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Geng X, Xu ZQ, Tu CZ, Peng J, Jin X, Ye L, Zhang AY, Gu YQ, Feng ZG. Hydrogel Complex Electrospun Scaffolds and Their Multiple Functions in In Situ Vascular Tissue Engineering. ACS APPLIED BIO MATERIALS 2021; 4:2373-2384. [DOI: 10.1021/acsabm.0c01225] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Xue Geng
- School of Materials Science & Engineering, Beijing Institution of Technology, Beijing 100081, China
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, Beijing 100081, China
| | - Ze-Qin Xu
- Vascular Surgery, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Cheng-Zhao Tu
- School of Materials Science & Engineering, Beijing Institution of Technology, Beijing 100081, China
| | - Jia Peng
- School of Materials Science & Engineering, Beijing Institution of Technology, Beijing 100081, China
| | - Xin Jin
- School of Materials Science & Engineering, Beijing Institution of Technology, Beijing 100081, China
| | - Lin Ye
- School of Materials Science & Engineering, Beijing Institution of Technology, Beijing 100081, China
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, Beijing 100081, China
| | - Ai-Ying Zhang
- School of Materials Science & Engineering, Beijing Institution of Technology, Beijing 100081, China
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, Beijing 100081, China
| | - Yong-Quan Gu
- Vascular Surgery, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Zeng-Guo Feng
- School of Materials Science & Engineering, Beijing Institution of Technology, Beijing 100081, China
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, Beijing 100081, China
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Xu Z, Feng Z, Guo L, Ye L, Tong Z, Geng X, Wang C, Jin X, Hui X, Gu Y. Biocompatibility evaluation of heparin-conjugated poly(ε-caprolactone) scaffolds in a rat subcutaneous implantation model. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2020; 31:76. [PMID: 32761269 DOI: 10.1007/s10856-020-06419-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 07/27/2020] [Indexed: 06/11/2023]
Abstract
Vascular grafts prepared from synthetic polymers have serious shortcomings that can be resolved by surface modification, such as by immobilizing heparin. In this study, the mechanical properties, biocompatibility, anticoagulation property, and water contact angle of two heparin-conjugated poly(ε-caprolactone) scaffolds (PCL-hexamethylendiamine-heparin, PCL-HMD-H. PCL-lysine-heparin, PCL-LYS-H) were compared to identify a preferred heparin conjugation method. An evaluation of the subcutaneous tissue biocompatibility of the scaffolds demonstrated that PCL-HMD-H had better endothelial cell proliferation than the PCL-LYS-H and was therefore a promising scaffold candidate for use in vascular tissue-engineering.
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Affiliation(s)
- Zeqin Xu
- Department of Vascular Surgery, Xuan Wu Hospital and Institute of Vascular Surgery, Capital Medical University, 100053, Beijing, China
| | - Zengguo Feng
- School of Materials Science & Engineering, Beijing Institute of Technology, 100081, Beijing, China
| | - Lianrui Guo
- Department of Vascular Surgery, Xuan Wu Hospital and Institute of Vascular Surgery, Capital Medical University, 100053, Beijing, China
| | - Lin Ye
- School of Materials Science & Engineering, Beijing Institute of Technology, 100081, Beijing, China
| | - Zhu Tong
- Department of Vascular Surgery, Xuan Wu Hospital and Institute of Vascular Surgery, Capital Medical University, 100053, Beijing, China
| | - Xue Geng
- School of Materials Science & Engineering, Beijing Institute of Technology, 100081, Beijing, China
| | - Cong Wang
- Department of Vascular Surgery, Xuan Wu Hospital and Institute of Vascular Surgery, Capital Medical University, 100053, Beijing, China
| | - Xin Jin
- School of Materials Science & Engineering, Beijing Institute of Technology, 100081, Beijing, China
| | - Xin Hui
- School of Materials Science & Engineering, Beijing Institute of Technology, 100081, Beijing, China
| | - Yongquan Gu
- Department of Vascular Surgery, Xuan Wu Hospital and Institute of Vascular Surgery, Capital Medical University, 100053, Beijing, China.
