A systematic study of nitric acid passivation was investigated to enhance the general corrosion resistance of biomedical high-nitrogen nickel-free stainless steels(HNSs).After passivation,the corrosion rate of HNS cou...A systematic study of nitric acid passivation was investigated to enhance the general corrosion resistance of biomedical high-nitrogen nickel-free stainless steels(HNSs).After passivation,the corrosion rate of HNS could dramatically reduce to 1/20 of the untreated in 37℃0.9 wt% NaCl solutions.Then,the passive film on HNS was analyzed by X-ray photoelectron spectroscopy.It was found that chromium enrichment in the passive film and nitrogen enrichment in the film/metal interface contributed to the improvement in general corrosion resistance of HNS.展开更多
A composite coating was fabricated on pure magnesium by hydrothermal treatment in order to reduce its degradation in body environment. The coating was character- ized by scanning electron microscopy （SEM） and X-ray ...A composite coating was fabricated on pure magnesium by hydrothermal treatment in order to reduce its degradation in body environment. The coating was character- ized by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The XRD pattern showed that the main composition of the coating was a mixture of CaSiO3, MgSiO3 and Mg（OH）2. Electrochemical test showed that the corrosion current den- sity （icor~） of the coated magnesium was decreased by about two orders of magnitude compared with that of the bare magnesium, and the EIS measurement also showed that the corrosion resistant performance of the coated magnesium was significantly enhanced. Meanwhile, weight loss test showed that the weight loss of the coated magnesium was lower than that of the bare magnesium. Hence, the present study indicated that the composite coating could greatly slow down the degradation of pure magnesium.展开更多
To improve the corrosion rate and suppress the local corrosion,a novel biodegradable high nitrogen(N)FeMnN alloy was developed,and the effects of N content on the corrosion behaviors were systematically investigated.I...To improve the corrosion rate and suppress the local corrosion,a novel biodegradable high nitrogen(N)FeMnN alloy was developed,and the effects of N content on the corrosion behaviors were systematically investigated.It was found that,as the N content increased,the corrosion rate was significantly enhanced in both Hank’s solution and simulated gastric fluid.Meanwhile,as the N content increased,the size and depth of pits decreased obviously,and the number of pits increased,which presented a more uniform corrosion morphology.X-ray photoelectron spectroscopy(XPS)results indicated that N existed in the form of NH_(4)^(+) in the corrosion products and[FeN]clusters in the matrix.The[FeN]clusters would simultane-ously improve the corrosion rate and suppress the local corrosion,which provides a new perspective for the development of biodegradable Fe alloy.展开更多
Mg-Zn-Nd alloy is a promising biodegradable metal material for surgical staples during the reconstruction of digestive tract due to its good biocompatibility and suitable mechanical properties.However,its deformation ...Mg-Zn-Nd alloy is a promising biodegradable metal material for surgical staples during the reconstruction of digestive tract due to its good biocompatibility and suitable mechanical properties.However,its deformation property and corrosion resistance should be improved to make better safety and effectiveness of staples.In the present study,bi-direction drawing was adopted to maintain the initial texture characteristics,and improve mechanical property and corrosion resistance of Mg-2Zn-0.5Nd alloy.The results showed that the microstructure after bi-direction did not change too much,but the texture could maintain its initial characteristics.The ductility of the alloy with 60%accumulative area reduction after bi-direction drawing was increased by 70%,indicating that an outstanding deformation property of Mg-Zn-Nd alloy can be obtained by bi-direction drawing.The corrosion resistance was also improved after bi-direction drawing compared with that under single direction drawing.展开更多
Mg-Cu alloys are promising antibacterial implant materials.However,their clinical applications have been impeded by their high initial biodegradation rate,which can be alleviated using nanotechnology by for example su...Mg-Cu alloys are promising antibacterial implant materials.However,their clinical applications have been impeded by their high initial biodegradation rate,which can be alleviated using nanotechnology by for example surface nanomodification to obtain a gradient nanostructured surface layer.The present work(i)produced a gradient nanostructured surface layer with a∼500µm thickness on a Mg-0.2 Cu alloy by a surface mechanical grinding treatment(SMGT),and(ii)studied the biodegradation behavior in Hank's solution.The initial biodegradation rate of the SMGTed samples was significantly lower than that of the unSMGTed original counterparts,which was attributed to the surface nanocrystallization,and the fragmentation and re-dissolution of Mg_(2)Cu particles in the surface of the SMGTed Mg-0.2 Cu alloy.Furthermore,the SMGTed Mg-0.2 Cu alloy had good antibacterial efficacy.This work creatively used SMGT technology to produce a high-performance Mg alloy implant material.展开更多
Lung cancer has one of the highest rates of incidence and mortality worldwide,mak-ing research on its mechanisms and treatments crucial.Animal models are essential in lung cancer research as they accurately replicate ...Lung cancer has one of the highest rates of incidence and mortality worldwide,mak-ing research on its mechanisms and treatments crucial.Animal models are essential in lung cancer research as they accurately replicate the biological characteristics and treatment outcomes seen in human diseases.Currently,various lung cancer models have been established,including chemical induction models,orthotopic transplan-tation models,ectopic transplantation models,metastasis models,and gene editing mouse models.Additionally,lung cancer grafts can be categorized into two types:tissue-based and cell-based grafts.This paper summarizes the phenotypes,advan-tages,and disadvantages of various induction methods based on their modeling tech-niques.The goal is to enhance the simulation of clinical lung cancer characteristics and to establish a solid foundation for future clinical research.展开更多
