201
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Hou L, Peck Y, Wang X, Wang D. Surface patterning and modification of polyurethane biomaterials using silsesquioxane-gelatin additives for improved endothelial affinity. Sci China Chem 2013. [DOI: 10.1007/s11426-013-4997-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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202
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Prasad A, Xiao N, Gong XY, Zarins CK, Figueroa CA. A computational framework for investigating the positional stability of aortic endografts. Biomech Model Mechanobiol 2013; 12:869-87. [PMID: 23143353 PMCID: PMC3638896 DOI: 10.1007/s10237-012-0450-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 10/19/2012] [Indexed: 10/27/2022]
Abstract
Endovascular aneurysm repair (Greenhalgh in N Engl J Med 362(20):1863-1871, 2010) techniques have revolutionized the treatment of thoracic and abdominal aortic aneurysm disease, greatly reducing the perioperative mortality and morbidity associated with open surgical repair techniques. However, EVAR is not free of important complications such as late device migration, endoleak formation and fracture of device components that may result in adverse events such as aneurysm enlargement, need for long-term imaging surveillance and secondary interventions or even death. These complications result from the device inability to withstand the hemodynamics of blood flow and to keep its originally intended post-operative position over time. Understanding the in vivo biomechanical working environment experienced by endografts is a critical factor in improving their long-term performance. To date, no study has investigated the mechanics of contact between device and aorta in a three-dimensional setting. In this work, we developed a comprehensive Computational Solid Mechanics and Computational Fluid Dynamics framework to investigate the mechanics of endograft positional stability. The main building blocks of this framework are: (1) Three-dimensional non-planar aortic and stent-graft geometrical models, (2) Realistic multi-material constitutive laws for aorta, stent, and graft, (3) Physiological values for blood flow and pressure, and (4) Frictional model to describe the contact between the endograft and the aorta. We introduce a new metric for numerical quantification of the positional stability of the endograft. Lastly, in the results section, we test the framework by investigating the impact of several factors that are clinically known to affect endograft stability.
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Affiliation(s)
- Anamika Prasad
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Nan Xiao
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- Department of Biomedical Engineering, King’s College London, London SE1 7EH, UK
| | - Xiao-Yan Gong
- Medical Implant Mechanics LLC, 26895 Aliso Creek Road, Aliso Viejo, CA 92656, USA
| | | | - C. Alberto Figueroa
- Department of Biomedical Engineering, King’s College London, London SE1 7EH, UK
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203
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Air-Spun PLA Nanofibers Modified with Reductively Sheddable Hydrophilic Surfaces for Vascular Tissue Engineering: Synthesis and Surface Modification. Macromol Rapid Commun 2013; 35:447-53. [DOI: 10.1002/marc.201300609] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Revised: 08/29/2013] [Indexed: 01/10/2023]
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204
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Pontini A, Tocco I, Pandis L, Bassetto F, Vindigni V. Alternative conduits for microvascular anastomoses. Surg Innov 2013; 21:277-82. [PMID: 23965592 DOI: 10.1177/1553350613500721] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Thrombotic events in vascular substitutes are the main cause of obliteration of most microvascular prostheses and subsequent failure of microvascular anastomoses. The development of new biomaterials for vascular replacement aims to obtain an ideal graft for microvascular surgery. Completely bioresorbable vascular prostheses with the capacity to induce regeneration and growth of a new vascular segment seem to overcome the limitations of contemporary artificial prostheses, mostly made of artificial materials and lacking the capacity to grow and be remodeled. Autologous vessels are currently the most used material for small-diameter arterial replacement. Immune acceptance is a major advantage offered by this technique, but the time required is a limitation in emergency surgery. The need for a prosthetic graft that would have the same properties as a small-diameter conduit has led investigators to pursue many avenues in vascular biology. This article details the development of microvascular synthetic prostheses, clarifying the current status and the future aims.
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205
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Uzarski JS, Van de Walle AB, McFetridge PS. In vitro method for real-time, direct observation of cell-vascular graft interactions under simulated blood flow. Tissue Eng Part C Methods 2013; 20:116-28. [PMID: 23679070 DOI: 10.1089/ten.tec.2012.0771] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
In the development of engineered vascular grafts, assessing the material's interactive properties with peripheral blood cells and its capacity to endothelialize are important for predicting in vivo graft behavior. Current in vitro techniques used for characterizing cell adhesion at the surface of engineered scaffolds under flow only facilitate a terminal quantification of cell/surface interactions. Here, we present the design of an innovative flow chamber for real-time analysis of blood-biomaterial interactions under controllable hemodynamic conditions. Decellularized human umbilical veins (dHUV) were used as model vascular allografts to characterize platelet, leukocyte, and endothelial cell (EC) adhesion dynamics. Confluent EC monolayers adhered to the lumenal surface of the grafting material were flow conditioned to resist arterial shear stress levels (up to 24 dynes/cm(2)) over a 48 h period, and shown to maintain viability over the 1 week assessment period. The basement membrane was imaged while whole blood/neutrophil suspensions were perfused across the HUV surface to quantify cell accumulation. This novel method facilitates live visualization of dynamic events, including cell adhesion, migration, and morphological adaptation at the blood-graft interface on opaque materials, and it can be used for preliminary assessment of clinically relevant biomaterials before implantation.
