Advancing biodegradable medical implants,along with an in-depth understanding of their degradation mechanisms,is critical to revolutionizing orthopedic medicine and improving patient outcomes.MgZnCa metallic glass(MG)...Advancing biodegradable medical implants,along with an in-depth understanding of their degradation mechanisms,is critical to revolutionizing orthopedic medicine and improving patient outcomes.MgZnCa metallic glass(MG)stands out among degradable metallic materials due to its superior potential for orthopedic applications than traditional crystalline alloys.Despite its advantages,there has been a lack of comprehensive insight into the degradation behavior of MgZnCa MG,particularly under conditions simulating daily activities of patients.In this work,the degradation mechanism of MgZnCa MG is elucidated,highlighting the formation of a distinctive Zn-rich amorphous layer that markedly decelerates the matrix degradation.Detailed analysis reveals that the unique amorphous structure of MgZnCa MG facilitates the selective dissolution of Mg and Ca,resulting in numerous vacancies within the matrix.These vacancies facilitate the inward migration of Zn atoms,culminating in the formation of a dense Zn-rich layer.This cyclical formation and dissolution of the Zn-rich layer serve as a buffer in the degradation pathway,thus ensuring a degradation rate for MgZnCa MG that is significantly slower than that of its crystalline counterparts.展开更多
There is an increasing interest in biodegradable materials,such as magnesium,for orthopaedic implants.This is driven by their potential to address challenges like stress shielding and the need for secondary removal su...There is an increasing interest in biodegradable materials,such as magnesium,for orthopaedic implants.This is driven by their potential to address challenges like stress shielding and the need for secondary removal surgery.In this study,biodegradable magnesium alloys were produced using the Vacuum Induction Casting technique.The impact of micro-alloying Zn and Ca in Mg-xZn-0.2Ca(x=0.1,0.2,0.3,and 0.4 wt%)alloys on corrosion resistance,cytocompatibility,and early-stage inflammatory response was investigated.XRD and SEM-EDS analysis confirmed the presence of Ca_(2)Mg_(6)Zn_(3)secondary phases in all alloys.The Mg-0.3Zn-0.2Ca alloy exhibited the lowest corrosion rate and an elastic modulus of 36.8 GPa,resembling that of natural bone.Electrochemical measurements indicated a correlation between grain size and secondary phase volume fraction in explaining corrosion behaviour.In vitro degradation in simulated body fluid(SBF)for 21 days showed hydroxyapatite formation on alloy surfaces,aligning with electrochemical studies.In vitro cytotoxicity tests demonstrated the cytocompatibility of all alloys,with Mg-0.3Zn-0.2Ca having the highest cell viability over a 6-day cell culture.Investigation into the inflammatory response with RAW-Blue macrophages revealed the anti-inflammatory properties of Mg-0.3Zn-0.2Ca alloys.Micro-alloying with 0.3 wt%Zn and 0.2 wt%Ca enhanced mechanical properties,corrosion resistance,cytocompatibility,and immunomodulatory properties.This positions the Mg-0.3Zn-0.2Ca alloy as a promising biodegradable implant for bone fixation applications.展开更多
The aim of the present study is to evaluate the effect of alloy processing and composition as well as the pH control and testing medium on the in vitro corrosion performance of Mg-Zn-Ca systems for biodegradable impla...The aim of the present study is to evaluate the effect of alloy processing and composition as well as the pH control and testing medium on the in vitro corrosion performance of Mg-Zn-Ca systems for biodegradable implants.The grain size and secondary phases were analyzed by optical microscopy,scanning electron microscopy,transmission electron microscopy,and X-ray diffraction.Scanning kelvin probe force microscopy(SKPFM)was used to analyze the Volta potential values of the second phases.The corrosion performance of the three alloys was evaluated by electrochemical and hydrogen evolution methods inα-MEM with and without organic species(i.e.complete and inorganicα-MEM).Two strategies were followed to evaluate the influence of the pH on the corrosion behavior:daily solution replacement and CO_(2)flow based pH control.For all the materials,the organic medium accelerates the corrosion process.Constant pH maintained by CO_(2)flow through the medium results in considerably higher corrosion rates for all alloys.The impact of pH is lesser on the as-cast alloys due to the barrier effect of the secondary phases,particularly pronounced in the Mg1Zn1Ca alloy which showed the lowest corrosion rate.The wrought Mg0.5Zn0.2Ca alloy that lacks the refined secondary phase network and exhibits high number of twins undergoes accelerated uniform corrosion under constant pH conditions.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52022100 and 52371155)financially support from Basic Research Support Program of Huazhong University of Science and Technology(No.2023BR013).
