In this paper,a scaffold,which mimics the morphology and mechanical properties of a native blood vessel is reported.The scaffold was prepared by sequential bi-layer electrospinning on a rotating mandrel-type collector...In this paper,a scaffold,which mimics the morphology and mechanical properties of a native blood vessel is reported.The scaffold was prepared by sequential bi-layer electrospinning on a rotating mandrel-type collector.The tubular scaffolds(inner diameter 4 mm,length 3 cm)are composed of a polyurethane(PU)fibrous outer-layer and a gelatin-heparin fibrous inner-layer.They were fabricated by electrospinning technology,which enables control of the composition,structure,and mechanical properties of the scaffolds.The microstructure,fiber morphology and mechanical properties of the scaffolds were examined by means of scanning electron microscopy(SEM)and tensile tests.The PU/gelatinheparin tubular scaffolds have a porous structure.The scaffolds achieved a breaking strength(3.7±0.13 MPa)and an elongation at break(110±8%)that are appropriate for artificial blood vessels.When the scaffolds were immersed in water for 1 h,the breaking strength decreased slightly to 2.2±0.3 MPa,but the elongation at break increased to 14521%.In platelet adhesion tests the gelatin-heparin fibrous scaffolds showed a significant suppression of platelet adhesion.Heparin was released from the scaffolds at a fairly uniform rate during the period of 2nd day to 9th day.The scaffolds are expected to mimic the complex matrix structure of native arteries,and to have good biocompatibility as an artificial blood vessel owing to the heparin release.展开更多
Polycarbonate urethane(PCU)nano-fibers were fabricated via electrospinning using N,Ndimethylformamide(DMF)and tetrahydrofuran(THF)as the mixed solvent.The effect of volume ratios of DMF and THF in the mixed solvent on...Polycarbonate urethane(PCU)nano-fibers were fabricated via electrospinning using N,Ndimethylformamide(DMF)and tetrahydrofuran(THF)as the mixed solvent.The effect of volume ratios of DMF and THF in the mixed solvent on the fiber structures was investigated.The results show that nano-fibers with a narrow diameter distribution and a few defects were obtained when mixed solvent with the appropriate volume ratio of DMF and THF as 1∶1.When the proportion of DMF was more than 75%in the mixed solvent,it was easy to form many beaded fibers.The applied voltage in the electrospinning process has a significant influence on the morphology of fibers.When the electric voltage was set between 22 and 32 kV,the average diameters of the fibers were found between 420 and 570 nm.Scanning electron microscopy(SEM)images showed that fiber diameter and structural morphology of the electrospun PCU membranes are a function of the polymer solution concentration.When the concentration of PCU solution was 6.0 wt-%,a beaded-fiber microstructure was obtained.With increasing the concentration of PCU solutions above 6.0 wt-%,beaded fiber decreased and finally disappeared.However,when the PCU concentration was over 14.0 wt-%,the average diameter of fibers became large,closed to 2μm,because of the high solution viscosity.The average diameter of nanofibers increased linearly with increasing the volume flow rate of the PCU solution(10.0 wt-%)when the applied voltagewas 24 kV.The results show that the morphology of PCU fibers could be controlled by electrospinning parameters,such as solution concentration,electric voltage and flow rate.展开更多
基金financially supported by the Program for New Century of Excellent Talents in University(NCET-07-0596)Ministry of Education of China,by the International Cooperation from the Ministry of Science and Technology of China(MOST No.2008DFA51170)+2 种基金by the Science and Technology Project of Tianjin Municipal Science and Technology Commission(No.08ZCKFSF03300)The project is funded by the Tianjin University-Helmholtz-Zentrum Geesthacht Joint Laboratory for BiomaterialsRegenerative Medicine,which is financed by MOST and the German Federal Ministry of Education and Research(BMBF).
文摘In this paper,a scaffold,which mimics the morphology and mechanical properties of a native blood vessel is reported.The scaffold was prepared by sequential bi-layer electrospinning on a rotating mandrel-type collector.The tubular scaffolds(inner diameter 4 mm,length 3 cm)are composed of a polyurethane(PU)fibrous outer-layer and a gelatin-heparin fibrous inner-layer.They were fabricated by electrospinning technology,which enables control of the composition,structure,and mechanical properties of the scaffolds.The microstructure,fiber morphology and mechanical properties of the scaffolds were examined by means of scanning electron microscopy(SEM)and tensile tests.The PU/gelatinheparin tubular scaffolds have a porous structure.The scaffolds achieved a breaking strength(3.7±0.13 MPa)and an elongation at break(110±8%)that are appropriate for artificial blood vessels.When the scaffolds were immersed in water for 1 h,the breaking strength decreased slightly to 2.2±0.3 MPa,but the elongation at break increased to 14521%.In platelet adhesion tests the gelatin-heparin fibrous scaffolds showed a significant suppression of platelet adhesion.Heparin was released from the scaffolds at a fairly uniform rate during the period of 2nd day to 9th day.The scaffolds are expected to mimic the complex matrix structure of native arteries,and to have good biocompatibility as an artificial blood vessel owing to the heparin release.
基金This work has been financially supported by Program for New Century Excellent Talents in University“NCET,”NCET-07-0596Ministry of Education ofChina,by the International Cooperation from Ministry of Science and Technology of China(Grant No.2008DFA51170)by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry.
文摘Polycarbonate urethane(PCU)nano-fibers were fabricated via electrospinning using N,Ndimethylformamide(DMF)and tetrahydrofuran(THF)as the mixed solvent.The effect of volume ratios of DMF and THF in the mixed solvent on the fiber structures was investigated.The results show that nano-fibers with a narrow diameter distribution and a few defects were obtained when mixed solvent with the appropriate volume ratio of DMF and THF as 1∶1.When the proportion of DMF was more than 75%in the mixed solvent,it was easy to form many beaded fibers.The applied voltage in the electrospinning process has a significant influence on the morphology of fibers.When the electric voltage was set between 22 and 32 kV,the average diameters of the fibers were found between 420 and 570 nm.Scanning electron microscopy(SEM)images showed that fiber diameter and structural morphology of the electrospun PCU membranes are a function of the polymer solution concentration.When the concentration of PCU solution was 6.0 wt-%,a beaded-fiber microstructure was obtained.With increasing the concentration of PCU solutions above 6.0 wt-%,beaded fiber decreased and finally disappeared.However,when the PCU concentration was over 14.0 wt-%,the average diameter of fibers became large,closed to 2μm,because of the high solution viscosity.The average diameter of nanofibers increased linearly with increasing the volume flow rate of the PCU solution(10.0 wt-%)when the applied voltagewas 24 kV.The results show that the morphology of PCU fibers could be controlled by electrospinning parameters,such as solution concentration,electric voltage and flow rate.
