BACKGROUND ATP-binding cassette subfamily B member 4(ABCB4)deficiency is associated with cholestatic liver disease primarily because of missense mutations,and many variants remain unidentified.Here,we validate the pat...BACKGROUND ATP-binding cassette subfamily B member 4(ABCB4)deficiency is associated with cholestatic liver disease primarily because of missense mutations,and many variants remain unidentified.Here,we validate the pathogenicity and mechanism of ABCB4 variants in clinical and in vitro trials,hypothesizing that these variants are responsible for impaired biliary function and contribute to the development of cholestatic liver diseases.AIM To clarify the functional features and pathogenicity of ABCB4 variants.METHODS Clinical data were collected from five patients with cholestatic liver disease that was initially not detected by routine examinations.Later,whole-exome sequencing confirmed ABCB4 variants and the patients were treated from January 2017 to December 2023.Pathogenic mechanisms were analyzed using bioinformatics tools,and a cell model in vitro was established to investigate ABCB4 mRNA expression,multidrug resistance protein 3(MDR3)expression,cellular localization,and phosphatidylcholine secretion.Results were compared using Student's t-tests.RESULTS Five missense variants(c.1757T>A,c.1865G>A,c.2362C>T,c.2777C>T and c.3250C>T),one intron variant(c.537-32G>T),and one synonymous(c.C504T)variant were identified.Three of the five patients had various degrees of cholestasis,two presented with liver cirrhosis,and all had elevated gamma-glutamyl transferase.Three of the four patients who underwent a liver biopsy had bile duct dilation,and one had gallstones.Two of the four patients had normal and reduced MDR3 immunohistochemical levels.Bioinformatic analysis indicated that these variants were likely pathogenic except c.C504T variant.None of the missense variants influenced subcellular MDR3 Localization in vitro.However,the c.1865G>A variant significantly decreased ABCB4 mRNA values,and all missense variants down-regulated phosphatidylcholine secretion.CONCLUSION This study uncovered new ABCB4 variants and emphasized the pathogenic potential of specific variants.The findings from five patients provided insight into the pathogenic mechanisms underlying ABCB4-related diseases.展开更多
Additive manufacturing (AM) of zinc-based biodegradable materials is a hot research topic,especially for bone-scaffold applications,because of the moderate degradation rate,good biocompatibility,and suitable mechanica...Additive manufacturing (AM) of zinc-based biodegradable materials is a hot research topic,especially for bone-scaffold applications,because of the moderate degradation rate,good biocompatibility,and suitable mechanical properties of these materials.Furthermore,AM enables the fabrication of complex internal structures suitable for implants.Literature on the AM of degradable zinc-based biomaterials from the Web of Science Core Collection was evaluated in this review.The bibliometric tool CiteSpace was used to analyze historical characteristics,evolving research topics,and emerging trends in this field.Our research results predict that the composition,processing techniques,in vitro biocompatibility,and manufacturing quality of biodegradable AM zinc-basedmaterials will continue to be hot topics in recent years.To address implant requirements,particularly for bone-repair materials,the mechanical properties of materials (including the resistance to degradation,creep,and aging),degradation rates,in-vivo biocompatibility,and specialized processing techniques that affect these properties (such as coating processes,heat treatments,material surface structures,and micros truc tural compositions) will become hot research topics in the future.We propose future research directions based on an in-depth analysis of four main topics of AM biodegradable zinc-based materials (manufacturing quality,material composition,unit configuration,and biocompatibility).The findings provide important guidance for future theoretical research and industrial development of AM zinc-based biomaterials.展开更多
Peri-implantitis is a bacterial infection that causes soft tissue inflammatory lesions and alveolar bone resorption,ultimately resulting in implant failure.Dental implants for clinical use barely have antibacterial pr...Peri-implantitis is a bacterial infection that causes soft tissue inflammatory lesions and alveolar bone resorption,ultimately resulting in implant failure.Dental implants for clinical use barely have antibacterial properties,and bacterial colonization and biofilm formation on the dental implants are major causes of peri-implantitis.Treatment strategies such as mechanical debridement and antibiotic therapy have been used to remove dental plaque.However,it is particularly important to prevent the occurrence of peri-implantitis rather than treatment.Therefore,the current research spot has focused on improving the antibacterial properties of dental implants,such as the construction of specific micro-nano surface texture,the introduction of diverse functional coatings,or the application of materials with intrinsic antibacterial properties.The aforementioned antibacterial surfaces can be incorporated with bioactive molecules,metallic nanoparticles,or other functional components to further enhance the osteogenic properties and accelerate the healing process.In this review,we summarize the recent developments in biomaterial science and the modification strategies applied to dental implants to inhibit biofilm formation and facilitate bone-implant integration.Furthermore,we summarized the obstacles existing in the process of laboratory research to reach the clinic products,and propose corresponding directions for future developments and research perspectives,so that to provide insights into the rational design and construction of dental implants with the aim to balance antibacterial efficacy,biological safety,and osteogenic property.展开更多
