within 60 min. Moreover, the composites maintain a capacity retention rate of ~ 99% after 100 cycles at 275 °C. Experimental studies and theoretical calculations demonstrate that the in-situ formed VH2/V catalysts, unique 2D structure of H-V2O5 nanosheets, and abundant oxygen vacancies positively contribute to the improved hydrogen sorption properties. Notably, the existence of oxygen vacancies plays a double role, which could not only directly accelerate the hydrogen ab/de-sorption rate of MgH2, but also indirectly affect the activity of the catalytic phase VH2/V, thereby further boosting the hydrogen storage performance of MgH2. This work highlights an oxygen vacancy excited "hydrogen pump" effect of VH2/V on the hydrogen sorption of Mg/MgH2. The strategy developed here may pave a new way toward the development of oxygen vacancy-rich transition metal oxides catalyzed hydride systems.

4.
Natl Sci Rev ; 10(5): nwad063, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37056424

RESUMO

It is a great challenge to effectively eradicate biofilm and cure biofilm-infected diseases because dense extracellular polymeric substance matrix prevents routine antibacterial agents from penetrating into biofilm. H2 is an emerging energy-regulating molecule possessing both high biosafety and high tissue permeability. In this work, we propose a concept of sonocatalytic hydrogen/hole-combined 'inside/outside-cooperation' anti-biofilm for promoting bacteria-infected diabetic wound healing based on two-dimensional piezoelectric nanomaterials. Proof-of-concept experiments using C3N4 nanosheets as a representative piezoelectric catalyst with wide band gap and high biosafety have verified that sonocatalytically generated H2 and holes rapidly penetrate into biofilm to inhibit bacterial energy metabolism and oxidatively deprive polysaccharides/NADH in biofilm to destroy the bacterial membrane/electron transport chain, respectively, inside/outside-cooperatively eradicating biofilm. A bacteria-infected diabetic wound model is used to confirm the excellent in vivo antibacterial performance of sonocatalytic hydrogen/hole-combined therapy, remarkably improving bacteria-infected diabetic wound healing. The proposed strategy of sonocatalytic hole/hydrogen-combined 'inside/outside-cooperation' will make a highway for treatment of deep-seated biofilm infection.

5.
Nat Commun ; 13(1): 5838, 2022 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-36192418

RESUMO

Magnesium alloys with high strength and excellent corrosion resistance are always sought-after in light-weighting structural components for automotive and aerospace applications. However, for most magnesium alloys that have a high specific strength, they usually have an inferior corrosion resistance and vice versa. In this work, we successfully develop a Mg-11Y-1Al (wt. %) alloy through conventional casting, solution treatment followed by extrusion. The overall properties of this alloy feature with a corrosion rate lower than 0.2 mm y-1, high yield strength of 350 MPa and moderate tensile elongation of 8%, the combination of which shows competitive advantage over other comparative magnesium alloys in the literature. It is found that a thin and dense protective film of Y2O3/Y(OH)3 can be fast developed with the aid of Al2O3/Al(OH)3 deposition to isolate this alloy from further attack of corrosion medium. Meanwhile, the refined grains, weak texture and activation of non-basal slip systems co-contribute to the high strength and good ductility. Our findings are expected to inspire the design of next-generation high performance magnesium alloys.

6.
Sci Rep ; 12(1): 7367, 2022 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-35513685

RESUMO

Zingiber officinale Roscoe extract, Raphanus sativus L. extract, Rheum palmatum extract, Coptis chinensis extract, Glycyrrhiza uralensis extract (GUE), Potentilla discolor extract (PDE) and Taraxacum officinale extract (TOE) were screened for the green corrosion inhibitors of AZ91 alloy in saline environment. The experiment results demonstrated that GUE, PDE and TOE can significantly enhance the corrosion resistance of AZ91 alloy by 73.4, 87.6 and 84.6%, respectively. Surface characterization using FTIR, UV-Vis and XPS revealed that the organic compounds of GUE, PDE and TOE can interact with the alloy surface to form a protective physisorbed film, effectively mitigating the corrosion process of AZ91 alloy. The present results may be helpful to discover the new green inhibitors with high inhibition efficiency for AZ91 alloy.


