The Experts below are selected from a list of 240 Experts worldwide ranked by ideXlab platform
Nafiseh Jirofti - One of the best experts on this subject based on the ideXlab platform.
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small Diameter Vascular Graft using co electrospun composite pcl pu nanofibers
Biomedical Materials, 2018Co-Authors: Nafiseh Jirofti, Davod Mohebbikalhori, Abdolreza Samimi, Afra Hadjizadeh, Gholam Hossein KazemzadehAbstract:Small-Diameter Vascular scaffolds have been developed by a co-electrospinning method using polyethylene terephthalate (PCL) and elastic polytetrafluoroethylene (PU) as biopolymers with long degradation time. Although they possess favorable properties, individually these two polymers do not meet the requirements for the production of synthetic Vascular scaffolds. The co-electrospinning method was adopted to develop and mechanically improve the composite PCL/PU Vascular scaffolds. The morphological, mechanical and biological properties of these Vascular scaffolds were evaluated through scanning electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, compliance, tensile testing and MTT assay. The in vivo study of the Vascular scaffolds was performed by implanting them on rat and sheep models. The compliance of the composite Vascular scaffolds improved by up to 43% through an increased percentage of PU from 10%–90%. The obtained UTS of the scaffolds at 10%, 25%, 50%, 75% and 90% of PU were 4.7 ± 0.34, 3.4 ± 0.6, 4.8 ± 0.62, 2.2 ± 0.34 and 4.4 ± 1.9 MPa, respectively. The results of MTT assays indicated that the cell growth on the scaffolds was augmented when compared to the control, from day one to day seven. Mild edema, mild foreign-body granulomatous reaction and mild fibrosis were observed by pathology test as the side effects in the composite scaffold with 50% PCL. Doppler ultrasound and angiography images confirm that no aneurysm, thrombogenesis, neointimal hyperplasia or occlusion exist, and there is complete patency at the end of an eight month investigation. The fabricated composite Vascular scaffolds provide appropriate mechanical and biological properties and clinical requirements, indicating their required potential to be applied as a small-Diameter Vascular Graft.
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Small-Diameter Vascular Graft using co-electrospun composite PCL/PU nanofibers
Biomedical Materials, 2018Co-Authors: Nafiseh Jirofti, Abdolreza Samimi, Afra Hadjizadeh, Davod Mohebbi-kalhori, Gholam Hossein KazemzadehAbstract:Small-Diameter Vascular scaffolds have been developed by a co-electrospinning method using polyethylene terephthalate (PCL) and elastic polytetrafluoroethylene (PU) as biopolymers with long degradation time. Although they possess favorable properties, individually these two polymers do not meet the requirements for the production of synthetic Vascular scaffolds. The co-electrospinning method was adopted to develop and mechanically improve the composite PCL/PU Vascular scaffolds. The morphological, mechanical and biological properties of these Vascular scaffolds were evaluated through scanning electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, compliance, tensile testing and MTT assay. The in vivo study of the Vascular scaffolds was performed by implanting them on rat and sheep models. The compliance of the composite Vascular scaffolds improved by up to 43% through an increased percentage of PU from 10%–90%. The obtained UTS of the scaffolds at 10%, 25%, 50%, 75% and 90% of PU were 4.7 ± 0.34, 3.4 ± 0.6, 4.8 ± 0.62, 2.2 ± 0.34 and 4.4 ± 1.9 MPa, respectively. The results of MTT assays indicated that the cell growth on the scaffolds was augmented when compared to the control, from day one to day seven. Mild edema, mild foreign-body granulomatous reaction and mild fibrosis were observed by pathology test as the side effects in the composite scaffold with 50% PCL. Doppler ultrasound and angiography images confirm that no aneurysm, thrombogenesis, neointimal hyperplasia or occlusion exist, and there is complete patency at the end of an eight month investigation. The fabricated composite Vascular scaffolds provide appropriate mechanical and biological properties and clinical requirements, indicating their required potential to be applied as a small-Diameter Vascular Graft.