Interbody fusion is recognized as the golden standard of surgical intervention for degenerative disc disease(DDD).Interbody fusion cage made of polyetheretherketone(PEEK)is commonly used in lumbar interbody fusion sur...Interbody fusion is recognized as the golden standard of surgical intervention for degenerative disc disease(DDD).Interbody fusion cage made of polyetheretherketone(PEEK)is commonly used in lumbar interbody fusion surgery in the treatment of DDD worldwide.However,there are some limitations of PEEK including their bio-inert nature and impediment to host bone integration.This study aimed to evaluate the degradation profile and osteoinductive potential of biodegradable Mg-Zn-Nd-Zr cages with/without micro-arc oxidation(MAO)coatings.The Mg-Zn-Nd-Zr alloy cages,whether coated with MAO or not,demonstrated commendable biocompatibility and biomechanical properties.Immersion and electrochemical tests show better corrosion resistance of MAO coatings in vitro.mRNA sequencing,RT-qPCR and Western blotting revealed that Mg-Zn-Nd-Zr and Mg-Zn-Nd-Zr/MAO had a better effectiveness on osteoinductivity.In vivo evaluations in ovine models over 12 weeks and 24 weeks post-implantation revealed radiological and histological evidence of enhanced bone formation adjacent to the Mg-Zn-Nd-Zr alloy cages compared to PEEK counterparts.Moreover,the MAO-coated cages exhibited a reduced propensity for gas formation.The Mg-Zn-Nd-Zr alloy is as a superior osteoinductive material compared with PEEK,with the MAO coating offering an advantage in mitigating gas production.Nonetheless,further research is warranted to refine the alloy's composition or surface treatments,particularly to address the challenges associated with rapid gas evolution during the early post-implantation period.展开更多
Regarding the current materials used for suture anchors for rotator cuff repair,there are still limitations in terms of degradability,mechanical properties,and bioactivities in clinical applications.Magnesium alloys h...Regarding the current materials used for suture anchors for rotator cuff repair,there are still limitations in terms of degradability,mechanical properties,and bioactivities in clinical applications.Magnesium alloys have preliminarily been shown to promote tendon-bone healing with good prospects for application as anchor materials.However,the design of anchor structures for the degradation characteristics of magnesium alloy materials has not been considered,which is critical for the practical application of magnesium alloy anchors.The mechanism by which magnesium promotes tendon bone healing remains to be clarified.Here,we proposed a novel split hollowed magnesium alloy suture anchors for the repair of rabbit rotator cuff injury.We found that novel split hollowed magnesium alloy anchors structure effectively solved the problem of failure due to degradation of traditional eyelet structure,providing reliable suture fixation.The open architecture facilitates the metabolic resorption of the degradation products of and promotes the ingrowth of bone tissue.Histological staining showed that magnesium anchors have better ability to promote regeneration at the fibrocartilage interface compared to PLLA anchors.The higher expression of fibrocartilage markers(Aggrecan,COL2A1,and Sox9)at the tendon-bone interface in magnesium anchors,which promotes chondrocyte differentiation at the tendon-bone interface and matrix formation,which is more conducive to achieving regeneration and maturation of fibrocartilage enthesis.Hence,this study provides a basis for further research on the clinical application of degradable magnesium alloy suture anchors.展开更多
With attractive research and development of biomaterials, more and more opportunities have been brought to the treatments of human tissue repairs. The implant is usually no need to exist in the body accompanied with t...With attractive research and development of biomaterials, more and more opportunities have been brought to the treatments of human tissue repairs. The implant is usually no need to exist in the body accompanied with the recovery or regeneration of the tissue lesions, and the long-term effect of exotic substance to human body should be reduced as lower as possible. For this purpose, biodegradable materials, including polymers, magnesium alloys and ceramics, have attracted much attention for medical applications due to their biodegradable characters in body environment. This paper in turn introduces these three different types of widely studied biodegradable materials as well as their advantages as implants in applications for bone repairs. Relevant history and research progresses are summarized.展开更多
RE-containing Mg alloys used as biodegradable medical implants exhibit good promising application due to their good mechanical properties and degradation resistance. In this work, effect of Gd on the microstructure, m...RE-containing Mg alloys used as biodegradable medical implants exhibit good promising application due to their good mechanical properties and degradation resistance. In this work, effect of Gd on the microstructure, mechanical properties and biodegradation of as-cast Mg-2Zn-xGd-0.5Zr alloys was investigated. The results showed that there were mainly α-Mg, I-phase, W-phase and MgZn2 phase in Mg-Zn-Gd-Zr alloys. With increase of the Gd content, the strength of the alloys was enhanced due to the second phase strengthening and grain refinement. The degradation resistance of Mg-2Zn-0.5Zr alloy was increased by adding 0.5%–1% Gd due to the uniformly distributed second phases which acted as a barrier to prevent the pitting corrosion. However, increasing Gd content to 2% reduced the degradation resistance of the alloy due to the galvanic corrosion between the matrix and the second phases.The good degradation resistance and mechanical properties of as-cast Mg-2Zn-1Gd-0.5Zr alloy makes it outstanding for biomaterial application.展开更多