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Bioprinted gelatin hydrogel platform promotes smooth muscle cell contractile phenotype maintenance. Biomed Microdevices 2018; 20:32. [PMID: 29594704 DOI: 10.1007/s10544-018-0274-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Three dimensional (3D) bioprinting has been proposed as a method for fabricating tissue engineered small diameter vascular prostheses. This technique not only involves constructing the structural features to obtain a desired pattern but the morphology of the pattern may also be used to influence the behavior of seeded cells. Herein, we 3D bioprinted a gelatin hydrogel microchannel construct to promote and preserve the contractile phenotype of vascular smooth muscle cells (vSMCs), which is crucial for vasoresponsiveness. The microchanneled surface of a gelatin hydrogel facilitated vSMC attachment and an elongated alignment along the microchannel direction. The cells displayed distinct F-actin anisotropy in the direction of the channel. The vSMC contractile phenotype was confirmed by the positive detection of contractile marker gene proteins (α-smooth muscle actin (α-SMA) and smooth muscle-myosin heavy chain (SM-MHC)). Having demonstrated the effectiveness of the hydrogel channels bioprinted on a film, the bioprinting was applied radially to the surface of a 3D tubular construct by integrating a rotating mandrel into the 3D bioprinter. The hydrogel microchannels printed on the 3D tubular vascular construct also orientated the vSMCs and strongly promoted the contractile phenotype. Together, our study demonstrated that microchannels bioprinted using a transglutaminase crosslinked gelatin hydrogel, could successfully promote and preserve vSMC contractile phenotype. Furthermore, the hydrogel bioink could be retained on the surface of a rotating polymer tube to print radial cell guiding channels onto a vascular graft construct.
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Madhavan K, Frid MG, Hunter K, Shandas R, Stenmark KR, Park D. Development of an electrospun biomimetic polyurea scaffold suitable for vascular grafting. J Biomed Mater Res B Appl Biomater 2018; 106:278-290. [PMID: 28130878 PMCID: PMC6080858 DOI: 10.1002/jbm.b.33853] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 11/15/2016] [Accepted: 01/01/2017] [Indexed: 12/19/2022]
Abstract
The optimization of biomechanical and biochemical properties of a vascular graft to render properties relevant to physiological environments is a major challenge today. These critical properties of a vascular graft not only regulate its stability and integrity, but also control invasion of cells for scaffold remodeling permitting its integration with native tissue. In this work, we have synthesized a biomimetic scaffold by electrospinning a blend of a polyurea, poly(serinol hexamethylene urea) (PSHU), and, a polyester, poly-ε-caprolactone (PCL). Mechanical properties of the scaffold were varied by varying polymer blending ratio and electrospinning flow rate. Mechanical characterization revealed that scaffolds with lower PSHU content relative to PCL content resulted in elasticity close to native mammalian arteries. We also found that increasing electrospinning flow rates also increased the elasticity of the matrix. Optimization of elasticity generated scaffolds that enabled vascular smooth muscle cells (SMCs) to adhere, grow and maintain a SMC phenotype. The 30/70 scaffold also underwent slower degradation than scaffolds with higher PSHU content, thereby, providing the best option for in vivo remodeling. Further, Gly-Arg-Gly-Asp-Ser (RGD) covalently conjugated to the polyurea backbone in 30/70 scaffold resulted in significantly increased clotting times. Reducing surface thrombogenicity by the conjugation of RGD is critical to avoiding intimal hyperplasia. Hence, biomechanical and biochemical properties of a vascular graft can be balanced by optimizing synthesis parameters and constituent components. For these reasons, the optimized RGD-conjugated 30/70 scaffold electrospun at 2.5 or 5 mL/h has great potential as a suitable material for vascular grafting applications. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 278-290, 2018.