Osteoporotic fractures often exhibit delayed healing and repair difficulties in which the bone immune microenvironment may play a critical role,but direct evidence remains elusive.Recently,magnesium(Mg)-based alloys h...Osteoporotic fractures often exhibit delayed healing and repair difficulties in which the bone immune microenvironment may play a critical role,but direct evidence remains elusive.Recently,magnesium(Mg)-based alloys have emerged as promising biodegradable materials capable of promoting fracture healing.Herein,we performed internal fixation of high-purity Mg implants for osteoporotic fractures and used single-cell studies to investigate and elucidate the cellular heterogeneity and dynamic changes that occurred during osteoporotic fracture repair.We observed an early increase in immature neutrophil numbers,together with anti-inflammatory changes in lymphocytes and macrophages.A cluster of macrophages exhibited pro-angiogenic capabilities activated via the TRPM7/S100A4 pathway.These findings provide new theoretical insights into the biological effects of Mg-based materials on the healing of osteoporotic fractures.展开更多
The clinic applications of bioabsorbable magnesium(Mg)and its alloys have been significantly restricted owing to their poor corrosion resistance.Besides elemental alloying,surface modification and functionality is a m...The clinic applications of bioabsorbable magnesium(Mg)and its alloys have been significantly restricted owing to their poor corrosion resistance.Besides elemental alloying,surface modification and functionality is a major approach to increasing corrosion resistance for magnesium alloys.This article reviews the cutting-edge advances and progress of biodegradable surface coatings upon Mg alloys over the last decades,aims to build up a knowledge framework of surface modification on biodegradable Mg alloys.A considerable number of conversion,deposition,mechanical and functional coatings and their preparation methods are discussed.The emphasis has been placed on the composition of chemical conversion and deposited coatings to overcome the disadvantages of adhesion,corrosion resistance and biocompatibility of a single coating for biomedical materials.The issues have been addressed on the integration of the structural and functional factors of the composite coatings.展开更多
Magnesium(Mg)alloys as a bioabsorbable light metal have shown great clinical potential as bone replacement implants.In this review,the categories,progress in cutting-edge preparation technologies and antibacterial mec...Magnesium(Mg)alloys as a bioabsorbable light metal have shown great clinical potential as bone replacement implants.In this review,the categories,progress in cutting-edge preparation technologies and antibacterial mechanisms of Mg alloys and considerable numbers of corrosion-resistant and functional coatings are summarized.The relationship among the microstructure(grain size,intermetallic compounds),biocorrosion resistance and biocompatibility for antibacterial Mg alloys is discussed.The challenge and outlooks of biomedical Mg alloys and coatings are proposed from an antibacterial perspective.展开更多
A TiO2 nanofilm was prepared on the surface of AZ31 magnesium alloy with controllable thickness through atomic layer deposition(ALD) technique, which can adjust the corrosion behaviors of AZ31 Mg alloy.Compared with t...A TiO2 nanofilm was prepared on the surface of AZ31 magnesium alloy with controllable thickness through atomic layer deposition(ALD) technique, which can adjust the corrosion behaviors of AZ31 Mg alloy.Compared with the untreated Mg alloys, corrosion current densities(icorr)can decline by 58% in the 200-cycles TiO2-covered Mg alloy and further decline by up to 74% with the thickness of nanofilm up to 63 nm(400 cycles).The subsequent modification with a cross-linked conversion layer of 3-aminopropyltriethoxysilane(APTES) by a dipping method can produce a compact silane coating on TiO2 nanofilm, which can seal pinholes of TiO2 nanofilm and serve as a barrier to further adjust the corrosion behavior of the substrate.The icorrcan decline about two orders of magnitude in the TiO2/silane composite coating.Making the adjustable corrosion rate come true, which can be attributed to the precise control on the thickness of metal oxide nanofilm and additional protection from the compact silane coating.In vitro study discloses that the TiO2/silane hybrid coating shows higher expression of alkaline phosphatase(ALP)and can promote cellular adhesion and proliferation with better cytocompatibility than untreated Mg alloy.展开更多
Organic coatings are the most widely employed approach for the promotion of corrosion resistance of magnesium(Mg)alloys.Unfortunately,traditional organic coatings are weakly bonded to Mg substrates due to physical ads...Organic coatings are the most widely employed approach for the promotion of corrosion resistance of magnesium(Mg)alloys.Unfortunately,traditional organic coatings are weakly bonded to Mg substrates due to physical adsorption.Herein,a polyethylacrylate(PEA)coating was fabricated on Mg-Zn-YNd alloy via electro-grafting.The surface structure and chemical composition were characterized by means of scanning electron microscope(SEM),energy dispersive X-ray spectroscopy(EDS),atomic force microscope(AFM)and Fourier transform infrared(FTIR)as well as time of flight-secondary ion mass spectrometer(To F-SIMS).The results showed that the surface roughness of PEA coating was dominated by scan rate;while the coverage and integrity of PEA coating were mainly affected by the monomer concentration and sweep circles.To F-SIMS results indicated that PEA coating was wholly covered on Mg alloy,and the presence of C2H3Mg-fragment confirmed the covalent bond between PEA coating and Mg alloy.In addition,DFT calculation results of the adsorption of EA molecules with Mg substrate agree well with the experimental phenomena and observation,suggesting that the electrons in 3s orbit of Mg atoms and 2pz orbit of C1 atom participated in the formation of covalent bond between PEA coating and Mg substrate.Potentiodynamic polarization curves and immersion test demonstrated that the PEA coatings could effectively enhance the corrosion resistance of Mg alloy.The platelet adhesion results designated that platelets were barely visible on PEA coating,which implied that PEA coating could effectively prevent the thrombosis and coagulation of platelets.PEA coating might be a promising candidate coating of Mg alloy for cardiovascular stent.展开更多