Biodegradable magnesium alloys have been turned out to be a promising candidate for orthopedic applications.In this study,the mechanical properties,degradation behaviorand cytocompatibility of MgZn-Zr-Nd and Mg-Zn-Zr-...Biodegradable magnesium alloys have been turned out to be a promising candidate for orthopedic applications.In this study,the mechanical properties,degradation behaviorand cytocompatibility of MgZn-Zr-Nd and Mg-Zn-Zr-Y alloys were studied in comparison with pure Mg.Mechanical tests showed that the strength and ductility of Mg-Zn-Zr-Nd and Mg-Zn-Zr-Y alloys were excellent.The corrosion resistance analyzed by electrochemical test and immersion test in alpha modified eagle(α-MEM) medium with 10% fetal bovine serum(FBS) revealed the degradation of Mg-Zn-Zr-Nd and Mg-Zn-Zr-Y alloys were faster than pure Mg at an early stage but slowed down after long time immersion.The metal ion concentrations were consistent with the corrosion rate.Mg-Zn-Zr-Nd alloy shows better mechanical properties than pure Mg and better corrosion resistance than Mg-Zn-Zr-Y alloy.The direct and indirect in vitro tests with MC3 T3-E1 cells demonstrate that Mg-Zn-Zr-Nd shows the best cytocompatibility and osteogenesis.The results suggest that Mg-Zn-Zr-Nd alloy shows an ideal combination of mechanical,corrosive and biological properties.In summary,these results implying the Mg-Zn-Zr-Nd alloy has great potential to benefit the future development of orthopedic applications.展开更多
A fluoride conversion coating was successfully prepared on AZ31B magnesium alloy by chemical reaction in hydrofluoric acid. Morphologies, composition, bonding strength, corrosion properties, in vitro cytotoxicity and ...A fluoride conversion coating was successfully prepared on AZ31B magnesium alloy by chemical reaction in hydrofluoric acid. Morphologies, composition, bonding strength, corrosion properties, in vitro cytotoxicity and antibacterial properties of the coating were investigated, respectively. The scanning electron microscopy observations revealed a dense coating with some irregular pores. The thin-film X-ray diffraction analysis indicated that the coating was mainly composed of MgO and MgF2. The electrochemical impedance spectroscopy results showed that the fluoride conversion coating significantly improved the corrosion resistance of AZ31B. The hydroxyapatite formed on the surface of the fluoride coated AZ31 B after being immersed in the simulated blood plasma indicated the good bioactivity of the material. The in vitro cytotoxicity test showed that the fluoride coated AZ31B alloy was not toxic to BMMSCs （human bone marrow-derived mesenchymal stem cells）. It was also found that the fluoride coated AZ31 B alloy had antibacterial capability.展开更多
The application of a single pass of friction stir processing(FSP) to Mg-Nd-Zn alloy resulted in grain refinement, texture evolution and redistribution of second phases, which improved corrosion resistance.In this work...The application of a single pass of friction stir processing(FSP) to Mg-Nd-Zn alloy resulted in grain refinement, texture evolution and redistribution of second phases, which improved corrosion resistance.In this work, an as-rolled Mg-Nd-Zn alloy was subjected to FSP. The microstructure in the processed zone of the FS-400 rpm alloy exhibited refined grains, a more homogenous grain size distribution, less second phases, and stronger basal plane texture. The corrosion behavior assessed using immersion tests and electrochemical tests in Hank’s solution indicated that the FS-400 rpm alloy had a lower corrosion rate, which was attributed to the increase of basal plane intensity and grain refinement. The hardness was lowered slightly and the elongation was increased, which might be attributed to the redistribution of the crushed second phases.展开更多
Three-dimensional honeycomb-structured magnesium （Mg） scaffolds with interconnected pores of accurately controlled pore size and porosity were fabricated by laser perforation technique. Biodegradable and bioactiveβ...Three-dimensional honeycomb-structured magnesium （Mg） scaffolds with interconnected pores of accurately controlled pore size and porosity were fabricated by laser perforation technique. Biodegradable and bioactiveβ- tricalcium phosphate （β-TCP） coatings were prepared on and the biodegradation mechanism was simply evaluated the porous Mg to further improve its biocompatibility, in vitro. It was found that the mechanical properties of this type of porous Mg significantly depended on its porosity. Elastic modulus and compressive strength similar to human bones could be obtained for the porous Mg with porosity of 42.6%-51%. It was observed that the human osteosarcoma cells （UMR106） were well adhered and proliferated on the surface of the β- TCP coated porous Mg, which indicates that theβ-TCP coated porous Mg is promising to be a bone tissue engineering scaffold material.展开更多
Magnesium(Mg) alloys have attracted a wealth of attention in orthopedic fields for their superior mechanical properties, degradability,and excellent biocompatibility. Consistently, to resolve the issues on rapid degra...Magnesium(Mg) alloys have attracted a wealth of attention in orthopedic fields for their superior mechanical properties, degradability,and excellent biocompatibility. Consistently, to resolve the issues on rapid degradation, more studies are dedicated to the researches on the composition design, preparation and processing, surface modification, the degradation modes of Mg alloys. Nevertheless, the mechanisms by which Mg alloys promote bone healing remain elusive. This review gives an account of specific mechanisms on Mg alloys promoting bone healing from four aspects, immunomodulatory, angiogenesis, osteogenesis and regulation of osteoclast function. We highlight the regulation of Mg alloys on the functional status and interactions of numerous cells that are involved in bone healing, including immune cells, osteogenicrelated cells, osteoclasts, endothelial cells(ECs), nerve cells, etc., and summarize the signaling pathways involved, with the aim to provide the basis and support on future investigation on mechanisms on Mg alloys driving bone regeneration. More importantly, it provides a rationale and a general new basis for the application of Mg alloys in orthopedic fields.展开更多