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Affiliation(s)
- Joseph S Uzarski
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida , Gainesville, Florida
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206
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Davis LM, Callanan A, Carroll GT, Doyle BJ, Walsh MT, McGloughlin TM. On the potential of hydrated storage for naturally derived ECMs and associated effects on mechanical and cellular performance. J Biomed Mater Res B Appl Biomater 2013; 102:89-97. [DOI: 10.1002/jbm.b.32985] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 04/22/2013] [Accepted: 05/05/2013] [Indexed: 01/16/2023]
Affiliation(s)
- L. M. Davis
- Centre for Applied Biomedical Engineering Research (CABER); Department of Mechanical; Aeronautical and Biomedical Engineering, University of Limerick; Limerick Ireland
- Materials and Surface Science Institute (MSSI); University of Limerick; Limerick Ireland
| | - A. Callanan
- Centre for Applied Biomedical Engineering Research (CABER); Department of Mechanical; Aeronautical and Biomedical Engineering, University of Limerick; Limerick Ireland
- Materials and Surface Science Institute (MSSI); University of Limerick; Limerick Ireland
- Institute for Materials and Processes (IMP); School of Engineering, The University of Edinburgh
| | - G. T. Carroll
- Centre for Applied Biomedical Engineering Research (CABER); Department of Mechanical; Aeronautical and Biomedical Engineering, University of Limerick; Limerick Ireland
- Materials and Surface Science Institute (MSSI); University of Limerick; Limerick Ireland
| | - B. J. Doyle
- Centre for Applied Biomedical Engineering Research (CABER); Department of Mechanical; Aeronautical and Biomedical Engineering, University of Limerick; Limerick Ireland
- Materials and Surface Science Institute (MSSI); University of Limerick; Limerick Ireland
- Intelligent Systems for Medicine Laboratory; School of Mechanical and Chemical Engineering, The University of Western Australia; Perth Australia
- Centre for Cardiovascular Science; The University of Edinburgh; Edinburgh UK
| | - M. T. Walsh
- Centre for Applied Biomedical Engineering Research (CABER); Department of Mechanical; Aeronautical and Biomedical Engineering, University of Limerick; Limerick Ireland
- Materials and Surface Science Institute (MSSI); University of Limerick; Limerick Ireland
| | - T. M. McGloughlin
- Centre for Applied Biomedical Engineering Research (CABER); Department of Mechanical; Aeronautical and Biomedical Engineering, University of Limerick; Limerick Ireland
- Materials and Surface Science Institute (MSSI); University of Limerick; Limerick Ireland
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207
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Riescher S, Wehner D, Schmid T, Zimmermann H, Hartmann B, Schmid C, Lehle K. Titaniumcarboxonitride layer increased biocompatibility of medical polyetherurethanes. J Biomed Mater Res B Appl Biomater 2013; 102:141-8. [DOI: 10.1002/jbm.b.32990] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 03/20/2013] [Accepted: 05/28/2013] [Indexed: 12/12/2022]
Affiliation(s)
- Sebastian Riescher
- Department of Cardiothoracic Surgery; University Medical Centre Regensburg; Franz-Josef-Strauss-Allee 11 93042 Regensburg Germany
| | - Daniel Wehner
- Dualis Medtech GmbH; Am Technologiepark 8+10 82229 Seefeld Germany
| | - Thomas Schmid
- Dualis Medtech GmbH; Am Technologiepark 8+10 82229 Seefeld Germany
| | | | - Björn Hartmann
- pfm medical titanium gmbh; Hoefener Str. 45 90431 Nürnberg Germany
| | - Christof Schmid
- Department of Cardiothoracic Surgery; University Medical Centre Regensburg; Franz-Josef-Strauss-Allee 11 93042 Regensburg Germany
| | - Karla Lehle
- Department of Cardiothoracic Surgery; University Medical Centre Regensburg; Franz-Josef-Strauss-Allee 11 93042 Regensburg Germany
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208
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Ino JM, Sju E, Ollivier V, Yim EKF, Letourneur D, Le Visage C. Evaluation of hemocompatibility and endothelialization of hybrid poly(vinyl alcohol) (PVA)/gelatin polymer films. J Biomed Mater Res B Appl Biomater 2013; 101:1549-59. [PMID: 23846987 DOI: 10.1002/jbm.b.32977] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 04/29/2013] [Accepted: 05/01/2013] [Indexed: 11/08/2022]
Abstract