The microstructure, mechanical properties and electrical conductivity of the room-temperature and cryogenically rolled Cu-0.2wt.%Mg alloy were investigated by transmission electron microscopy (TEM), electron backscatt...The microstructure, mechanical properties and electrical conductivity of the room-temperature and cryogenically rolled Cu-0.2wt.%Mg alloy were investigated by transmission electron microscopy (TEM), electron backscattered diffraction (EBSD), hardness measurement, tensile tests and electrical conductivity measurement. The results show that for the cryorolled sample, the grain size is decreased by 41% compared with the sample processed at room temperature. With increasing thickness reduction, the microhardness of the alloy continuously increases and the electrical conductivity decreases. For the sample with 90% thickness reduction rolled at cryogenic temperature, the tensile strength and the electrical conductivity are 726 MPa and 74.5% IACS, respectively. The improved tensile strength can be mainly attributed to the grain boundaries strengthening and dislocation strengthening.展开更多
Mg alloys possess biodegradability,suitable mechanical properties,and biocompatibility,which make them possible to be used as biodegradable implants.However,the uncontrollable degradation of Mg alloys limits their gen...Mg alloys possess biodegradability,suitable mechanical properties,and biocompatibility,which make them possible to be used as biodegradable implants.However,the uncontrollable degradation of Mg alloys limits their general applications.In addition to the factors from the metallic materials themselves,like alloy compositions,heat treatment process and microstructure,some external factors,relating to the test/service environment,also affect the degradation rate of Mg alloys,such as inorganic salts,bioorganic small molecules,bioorganic macromolecules.The influence of bioorganic molecules on Mg corrosion and its protection has attracted more and more attentions.In this work,the cutting-edge advances in the influence of bioorganic molecules(i.e.,protein,glucose,amino acids,vitamins and polypeptide)and their coupling effect on Mg degradation and the formation of protection coatings were reviewed.The research orientations of biomedical Mg alloys in exploring degradation mechanisms in vitro were proposed,and the impact of bioorganic molecules on the protective approaches were also explored.展开更多
In the present study,the effect of Zn content on the microstructure and deformation behavior of the as-cast Mg-Zn-Y-Nd alloy has been investigated.The results showed that as Zn content increased,the volume fraction of...In the present study,the effect of Zn content on the microstructure and deformation behavior of the as-cast Mg-Zn-Y-Nd alloy has been investigated.The results showed that as Zn content increased,the volume fraction of secondary phases increased.Moreover,the phase transformation from W-phase to W-phase and I-phase occurred.In the as-cast state,W-phase exists as eutectic and large block form.When Zn content increases to 6 and 8%（wt%）,small I-phase could precipitate around W-phase particles.Additionally,the effect of Zn content on the tensile properties and deformation behavior varies with the testing temperature.At room temperature,the tensile strength increases with Zn content,whereas the elongation increases initially and then decreases.At 250℃,as Zn content increases,the tensile strength decreases initially and then increases slightly,whereas the elongation decreases.At 350℃,the elongation increases with Zn content,whereas the tensile strength decreases initially and then increases slightly.展开更多
Controlling the corrosion rate is critical for practical applications of Mg-based alloys. In this work, we constructed a protective coating of hybrid polycaprolactone(H-PCL)/indocyanine green(ICG) on AZ31 Mg alloy,who...Controlling the corrosion rate is critical for practical applications of Mg-based alloys. In this work, we constructed a protective coating of hybrid polycaprolactone(H-PCL)/indocyanine green(ICG) on AZ31 Mg alloy,whose degradation rate was controlled by 808-nm nearinfrared(NIR) light irradiation. The corrosion behaviors of H-PCL/ICG coated Mg alloys were systematically investigated by potentiodynamic polarization tests, electrochemical impedance spectroscopy(EIS) and hydrogen evolution experiments. The results disclosed that the H-PCL/ICG composite coating could effectively protect Mg alloy from corroding without NIR light irradiation. In contrast, under 808-nm NIR light irradiation, the corrosion resistance of this composite coating was decreased significantly, i.e., the corrosion current density(i_(corr))increasedfrom(8.81 ± 1.068) 9 10^(-8) to(1.22 ± 0.545) 9 10^(-6) A·cm^(-2). This is because the component of ICG in the coating was excited to produce heat locally, which triggered the glass transition temperature(T_(g)) of H-PCL in the coating, resulting in the motion of the molecular chain segment. Consequently, the electrolytes penetrated the coating and corroded the Mg substrate. In vitro biological experiment indicated that the synthesized coating exhibited good cytocompatibility.Hence, these findings will provide a new strategy for designing novel photoresponsive coatings to remotely adjust the degradation rate of biodegradable metals for biomedical applications.展开更多
Abdominal aortic aneurysm(AAA) is one of the most common and catastrophic manifestations of the acute aortic syndrome that can be treated with endovascular aneurysm repair(EVAR) which requires a specially designed ste...Abdominal aortic aneurysm(AAA) is one of the most common and catastrophic manifestations of the acute aortic syndrome that can be treated with endovascular aneurysm repair(EVAR) which requires a specially designed stent-graft system.In this work, a self-expanding nickel–titanium(nitinol) stent-graft system is aiming at AAA using finite element analysis(FEA) methods to analyze both fatigue behaviors and radial forces.Based on the systematic analysis of the parametric variations, a final stent-graft system was developed by the selection and arrangement of the individual stent components, targeting an optimal performance for the treatment of AAA.Experimental tests, animal tests and clinical trials were carried out to confirm the results.Both animal trials and clinical trials showed comparable curative effects with Medtronic Endurant stent-graft(SG) systems.展开更多