Assuntos
Ligas , Magnésio , Corrosão , Medicina Tradicional Chinesa , Extratos Vegetais/farmacologia
7.
Materials (Basel) ; 14(6)2021 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-33799404

RESUMO

A method of forming an Mg/Al intermetallic compound coating enriched with Mg17Al12 and Mg2Al3 was developed by heat treatment of electrodeposition Al coatings on Mg alloy at 350 °C. The composition of the Mg/Al intermetallic compounds could be tuned by changing the thickness of the Zn immersion layer. The morphology and composition of the Mg/Al intermetallic compound coatings were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and electron backscattered diffraction (EBSD). Nanomechanical properties were investigated via nano-hardness (nHV) and the elastic modulus (EIT), and the corrosion behavior was studied through hydrogen evolution and potentiodynamic (PD) polarization. The compact and uniform Al coating was electrodeposited on the Zn-immersed AZ91D substrate. After heat treatment, Mg2Al3 and Mg17Al12 phases formed, and as the thickness of the Zn layer increased from 0.2 to 1.8 µm, the ratio of Mg2Al3 and Mg17Al12 varied from 1:1 to 4:1. The nano-hardness increased to 2.4 ± 0.5 GPa and further improved to 3.5 ± 0.1 GPa. The Mg/Al intermetallic compound coating exhibited excellent corrosion resistance and had a prominent effect on the protection of the Mg alloy matrix. The control over the ratio of intermetallic compounds by varying the thickness of the Zn immersion layer can be an effective approach to achieve the optimal comprehensive performance. As the Zn immersion time was 4 min, the obtained intermetallic compounds had relatively excellent comprehensive properties.

8.
J Orthop Translat ; 27: 96-100, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33520654

RESUMO

BACKGROUND: /Objective: This study aimed to evaluate the effectiveness and safety of treating medial malleolar fractures using our patented Mg-Nd-Zn-Zr alloy (abbr. JDBM) screws with Ca-P coating, in order to provide a solid basis for their further clinical translation. METHODS: Nine patients with medial malleolar fractures were treated using coated JDBM screws. All patients had closed injuries, and none had open fractures. Postoperative radiography was performed to evaluate fracture healing and degradation of the JDBM screws. The visual analogue scale (VAS) was used to evaluate the degree of postoperative pain perceived by the patients, and the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot scoring system was used to evaluate their postoperative ankle function. Postoperative complications, including infection, failure of internal fixation, and malunion, were carefully recorded during follow-up. RESULTS: The mean follow-up time was 12.2 â€‹± â€‹4.9 months. After the operation, all patients achieved good medial malleolar fracture alignment, and none of them experienced breakage of the JDBM screws before fracture healing. Postoperative radiography indicated JDBM screws gradually degradated with implantation time, and obvious degradation could be observed 12 months, postoperatively. At the final follow-up, the patients' mean VAS score was 2.3 â€‹± â€‹1.9. The mean AOFAS score was 90.4 â€‹± â€‹8.9, with excellent or good rates of 88.9%. None of the patients experienced infection, failure of internal fixation, malunion, or other complications. CONCLUSION: Coated biodegradable JDBM screws are effective for the treatment of medial malleolar fractures, and have good prospects for further clinical translation in the future. TRANSLATIONAL POTENTIAL STATEMENT: The results of this study indicates coated biodegradable JDBM screw is an alternative internal fixation instrument for fracture treatment and has excellent prospects for clinical translation.