Torsional properties are important performance parameters for bone screw applications,but they are seldom studied,especially for newly developed biodegradable Mg alloys.In this study,WE43 Mg alloy with different micro...Torsional properties are important performance parameters for bone screw applications,but they are seldom studied,especially for newly developed biodegradable Mg alloys.In this study,WE43 Mg alloy with different microstructures was achieved by equal channel angular pressing(ECAP)and heat treatment,and their torsional properties were studied.In addition,tensile properties were also tested as a comparison.The results indicated that grain refinement led to higher torsional strength and ductility,while the second phases improved the torsional strength but reduced the ductility.The texture was strengthened after ECAP,as a result the tensile strength increased,but the torsional strength did not increase and even decreased,especially for 2-pass ECAP sample with a typical basal fiber texture.The basal plane orientation deviation from the extrusion direction after 4-pass ECAP resulted in higher torsional strength and lower torsional ductility,but lower tensile strength and higher tensile ductility were obtained.This implied that a strong fiber texture would reduce the torsional strength but improve the torsional ductility,which was different from its effect on tensile properties.展开更多
In the present work, the biodegradable behavior, cytocompatibility and osteogenesis activity of a Mg69Zn27Ca4 metal glass were investigated. Electrochemical test, immersion test, cytotoxicity test and histopathologica...In the present work, the biodegradable behavior, cytocompatibility and osteogenesis activity of a Mg69Zn27Ca4 metal glass were investigated. Electrochemical test, immersion test, cytotoxicity test and histopathological evaluation were carried out. The results showed that there was a dense protective layer formed on the surface of Mg69Zn27Ca4 metal glass which could inhibit the degradation process in the Hank’s solution. In vitro cytotoxicity test showed that Mg69Zn27Ca4 metal glass had good biocompatibility. Histopathological evaluation showed that the degradation of Mg69Zn27Ca4 metal glass could promote the new bone formation with no obvious inflammatory reactions. After 2 months implantation, the diameter of the bone defect was reduced from the original φ6 mm to φ3.35 ± 0.40 mm with the degradation of Mg69Zn27Ca4 metal glass. Therefore, it can be concluded that Mg69Zn27Ca4 glass has great potential to be used as bone substitutes.展开更多
In the present study, a Si-containing coating was fabricated on AZ31B Mg alloy. Cytocompatibility of the coated alloy was evaluated by both indirect and direct contact methods, respectively. Effects of a number of inc...In the present study, a Si-containing coating was fabricated on AZ31B Mg alloy. Cytocompatibility of the coated alloy was evaluated by both indirect and direct contact methods, respectively. Effects of a number of incubation variables on the sensitivity and reproducibility of the hemolysis test were also examined by using positively and negatively responding biomaterials. Cytocompatibility testing results indicated that cell condition, cell adherence, cell proliferation and extracellular matrix secretion of the coated alloy were improved compared with those of the uncoated alloy for different extraction and co-culture time. The hemolysis test suggested that hemolysis testing conditions were critical to determine the hemolysis of the alloy. It was also found that 1 day in vitro degradation of the uncoated AZ31B alloy had no destructive effect on erythrocyte. As for the coated AZ31B alloy at any time point, the hemolysis rate was much lower than 5%, the safe value for biomaterials. These in vitro experimental results indicate that the Si-containing coating is effective to improve the cytocompatibility and hemolysis behaviors of AZ31B alloy during its degradation.展开更多
Bone graft substitutes are widely-studied as alternatives to bone grafts in the clinic. The currently available products are mostly ceramics and polymers. Considerable progress has been made in the study of the biodeg...Bone graft substitutes are widely-studied as alternatives to bone grafts in the clinic. The currently available products are mostly ceramics and polymers. Considerable progress has been made in the study of the biodegradable magnesium alloys, which possess the necessary attributions of a suitable substitute, including an excellent mechanical property. In the present study, a minipig model of a lateral tibial plateau defect was used to evaluate the effectiveness of a magnesium alloy in the repair of a critical-sized defect. The micro-arc oxidation （MAO）-coated ZK60 alloy tablets and medical-grade calcium sulfate pellets were used as the test and control materials, respectively. Bone morphology was monitored by computed tomography after the implantation for 2 and 4 months. It was found that the bone morphology in minipigs following magnesium treatment was similar to that of the normal bone, whereas an abnormal and concave morphology was displayed following the calcium sulfate treatment. The average bone healing rate for the magnesium-treated defects was higher than that of the calcium sulfate-treated defects at the first 4 months following the implantation. Overall, magnesium treatment appeared to calcium sulfate treatment. Thus, the MAO-coated ZK60 al substitute, and further research on its biological activity in improve the defect repair as compared with the oy appears to be a useful biocompatible bone graft vivo is needed.展开更多
Fine grained ZN20 alloy was obtained by combining equal-channel angular pressing(ECAP)with extrusion.Microstructural observation showed an obvious grain refinement with an average grain size of 10μm after ECAP.The or...Fine grained ZN20 alloy was obtained by combining equal-channel angular pressing(ECAP)with extrusion.Microstructural observation showed an obvious grain refinement with an average grain size of 10μm after ECAP.The original bimodal-grained structure composed of coarse grains with strong basal texture and fine grains with random texture was substituted by a new kind of bimodal-grained structure with finer grains and more random texture after 4 passes ECAP at 300℃.The combination of grain refinement and texture weakening caused the ductility can be increased by 40%compared with the as-extruded alloy.Immersion test in simulated intestinal fluid revealed an improvement of corrosion resistance after ECAP.Grain refinement can stable the corrosion product layer and basal texture is more beneficial for the corrosion resistance than the non-basal texture.展开更多
基金supported by the National Natural Science Foundation of China(No.51801220)the Key Program of China on Biomedical Materials Research and Tissue and Organ Replacement(No.2016YFC1101804 and 2016YFC1100604)the Shenyang Key R&D and Technology Transfer Program(No.Z18-0-027).