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Affiliation(s)
- Krishna Madhavan
- Department of Bioengineering, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, 80045, USA
- Cardiovascular Pulmonary Group, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Maria G. Frid
- Department of Pediatrics, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, 80045, USA
- Cardiovascular Pulmonary Group, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Kendall Hunter
- Department of Bioengineering, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, 80045, USA
- Cardiovascular Pulmonary Group, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Robin Shandas
- Department of Bioengineering, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, 80045, USA
- Department of Pediatrics, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, 80045, USA
- Department of Surgery, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, 80045, USA
- Cardiovascular Pulmonary Group, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Kurt R. Stenmark
- Department of Pediatrics, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, 80045, USA
- Cardiovascular Pulmonary Group, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Daewon Park
- Department of Bioengineering, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, 80045, USA
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Wang F, Zhang J, Wang R, Gu Y, Li J, Wang C. Triton X-100 combines with chymotrypsin: A more promising protocol to prepare decellularized porcine carotid arteries. Biomed Mater Eng 2017; 28:531-543. [PMID: 28854493 DOI: 10.3233/bme-171694] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Morbidity and mortality of cardiovascular diseases are increasing in recent years. To solve these problems, vascular transplantation has become a common approach. Decellularization has been a hot spot of tissue engineering to prepare vessel substitutes for vascular transplantation. However, there is no established canonical protocol for decellularization thus far. OBJECTIVE To further understand the decellularization effect of decellularization protocols and the causal relationship between decellularization and mechanical properties. METHODS Three decellularization protocols including two chemical protocols based on SDS and Trypsin respectively and a combination of Triton X-100 with chymotrypsin were adopted to obtain decellularized porcine carotid arteries in our study. After decellularization, histological analysis, scanning electron microscopy and mechanical tests were performed to evaluate their efficiency on removing of cellular components, retention of extracellular matrix and influence on mechanical properties. RESULTS All these decellularization protocols used in our study were efficient to remove cellular components. However, SDS and trypsin performed more disruptive effect on ECM structure and mechanical properties of native arteries while Triton X-100 combines with chymotrypsin had no significant disruptive effect. CONCLUSIONS Compared with decellularization protocols based on SDS and trypsin, Triton X-100 combines with chymotrypsin used in our study may be a more promising protocol to prepare decellularized porcine carotid arteries for vascular tissue engineering applications.
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Affiliation(s)
- Fei Wang
- Department of Vascular Surgery, Xuan Wu Hospital, Capital Medical University, Beijing, P.R. China.,Institute of Vascular Surgery, Capital Medical University, Beijing, P.R. China
| | - Jian Zhang
- Department of Vascular Surgery, Xuan Wu Hospital, Capital Medical University, Beijing, P.R. China.,Institute of Vascular Surgery, Capital Medical University, Beijing, P.R. China
| | - Rong Wang
- Department of Central Laboratory, Xuan Wu Hospital, Capital Medical University, Beijing, P.R. China
| | - Yongquan Gu
- Department of Vascular Surgery, Xuan Wu Hospital, Capital Medical University, Beijing, P.R. China.,Institute of Vascular Surgery, Capital Medical University, Beijing, P.R. China
| | - Jianxin Li
- Department of Vascular Surgery, Xuan Wu Hospital, Capital Medical University, Beijing, P.R. China.,Institute of Vascular Surgery, Capital Medical University, Beijing, P.R. China
| | - Cong Wang
- Department of Vascular Surgery, Xuan Wu Hospital, Capital Medical University, Beijing, P.R. China.,Institute of Vascular Surgery, Capital Medical University, Beijing, P.R. China
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Zhu GC, Wang ZG, Bian C, Zhang JW, Hu ZW, Hou GF, Guo W, Ma C. Mesoatrial Shunt for Budd-Chiari Syndrome. Ann Vasc Surg 2017; 47:62-68. [PMID: 28739463 DOI: 10.1016/j.avsg.2017.07.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 02/14/2017] [Accepted: 07/18/2017] [Indexed: 11/18/2022]
Abstract
BACKGROUND The long-term efficacy of mesoatrial shunt (MAS) for Budd-Chiari syndrome (BCS) is not well studied. The purpose of our study was to investigate the long-term outcome and efficacy of MAS for BCS. METHODS We retrospectively evaluated 11 patients who underwent MAS for BCS from April 1986 to November 1995. Records of patients' clinical presentations, laboratorial investigation, Doppler duplex ultrasonography, radiologic image, and treatment outcomes were all retrieved and analyzed. RESULTS Follow-up intervals ranged from 1 year and 2 months to 30 years and 2 months (mean, 17 years and 8 months). Portal pressure decreased significantly from 35.72 ± 3.52 cm H2O to 27.86 ± 5.83 cm H2O post-MAS (P = 0.001). The 5-year, 10-year, and 20-year patency were 72.7%, 54.5%, 36.4%, respectively; 63.3% of patients had survived for more than 10 years and 45.5% for more than 20 years. A male has been alive with patent shunt for 28 years and 1 month. CONCLUSIONS The MAS with enforced rings is an effective therapeutic modality for BCS with cautious perioperative management.