9.
Front Plant Sci ; 11: 595376, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33362825

RESUMO

Magnesium hydride (MgH2) is a promising solid-state hydrogen source with high storage capacity (7.6 wt%). Although it is recently established that MgH2 has potential applications in medicine because it sustainably supplies hydrogen gas (H2), the biological functions of MgH2 in plants have not been observed yet. Also, the slow reaction kinetics restricts its practical applications. In this report, MgH2 (98% purity; 0.5-25 µm size) was firstly used as a hydrogen generation source for postharvest preservation of flowers. Compared with the direct hydrolysis of MgH2 in water, the efficiency of hydrogen production from MgH2 hydrolysis could be greatly improved when the citrate buffer solution is introduced. These results were further confirmed in the flower vase experiment by showing higher efficiency in increasing the production and the residence time of H2 in solution, compared with hydrogen-rich water. Mimicking the response of hydrogen-rich water and sodium hydrosulfide (a hydrogen sulfide donor), subsequent experiments discovered that MgH2-citrate buffer solution not only stimulated hydrogen sulfide (H2S) synthesis but also significantly prolonged the vase life of cut carnation flowers. Meanwhile, redox homeostasis was reestablished, and the increased transcripts of representative senescence-associated genes, including DcbGal and DcGST1, were partly abolished. By contrast, the discussed responses were obviously blocked by the inhibition of endogenous H2S with hypotaurine, an H2S scavenger. These results clearly revealed that MgH2-supplying H2 could prolong the vase life of cut carnation flowers via H2S signaling, and our results, therefore, open a new window for the possible application of hydrogen-releasing materials in agriculture.

10.
Materials (Basel) ; 13(23)2020 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-33276693

RESUMO

The Al coatings achieved via electrodeposition on a Cu electrode from AlCl3-NaCl-KCl (80-10-10 wt.%) molten salts electrolyte with Tetramethylammonium Chloride (TMACl) and Sodium Iodide (NaI) additives is reported. The effect of the two additives on electrodeposition were investigated by cyclic voltammetry (CV), chronopotentiometry (CP), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Results reveal that compact and smooth Al coatings are obtained at 150 °C by the electrodeposition process from the electrolyte with 1% TMACl and 10% NaI. The Al coatings exhibit great corrosion resistance close to that of pure Al plate, with a corrosion current of 3.625 µA. The average particle size is approximately 2 ± 1 µm and the average thickness of the Al layer is approximately 7 ± 2 µm. The nucleation/growth process exhibits irrelevance with TMACl or NaI during the electrodeposition of Al. TMACl cannot affect and improve the electrodeposition effectively. However, the addition of TMACl and NaI can intensify the cathodic polarization, producing an inhibition of Al deposition, and contribute to form uniform Al deposits. This can increase the conductivity and facilitate in refining the size of Al particles, contributing to forming a continuous, dense and uniform layer of Al coating, which can be used as effective additives in molten salts electrolyte.

11.
ACS Appl Mater Interfaces ; 12(26): 29605-29613, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32510191

RESUMO

Nanomodification and amorphization are vital for improving the hydrogenation properties of magnesium (Mg)-based alloys. However, comparisons of their positive effects have been rarely presented because their usual fabrication process of annealing is hard to control. In this study, after tuning the composition fluctuation range, self-assembled well-ordered multilayer Mg0.7Gd0.3 films with an excessive amount of nanosized crystals were fabricated by deviating substrates to the edge of the sample stage, while relatively low crystallinity was gained at the center of the sample stage with a small composition fluctuation. It was demonstrated that the hydrogen diffusion rate in the sample deposited at the center with excessive amorphous regions was higher than that of the film fabricated at the edge with excessive nanocrystals regions. Besides, optical conversion ranges were monitored before and after the hydrogen absorption process. Films with large composition fluctuation possessed a high optical reflectance conversion range because the interference effects occurring inside improved their initial reflectance. However, films with small composition fluctuation inside gained a large transmittance conversion range due to their small nanostructured region.

12.
Mater Sci Eng C Mater Biol Appl ; 113: 111007, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32487410

RESUMO

In the present study, the effects of Zn-3Cu-xFe (x = 0, 0.2, 0.5 wt%) alloys on endothelial cells (EA.hy926) and smooth muscle cells (A7r5), the hemocompatibility and antibacterial properties were also evaluated. The cell viability of EA.hy926 cells and A7r5 cells decreased with the increasing of extract concentration. At the same Zn2+ concentration (over 6 ppm), the cell viability of EA.hy926 cells increased with the addition of Cu or Cu and Fe content, but no significant effect on A7r5 cells was observed. The hemolysis rate of Zn-3Cu-xFe alloys samples was about 1%, and there was no adversely affected on platelets adhering to the surface of the Zn alloys. As Fe content increases in the Zn-Cu-Fe alloys, the antibacterial lower concentrations against Staphylococcus aureus and Escherichia coli was improved due to the higher degradation rate and more Zn2+ and Cu2+ released. Our previous study already showed that the Zn-Cu-Fe alloy exhibited excellent mechanical properties and moderate degradation rate. Based on the above results, the in vitro biocompatibilities and antibacterial properties of Zn-3Cu alloy are significantly improved by the alloying of trace Fe, and the hemocompatibility is not adversely affected, which indicated that Zn-Cu-Fe alloy is a promising vascular stents candidate material.