文摘A systematic study of nitric acid passivation was investigated to enhance the general corrosion resistance of biomedical high-nitrogen nickel-free stainless steels(HNSs).After passivation,the corrosion rate of HNS could dramatically reduce to 1/20 of the untreated in 37℃0.9 wt% NaCl solutions.Then,the passive film on HNS was analyzed by X-ray photoelectron spectroscopy.It was found that chromium enrichment in the passive film and nitrogen enrichment in the film/metal interface contributed to the improvement in general corrosion resistance of HNS.
基金financially supported by the National Natural Science Foundation of China (No. 30970715)National Basic Research Program of China(No. 2012CB619101)
文摘A composite coating was fabricated on pure magnesium by hydrothermal treatment in order to reduce its degradation in body environment. The coating was character- ized by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The XRD pattern showed that the main composition of the coating was a mixture of CaSiO3, MgSiO3 and Mg（OH）2. Electrochemical test showed that the corrosion current den- sity （icor~） of the coated magnesium was decreased by about two orders of magnitude compared with that of the bare magnesium, and the EIS measurement also showed that the corrosion resistant performance of the coated magnesium was significantly enhanced. Meanwhile, weight loss test showed that the weight loss of the coated magnesium was lower than that of the bare magnesium. Hence, the present study indicated that the composite coating could greatly slow down the degradation of pure magnesium.
基金This work was financially supported by the National Natural Science Foundation of China(Grant No.51801220).
文摘To improve the corrosion rate and suppress the local corrosion,a novel biodegradable high nitrogen(N)FeMnN alloy was developed,and the effects of N content on the corrosion behaviors were systematically investigated.It was found that,as the N content increased,the corrosion rate was significantly enhanced in both Hank’s solution and simulated gastric fluid.Meanwhile,as the N content increased,the size and depth of pits decreased obviously,and the number of pits increased,which presented a more uniform corrosion morphology.X-ray photoelectron spectroscopy(XPS)results indicated that N existed in the form of NH_(4)^(+) in the corrosion products and[FeN]clusters in the matrix.The[FeN]clusters would simultane-ously improve the corrosion rate and suppress the local corrosion,which provides a new perspective for the development of biodegradable Fe alloy.
基金This work was financially supported by the National Key Research and Development Program of China(No.2016YFC1101804,2016YFC1100604)Natural Science Foundation of Liaoning Province of China(No.2019-MS-326)Youth Innovation Promotion Association,CAS and National Natural Science Foundation of China(No.51971222,51801220)。
文摘Mg-Zn-Nd alloy is a promising biodegradable metal material for surgical staples during the reconstruction of digestive tract due to its good biocompatibility and suitable mechanical properties.However,its deformation property and corrosion resistance should be improved to make better safety and effectiveness of staples.In the present study,bi-direction drawing was adopted to maintain the initial texture characteristics,and improve mechanical property and corrosion resistance of Mg-2Zn-0.5Nd alloy.The results showed that the microstructure after bi-direction did not change too much,but the texture could maintain its initial characteristics.The ductility of the alloy with 60%accumulative area reduction after bi-direction drawing was increased by 70%,indicating that an outstanding deformation property of Mg-Zn-Nd alloy can be obtained by bi-direction drawing.The corrosion resistance was also improved after bi-direction drawing compared with that under single direction drawing.
基金Financially supported by Natural Science Foundation of China(No.51874368).
文摘Mg-Cu alloys are promising antibacterial implant materials.However,their clinical applications have been impeded by their high initial biodegradation rate,which can be alleviated using nanotechnology by for example surface nanomodification to obtain a gradient nanostructured surface layer.The present work(i)produced a gradient nanostructured surface layer with a∼500µm thickness on a Mg-0.2 Cu alloy by a surface mechanical grinding treatment(SMGT),and(ii)studied the biodegradation behavior in Hank's solution.The initial biodegradation rate of the SMGTed samples was significantly lower than that of the unSMGTed original counterparts,which was attributed to the surface nanocrystallization,and the fragmentation and re-dissolution of Mg_(2)Cu particles in the surface of the SMGTed Mg-0.2 Cu alloy.Furthermore,the SMGTed Mg-0.2 Cu alloy had good antibacterial efficacy.This work creatively used SMGT technology to produce a high-performance Mg alloy implant material.
基金Sichuan Provincial Administration of Traditional Chinese Medicine,Grant/Award Number:2023MS564National Natural Science Foundation of China,Grant/Award Number:82474436。
文摘Lung cancer has one of the highest rates of incidence and mortality worldwide,mak-ing research on its mechanisms and treatments crucial.Animal models are essential in lung cancer research as they accurately replicate the biological characteristics and treatment outcomes seen in human diseases.Currently,various lung cancer models have been established,including chemical induction models,orthotopic transplan-tation models,ectopic transplantation models,metastasis models,and gene editing mouse models.Additionally,lung cancer grafts can be categorized into two types:tissue-based and cell-based grafts.This paper summarizes the phenotypes,advan-tages,and disadvantages of various induction methods based on their modeling tech-niques.The goal is to enhance the simulation of clinical lung cancer characteristics and to establish a solid foundation for future clinical research.
