Refractory metal niobium(Nb) incorporated with a small amount of silver(Ag),the resulting Nb-Ag twophase alloys,were fabricated by mechanical alloying and spark plasma sintering.The microstructure,mechanical propertie...Refractory metal niobium(Nb) incorporated with a small amount of silver(Ag),the resulting Nb-Ag twophase alloys,were fabricated by mechanical alloying and spark plasma sintering.The microstructure,mechanical properties,wear resistance,corrosion behavior,in vitro and in vivo antibacterial properties and biocompatibility of the Nb-Ag alloys were systematically investigated.The results show that the mechanical properties,wear resistance,corrosion resistance and antibacterial ability were significantly enhanced after addition of 5 at.% Ag.The fabricated Nb-5 at.% Ag alloy demonstrates high yield strength of up to ~1486 MPa and fracture strain of ~35 %.The precipitated Ag particles could reduce friction and wear.The enhanced corrosion resistance was attributed to the higher relative density of the sintered alloys and the formation of a stable and dense passive film of niobium and silver oxides.In vitro and in vivo evaluations show that the Nb-5 at.% Ag alloy also has strong antibacterial activity and good biocompatibility and osteointegration ability.These results demonstrate great potential of the nanostructured Nb-Ag alloys for dental and orthopedic implants.展开更多
Fully bioresorbable vascular scaffolds(BVSs)aim to overcome the limitations of metallic drug-eluting stents(DESs).However,polymer-based BVSs,such as Abbott’s Absorb,the only US FDA-approved BVS,have had limited use d...Fully bioresorbable vascular scaffolds(BVSs)aim to overcome the limitations of metallic drug-eluting stents(DESs).However,polymer-based BVSs,such as Abbott’s Absorb,the only US FDA-approved BVS,have had limited use due to increased strut thickness(157μm for Absorb),exacerbated tissue inflammation,and increased risk of major cardiac events leading to inferior clinical performance when compared to metallic DESs.Herein we report the development of a drug-eluting BVS(DE-BVS)through the innovative use of a photopolymerizable,citrate-based biomaterial and a high-precision additive manufacturing process.BVS with a clinically relevant strut thickness of 62μm can be produced in a high-throughput manner,i.e.one BVS per minute,and controlled release of the anti-restenosis drug everolimus can be achieved by engineering the structure of polymer coatings to fabricate drug-eluting BVS.We achieved the successful deployment of BVSs and DE-BVSs in swine coronary arteries using a custom-built balloon catheter and BVS delivery system and confirmed BVS safety and efficacy regarding maintenance of vessel patency for 28 days,observing an inflammation profile for BVS and DE-BVS that was comparable to the commercial XIENCE^(TM)DES(Abbott Vascular).展开更多
Implant-associated infections are generally difficult to cure owing to the bacterial antibiotic resistance which is attributed to the widespread usage of antibiotics.Given the global threat and increasing influence of...Implant-associated infections are generally difficult to cure owing to the bacterial antibiotic resistance which is attributed to the widespread usage of antibiotics.Given the global threat and increasing influence of antibiotic resistance,there is an urgent demand to explore novel antibacterial strategies other than using antibiotics.Recently,using a certain surface topography to provide a more persistent antibacterial solution attracts more and more attention.However,the clinical application of biomimetic nano-pillar array is not satisfactory,mainly because its antibacterial ability against Gram-positive strain is not good enough.Thus,the pillar array should be equipped with other antibacterial agents to fulfill the bacteriostatic and bactericidal requirements of clinical application.Here,we designed a novel model substrate which was a combination of periodic micro/nano-pillar array and TiO2 for basically understanding the topographical bacteriostatic effects of periodic micro/nano-pillar array and the photocatalytic bactericidal activity of TiO2.Such innovation may potentially exert the synergistic effects by integrating the persistent topographical antibacterial activity and the non-invasive X-ray induced photocatalytic antibacterial property of TiO2 to combat against antibiotic-resistant implant-associated infections.First,to separately verify the topographical antibacterial activity of TiO2 periodic micro/nano-pillar array,we systematically investigated its effects on bacterial adhesion,growth,proliferation,and viability in the dark without involving the photocatalysis of TiO2.The pillar array with sub-micron motif size can significantly inhibit the adhesion,growth,and proliferation of Staphylococcus aureus(S.aureus)and Escherichia coli(E.coli).Such antibacterial ability is mainly attributed to a spatial confinement size-effect and limited contact area availability generated by the special topography of pillar array.Moreover,the pillar array is not lethal to S.aureus and E.coli in 24 h.Then,the X-ray induced photocatalytic antibacterial property of TiO2 periodic micro/nano-pillar array in vitro and in vivo will be systematically studied in a future work.This study could shed light on the direction of surface topography design for future medical implants to combat against antibiotic-resistant implant-associated infections without using antibiotics.展开更多
基金financially supported by the Natural Science Foundation of Guangdong(Grant No.2019A1515011755)the Fundamental Research Program of Shenzhen(Grant Nos.JCYJ20170412153039309 and JCYJ20170307110418960)the Natural Science Foundation of Tianjin(General Program,No.18JCYBJC19500),China。
文摘Refractory metal niobium(Nb) incorporated with a small amount of silver(Ag),the resulting Nb-Ag twophase alloys,were fabricated by mechanical alloying and spark plasma sintering.The microstructure,mechanical properties,wear resistance,corrosion behavior,in vitro and in vivo antibacterial properties and biocompatibility of the Nb-Ag alloys were systematically investigated.The results show that the mechanical properties,wear resistance,corrosion resistance and antibacterial ability were significantly enhanced after addition of 5 at.% Ag.The fabricated Nb-5 at.% Ag alloy demonstrates high yield strength of up to ~1486 MPa and fracture strain of ~35 %.The precipitated Ag particles could reduce friction and wear.The enhanced corrosion resistance was attributed to the higher relative density of the sintered alloys and the formation of a stable and dense passive film of niobium and silver oxides.In vitro and in vivo evaluations show that the Nb-5 at.% Ag alloy also has strong antibacterial activity and good biocompatibility and osteointegration ability.These results demonstrate great potential of the nanostructured Nb-Ag alloys for dental and orthopedic implants.