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Affiliation(s)
- Guang-Chang Zhu
- Department of Cardiovascular Surgery, The General Hospital of the PLA Rocket Force, Beijing Normal University, Beijing, China
| | - Zhong-Gao Wang
- Department of Cardiovascular Surgery, The General Hospital of the PLA Rocket Force, Beijing Normal University, Beijing, China; Department of Vascular Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China.
| | - Ce Bian
- Department of Cardiovascular Surgery, The General Hospital of the PLA Rocket Force, Beijing Normal University, Beijing, China
| | - Jian-Wei Zhang
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Zhi-Wei Hu
- Department of Cardiovascular Surgery, The General Hospital of the PLA Rocket Force, Beijing Normal University, Beijing, China
| | - Guo-Feng Hou
- Department of Cardiovascular Surgery, The General Hospital of the PLA Rocket Force, Beijing Normal University, Beijing, China
| | - Wei Guo
- Department of Cardiovascular Surgery, The General Hospital of the PLA Rocket Force, Beijing Normal University, Beijing, China
| | - Chao Ma
- Department of Cardiovascular Surgery, The General Hospital of the PLA Rocket Force, Beijing Normal University, Beijing, China
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Xu ZC, Zhang Q, Li H. Engineering of the human vessel wall with hair follicle stem cells in vitro. Mol Med Rep 2016; 15:417-422. [PMID: 27959397 DOI: 10.3892/mmr.2016.6013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 10/11/2016] [Indexed: 11/05/2022] Open
Abstract
Hair follicle stem cells (HFSCs) are increasingly used as a stem cell paradigm in vascular tissue engineering due to the fact that they are a rich source of easily accessible multipotent adult stem cells. Promising results have been demonstrated with small diameter (less than 6 mm) tissue engineered blood vessels under low blood pressure, however engineering large vessels (>6 mm in diameter) remains a challenge due to the fact it demands a higher number of seed cells and higher quality biomechanical properties. The aim of the current study was to engineer a large vessel (6 mm in diameter) with differentiated smooth muscle cells (SMCs) induced from human (h)HFSCs using transforming growth factor‑β1 and platelet‑derived growth factor BB in combination with low‑serum culture medium. The cells were seeded onto polyglycolic acid and then wrapped around a silicone tube and further cultured in vitro. A round vessel wall was formed subsequent to 8 weeks of culture. Histological examination indicated that layers of smooth muscle‑like cells and collagenous fibres were oriented in the induced group. In contrast, disorganised cells and collagenous fibres were apparent in the undifferentiated group. The approach developed in the current study demonstrated potential for constructing large muscular vessels with differentiated SMCs induced from hHFSCs.