基金supported by the National Natural Science Foundation of China(82172392)the National Natural Science Foundation of China(82372401)+1 种基金the Beijing Natural Science Foundation(L202033)the Basic Applied Research Program of Liaoning Province of China(2022020347-JH2/1013)。
文摘Interbody fusion is recognized as the golden standard of surgical intervention for degenerative disc disease(DDD).Interbody fusion cage made of polyetheretherketone(PEEK)is commonly used in lumbar interbody fusion surgery in the treatment of DDD worldwide.However,there are some limitations of PEEK including their bio-inert nature and impediment to host bone integration.This study aimed to evaluate the degradation profile and osteoinductive potential of biodegradable Mg-Zn-Nd-Zr cages with/without micro-arc oxidation(MAO)coatings.The Mg-Zn-Nd-Zr alloy cages,whether coated with MAO or not,demonstrated commendable biocompatibility and biomechanical properties.Immersion and electrochemical tests show better corrosion resistance of MAO coatings in vitro.mRNA sequencing,RT-qPCR and Western blotting revealed that Mg-Zn-Nd-Zr and Mg-Zn-Nd-Zr/MAO had a better effectiveness on osteoinductivity.In vivo evaluations in ovine models over 12 weeks and 24 weeks post-implantation revealed radiological and histological evidence of enhanced bone formation adjacent to the Mg-Zn-Nd-Zr alloy cages compared to PEEK counterparts.Moreover,the MAO-coated cages exhibited a reduced propensity for gas formation.The Mg-Zn-Nd-Zr alloy is as a superior osteoinductive material compared with PEEK,with the MAO coating offering an advantage in mitigating gas production.Nonetheless,further research is warranted to refine the alloy's composition or surface treatments,particularly to address the challenges associated with rapid gas evolution during the early post-implantation period.
基金supported by Capital Health Development Research Special Project(2022-2-5051)DongGuan Innovative Research Team Program.Basic applied research program of Liaoning Province of China(No.2022020347-JH2/1013)。
文摘Regarding the current materials used for suture anchors for rotator cuff repair,there are still limitations in terms of degradability,mechanical properties,and bioactivities in clinical applications.Magnesium alloys have preliminarily been shown to promote tendon-bone healing with good prospects for application as anchor materials.However,the design of anchor structures for the degradation characteristics of magnesium alloy materials has not been considered,which is critical for the practical application of magnesium alloy anchors.The mechanism by which magnesium promotes tendon bone healing remains to be clarified.Here,we proposed a novel split hollowed magnesium alloy suture anchors for the repair of rabbit rotator cuff injury.We found that novel split hollowed magnesium alloy anchors structure effectively solved the problem of failure due to degradation of traditional eyelet structure,providing reliable suture fixation.The open architecture facilitates the metabolic resorption of the degradation products of and promotes the ingrowth of bone tissue.Histological staining showed that magnesium anchors have better ability to promote regeneration at the fibrocartilage interface compared to PLLA anchors.The higher expression of fibrocartilage markers(Aggrecan,COL2A1,and Sox9)at the tendon-bone interface in magnesium anchors,which promotes chondrocyte differentiation at the tendon-bone interface and matrix formation,which is more conducive to achieving regeneration and maturation of fibrocartilage enthesis.Hence,this study provides a basis for further research on the clinical application of degradable magnesium alloy suture anchors.
基金the financial support of the National Basic Research Program of China(973 Program, No.2012CB619101)
文摘With attractive research and development of biomaterials, more and more opportunities have been brought to the treatments of human tissue repairs. The implant is usually no need to exist in the body accompanied with the recovery or regeneration of the tissue lesions, and the long-term effect of exotic substance to human body should be reduced as lower as possible. For this purpose, biodegradable materials, including polymers, magnesium alloys and ceramics, have attracted much attention for medical applications due to their biodegradable characters in body environment. This paper in turn introduces these three different types of widely studied biodegradable materials as well as their advantages as implants in applications for bone repairs. Relevant history and research progresses are summarized.
基金supported by the Key Program of China on Biomedical Materials Research and Tissue and Organ Replacement (Nos.2016YFC1101804,2016YFC1100604)Institute of Metal Research,Chinese Academy of Sciences (No.2015-ZD01)the Foundation of Jiangsu Collaborative Innovation Center of Biomedical Functional Materials
文摘RE-containing Mg alloys used as biodegradable medical implants exhibit good promising application due to their good mechanical properties and degradation resistance. In this work, effect of Gd on the microstructure, mechanical properties and biodegradation of as-cast Mg-2Zn-xGd-0.5Zr alloys was investigated. The results showed that there were mainly α-Mg, I-phase, W-phase and MgZn2 phase in Mg-Zn-Gd-Zr alloys. With increase of the Gd content, the strength of the alloys was enhanced due to the second phase strengthening and grain refinement. The degradation resistance of Mg-2Zn-0.5Zr alloy was increased by adding 0.5%–1% Gd due to the uniformly distributed second phases which acted as a barrier to prevent the pitting corrosion. However, increasing Gd content to 2% reduced the degradation resistance of the alloy due to the galvanic corrosion between the matrix and the second phases.The good degradation resistance and mechanical properties of as-cast Mg-2Zn-1Gd-0.5Zr alloy makes it outstanding for biomaterial application.