Deep tissue infections caused by pathogenic bacteria seriously threat the lives of patients.In this study a smart heterostructured Au/Cu-BTA(BTA=1,2,4,5-benzenetetramine)with microwave(MW)response is synthesized via N...Deep tissue infections caused by pathogenic bacteria seriously threat the lives of patients.In this study a smart heterostructured Au/Cu-BTA(BTA=1,2,4,5-benzenetetramine)with microwave(MW)response is synthesized via NaBH_(4)reduction of HAuCl_(4)on the Cu-BTA.Au/Cu-BTA exhibits excellent hyperthermy and dynamics under MW irradiation.The MW thermal mechanism of Au/Cu-BTA is attributed to the excellen dielectric loss and polarization of the heterogeneous interface.Meanwhile,the surface energy levels of the Cu-BTA interface alleviate the difficulty of electron hopping through multistage transition.Therefore,MW can excite Cu-BTA to produce free electrons.Subsequently,Au nanoparticles rapidly increase electron transfer and inhibit electron-hole recombination.Hence,the yields of reactive oxygen species can be enhanced for MW dynamic therapy Consequently,under 10 min of MW irradiation,Au/Cu-BTA killed 99.998%±0.001% of Gram-positive Staphylococcus aureus,99.966%±0.014% of methicillin-resistant Staphylococcus aureus,and 96.871%±0.831% of Gram-negative Pseudomonas aeruginosa.The effective MW bacteria-killing strategy designed in this study shows significant potential for application in the MW-responsive treatment of deep tissue infections without antibiotics.展开更多
The influences of die parameters on shear strain were investigated by using two-dimensional finite element simulation.New formulas of shear strain were proposed.According to the results of formulas,the shear strain sh...The influences of die parameters on shear strain were investigated by using two-dimensional finite element simulation.New formulas of shear strain were proposed.According to the results of formulas,the shear strain showed a linear dependence on the difference between internal and external fillet radius and the slope was determined by the intersection angle.The simulation results indicated that the velocities of the points from different zones were different in the specimen and the motion trajectories of different points did not follow geometrical laws.The influences of the average velocity and the motion trajectory on shear strain were incorporated in the formula to calculate the shear strain produced during equalchannel angular pressing process.The reliability of simulation results has been partially validated by experiments.展开更多
Martensitic transformation, microstructure, and magnetic properties of Ti-doped Ni43-xTixCo7Mn43Sn7（at%）（x = 0, 0.5, 1.0, 2.0, and 4.0） shape memory alloys were investigated. The results show that transformation t...Martensitic transformation, microstructure, and magnetic properties of Ti-doped Ni43-xTixCo7Mn43Sn7（at%）（x = 0, 0.5, 1.0, 2.0, and 4.0） shape memory alloys were investigated. The results show that transformation temperatures of Ni43Co7Mn43Sn7 can be efficiently adjusted by the substitution of Ti for Ni. For example, the martensitic transformation starting temperature（Ms） is reduced by about 278 K with 4 at% addition of Ti. Room temperature microstructure evolves from single tetragonal martensite for the Ti-free alloy to dual phases（tetragonal martensite ＋ second phase） with 0.5 at%, 1.0 at%, and2.0 at% addition of Ti to dual phases（cubic austenite ＋ second phase） for 4.0 at% Ti-doped alloy. The mechanical properties can be obviously improved by adding an appropriate amount of Ti. A noteworthy point is that magnetic-field-induced reverse transformation is observed in Ni39Ti4Co7Mn43Sn7 alloy.展开更多
In the present work, a CuCrZr alloy characterized by ultrafine grains and nanoscale particles was prepared by equalchannel angular pressing （ECAP） at 450℃. A desired combination of a tensile strength （580 MPa） an...In the present work, a CuCrZr alloy characterized by ultrafine grains and nanoscale particles was prepared by equalchannel angular pressing （ECAP） at 450℃. A desired combination of a tensile strength （580 MPa） and an electrical conductivity （81% International Annealed Copper Standard） is simultaneously obtained in the as-ECAP-processed CuCrZr alloy without additional aging treatment. The improved properties can be mainly attributed to the ultrafine grains and nanoscale precipitates. This processing may pave a way to develop the CuCrZr alloys having high strength and high electrical conductivity for engineering applications.展开更多
Currently,the widely investigated Mg,Fe and their alloys are facing the corrosion rate problems,either too fast or too slow.Zn has standard electrode potentials between Mg and Fe,implying a more apposite degradation r...Currently,the widely investigated Mg,Fe and their alloys are facing the corrosion rate problems,either too fast or too slow.Zn has standard electrode potentials between Mg and Fe,implying a more apposite degradation rate[1].Moreover,Zn is an essen-展开更多
Protein exerts a critical influence on the degradation behavior of absorbable magnesium(Mg)-based implants.However,the interaction mechanism between protein and a micro-arc oxidation(MAO)coating on Mg alloys remains u...Protein exerts a critical influence on the degradation behavior of absorbable magnesium(Mg)-based implants.However,the interaction mechanism between protein and a micro-arc oxidation(MAO)coating on Mg alloys remains unclear.Hereby,a MAO coating was fabricated on AZ31 Mg alloy.And its degradation behavior in phosphate buffer saline(PBS)containing bovine serum albumin(BSA)was investigated and compared with that of the uncoated alloy.Surface morphologies and chemical compositions were studied using Field-emission scanning electron microscope(FE-SEM),Fourier transform infrared spectrophotometer(FT-IR)and X-ray diffraction(XRD).The degradation behavior of the bare Mg alloy and its MAO coating was studied through electrochemical and hydrogen evolution tests.Cytotoxicity assay was applied to evaluate the biocompatibility of Mg alloy substrate and MAO coating.Results indicated that the presence of BSA decreased the degradation rate of Mg alloy substrate because BSA(RCH(NH2)COO‾)molecules combined with Mg2+ions to form(RCH(NH2)COO)2Mg and thus inhibited the dissolution of Mg(OH)2 by impeding the attack of Cl‾ions.In the case of MAO coated Mg alloy,the adsorption of BSA on MAO coating and the formation of(RCH(NH2)COO)2Mg exhibited a synergistic effect and enhanced the corrosion resistance of the coated alloy significantly.Furthermore,cell bioactive assay suggested that the MAO coating had good viability for MG63 cells due to its high surface area.展开更多
基金Supported by the National Natural Science Foundation of China,No.81970454.