Assuntos
Ligas/química , Materiais Biocompatíveis/química , Cobre/química , Ferro/química , Stents , Zinco/química , Implantes Absorvíveis , Ligas/farmacologia , Animais , Materiais Biocompatíveis/farmacologia , Plaquetas/citologia , Plaquetas/fisiologia , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cobre/metabolismo , Escherichia coli/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Humanos , Ferro/metabolismo , Antígeno Nuclear de Célula em Proliferação/genética , Antígeno Nuclear de Célula em Proliferação/metabolismo , Ratos , Staphylococcus aureus/efeitos dos fármacos , Zinco/metabolismo
13.
Biomaterials ; 221: 119414, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31419654

RESUMO

The performance of biodegradable magnesium alloy stents (BMgS) requires special attention to non-uniform residual stress distribution and stress concentration, which can accelerate localized degradation after implantation. We now report on a novel concept in stent shape optimization using a finite element method (FEM) toolkit. A Mg-Nd-Zn-Zr alloy with uniform degradation behavior served as the basis of our BMgS. Comprehensive in vitro evaluations drove stent optimization, based on observed crimping and balloon inflation performance, measurement of radial strength, and stress condition validation via microarea-XRD. Moreover, a Rapamycin-eluting polymer coating was sprayed on the prototypical BMgS to improve the corrosion resistance and release anti-hyperplasia drugs. In vivo evaluation of the optimized coated BMgS was conducted in the iliac artery of New Zealand white rabbit with quantitative coronary angiography (QCA), optical coherence tomography (OCT) and micro-CT observation at 1, 3, 5-month follow-ups. Neither thrombus or early restenosis was observed, and the coated BMgS supported the vessel effectively prior to degradation and allowed for arterial healing thereafter. The proposed shape optimization framework based on FEM provides an novel concept in stent design and in-depth understanding of how deformation history affects the biomechanical performance of BMgS. Computational analysis tools can indeed promote the development of biodegradable magnesium stents.


Assuntos
Magnésio/química , Sirolimo/química , Ligas/química , Animais , Angiografia Coronária , Análise de Elementos Finitos , Polímeros/química , Coelhos , Tomografia de Coerência Óptica , Microtomografia por Raio-X
14.
ACS Biomater Sci Eng ; 5(3): 1623-1634, 2019 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-33405635

RESUMO

Various kinds of biodegradable Mg alloys have been developed in recent years due to their appropriate mechanical properties, biodegradation, and good biocompatibility. In this study, Mg-2.0Zn-xGd alloys (x = 0.5, 1.0, 1.5, and 2.0 wt %) were prepared. Hot extrusion was applied in order to refine the microstructure and improve the degradation resistance. The microstructure, mechanical properties, and in vitro degradation behavior of Mg-2.0Zn-xGd alloys were investigated first. The as-extruded Mg-2.0Zn-1.0Gd alloy exhibits excellent mechanical properties (UTS 338 MPa, YS 284 MPa, elongation 24%) and low in vitro degradation rate (0.24 mm/year) with uniform degradation morphology, and then, this alloy was selected for further assessments. The cytotoxicity of as-extruded Mg-2.0Zn-1.0Gd alloy to MC3T3-E1 cell is found to be grade 0-1, indicating good biocompatibility. The in vivo experiment shows that the in vivo degradation rate of this alloy is about 0.31 mm/y after 30 days implantation in cranial defect of Sprague-Dawley rats. All of these indicate a promising prospect of Mg-2.0Zn-1.0Gd alloy as biodegradable applications, especially as orthopedic implants.