基金financially supported by the National Natural Science Foundation of China(No.U1737102)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(No.2017QNRC001)+1 种基金the Shenyang Key R&D and Technology Transfer Program(No.Z18-0-027)the Key Program of China on Biomedical Materials Research and Tissue and Organ Replacement(Nos.2016YFC1101804 and 2016YFC1100604)。
文摘Biodegradable magnesium alloys have been turned out to be a promising candidate for orthopedic applications.In this study,the mechanical properties,degradation behaviorand cytocompatibility of MgZn-Zr-Nd and Mg-Zn-Zr-Y alloys were studied in comparison with pure Mg.Mechanical tests showed that the strength and ductility of Mg-Zn-Zr-Nd and Mg-Zn-Zr-Y alloys were excellent.The corrosion resistance analyzed by electrochemical test and immersion test in alpha modified eagle(α-MEM) medium with 10% fetal bovine serum(FBS) revealed the degradation of Mg-Zn-Zr-Nd and Mg-Zn-Zr-Y alloys were faster than pure Mg at an early stage but slowed down after long time immersion.The metal ion concentrations were consistent with the corrosion rate.Mg-Zn-Zr-Nd alloy shows better mechanical properties than pure Mg and better corrosion resistance than Mg-Zn-Zr-Y alloy.The direct and indirect in vitro tests with MC3 T3-E1 cells demonstrate that Mg-Zn-Zr-Nd shows the best cytocompatibility and osteogenesis.The results suggest that Mg-Zn-Zr-Nd alloy shows an ideal combination of mechanical,corrosive and biological properties.In summary,these results implying the Mg-Zn-Zr-Nd alloy has great potential to benefit the future development of orthopedic applications.
基金the financial support of the National Basic Research Program of China(973 Program,No.2012CB619101)the Basic Application Research of Yunnan Province(No. KKSA201151053)
文摘A fluoride conversion coating was successfully prepared on AZ31B magnesium alloy by chemical reaction in hydrofluoric acid. Morphologies, composition, bonding strength, corrosion properties, in vitro cytotoxicity and antibacterial properties of the coating were investigated, respectively. The scanning electron microscopy observations revealed a dense coating with some irregular pores. The thin-film X-ray diffraction analysis indicated that the coating was mainly composed of MgO and MgF2. The electrochemical impedance spectroscopy results showed that the fluoride conversion coating significantly improved the corrosion resistance of AZ31B. The hydroxyapatite formed on the surface of the fluoride coated AZ31 B after being immersed in the simulated blood plasma indicated the good bioactivity of the material. The in vitro cytotoxicity test showed that the fluoride coated AZ31B alloy was not toxic to BMMSCs （human bone marrow-derived mesenchymal stem cells）. It was also found that the fluoride coated AZ31 B alloy had antibacterial capability.
基金finnacially supported by the Chinese Natural Science Foundation (No. 51874368)the Key Program of China on Biomedical Materials Research and Tissue and Organ Replacement (Nos. 2016YFC1101804 and 2016YFC1100604)Institute of Metal Research, Chinese Academy of Sciences (No. 2015-ZD01)
文摘The application of a single pass of friction stir processing(FSP) to Mg-Nd-Zn alloy resulted in grain refinement, texture evolution and redistribution of second phases, which improved corrosion resistance.In this work, an as-rolled Mg-Nd-Zn alloy was subjected to FSP. The microstructure in the processed zone of the FS-400 rpm alloy exhibited refined grains, a more homogenous grain size distribution, less second phases, and stronger basal plane texture. The corrosion behavior assessed using immersion tests and electrochemical tests in Hank’s solution indicated that the FS-400 rpm alloy had a lower corrosion rate, which was attributed to the increase of basal plane intensity and grain refinement. The hardness was lowered slightly and the elongation was increased, which might be attributed to the redistribution of the crushed second phases.
基金supported by Chinese Academy of Sciences (The Applied Research of Bioactive Bone Implantation Materials, No. KGCX2-YW-207)
文摘Three-dimensional honeycomb-structured magnesium （Mg） scaffolds with interconnected pores of accurately controlled pore size and porosity were fabricated by laser perforation technique. Biodegradable and bioactiveβ- tricalcium phosphate （β-TCP） coatings were prepared on and the biodegradation mechanism was simply evaluated the porous Mg to further improve its biocompatibility, in vitro. It was found that the mechanical properties of this type of porous Mg significantly depended on its porosity. Elastic modulus and compressive strength similar to human bones could be obtained for the porous Mg with porosity of 42.6%-51%. It was observed that the human osteosarcoma cells （UMR106） were well adhered and proliferated on the surface of the β- TCP coated porous Mg, which indicates that theβ-TCP coated porous Mg is promising to be a bone tissue engineering scaffold material.
基金supported by grants from The National Key Research and Development Program of China (No. 2020YFC1107501)National Natural Science Foundation of China (No. 51971222)+2 种基金STS program (No. 20201600200042)Dong Guan Innovative Research Team Program, the Natural Science Foundation of Liaoning Province (2021-BS-103)the China Postdoctoral Science Foundation Grant (2020M681020)。
文摘Magnesium(Mg) alloys have attracted a wealth of attention in orthopedic fields for their superior mechanical properties, degradability,and excellent biocompatibility. Consistently, to resolve the issues on rapid degradation, more studies are dedicated to the researches on the composition design, preparation and processing, surface modification, the degradation modes of Mg alloys. Nevertheless, the mechanisms by which Mg alloys promote bone healing remain elusive. This review gives an account of specific mechanisms on Mg alloys promoting bone healing from four aspects, immunomodulatory, angiogenesis, osteogenesis and regulation of osteoclast function. We highlight the regulation of Mg alloys on the functional status and interactions of numerous cells that are involved in bone healing, including immune cells, osteogenicrelated cells, osteoclasts, endothelial cells(ECs), nerve cells, etc., and summarize the signaling pathways involved, with the aim to provide the basis and support on future investigation on mechanisms on Mg alloys driving bone regeneration. More importantly, it provides a rationale and a general new basis for the application of Mg alloys in orthopedic fields.