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Fabrication and Characterization of Electrospun Bi-Hybrid PU/PET Scaffolds for Small-Diameter Vascular Grafts Applications
Cardiovascular Engineering and Technology, 2018Co-Authors: Marziyeh Khodadoust, Davod Mohebbi-kalhori, Nafiseh JiroftiAbstract:In spite of advances have been made during the past decades, the problems associated with small-Diameter Vascular Grafts, including low patency and compliance mismatch and in consequence of that thrombosis, aneurysm and intimal hyperplasia are still challenges. To address these problems, net polyurethane (PU) and poly (ethylene terephthalate) (PET) polymers and hybrid PU/PET were electrospun to create three different types of small-Diameter Vascular scaffolds due to their unique physicochemical characteristics: PU, PET, and novel hybrid PU/PET scaffolds. The results show that the PU and PET composite can improve the mechanical properties of the tissue-engineered Vascular scaffolds in the range of the native vessels where the non-cytotoxicity characteristic of these well-known polymers is still immutable. The compliance and stiffness factor of the fabricated hybrid scaffolds were 4.468 ± 0.177 and 22.718 ± 0.896%/0.01 mmHg, respectively, which were significantly different with that of the net PU and PET electrospun scaffolds. Other properties such as ultimate tensile stress (UTS) (3.56 ± 1.21 MPa) were also in good accordance with the native vessels. Furthermore, FT-IR analysis testified the presence of both PU and PET in the hybrid scaffolds. Overall, we were able to fabricate a hybrid scaffold as a small-Diameter Vascular Graft that mechanically matched the gold standard of blood vessel substitution.
Shufang Wang - One of the best experts on this subject based on the ideXlab platform.
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electrospun poly e caprolactone scaffold modified with catalytic nitric oxide generation and heparin for small Diameter Vascular Graft
RSC Advances, 2017Co-Authors: Yaping Wang, Siyuan Chen, Di Tang, Li Jiang, Deling Kong, Shufang WangAbstract:Vascular Grafts are significantly needed in peripheral Vascular surgery; however, small Diameter Grafts are not always available, and synthetic Grafts perform poorly because of acute thrombosis and neointimal proliferation after implantation. This study used electrospun poly-e-caprolactone (PCL) as the matrix material to build a small-Diameter Vascular Graft. Organoselenium modified polyethyleneimine (SePEI), which can catalyze the production of nitric oxide from S-nitrosothiols, and heparin (Hep) were introduce through layer-by-layer (LbL) assembly in order to prepare a new Vascular Graft with improved histocompatibility and biological function. Static water contact angle measurement showed that SePEI and Hep had improved the hydrophilicity of the material, which is desirable for an active Vascular Graft. The results showed that the mechanical property and histocompatibility of the SePEI/Hep loaded material could meet the demands of Vascular Grafts. The results of cellular experiments showed that the SePEI/Hep loaded material could promote the proliferation and adhesion of endothelial cells, which is beneficial to the rapid endothelialization of Vascular Grafts. And this material could inhibit the adhesion and spreading of smooth muscle cells, which can prevent the post-implantation restenosis. The SePEI/Hep loaded material could inhibit the activation of macrophages, which is very important in reducing inflammation following Graft implantation.
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Electrospun poly-ε-caprolactone scaffold modified with catalytic nitric oxide generation and heparin for small-Diameter Vascular Graft
RSC Advances, 2017Co-Authors: Yaping Wang, Siyuan Chen, Di Tang, Li Jiang, Deling Kong, Shufang WangAbstract:Vascular Grafts are significantly needed in peripheral Vascular surgery; however, small Diameter Grafts are not always available, and synthetic Grafts perform poorly because of acute thrombosis and neointimal proliferation after implantation. This study used electrospun poly-e-caprolactone (PCL) as the matrix material to build a small-Diameter Vascular Graft. Organoselenium modified polyethyleneimine (SePEI), which can catalyze the production of nitric oxide from S-nitrosothiols, and heparin (Hep) were introduce through layer-by-layer (LbL) assembly in order to prepare a new Vascular Graft with improved histocompatibility and biological function. Static water contact angle measurement showed that SePEI and Hep had improved the hydrophilicity of the material, which is desirable for an active Vascular Graft. The results showed that the mechanical property and histocompatibility of the SePEI/Hep loaded material could meet the demands of Vascular Grafts. The results of cellular experiments showed that the SePEI/Hep loaded material could promote the proliferation and adhesion of endothelial cells, which is beneficial to the rapid endothelialization of Vascular Grafts. And this material could inhibit the adhesion and spreading of smooth muscle cells, which can prevent the post-implantation restenosis. The SePEI/Hep loaded material could inhibit the activation of macrophages, which is very important in reducing inflammation following Graft implantation.