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Affiliation(s)
- Zhi-Cheng Xu
- Department of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200011, P.R. China
| | - Qun Zhang
- Department of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200011, P.R. China
| | - Hong Li
- Department of Life Information and Instrument Engineering, Hangzhou Electronic Science and Technology University, Hangzhou, Zhejiang 310058, P.R. China
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Boire TC, Balikov DA, Lee Y, Guth CM, Cheung-Flynn J, Sung HJ. Biomaterial-Based Approaches to Address Vein Graft and Hemodialysis Access Failures. Macromol Rapid Commun 2016; 37:1860-1880. [PMID: 27673474 PMCID: PMC5156561 DOI: 10.1002/marc.201600412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/15/2016] [Indexed: 12/19/2022]
Abstract
Veins used as grafts in heart bypass or as access points in hemodialysis exhibit high failure rates, thereby causing significant morbidity and mortality for patients. Interventional or revisional surgeries required to correct these failures have been met with limited success and exorbitant costs, particularly for the US Centers for Medicare & Medicaid Services. Vein stenosis or occlusion leading to failure is primarily the result of neointimal hyperplasia. Systemic therapies have achieved little long-term success, indicating the need for more localized, sustained, biomaterial-based solutions. Numerous studies have demonstrated the ability of external stents to reduce neointimal hyperplasia. However, successful results from animal models have failed to translate to the clinic thus far, and no external stent is currently approved for use in the US to prevent vein graft or hemodialysis access failures. This review discusses current progress in the field, design considerations, and future perspectives for biomaterial-based external stents. More comparative studies iteratively modulating biomaterial and biomaterial-drug approaches are critical in addressing mechanistic knowledge gaps associated with external stent application to the arteriovenous environment. Addressing these gaps will ultimately lead to more viable solutions that prevent vein graft and hemodialysis access failures.
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Affiliation(s)
- Timothy C Boire
- Department of Biomedical Engineering, Vanderbilt University, 37235, Nashville, TN, USA
| | - Daniel A Balikov
- Department of Biomedical Engineering, Vanderbilt University, 37235, Nashville, TN, USA
| | - Yunki Lee
- Department of Biomedical Engineering, Vanderbilt University, 37235, Nashville, TN, USA
| | - Christy M Guth
- Division of Vascular Surgery, Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, 37235, USA
| | - Joyce Cheung-Flynn
- Division of Vascular Surgery, Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, 37235, USA
| | - Hak-Joon Sung
- Department of Biomedical Engineering, Vanderbilt University, 37235, Nashville, TN, USA
- Severance Biomedical Science Institute, College of Medicine, Yonsei University, Seoul, 120-752, Republic of Korea
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Hauser S, Jung F, Pietzsch J. Human Endothelial Cell Models in Biomaterial Research. Trends Biotechnol 2016; 35:265-277. [PMID: 27789063 DOI: 10.1016/j.tibtech.2016.09.007] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 09/15/2016] [Accepted: 09/28/2016] [Indexed: 01/05/2023]
Abstract
Endothelial cell (EC) models have evolved as important tools in biomaterial research due to ubiquitously occurring interactions between implanted materials and the endothelium. However, screening the available literature has revealed a gap between material scientists and physiologists in terms of their understanding of these biomaterial-endothelium interactions and their relative importance. Consequently, EC models are often applied in nonphysiological experimental setups, or too extensive conclusions are drawn from their results. The question arises whether this might be one reason why, among the many potential biomaterials, only a few have found their way into the clinic. In this review, we provide an overview of established EC models and possible selection criteria to enable researchers to determine the most reliable and relevant EC model to use.
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Affiliation(s)
- Sandra Hauser
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Department Radiopharmaceutical and Chemical Biology, Dresden, Germany
| | - Friedrich Jung
- Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, Teltow, Germany; Helmholtz Virtual Institute 'Multifunctional Biomaterials for Medicine', Teltow, Germany
| | - Jens Pietzsch
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Department Radiopharmaceutical and Chemical Biology, Dresden, Germany; Technische Universität Dresden, Department of Chemistry and Food Chemistry, Dresden, Germany.
