The back-flow of an aortic valvo-pump will re-duce the pumping flow rate but can wash out the gap between the rotor and the stator, and thus can improve the antithrombogenicity of the de-vice. To investigate the regur...The back-flow of an aortic valvo-pump will re-duce the pumping flow rate but can wash out the gap between the rotor and the stator, and thus can improve the antithrombogenicity of the de-vice. To investigate the regurgitation of a 23mm OD aortic valvo-pump, its closed impeller was replaced by a cylinder and hereby the valvo- pump had lost its pumping function. The pres-sure head crossing the aortic valvo-pump was maintained by a locally made pulsatile centrifugal pump, beating rhythmically from 30 to 120mmHg. The back flow from outlet to inlet of valvo-pump via the above-mentioned gap was measured. Results demonstrated that this gap and the pressure head had remarkable effect on back- flow;a larger gap and/or a larger pressure head would lead to a larger back-flow. By 0,20mm gap and 100mmHg pressure head, the valvo-pump had ca. 0,8 l/min back-flow. Instantaneous meas-urement indicated that the back-flow had a pul-satile form with high rate during diastole while low rate during systole of the natural heart imi-tated by pulsatile centrifugal pump. The pump rotated at 12500rpm, 15000rpm and 17500rpm respectively, but it was found the rotating speed had no affection on back-flow. This investigation provides a basis for pump design seeking for both increase of the flow rate and improvement of the compatibility;the former is particularly important for a mini axial pump and the latter is extremely difficult for closed impeller.展开更多
Rapid formation of a continuous endothelial cell(EC)monolayer with healthy endothelium function on the luminal surface of vascular implants is imperative to improve the longtime patency of small-diameter vascular impl...Rapid formation of a continuous endothelial cell(EC)monolayer with healthy endothelium function on the luminal surface of vascular implants is imperative to improve the longtime patency of small-diameter vascular implants.In the present study,we combined the contact guidance effects of aligned nanofibers,which enhance EC adhesion and proliferation because of its similar fiber scale with native vascular basement membranes,and aligned microfibers,which could induce EC elongation effectively and allow ECs infiltration.It was followed by successive immobilization of collagen IV and laminin to fabricate a biomimetic basement membrane(BBM)with structural and compositional biomimicry.The hemolysis assay and platelet adhesion results showed that the BBM exhibited excellent hemocompatibility.Meanwhile,the adhered human umbilical vein endothelial cells(HUVECs)onto theBBMaligned along the orientation of the microfibers with an elongated morphology,and the data demonstrated that the BBM showed favorable effects on EC attachment,proliferation,and viability.The oriented EC monolayer formed on the BBM exhibited improved antithrombotic capability as indicated by higher production of nitric oxide and prostacyclin(PGI2).Furthermore,fluorescence images indicated that HUVECs could infiltrate into the BBM,implying theBBM’s ability to enhance transmural endothelialization.Hence,theBBMpossessed the properties to regulate ECbehaviors and allow transmural ingrowth,demonstrating the potential to be applied as the luminal surface of small-diameter vascular implants for rapid endothelialization.展开更多
文摘The back-flow of an aortic valvo-pump will re-duce the pumping flow rate but can wash out the gap between the rotor and the stator, and thus can improve the antithrombogenicity of the de-vice. To investigate the regurgitation of a 23mm OD aortic valvo-pump, its closed impeller was replaced by a cylinder and hereby the valvo- pump had lost its pumping function. The pres-sure head crossing the aortic valvo-pump was maintained by a locally made pulsatile centrifugal pump, beating rhythmically from 30 to 120mmHg. The back flow from outlet to inlet of valvo-pump via the above-mentioned gap was measured. Results demonstrated that this gap and the pressure head had remarkable effect on back- flow;a larger gap and/or a larger pressure head would lead to a larger back-flow. By 0,20mm gap and 100mmHg pressure head, the valvo-pump had ca. 0,8 l/min back-flow. Instantaneous meas-urement indicated that the back-flow had a pul-satile form with high rate during diastole while low rate during systole of the natural heart imi-tated by pulsatile centrifugal pump. The pump rotated at 12500rpm, 15000rpm and 17500rpm respectively, but it was found the rotating speed had no affection on back-flow. This investigation provides a basis for pump design seeking for both increase of the flow rate and improvement of the compatibility;the former is particularly important for a mini axial pump and the latter is extremely difficult for closed impeller.
基金This work was supported by the Fundamental Research Funds for the Central Universities(Nos.2232019G-06 and 2232019A3-06)111 project(No.PB0719035)+1 种基金The authors at University of Wisconsin-Madison would like to acknowledge the partial support by the Wisconsin Institute for Discovery(WID),the NHLBI of the National Institutes of Health(No.U01HL134655)the Kuo K.and Cindy F.Wang Professorship.Chenglong Yu also acknowledged the fellowship from the China Scholarship Council(CSC)under the Grant CSC No.201906630070.
文摘Rapid formation of a continuous endothelial cell(EC)monolayer with healthy endothelium function on the luminal surface of vascular implants is imperative to improve the longtime patency of small-diameter vascular implants.In the present study,we combined the contact guidance effects of aligned nanofibers,which enhance EC adhesion and proliferation because of its similar fiber scale with native vascular basement membranes,and aligned microfibers,which could induce EC elongation effectively and allow ECs infiltration.It was followed by successive immobilization of collagen IV and laminin to fabricate a biomimetic basement membrane(BBM)with structural and compositional biomimicry.The hemolysis assay and platelet adhesion results showed that the BBM exhibited excellent hemocompatibility.Meanwhile,the adhered human umbilical vein endothelial cells(HUVECs)onto theBBMaligned along the orientation of the microfibers with an elongated morphology,and the data demonstrated that the BBM showed favorable effects on EC attachment,proliferation,and viability.The oriented EC monolayer formed on the BBM exhibited improved antithrombotic capability as indicated by higher production of nitric oxide and prostacyclin(PGI2).Furthermore,fluorescence images indicated that HUVECs could infiltrate into the BBM,implying theBBM’s ability to enhance transmural endothelialization.Hence,theBBMpossessed the properties to regulate ECbehaviors and allow transmural ingrowth,demonstrating the potential to be applied as the luminal surface of small-diameter vascular implants for rapid endothelialization.