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rapid in situ endothelialization of a small Diameter Vascular Graft with catalytic nitric oxide generation and promoted endothelial cell adhesion
Journal of Materials Chemistry B, 2015Co-Authors: Yuanyuan Wang, Siyuan Chen, Di Tang, Deling Kong, Shufang WangAbstract:Thrombosis and neointimal hyperplasia are the main causes for the failure of small Diameter Vascular Grafts, and a complete and functional endothelium is essential in preventing these problems. Therefore, Grafts that could be endothelialized rapidly are highly desirable. This study constructed a Vascular Graft with catalytic nitric oxide (NO) generation and promoted endothelial cell (EC) adhesion for rapid in situ endothelialization, and examined the in vivo performance of an NO-generating Vascular Graft for the first time. A macroporous electrospun polycaprolactone (PCL) Graft was prepared and modified via layer-by-layer self-assembly. Organoselenium immobilized polyethyleneimine was loaded onto the Graft for in situ catalytic NO generation, while hyaluronic acid was Grafted with an EC specific peptide Arg–Glu–Asp–Val and deposited to promote EC adhesion. This dual-modified material generated a strong and sustained flow of NO from S-nitrosoglutathione and significantly enhanced EC adhesion in vitro. In a co-culture experiment of ECs and smooth muscle cells (SMCs), this material promoted the adhesion of ECs and increased the EC/SMC ratio. After implantation in rats, the modified Grafts showed a remarkably promoted endothelialization compared to PCL ones with an endothelium coverage of 89% versus 55% after 4 weeks, and the ECs on modified Grafts were better organized in a pattern similar to that of the native vessel. The results indicated that the combination of catalytic NO generation and promoted EC adhesion proposed in this work may be a promising method for rapid endothelialization of small Diameter Vascular Grafts.
Gholam Hossein Kazemzadeh - One of the best experts on this subject based on the ideXlab platform.
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small Diameter Vascular Graft using co electrospun composite pcl pu nanofibers
Biomedical Materials, 2018Co-Authors: Nafiseh Jirofti, Davod Mohebbikalhori, Abdolreza Samimi, Afra Hadjizadeh, Gholam Hossein KazemzadehAbstract:Small-Diameter Vascular scaffolds have been developed by a co-electrospinning method using polyethylene terephthalate (PCL) and elastic polytetrafluoroethylene (PU) as biopolymers with long degradation time. Although they possess favorable properties, individually these two polymers do not meet the requirements for the production of synthetic Vascular scaffolds. The co-electrospinning method was adopted to develop and mechanically improve the composite PCL/PU Vascular scaffolds. The morphological, mechanical and biological properties of these Vascular scaffolds were evaluated through scanning electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, compliance, tensile testing and MTT assay. The in vivo study of the Vascular scaffolds was performed by implanting them on rat and sheep models. The compliance of the composite Vascular scaffolds improved by up to 43% through an increased percentage of PU from 10%–90%. The obtained UTS of the scaffolds at 10%, 25%, 50%, 75% and 90% of PU were 4.7 ± 0.34, 3.4 ± 0.6, 4.8 ± 0.62, 2.2 ± 0.34 and 4.4 ± 1.9 MPa, respectively. The results of MTT assays indicated that the cell growth on the scaffolds was augmented when compared to the control, from day one to day seven. Mild edema, mild foreign-body granulomatous reaction and mild fibrosis were observed by pathology test as the side effects in the composite scaffold with 50% PCL. Doppler ultrasound and angiography images confirm that no aneurysm, thrombogenesis, neointimal hyperplasia or occlusion exist, and there is complete patency at the end of an eight month investigation. The fabricated composite Vascular scaffolds provide appropriate mechanical and biological properties and clinical requirements, indicating their required potential to be applied as a small-Diameter Vascular Graft.