15.
Science ; 362(6420): 1276-1281, 2018 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-30409809

RESUMO

Achieving high catalytic performance with the lowest possible amount of platinum is critical for fuel cell cost reduction. Here we describe a method of preparing highly active yet stable electrocatalysts containing ultralow-loading platinum content by using cobalt or bimetallic cobalt and zinc zeolitic imidazolate frameworks as precursors. Synergistic catalysis between strained platinum-cobalt core-shell nanoparticles over a platinum-group metal (PGM)-free catalytic substrate led to excellent fuel cell performance under 1 atmosphere of O2 or air at both high-voltage and high-current domains. Two catalysts achieved oxygen reduction reaction (ORR) mass activities of 1.08 amperes per milligram of platinum (A mgPt -1) and 1.77 A mgPt -1 and retained 64% and 15% of initial values after 30,000 voltage cycles in a fuel cell. Computational modeling reveals that the interaction between platinum-cobalt nanoparticles and PGM-free sites improves ORR activity and durability.

16.
RSC Adv ; 8(34): 18959-18965, 2018 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-35539653

RESUMO

In this work, Mg2Ni(Fe)H4 was synthesized using precursors of nano Ni(Fe) composite powder prepared through arc plasma method and coarse-grained Mg powder. The microstructure, composition, phase components and the hydrogen storage properties of the Mg-Ni(Fe) composite were carefully investigated. It is observed that the Mg2Ni(Fe)H4 particles formed from the Mg-Ni(Fe) composite have a diameter of 100-240 nm and a portion of Fe in the Ni(Fe) nano particles transformed into α-Fe nano particles with the diameter of 40-120 nm. DSC measurements showed that the peak desorption temperature of the Mg2Ni(Fe)H4 was reduced to 501 K and the apparent activation energy for hydrogen desorption of the Mg2Ni(Fe)H4 was 97.2 kJ mol-1 H2. The formation enthalpy of Mg2Ni(Fe)H4 was measured to be -53.1 kJ mol-1 H2. The improvements in hydrogen sorption kinetics and thermodynamics can be attributed to the catalytic effect from α-Fe nano particles and the destabilization of Mg2NiH4 caused by the partial substitution of Ni by Fe, respectively.

17.
ACS Biomater Sci Eng ; 4(11): 3864-3873, 2018 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-33429615

RESUMO

Biodegradable magnesium alloy stents exhibit deficient corrosion period for clinic applications, making the protective polymer coating more crucial than drug-eluting stents with the permanent metal scaffold. We implemented a cohesive method based on a finite element analysis method to predict the integrity of adhesive between coating and stent during the crimping and deployment. For the first time, the three-dimensional quantitative modeling reveals the process of polymer coating delamination and stress concentration. The fracture and microcracks of coatings were consistent with the simulation result, confirmed by the scanning electron microscopy observation. Moreover, we analyzed four possible factors, i.e., stent design, strut material, coating polymer, and thickness of the coating, affecting the stent-coating damage and the distribution of the stress in coatings. Mg-Nd-Zn-Zr alloy with lower yield strength performed a more uniform strain distribution and more favorable adhesion of the coating than the commercial magnesium alloy AZ31. Shape optimization of stent design improves the strain and stress distribution of coating remarkably, avoiding coating delamination. Additionally, PLGA coating with lower elastic modulus and yield strength tends to follow the deformation of the stent better and to adhere on the surface more tightly, compared to PLLA polymer. A reduction in coating thickness and an increase in the strength of stent-coating interface improve the resistance to delamination. Our framework based on cohesive method provides an in-depth understanding of stent-coating damage and shows the way of computational analyses could be implemented in the design of coated biodegradable magnesium stents.