文摘BACKGROUND ATP-binding cassette subfamily B member 4(ABCB4)deficiency is associated with cholestatic liver disease primarily because of missense mutations,and many variants remain unidentified.Here,we validate the pathogenicity and mechanism of ABCB4 variants in clinical and in vitro trials,hypothesizing that these variants are responsible for impaired biliary function and contribute to the development of cholestatic liver diseases.AIM To clarify the functional features and pathogenicity of ABCB4 variants.METHODS Clinical data were collected from five patients with cholestatic liver disease that was initially not detected by routine examinations.Later,whole-exome sequencing confirmed ABCB4 variants and the patients were treated from January 2017 to December 2023.Pathogenic mechanisms were analyzed using bioinformatics tools,and a cell model in vitro was established to investigate ABCB4 mRNA expression,multidrug resistance protein 3(MDR3)expression,cellular localization,and phosphatidylcholine secretion.Results were compared using Student's t-tests.RESULTS Five missense variants(c.1757T>A,c.1865G>A,c.2362C>T,c.2777C>T and c.3250C>T),one intron variant(c.537-32G>T),and one synonymous(c.C504T)variant were identified.Three of the five patients had various degrees of cholestasis,two presented with liver cirrhosis,and all had elevated gamma-glutamyl transferase.Three of the four patients who underwent a liver biopsy had bile duct dilation,and one had gallstones.Two of the four patients had normal and reduced MDR3 immunohistochemical levels.Bioinformatic analysis indicated that these variants were likely pathogenic except c.C504T variant.None of the missense variants influenced subcellular MDR3 Localization in vitro.However,the c.1865G>A variant significantly decreased ABCB4 mRNA values,and all missense variants down-regulated phosphatidylcholine secretion.CONCLUSION This study uncovered new ABCB4 variants and emphasized the pathogenic potential of specific variants.The findings from five patients provided insight into the pathogenic mechanisms underlying ABCB4-related diseases.
基金financially supported by grants from the National Key Technology R&D Program of China(No.2023YFB3810100)the National Natural Science Foundation of China(Nos.32471366,12302406,82270535)+2 种基金Science and Technology Innovation Project of JinFeng LaboratoryChongqingChina(No.jfkyjf202203001)
文摘Additive manufacturing (AM) of zinc-based biodegradable materials is a hot research topic,especially for bone-scaffold applications,because of the moderate degradation rate,good biocompatibility,and suitable mechanical properties of these materials.Furthermore,AM enables the fabrication of complex internal structures suitable for implants.Literature on the AM of degradable zinc-based biomaterials from the Web of Science Core Collection was evaluated in this review.The bibliometric tool CiteSpace was used to analyze historical characteristics,evolving research topics,and emerging trends in this field.Our research results predict that the composition,processing techniques,in vitro biocompatibility,and manufacturing quality of biodegradable AM zinc-basedmaterials will continue to be hot topics in recent years.To address implant requirements,particularly for bone-repair materials,the mechanical properties of materials (including the resistance to degradation,creep,and aging),degradation rates,in-vivo biocompatibility,and specialized processing techniques that affect these properties (such as coating processes,heat treatments,material surface structures,and micros truc tural compositions) will become hot research topics in the future.We propose future research directions based on an in-depth analysis of four main topics of AM biodegradable zinc-based materials (manufacturing quality,material composition,unit configuration,and biocompatibility).The findings provide important guidance for future theoretical research and industrial development of AM zinc-based biomaterials.
基金supported by the National Key Research and Development Program of China(2023YFC2412600)the National Natural Science Foundation of China(52271243,52171233,82370924,82170929)+3 种基金the Beijing Natural Science Foundation(L212014)the Beijing Nova Program(20230484459)the National Clinical Key Discipline Construction Project(PKUSSNKP-T202103)the Research Foundation of Peking University School and Hospital of Stomatology(PKSS20230104).
文摘Peri-implantitis is a bacterial infection that causes soft tissue inflammatory lesions and alveolar bone resorption,ultimately resulting in implant failure.Dental implants for clinical use barely have antibacterial properties,and bacterial colonization and biofilm formation on the dental implants are major causes of peri-implantitis.Treatment strategies such as mechanical debridement and antibiotic therapy have been used to remove dental plaque.However,it is particularly important to prevent the occurrence of peri-implantitis rather than treatment.Therefore,the current research spot has focused on improving the antibacterial properties of dental implants,such as the construction of specific micro-nano surface texture,the introduction of diverse functional coatings,or the application of materials with intrinsic antibacterial properties.The aforementioned antibacterial surfaces can be incorporated with bioactive molecules,metallic nanoparticles,or other functional components to further enhance the osteogenic properties and accelerate the healing process.In this review,we summarize the recent developments in biomaterial science and the modification strategies applied to dental implants to inhibit biofilm formation and facilitate bone-implant integration.Furthermore,we summarized the obstacles existing in the process of laboratory research to reach the clinic products,and propose corresponding directions for future developments and research perspectives,so that to provide insights into the rational design and construction of dental implants with the aim to balance antibacterial efficacy,biological safety,and osteogenic property.
基金financially supported by the National Natural Science Foundation of China(Nos.81871742 and 82102538)Shanghai Sailing Program(No.21YF1405800)+2 种基金Shanghai Pudong Science and Technology Development Funding(No.PKJ2020-Y44)the Featured Clinical Discipline Project of Shanghai Pudong New District(No.Pwyts2021-03)the support of the National Engineering Research Center of Light Alloy Net Forming,Shanghai Jiao Tong University
文摘Osteoporotic fractures often exhibit delayed healing and repair difficulties in which the bone immune microenvironment may play a critical role,but direct evidence remains elusive.Recently,magnesium(Mg)-based alloys have emerged as promising biodegradable materials capable of promoting fracture healing.Herein,we performed internal fixation of high-purity Mg implants for osteoporotic fractures and used single-cell studies to investigate and elucidate the cellular heterogeneity and dynamic changes that occurred during osteoporotic fracture repair.We observed an early increase in immature neutrophil numbers,together with anti-inflammatory changes in lymphocytes and macrophages.A cluster of macrophages exhibited pro-angiogenic capabilities activated via the TRPM7/S100A4 pathway.These findings provide new theoretical insights into the biological effects of Mg-based materials on the healing of osteoporotic fractures.