基金supported financially by the Key Program of China on Biomedical Materials Research and Tissue and Organ Replacement(Nos.2016YFC11018 and 2016YFC1100604)the Shenyang Key R&D and Technology Transfer Program(No.Z18-0-027)the National Natural Science Foundation of China(No.51801220)。
文摘Torsional properties are important performance parameters for bone screw applications,but they are seldom studied,especially for newly developed biodegradable Mg alloys.In this study,WE43 Mg alloy with different microstructures was achieved by equal channel angular pressing(ECAP)and heat treatment,and their torsional properties were studied.In addition,tensile properties were also tested as a comparison.The results indicated that grain refinement led to higher torsional strength and ductility,while the second phases improved the torsional strength but reduced the ductility.The texture was strengthened after ECAP,as a result the tensile strength increased,but the torsional strength did not increase and even decreased,especially for 2-pass ECAP sample with a typical basal fiber texture.The basal plane orientation deviation from the extrusion direction after 4-pass ECAP resulted in higher torsional strength and lower torsional ductility,but lower tensile strength and higher tensile ductility were obtained.This implied that a strong fiber texture would reduce the torsional strength but improve the torsional ductility,which was different from its effect on tensile properties.
基金financially supported by the Key Program of China on Biomedical Materials Research and Tissue and Organ Replacement (Nos. 2016YFC1101804 and 2016YFC1100604)the Shenyang Key Research & Development and Technology Transfer Program (No. Z18-0-027)
文摘In the present work, the biodegradable behavior, cytocompatibility and osteogenesis activity of a Mg69Zn27Ca4 metal glass were investigated. Electrochemical test, immersion test, cytotoxicity test and histopathological evaluation were carried out. The results showed that there was a dense protective layer formed on the surface of Mg69Zn27Ca4 metal glass which could inhibit the degradation process in the Hank’s solution. In vitro cytotoxicity test showed that Mg69Zn27Ca4 metal glass had good biocompatibility. Histopathological evaluation showed that the degradation of Mg69Zn27Ca4 metal glass could promote the new bone formation with no obvious inflammatory reactions. After 2 months implantation, the diameter of the bone defect was reduced from the original φ6 mm to φ3.35 ± 0.40 mm with the degradation of Mg69Zn27Ca4 metal glass. Therefore, it can be concluded that Mg69Zn27Ca4 glass has great potential to be used as bone substitutes.
基金the financial support of the project from the National Basic Research Program(No.2012CB619101)the National Natural Science Foundation of China(No.30970715)
文摘In the present study, a Si-containing coating was fabricated on AZ31B Mg alloy. Cytocompatibility of the coated alloy was evaluated by both indirect and direct contact methods, respectively. Effects of a number of incubation variables on the sensitivity and reproducibility of the hemolysis test were also examined by using positively and negatively responding biomaterials. Cytocompatibility testing results indicated that cell condition, cell adherence, cell proliferation and extracellular matrix secretion of the coated alloy were improved compared with those of the uncoated alloy for different extraction and co-culture time. The hemolysis test suggested that hemolysis testing conditions were critical to determine the hemolysis of the alloy. It was also found that 1 day in vitro degradation of the uncoated AZ31B alloy had no destructive effect on erythrocyte. As for the coated AZ31B alloy at any time point, the hemolysis rate was much lower than 5%, the safe value for biomaterials. These in vitro experimental results indicate that the Si-containing coating is effective to improve the cytocompatibility and hemolysis behaviors of AZ31B alloy during its degradation.
基金the financial support of National Basic Research Program of China(973 Program,No.2012CB 619101)the National Natural Science Foundation of China (Nos.30970715 and 81101387)
文摘Bone graft substitutes are widely-studied as alternatives to bone grafts in the clinic. The currently available products are mostly ceramics and polymers. Considerable progress has been made in the study of the biodegradable magnesium alloys, which possess the necessary attributions of a suitable substitute, including an excellent mechanical property. In the present study, a minipig model of a lateral tibial plateau defect was used to evaluate the effectiveness of a magnesium alloy in the repair of a critical-sized defect. The micro-arc oxidation （MAO）-coated ZK60 alloy tablets and medical-grade calcium sulfate pellets were used as the test and control materials, respectively. Bone morphology was monitored by computed tomography after the implantation for 2 and 4 months. It was found that the bone morphology in minipigs following magnesium treatment was similar to that of the normal bone, whereas an abnormal and concave morphology was displayed following the calcium sulfate treatment. The average bone healing rate for the magnesium-treated defects was higher than that of the calcium sulfate-treated defects at the first 4 months following the implantation. Overall, magnesium treatment appeared to calcium sulfate treatment. Thus, the MAO-coated ZK60 al substitute, and further research on its biological activity in improve the defect repair as compared with the oy appears to be a useful biocompatible bone graft vivo is needed.
基金financially supported by the National Key Research and Development Program of China(No.2016YFC1101804,2016YFC1100604)Natural Science Foundation of Liaoning Province of China(No.2019-MS-326)Youth Innovation Promotion Association,CAS and National Natural Science Foundation of China(No.51971222,51801220)。
文摘Fine grained ZN20 alloy was obtained by combining equal-channel angular pressing(ECAP)with extrusion.Microstructural observation showed an obvious grain refinement with an average grain size of 10μm after ECAP.The original bimodal-grained structure composed of coarse grains with strong basal texture and fine grains with random texture was substituted by a new kind of bimodal-grained structure with finer grains and more random texture after 4 passes ECAP at 300℃.The combination of grain refinement and texture weakening caused the ductility can be increased by 40%compared with the as-extruded alloy.Immersion test in simulated intestinal fluid revealed an improvement of corrosion resistance after ECAP.Grain refinement can stable the corrosion product layer and basal texture is more beneficial for the corrosion resistance than the non-basal texture.