18.
RSC Adv ; 8(17): 9211-9217, 2018 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-35541869

RESUMO

A new hydrogen storage composite containing NaBH4 and a 3d transition metal fluoride, 3NaBH4/ScF3, was synthesized via ball milling. The composite shows no reaction during milling and its dehydriding process can be divided into three steps upon heating: (i) partial substitution of H- by F- in NaBH4 to form NaBH x F4-x at the early stage, releasing about 0.19 wt% of hydrogen; (ii) formations of Na3ScF6, NaBF4 and ScB2 through the reaction between NaBH4 and ScF3, with 2.52 wt% of hydrogen release and a dehydriding activation energy of 162.67 kJ mol-1 H2; (iii) further reaction of residual NaBH4 and Na3ScF6 to form NaF, B and ScB2, with a dehydriding activation energy of 169.37 kJ mol-1 H2. The total hydrogen release of the composite reaches 5.54 wt% at 530 °C. The complete dehydrided composite cannot be rehydrogenated while the products after the second dehydriding step can be hydrogenated with an absorption activation energy of 44.58 kJ mol-1 H2. These results demonstrate that by adding 3d transition metal fluorides into NaBH4, a partial reversibility in NaBH4 can be achieved.

19.
Sci Rep ; 7: 46343, 2017 04 11.
Artigo em Inglês | MEDLINE | ID: mdl-28397881

RESUMO

We report a Mg alloy Mg-2.2Nd-0.1Zn-0.4Zr (wt.%, denoted as JDBM-2) showing great potential in clinical vascular stent application by integrating the advantages of traditional medical stainless steel and polymer. This alloy exhibits high yield strength and elongation of 276 ± 6 MPa and 34.3 ± 3.4% respectively. The JDBM-2 with a stable degradation surface results in a highly homogeneous degradation mechanism and long-term structural and mechanical durability. In vitro cytotoxicity test of the Mg extract via human vascular endothelial cells (HUVECs) indicates that the corrosion products are well tolerated by the tested cells and potentially negligible toxic effect on arterial vessel walls. This alloy also exhibits compromised foreign body response (FBR) determined by human peripheral blood derived macrophage adhesion, foreign body giant cell (FBGC) formation and inflammatory cytokine and chemokine secretion. Finally, vascular stents manufactured from the JDBM-2 were implanted into rabbits for long-term evaluation. The results confirm excellent tissue compatibility and up to 6-month structural and mechanical integrity of the stent in vivo. Thus, the JDBM-2 stent with up to 6-month structural and mechanical integrity and excellent tissue compatibility represents a major breakthrough in this field and a promising alternative to traditional medical stainless steel and polymer for the clinical application.


Assuntos
Ligas/química , Materiais Biocompatíveis/química , Magnésio/química , Stents , Angiografia , Animais , Sobrevivência Celular , Células Cultivadas , Células Endoteliais da Veia Umbilical Humana , Humanos , Teste de Materiais , Fenômenos Mecânicos , Coelhos , Propriedades de Superfície
20.
Mater Sci Eng C Mater Biol Appl ; 69: 407-13, 2016 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-27612729

RESUMO

Zn-based alloys have been viewed as new potential materials for biodegradable implants, such as cardiovascular stents, mainly in consideration of their lower corrosion rate when compared with that of Mg alloys. In this study we developed a new Zinc-4wt.%Copper (Zn-4Cu) alloy as a biodegradable material. Hot extrusion was applied to Zn-4Cu to refine the microstructure and consequently improve its mechanical properties and corrosion resistance. After extrusion, dendritic CuZn5 phases were broken and distributed along the extrusion direction. The grains were refined obviously due to dynamical recrystallization. The yield strength (YS), ultimate tensile strength (UTS) and elongation of the as-extruded alloy are 250±10MPa, 270±10MPa and 51±2%, respectively. The corrosion rate of the as-extruded alloy in Hank's solution is about 9.41(±1.34)µmyear(-1). In vitro evaluation shows that Zn-4Cu presents acceptable toxicity to human endothelial cells, and could effectively inhibit bacteria adhesion and biofilm formation. The present study indicates that the as-extruded Zn-4Cu alloy exhibits excellent strength and ductility, uniform and slow degradation, good biocompatibility and significant antibacterial effect, which make it an excellent candidate material for biodegradable implants, especially for cardiovascular stents application.


Assuntos
Ligas/química , Materiais Biocompatíveis/química , Cobre/química , Stents , Zinco/química , Implantes Absorvíveis , Ligas/farmacologia , Materiais Biocompatíveis/metabolismo , Materiais Biocompatíveis/farmacologia , Biofilmes/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Corrosão , Humanos , Staphylococcus aureus/fisiologia , Resistência à Tração
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