基金This research was financially supported by National Natural Science Foundation of China(51571134)SDUST Research Fund(2014TDJH104).
文摘The clinic applications of bioabsorbable magnesium(Mg)and its alloys have been significantly restricted owing to their poor corrosion resistance.Besides elemental alloying,surface modification and functionality is a major approach to increasing corrosion resistance for magnesium alloys.This article reviews the cutting-edge advances and progress of biodegradable surface coatings upon Mg alloys over the last decades,aims to build up a knowledge framework of surface modification on biodegradable Mg alloys.A considerable number of conversion,deposition,mechanical and functional coatings and their preparation methods are discussed.The emphasis has been placed on the composition of chemical conversion and deposited coatings to overcome the disadvantages of adhesion,corrosion resistance and biocompatibility of a single coating for biomedical materials.The issues have been addressed on the integration of the structural and functional factors of the composite coatings.
基金supported by the National Natural Science Foundation of China(No.51571134)the Shandong University of Science and Technology Research Fund(No.2014TDJH104)
文摘Magnesium(Mg)alloys as a bioabsorbable light metal have shown great clinical potential as bone replacement implants.In this review,the categories,progress in cutting-edge preparation technologies and antibacterial mechanisms of Mg alloys and considerable numbers of corrosion-resistant and functional coatings are summarized.The relationship among the microstructure(grain size,intermetallic compounds),biocorrosion resistance and biocompatibility for antibacterial Mg alloys is discussed.The challenge and outlooks of biomedical Mg alloys and coatings are proposed from an antibacterial perspective.
基金financially supported by the Natural Science Fund of Hubei Province (No.2018CFA064)the National Natural Science Foundation of China (NSFC) (Nos.51671081 and 51422102)+4 种基金the National Key Research and Development Program of China (No.2016YFC1100600, sub-project 2016YFC1100604)the Hong Kong Research Grants Council (RGC) General Research Funds (GRF) (Nos.11301215, 11205617 and 17214516)RGC/NSFC (N_HKU725-16)the Hong Kong Innovation and Technology Commission (ITC) (Nos.ITS/287/17 and GHX/002/14SZ)the Health and Medical Research Fund (No.03142446)
文摘A TiO2 nanofilm was prepared on the surface of AZ31 magnesium alloy with controllable thickness through atomic layer deposition(ALD) technique, which can adjust the corrosion behaviors of AZ31 Mg alloy.Compared with the untreated Mg alloys, corrosion current densities(icorr)can decline by 58% in the 200-cycles TiO2-covered Mg alloy and further decline by up to 74% with the thickness of nanofilm up to 63 nm(400 cycles).The subsequent modification with a cross-linked conversion layer of 3-aminopropyltriethoxysilane(APTES) by a dipping method can produce a compact silane coating on TiO2 nanofilm, which can seal pinholes of TiO2 nanofilm and serve as a barrier to further adjust the corrosion behavior of the substrate.The icorrcan decline about two orders of magnitude in the TiO2/silane composite coating.Making the adjustable corrosion rate come true, which can be attributed to the precise control on the thickness of metal oxide nanofilm and additional protection from the compact silane coating.In vitro study discloses that the TiO2/silane hybrid coating shows higher expression of alkaline phosphatase(ALP)and can promote cellular adhesion and proliferation with better cytocompatibility than untreated Mg alloy.
基金the Key Projects of the Joint Fund of the National Natural Science Foundation of China(No.U1804251)the National Natural Foundation of China(No.51671175)+1 种基金the National Key Research and Development Program of China(No.2017YFB0702500)the Key Research Projects for Universities of Henan Province(No.15A430050)。
文摘Organic coatings are the most widely employed approach for the promotion of corrosion resistance of magnesium(Mg)alloys.Unfortunately,traditional organic coatings are weakly bonded to Mg substrates due to physical adsorption.Herein,a polyethylacrylate(PEA)coating was fabricated on Mg-Zn-YNd alloy via electro-grafting.The surface structure and chemical composition were characterized by means of scanning electron microscope(SEM),energy dispersive X-ray spectroscopy(EDS),atomic force microscope(AFM)and Fourier transform infrared(FTIR)as well as time of flight-secondary ion mass spectrometer(To F-SIMS).The results showed that the surface roughness of PEA coating was dominated by scan rate;while the coverage and integrity of PEA coating were mainly affected by the monomer concentration and sweep circles.To F-SIMS results indicated that PEA coating was wholly covered on Mg alloy,and the presence of C2H3Mg-fragment confirmed the covalent bond between PEA coating and Mg alloy.In addition,DFT calculation results of the adsorption of EA molecules with Mg substrate agree well with the experimental phenomena and observation,suggesting that the electrons in 3s orbit of Mg atoms and 2pz orbit of C1 atom participated in the formation of covalent bond between PEA coating and Mg substrate.Potentiodynamic polarization curves and immersion test demonstrated that the PEA coatings could effectively enhance the corrosion resistance of Mg alloy.The platelet adhesion results designated that platelets were barely visible on PEA coating,which implied that PEA coating could effectively prevent the thrombosis and coagulation of platelets.PEA coating might be a promising candidate coating of Mg alloy for cardiovascular stent.
基金Project(51671064) supported by the National Natural Science Foundation of ChinaProject(HEUCFG201836) supported by the Fundamental Research Funds for the Central Universities,ChinaProject supported by the Key Laboratory of Superlight Materials & Surface Technology(Harbin Engineering University),Ministry of Education,China
文摘The microstructure, mechanical properties and electrical conductivity of the room-temperature and cryogenically rolled Cu-0.2wt.%Mg alloy were investigated by transmission electron microscopy (TEM), electron backscattered diffraction (EBSD), hardness measurement, tensile tests and electrical conductivity measurement. The results show that for the cryorolled sample, the grain size is decreased by 41% compared with the sample processed at room temperature. With increasing thickness reduction, the microhardness of the alloy continuously increases and the electrical conductivity decreases. For the sample with 90% thickness reduction rolled at cryogenic temperature, the tensile strength and the electrical conductivity are 726 MPa and 74.5% IACS, respectively. The improved tensile strength can be mainly attributed to the grain boundaries strengthening and dislocation strengthening.