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Small-Diameter Vascular Graft using co-electrospun composite PCL/PU nanofibers
Biomedical Materials, 2018Co-Authors: Nafiseh Jirofti, Abdolreza Samimi, Afra Hadjizadeh, Davod Mohebbi-kalhori, Gholam Hossein KazemzadehAbstract:Small-Diameter Vascular scaffolds have been developed by a co-electrospinning method using polyethylene terephthalate (PCL) and elastic polytetrafluoroethylene (PU) as biopolymers with long degradation time. Although they possess favorable properties, individually these two polymers do not meet the requirements for the production of synthetic Vascular scaffolds. The co-electrospinning method was adopted to develop and mechanically improve the composite PCL/PU Vascular scaffolds. The morphological, mechanical and biological properties of these Vascular scaffolds were evaluated through scanning electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, compliance, tensile testing and MTT assay. The in vivo study of the Vascular scaffolds was performed by implanting them on rat and sheep models. The compliance of the composite Vascular scaffolds improved by up to 43% through an increased percentage of PU from 10%–90%. The obtained UTS of the scaffolds at 10%, 25%, 50%, 75% and 90% of PU were 4.7 ± 0.34, 3.4 ± 0.6, 4.8 ± 0.62, 2.2 ± 0.34 and 4.4 ± 1.9 MPa, respectively. The results of MTT assays indicated that the cell growth on the scaffolds was augmented when compared to the control, from day one to day seven. Mild edema, mild foreign-body granulomatous reaction and mild fibrosis were observed by pathology test as the side effects in the composite scaffold with 50% PCL. Doppler ultrasound and angiography images confirm that no aneurysm, thrombogenesis, neointimal hyperplasia or occlusion exist, and there is complete patency at the end of an eight month investigation. The fabricated composite Vascular scaffolds provide appropriate mechanical and biological properties and clinical requirements, indicating their required potential to be applied as a small-Diameter Vascular Graft.
S Shorgashti - One of the best experts on this subject based on the ideXlab platform.
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fabrication of microporous thermoplastic polyurethane for use as small Diameter Vascular Graft material i phase inversion method
Journal of Biomedical Materials Research Part B, 2006Co-Authors: M T Khorasani, S ShorgashtiAbstract:Fabrication conditions of microporous thermoplastic polyurethane to be used in small-Diameter Vascular Grafts are studied. Porosity variations due to various factors such as concentration of PU solution, composition of coagulation bath, effect of coagulant temperature, and effect of dissolved air in PU solution are discussed. The liquid–liquid phase-inversion process used for preparation of PU films and the mechanism for the formation of microporous films are discussed. Surface and cross-section morphologies of PU films are studied with the use of scanning electron microscopy (SEM), and porosity value and mechanical strength of PU films are also determined. SEM photomicrographs show that PU films prepared in an alcoholic coagulant have uniform porous structure compared to films prepared in water coagulant. Increasing the polymer concentration and coagulant temperature (>23°C) decreases the macrovoid formation, as seen in cross sections of PU films. This enhances the tensile modulus of PU films. By using this process adjustment may be made on the morphology and compliance, as they are important factors in design and fabrication of small-Diameter Vascular Grafts. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
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Fabrication of microporous thermoplastic polyurethane for use as small‐Diameter Vascular Graft material. I. Phase‐inversion method
Journal of Biomedical Materials Research Part B, 2006Co-Authors: M T Khorasani, S ShorgashtiAbstract:Fabrication conditions of microporous thermoplastic polyurethane to be used in small-Diameter Vascular Grafts are studied. Porosity variations due to various factors such as concentration of PU solution, composition of coagulation bath, effect of coagulant temperature, and effect of dissolved air in PU solution are discussed. The liquid–liquid phase-inversion process used for preparation of PU films and the mechanism for the formation of microporous films are discussed. Surface and cross-section morphologies of PU films are studied with the use of scanning electron microscopy (SEM), and porosity value and mechanical strength of PU films are also determined. SEM photomicrographs show that PU films prepared in an alcoholic coagulant have uniform porous structure compared to films prepared in water coagulant. Increasing the polymer concentration and coagulant temperature (>23°C) decreases the macrovoid formation, as seen in cross sections of PU films. This enhances the tensile modulus of PU films. By using this process adjustment may be made on the morphology and compliance, as they are important factors in design and fabrication of small-Diameter Vascular Grafts. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Lu Wang - One of the best experts on this subject based on the ideXlab platform.