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Mubyana K, Koppes RA, Lee KL, Cooper JA, Corr DT. The influence of specimen thickness and alignment on the material and failure properties of electrospun polycaprolactone nanofiber mats. J Biomed Mater Res A 2016; 104:2794-800. [PMID: 27355844 DOI: 10.1002/jbm.a.35821] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 06/17/2016] [Accepted: 06/22/2016] [Indexed: 12/24/2022]
Abstract
Electrospinning is a versatile fabrication technique that has been recently expanded to create nanofibrous structures that mimic ECM topography. Like many materials, electrospun constructs are typically characterized on a smaller scale, and scaled up for various applications. This established practice is based on the assumption that material properties, such as toughness, failure stress and strain, are intrinsic to the material, and thus will not be influenced by specimen geometry. However, we hypothesized that the material and failure properties of electrospun nanofiber mats vary with specimen thickness. To test this, we mechanically characterized polycaprolactone (PCL) nanofiber mats of three different thicknesses in response to constant rate elongation to failure. To identify if any observed thickness-dependence could be attributed to fiber alignment, such as the effects of fiber reorientation during elongation, these tests were performed in mats with either random or aligned nanofiber orientation. Contrary to our hypothesis, the failure strain was conserved across the different thicknesses, indicating similar maximal elongation for specimens of different thickness. However, in both the aligned and randomly oriented groups, the ultimate tensile stress, short-range modulus, yield modulus, and toughness all decreased with increasing mat thickness, thereby indicating that these are not intrinsic material properties. These findings have important implications in engineered scaffolds for fibrous and soft tissue applications (e.g., tendon, ligament, muscle, and skin), where such oversights could result in unwanted laxity or reduced resistance to failure. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2794-2800, 2016.
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Affiliation(s)
- Kuwabo Mubyana
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York, 12180
| | - Ryan A Koppes
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York, 12180
| | - Kristen L Lee
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York, 12180
| | - James A Cooper
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York, 12180.,Musculoskeletal and Translational Tissue Engineering Research Lab©, P.O. Box 153, 7715 Crittenden Street, Philadelphia, Pennsylvania 19118
| | - David T Corr
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York, 12180.
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Fabrication and characterisation of biomimetic, electrospun gelatin fibre scaffolds for tunica media-equivalent, tissue engineered vascular grafts. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2015; 61:473-83. [PMID: 26838874 DOI: 10.1016/j.msec.2015.12.081] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 12/02/2015] [Accepted: 12/28/2015] [Indexed: 11/20/2022]
Abstract
It is increasingly recognised that biomimetic, natural polymers mimicking the extracellular matrix (ECM) have low thrombogenicity and functional motifs that regulate cell-matrix interactions, with these factors being critical for tissue engineered vascular grafts especially grafts of small diameter. Gelatin constitutes a low cost substitute of soluble collagen but gelatin scaffolds so far have shown generally low strength and suture retention strength. In this study, we have devised the fabrication of novel, electrospun, multilayer, gelatin fibre scaffolds, with controlled fibre layer orientation, and optimised gelatin crosslinking to achieve not only compliance equivalent to that of coronary artery but also for the first time strength of the wet tubular acellular scaffold (swollen with absorbed water) same as that of the tunica media of coronary artery in both circumferential and axial directions. Most importantly, for the first time for natural scaffolds and in particular gelatin, high suture retention strength was achieved in the range of 1.8-1.94 N for wet acellular scaffolds, same or better than that for fresh saphenous vein. The study presents the investigations to relate the electrospinning process parameters to the microstructural parameters of the scaffold, which are further related to the mechanical performance data of wet, crosslinked, electrospun scaffolds in both circumferential and axial tubular directions. The scaffolds exhibited excellent performance in human smooth muscle cell (SMC) proliferation, with SMCs seeded on the top surface adhering, elongating and aligning along the local fibres, migrating through the scaffold thickness and populating a transverse distance of 186 μm and 240 μm 9 days post-seeding for scaffolds of initial dry porosity of 74 and 83%, respectively.
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