基金National Natural Science Foundation of China(Grant No.52071191)Open Foundation of Hubei Key Laboratory of Advanced Technology for Automotive Components(No.XDQCKF2021006)。
文摘Mg alloys possess biodegradability,suitable mechanical properties,and biocompatibility,which make them possible to be used as biodegradable implants.However,the uncontrollable degradation of Mg alloys limits their general applications.In addition to the factors from the metallic materials themselves,like alloy compositions,heat treatment process and microstructure,some external factors,relating to the test/service environment,also affect the degradation rate of Mg alloys,such as inorganic salts,bioorganic small molecules,bioorganic macromolecules.The influence of bioorganic molecules on Mg corrosion and its protection has attracted more and more attentions.In this work,the cutting-edge advances in the influence of bioorganic molecules(i.e.,protein,glucose,amino acids,vitamins and polypeptide)and their coupling effect on Mg degradation and the formation of protection coatings were reviewed.The research orientations of biomedical Mg alloys in exploring degradation mechanisms in vitro were proposed,and the impact of bioorganic molecules on the protective approaches were also explored.
基金supported financially by the Shenzhen Technology Innovation Plan(Nos.CXZZ20140731091722497 and CXZZ20140419114548507)the Shenzhen Basic Research Project(Nos.JCYJ20150529162228734,JCYJ20160407090231002,JCYJ20150625155931806 and JCYJ20160427100211076)The Thirteen Five National Key Research and Development Plan(No.2016YFC1102601)
文摘In the present study,the effect of Zn content on the microstructure and deformation behavior of the as-cast Mg-Zn-Y-Nd alloy has been investigated.The results showed that as Zn content increased,the volume fraction of secondary phases increased.Moreover,the phase transformation from W-phase to W-phase and I-phase occurred.In the as-cast state,W-phase exists as eutectic and large block form.When Zn content increases to 6 and 8%（wt%）,small I-phase could precipitate around W-phase particles.Additionally,the effect of Zn content on the tensile properties and deformation behavior varies with the testing temperature.At room temperature,the tensile strength increases with Zn content,whereas the elongation increases initially and then decreases.At 250℃,as Zn content increases,the tensile strength decreases initially and then increases slightly,whereas the elongation decreases.At 350℃,the elongation increases with Zn content,whereas the tensile strength decreases initially and then increases slightly.
基金jointly supported by the Natural Science Fund of Hubei Province(No.2018CFA064)the National Natural Science Foundation of China(Nos.51871162 and 51671081)+3 种基金the National Science Fund for Distinguished Young Scholars(No.51925104)the Key Program of National Natural Science Foundation of China(No.51631007)Hong Kong ITC(Nos.ITS/287/17 and GHX/002/14SZ)the Health and Medical Research Fund(No.03142446)。
文摘Controlling the corrosion rate is critical for practical applications of Mg-based alloys. In this work, we constructed a protective coating of hybrid polycaprolactone(H-PCL)/indocyanine green(ICG) on AZ31 Mg alloy,whose degradation rate was controlled by 808-nm nearinfrared(NIR) light irradiation. The corrosion behaviors of H-PCL/ICG coated Mg alloys were systematically investigated by potentiodynamic polarization tests, electrochemical impedance spectroscopy(EIS) and hydrogen evolution experiments. The results disclosed that the H-PCL/ICG composite coating could effectively protect Mg alloy from corroding without NIR light irradiation. In contrast, under 808-nm NIR light irradiation, the corrosion resistance of this composite coating was decreased significantly, i.e., the corrosion current density(i_(corr))increasedfrom(8.81 ± 1.068) 9 10^(-8) to(1.22 ± 0.545) 9 10^(-6) A·cm^(-2). This is because the component of ICG in the coating was excited to produce heat locally, which triggered the glass transition temperature(T_(g)) of H-PCL in the coating, resulting in the motion of the molecular chain segment. Consequently, the electrolytes penetrated the coating and corroded the Mg substrate. In vitro biological experiment indicated that the synthesized coating exhibited good cytocompatibility.Hence, these findings will provide a new strategy for designing novel photoresponsive coatings to remotely adjust the degradation rate of biodegradable metals for biomedical applications.
基金supported by the National Key Research and Development Program of China (No.2018YFC1106600)
文摘Abdominal aortic aneurysm(AAA) is one of the most common and catastrophic manifestations of the acute aortic syndrome that can be treated with endovascular aneurysm repair(EVAR) which requires a specially designed stent-graft system.In this work, a self-expanding nickel–titanium(nitinol) stent-graft system is aiming at AAA using finite element analysis(FEA) methods to analyze both fatigue behaviors and radial forces.Based on the systematic analysis of the parametric variations, a final stent-graft system was developed by the selection and arrangement of the individual stent components, targeting an optimal performance for the treatment of AAA.Experimental tests, animal tests and clinical trials were carried out to confirm the results.Both animal trials and clinical trials showed comparable curative effects with Medtronic Endurant stent-graft(SG) systems.
