In the recent decades,zinc(Zn)and its alloys have been drawing attention as promising candidates for bioresorbable cardiovascular stents due to its degradation rate more suitable than magnesium(Mg)and iron(Fe)alloys.H...In the recent decades,zinc(Zn)and its alloys have been drawing attention as promising candidates for bioresorbable cardiovascular stents due to its degradation rate more suitable than magnesium(Mg)and iron(Fe)alloys.However,its mechanical properties need to be improved in order to meet the criteria for vascular stents.This work investigates the mechanical properties,biodegradability and biocompatibility of Zn-Mg and Zn-Cu alloys in order to determine a proper alloy composition for optimal stent performance.Nanoindentation measurements are performed to characterize the mechanical properties at the nanoscale as a function of the Zn microstructure variations induced by alloying.The biodegradation mechanisms are discussed and correlated to microstructure,mechanical performance and bacterial/cell response.Addition of Mg or Cu alloying elements refined the microstructure of Zn and enhanced yield strength(YS)and ultimate tensile strength(UTS)proportional to the volume fraction of secondary phases.Zn-1Mg showed the higher YS and UTS and better performance in terms of degradation stability in Hanks’solution.Zn-Cu alloys presented an antibacterial effect for S.aureus controlled by diffusion mechanisms and by contact.Biocompatibility was dependent on the degradation rate and the nature of the corrosion products.展开更多
Reactive oxygen and nitrogen species (RONS) are among the key factors in plasma medicine. They are generated by atmospheric plasmas in biological fluids, living tissues and in a variety of liquids. This ability of pla...Reactive oxygen and nitrogen species (RONS) are among the key factors in plasma medicine. They are generated by atmospheric plasmas in biological fluids, living tissues and in a variety of liquids. This ability of plasmas to create a delicate mix of RONS in liquids has been used to design remote or indirect treatments for oncological therapy by treating biological fluids by plasmas and putting them in contact with the tumour;Documented effects include selective cancer cell toxicity, even though the exact mechanisms involved are still under investigation. However, the "right" dose for suitable therapeutical activity is crucial and still under debate. The wide variety of plasma sources hampers comparisons. This review focuses on atmospheric pressure plasma jets as the most studied plasma devices in plasma medicine and compiles the conditions employed to generate RONS in relevant liquids and the concentration ranges obtained. The concentrations of H2O2, NO2^-, NO3^- and short-lived oxygen species are compared critically to provide a useful overview for the reader.展开更多
基金Financial support was received from Spanish Government,MINECO/FEDER,(RTI2018-098075-B-C21)the Agency for Administration of University and Research Grants of the Government of Catalonia(2017SGR-1165)L.C.C.thanks COFUND scheme(GA 712754)and SEV-2014-0425(2015-2019)for the financial support.
文摘In the recent decades,zinc(Zn)and its alloys have been drawing attention as promising candidates for bioresorbable cardiovascular stents due to its degradation rate more suitable than magnesium(Mg)and iron(Fe)alloys.However,its mechanical properties need to be improved in order to meet the criteria for vascular stents.This work investigates the mechanical properties,biodegradability and biocompatibility of Zn-Mg and Zn-Cu alloys in order to determine a proper alloy composition for optimal stent performance.Nanoindentation measurements are performed to characterize the mechanical properties at the nanoscale as a function of the Zn microstructure variations induced by alloying.The biodegradation mechanisms are discussed and correlated to microstructure,mechanical performance and bacterial/cell response.Addition of Mg or Cu alloying elements refined the microstructure of Zn and enhanced yield strength(YS)and ultimate tensile strength(UTS)proportional to the volume fraction of secondary phases.Zn-1Mg showed the higher YS and UTS and better performance in terms of degradation stability in Hanks’solution.Zn-Cu alloys presented an antibacterial effect for S.aureus controlled by diffusion mechanisms and by contact.Biocompatibility was dependent on the degradation rate and the nature of the corrosion products.
文摘Reactive oxygen and nitrogen species (RONS) are among the key factors in plasma medicine. They are generated by atmospheric plasmas in biological fluids, living tissues and in a variety of liquids. This ability of plasmas to create a delicate mix of RONS in liquids has been used to design remote or indirect treatments for oncological therapy by treating biological fluids by plasmas and putting them in contact with the tumour;Documented effects include selective cancer cell toxicity, even though the exact mechanisms involved are still under investigation. However, the "right" dose for suitable therapeutical activity is crucial and still under debate. The wide variety of plasma sources hampers comparisons. This review focuses on atmospheric pressure plasma jets as the most studied plasma devices in plasma medicine and compiles the conditions employed to generate RONS in relevant liquids and the concentration ranges obtained. The concentrations of H2O2, NO2^-, NO3^- and short-lived oxygen species are compared critically to provide a useful overview for the reader.