基金supported by the National Institutes of Health,United States(Grant:R01HL141933)Y.Ding was supported in part by the Center for Advanced Regenerative Engineering and American Heart Association Career Development Award(AHA,Grant:852772).The authors gratefully acknowledge Connor Alexander Moore and Casey Tan for their technical support in schematic illustration and data analysis,respectively.
文摘Fully bioresorbable vascular scaffolds(BVSs)aim to overcome the limitations of metallic drug-eluting stents(DESs).However,polymer-based BVSs,such as Abbott’s Absorb,the only US FDA-approved BVS,have had limited use due to increased strut thickness(157μm for Absorb),exacerbated tissue inflammation,and increased risk of major cardiac events leading to inferior clinical performance when compared to metallic DESs.Herein we report the development of a drug-eluting BVS(DE-BVS)through the innovative use of a photopolymerizable,citrate-based biomaterial and a high-precision additive manufacturing process.BVS with a clinically relevant strut thickness of 62μm can be produced in a high-throughput manner,i.e.one BVS per minute,and controlled release of the anti-restenosis drug everolimus can be achieved by engineering the structure of polymer coatings to fabricate drug-eluting BVS.We achieved the successful deployment of BVSs and DE-BVSs in swine coronary arteries using a custom-built balloon catheter and BVS delivery system and confirmed BVS safety and efficacy regarding maintenance of vessel patency for 28 days,observing an inflammation profile for BVS and DE-BVS that was comparable to the commercial XIENCE^(TM)DES(Abbott Vascular).
基金supported by the Natural Science Foundation of Tianjin(General Program,No.18JCYBJC19500)the Independent Innovation Fund of Tianjin University(No.2019XZS-0014)the Research Grants Council of Hong Kong(No.HKUST615408).
文摘Implant-associated infections are generally difficult to cure owing to the bacterial antibiotic resistance which is attributed to the widespread usage of antibiotics.Given the global threat and increasing influence of antibiotic resistance,there is an urgent demand to explore novel antibacterial strategies other than using antibiotics.Recently,using a certain surface topography to provide a more persistent antibacterial solution attracts more and more attention.However,the clinical application of biomimetic nano-pillar array is not satisfactory,mainly because its antibacterial ability against Gram-positive strain is not good enough.Thus,the pillar array should be equipped with other antibacterial agents to fulfill the bacteriostatic and bactericidal requirements of clinical application.Here,we designed a novel model substrate which was a combination of periodic micro/nano-pillar array and TiO2 for basically understanding the topographical bacteriostatic effects of periodic micro/nano-pillar array and the photocatalytic bactericidal activity of TiO2.Such innovation may potentially exert the synergistic effects by integrating the persistent topographical antibacterial activity and the non-invasive X-ray induced photocatalytic antibacterial property of TiO2 to combat against antibiotic-resistant implant-associated infections.First,to separately verify the topographical antibacterial activity of TiO2 periodic micro/nano-pillar array,we systematically investigated its effects on bacterial adhesion,growth,proliferation,and viability in the dark without involving the photocatalysis of TiO2.The pillar array with sub-micron motif size can significantly inhibit the adhesion,growth,and proliferation of Staphylococcus aureus(S.aureus)and Escherichia coli(E.coli).Such antibacterial ability is mainly attributed to a spatial confinement size-effect and limited contact area availability generated by the special topography of pillar array.Moreover,the pillar array is not lethal to S.aureus and E.coli in 24 h.Then,the X-ray induced photocatalytic antibacterial property of TiO2 periodic micro/nano-pillar array in vitro and in vivo will be systematically studied in a future work.This study could shed light on the direction of surface topography design for future medical implants to combat against antibiotic-resistant implant-associated infections without using antibiotics.