基金financially supported by the China National Funds for Distinguished Young Scientists(No.51925104)the National Natural Science Foundation of China(No.52173251)+2 种基金NSFC-Guangdong Province Joint Program(Key program No.U21A2084)the Central Guidance on Local Science and Technology Development Fund of Hebei Province(No.226Z1303G)Yanzhao Young Scientist Project(No.C2023202018)and Beijing Natural Science Foundation(No.7232338)。
文摘Deep tissue infections caused by pathogenic bacteria seriously threat the lives of patients.In this study a smart heterostructured Au/Cu-BTA(BTA=1,2,4,5-benzenetetramine)with microwave(MW)response is synthesized via NaBH_(4)reduction of HAuCl_(4)on the Cu-BTA.Au/Cu-BTA exhibits excellent hyperthermy and dynamics under MW irradiation.The MW thermal mechanism of Au/Cu-BTA is attributed to the excellen dielectric loss and polarization of the heterogeneous interface.Meanwhile,the surface energy levels of the Cu-BTA interface alleviate the difficulty of electron hopping through multistage transition.Therefore,MW can excite Cu-BTA to produce free electrons.Subsequently,Au nanoparticles rapidly increase electron transfer and inhibit electron-hole recombination.Hence,the yields of reactive oxygen species can be enhanced for MW dynamic therapy Consequently,under 10 min of MW irradiation,Au/Cu-BTA killed 99.998%±0.001% of Gram-positive Staphylococcus aureus,99.966%±0.014% of methicillin-resistant Staphylococcus aureus,and 96.871%±0.831% of Gram-negative Pseudomonas aeruginosa.The effective MW bacteria-killing strategy designed in this study shows significant potential for application in the MW-responsive treatment of deep tissue infections without antibiotics.
基金Item Sponsored by Fundamental Research Funds for Central Universities of China(HEUCF20151002)
文摘The influences of die parameters on shear strain were investigated by using two-dimensional finite element simulation.New formulas of shear strain were proposed.According to the results of formulas,the shear strain showed a linear dependence on the difference between internal and external fillet radius and the slope was determined by the intersection angle.The simulation results indicated that the velocities of the points from different zones were different in the specimen and the motion trajectories of different points did not follow geometrical laws.The influences of the average velocity and the motion trajectory on shear strain were incorporated in the formula to calculate the shear strain produced during equalchannel angular pressing process.The reliability of simulation results has been partially validated by experiments.
基金financially supported by the National Natural Science Foundation of China (Nos. 51101040 and 51201044)the Scientific Research Fund of Heilongjiang Provincial Education Department (No. 12513046)
文摘Martensitic transformation, microstructure, and magnetic properties of Ti-doped Ni43-xTixCo7Mn43Sn7（at%）（x = 0, 0.5, 1.0, 2.0, and 4.0） shape memory alloys were investigated. The results show that transformation temperatures of Ni43Co7Mn43Sn7 can be efficiently adjusted by the substitution of Ti for Ni. For example, the martensitic transformation starting temperature（Ms） is reduced by about 278 K with 4 at% addition of Ti. Room temperature microstructure evolves from single tetragonal martensite for the Ti-free alloy to dual phases（tetragonal martensite ＋ second phase） with 0.5 at%, 1.0 at%, and2.0 at% addition of Ti to dual phases（cubic austenite ＋ second phase） for 4.0 at% Ti-doped alloy. The mechanical properties can be obviously improved by adding an appropriate amount of Ti. A noteworthy point is that magnetic-field-induced reverse transformation is observed in Ni39Ti4Co7Mn43Sn7 alloy.
基金supported by the National Natural Science Foundation of China(51671064)the Fundamental Research Funds for the Central UniversitiesKey Laboratory of Superlight Materials and Surface Technology(Harbin Engineering University),Ministry of Education
文摘In the present work, a CuCrZr alloy characterized by ultrafine grains and nanoscale particles was prepared by equalchannel angular pressing （ECAP） at 450℃. A desired combination of a tensile strength （580 MPa） and an electrical conductivity （81% International Annealed Copper Standard） is simultaneously obtained in the as-ECAP-processed CuCrZr alloy without additional aging treatment. The improved properties can be mainly attributed to the ultrafine grains and nanoscale precipitates. This processing may pave a way to develop the CuCrZr alloys having high strength and high electrical conductivity for engineering applications.
文摘Currently,the widely investigated Mg,Fe and their alloys are facing the corrosion rate problems,either too fast or too slow.Zn has standard electrode potentials between Mg and Fe,implying a more apposite degradation rate[1].Moreover,Zn is an essen-
基金supported by the National Natural Science Foundation of China(51571134)the SDUST Research Fund(2014TDJH104).
文摘Protein exerts a critical influence on the degradation behavior of absorbable magnesium(Mg)-based implants.However,the interaction mechanism between protein and a micro-arc oxidation(MAO)coating on Mg alloys remains unclear.Hereby,a MAO coating was fabricated on AZ31 Mg alloy.And its degradation behavior in phosphate buffer saline(PBS)containing bovine serum albumin(BSA)was investigated and compared with that of the uncoated alloy.Surface morphologies and chemical compositions were studied using Field-emission scanning electron microscope(FE-SEM),Fourier transform infrared spectrophotometer(FT-IR)and X-ray diffraction(XRD).The degradation behavior of the bare Mg alloy and its MAO coating was studied through electrochemical and hydrogen evolution tests.Cytotoxicity assay was applied to evaluate the biocompatibility of Mg alloy substrate and MAO coating.Results indicated that the presence of BSA decreased the degradation rate of Mg alloy substrate because BSA(RCH(NH2)COO‾)molecules combined with Mg2+ions to form(RCH(NH2)COO)2Mg and thus inhibited the dissolution of Mg(OH)2 by impeding the attack of Cl‾ions.In the case of MAO coated Mg alloy,the adsorption of BSA on MAO coating and the formation of(RCH(NH2)COO)2Mg exhibited a synergistic effect and enhanced the corrosion resistance of the coated alloy significantly.Furthermore,cell bioactive assay suggested that the MAO coating had good viability for MG63 cells due to its high surface area.