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Hydrogel Small-Diameter Vascular Graft Reinforced with a Braided Fiber Strut with Improved Mechanical Properties
Polymers, 2019Co-Authors: Guoping Guan, Yufen Wu, Chenglong Yu, Meiyi Xing, Xingyou Hu, Hongjun Wang, Lu WangAbstract:Acute thrombosis remains the main limitation of small-Diameter Vascular Grafts (inner Diameter
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hydrogel small Diameter Vascular Graft reinforced with a braided fiber strut with improved mechanical properties
Polymers, 2019Co-Authors: Guoping Guan, Yufen Wu, Chenglong Yu, Meiyi Xing, Xingyou Hu, Hongjun Wang, Lu WangAbstract:Acute thrombosis remains the main limitation of small-Diameter Vascular Grafts (inner Diameter <6 mm) for bridging and bypassing of small arteries defects and occlusion. The use of hydrogel tubes represents a promising strategy. However, their low mechanical strength and high swelling tendency may limit their further application. In the present study, a hydrogel Vascular Graft of Ca alginate/polyacrylamide reinforced with a braided fiber strut was designed and fabricated with the assistance of a customized casting mold. Morphology, structure, swellability, mechanical properties, cyto- and hemocompatibility of the reinforced Graft were characterized. The results showed that the reinforced Graft was transparent and robust, with a smooth surface. Scanning electron microscopic examination confirmed a uniform porous structure throughout the hydrogel. The swelling of the reinforced Grafts could be controlled to 100%, obtaining clinically satisfactory mechanical properties. In particular, the dynamic circumferential compliance reached (1.7 ± 0.1)%/100 mmHg for 50–90 mmHg, a value significantly higher than that of expanded polytetrafluoroethylene (ePTFE) Vascular Grafts. Biological tests revealed that the reinforced Graft was non-cytotoxic and had a low hemolysis percentage (HP) corresponding to (0.9 ± 0.2)%. In summary, the braided fiber-reinforced hydrogel Vascular Grafts demonstrated both physical and biological superiority, suggesting their suitability for Vascular Grafts.
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Surface modification of polyvinyl alcohol (PVA)/polyacrylamide (PAAm) hydrogels with polydopamine and REDV for improved applicability
Journal of Biomedical Materials Research Part B, 2019Co-Authors: Yufen Wu, Chenglong Yu, Meiyi Xing, Lu Wang, Guoping GuanAbstract:Developing a small-Diameter Vascular Graft with a satisfactory performance in terms of mechanical and biological properties remains a challenging issue because of comprehensive requirements from clinical applications. Polyvinyl alcohol (PVA)/polyacrylamide (PAAm) hydrogels exhibit many desirable characteristics for small-Diameter Vascular Grafts because of their tunable mechanical properties, especially high compliance. However, poor cells adhesion hinders their application for endothelialization in situ. Therefore, in the present work, polydopamine (PDA) and tetrapeptide Arg-Glu-Asp-Val (REDV) were used to functionalize the hydrogels surface and improve cells adhesion. A series of characterizations were systematically conducted to examine the applicability of coated hydrogels to small-Diameter Vascular Grafts. Results showed that bare and coated hydrogels have appropriate structural stability, and no significant differences in tensile properties could be found after being coated with PDA or PDA-REDV. The hydrophilicity of the hydrogels decreased with the coatings of PDA and especially PDA-REDV to improve protein adsorption, porcine iliac artery endothelial cells (PIECs) adhesion, viability, proliferation, and spreading on the hydrogels. Lower hemolysis percentages and higher blood clotting index values were attained for the hydrogels, suggesting their satisfactory hemocompatibility. Overall, the present work provided insights into the development of a novel hydrogel-based small-Diameter Vascular Graft. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:117-127, 2020.
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promising poly caprolactone composite reinforced with weft knitted polyester for small Diameter Vascular Graft application
Advances in Materials Science and Engineering, 2014Co-Authors: Fujun Wang, Abedalwafa Mohammed, Chaojing Li, Lu WangAbstract:The present study was designed to improve the mechanical performance of a small-Diameter Vascular prosthesis made from a flexible membrane of poly(e-caprolactone) (PCL). PCL reinforcement was achieved by embedding a tubular fabric knitted from polyethylene terephthalate (PET) yarns within the freeze-dried composite structure. The knitting density of PET fabric influenced the mechanical properties of the new Vascular Graft. Results showed that the composite prototype has good mechanical properties, water permeability, elastic recovery, and suture retention strength. Increases in loop density increased compressive strength and suture retention strength and decreased elastic recovery. The new composite prototype Vascular Graft has promising potential applications in clinics because of its excellent mechanical properties.