文摘Advancing biodegradable medical implants,along with an in-depth understanding of their degradation mechanisms,is critical to revolutionizing orthopedic medicine and improving patient outcomes.MgZnCa metallic glass(MG)stands out among degradable metallic materials due to its superior potential for orthopedic applications than traditional crystalline alloys.Despite its advantages,there has been a lack of comprehensive insight into the degradation behavior of MgZnCa MG,particularly under conditions simulating daily activities of patients.In this work,the degradation mechanism of MgZnCa MG is elucidated,highlighting the formation of a distinctive Zn-rich amorphous layer that markedly decelerates the matrix degradation.Detailed analysis reveals that the unique amorphous structure of MgZnCa MG facilitates the selective dissolution of Mg and Ca,resulting in numerous vacancies within the matrix.These vacancies facilitate the inward migration of Zn atoms,culminating in the formation of a dense Zn-rich layer.This cyclical formation and dissolution of the Zn-rich layer serve as a buffer in the degradation pathway,thus ensuring a degradation rate for MgZnCa MG that is significantly slower than that of its crystalline counterparts.
基金funded by European Union’s Horizon 2020 Research and Innovation program and‘Magnesium based Nano Composites for Orthopedic Applications’MAGNACOM,project under the aegis of Programme for Early-Stage Researchers(PEARL,I-Site ULNE under the Marie Sklodowska-Curie grant agreement)supported by University of Lille(France)and Hauts-de-France region.
文摘There is an increasing interest in biodegradable materials,such as magnesium,for orthopaedic implants.This is driven by their potential to address challenges like stress shielding and the need for secondary removal surgery.In this study,biodegradable magnesium alloys were produced using the Vacuum Induction Casting technique.The impact of micro-alloying Zn and Ca in Mg-xZn-0.2Ca(x=0.1,0.2,0.3,and 0.4 wt%)alloys on corrosion resistance,cytocompatibility,and early-stage inflammatory response was investigated.XRD and SEM-EDS analysis confirmed the presence of Ca_(2)Mg_(6)Zn_(3)secondary phases in all alloys.The Mg-0.3Zn-0.2Ca alloy exhibited the lowest corrosion rate and an elastic modulus of 36.8 GPa,resembling that of natural bone.Electrochemical measurements indicated a correlation between grain size and secondary phase volume fraction in explaining corrosion behaviour.In vitro degradation in simulated body fluid(SBF)for 21 days showed hydroxyapatite formation on alloy surfaces,aligning with electrochemical studies.In vitro cytotoxicity tests demonstrated the cytocompatibility of all alloys,with Mg-0.3Zn-0.2Ca having the highest cell viability over a 6-day cell culture.Investigation into the inflammatory response with RAW-Blue macrophages revealed the anti-inflammatory properties of Mg-0.3Zn-0.2Ca alloys.Micro-alloying with 0.3 wt%Zn and 0.2 wt%Ca enhanced mechanical properties,corrosion resistance,cytocompatibility,and immunomodulatory properties.This positions the Mg-0.3Zn-0.2Ca alloy as a promising biodegradable implant for bone fixation applications.
基金The funding of the ADITIMAT-CM project(S2018/NMT4411,Regional Government of Madrid and EU Structural and Social Funds)PID2021-124341OB-C22(MCIU)+3 种基金the support of RYC-2017-21843the Portuguese Foundation for Science and Technology for the researcher grant(IF/01284/2015)the project CICECO-Aveiro Institute of Materials,UIDB/50011/2020&UIDP/50011/2020financed by national funds through the Portuguese Foundation for Science and Technology/MCTES
文摘The aim of the present study is to evaluate the effect of alloy processing and composition as well as the pH control and testing medium on the in vitro corrosion performance of Mg-Zn-Ca systems for biodegradable implants.The grain size and secondary phases were analyzed by optical microscopy,scanning electron microscopy,transmission electron microscopy,and X-ray diffraction.Scanning kelvin probe force microscopy(SKPFM)was used to analyze the Volta potential values of the second phases.The corrosion performance of the three alloys was evaluated by electrochemical and hydrogen evolution methods inα-MEM with and without organic species(i.e.complete and inorganicα-MEM).Two strategies were followed to evaluate the influence of the pH on the corrosion behavior:daily solution replacement and CO_(2)flow based pH control.For all the materials,the organic medium accelerates the corrosion process.Constant pH maintained by CO_(2)flow through the medium results in considerably higher corrosion rates for all alloys.The impact of pH is lesser on the as-cast alloys due to the barrier effect of the secondary phases,particularly pronounced in the Mg1Zn1Ca alloy which showed the lowest corrosion rate.The wrought Mg0.5Zn0.2Ca alloy that lacks the refined secondary phase network and exhibits high number of twins undergoes accelerated uniform corrosion under constant pH conditions.