Engineered grafts are still needed for small diameter blood vessels reconstruction. Ideal materials would prevent thrombosis and intimal hyperplasia by displaying hemocompatibility and mechanical properties close to those of native vessels. In this study, poly(vinyl alcohol) (PVA)/gelatin blends were investigated as a potential vascular support scaffold. We modified a chemically crosslinked PVA hydrogel by incorporation of gelatin to improve endothelial cell attachment with a single-step method. A series of crosslinked PVA/gelatin films with specific ratios set at 100:0, 99:1, 95:5, and 90:10 (w/w) were prepared and their mechanical properties were examined by uniaxial tensile testing. Tubes, obtained from sutured films, were found highly compliant (3.1-4.6%) and exhibited sufficient mechanical strength to sustain hemodynamic strains. PVA-based hydrogels maintained low level of platelet adhesion and low thrombogenic potential. Endothelial cell adhesion and proliferation were drastically improved on PVA/gelatin films with a feed gelatin content as low as 1% (w/w), leading to the formation of a confluent endothelium. Hydrogels with higher gelatin content did not sustain complete endothelialization because of modifications of the film surface, including phase segregation and formation of microdomains. Thus, PVA/gelatin (99:1, w/w) hydrogels appear as promising materials for the design of endothelialized vascular materials with long-term patency.
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Affiliation(s)
- Julia M Ino
- Inserm, U698, Cardiovascular Bio-Engineering, X. Bichat Hospital, 75018, Paris, France; Institut Galilée, University Paris 13, 93430, Villetaneuse, France
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209
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Development and characterization of poly(ε-caprolactone) hollow fiber membranes for vascular tissue engineering. J Memb Sci 2013. [DOI: 10.1016/j.memsci.2013.03.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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210
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Kakade S, Mani G. A comparative study of the effects of vitamin C, sirolimus, and paclitaxel on the growth of endothelial and smooth muscle cells for cardiovascular medical device applications. DRUG DESIGN DEVELOPMENT AND THERAPY 2013; 7:529-44. [PMID: 23836963 PMCID: PMC3699137 DOI: 10.2147/dddt.s45162] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Antiproliferative drugs such as sirolimus (SIR) and paclitaxel (PAT) are currently released from stents and vascular grafts to inhibit the growth of smooth muscle cells (SMCs), thereby preventing neointimal hyperplasia. However, these drugs delay or impair the growth of endothelial cells (ECs) on implant surfaces causing late thrombosis. Hence, there is a need to use alternative drugs in these implants to encourage the growth of ECs and to inhibit the growth of SMCs. Vitamin C (L-ascorbic acid [L-AA]) is one such drug which has been shown to encourage EC growth and inhibit SMC growth when orally administered or added directly to the cell cultures. In this research, four sets of in vitro cell culture experiments were carried out to compare the effects of L-AA, SIR, and PAT on the growth of ECs and SMCs under similar conditions, and to compare the effects of different doses of L-AA to determine the optimal dose for promoting maximum EC growth and inhibiting SMC growth. The ECs and SMCs treated with different drugs were characterized for their viability and proliferation, and morphology using the quantitative resazurin assay (as well as qualitative fluorescence microscopy characterization) and phase contrast microscopy, respectively, for up to 7 days. Also, the phenotype of ECs was characterized using immunofluorescence microscopy. Both SIR and PAT significantly inhibited the EC growth while L-AA significantly encouraged EC growth even more than that of the controls with no drugs. Also, L-AA significantly inhibited SMC growth although the inhibitory effect was inferior to that of SIR and PAT. The L-AA dosage study demonstrated that 100 μg and 300 μg of L-AA showed maximum EC growth after 7 days when compared to other dosages (1 μg, 500 μg, and 1000 μg) of L-AA and controls investigated in this study. Also, the 100 μg and 300 μg L-AA doses significantly inhibited the SMC growth. Thus, this study demonstrates that L-AA is a promising drug for potential use in stents and vascular grafts, to promote their endothelialization and inhibit neointimal hyperplasia.
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Affiliation(s)
- Sandeep Kakade
- Biomedical Engineering Program, The University of South Dakota, Sioux Falls, SD, USA
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211
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Abstract
Vascular occlusion remains the leading cause of death in Western countries, despite advances made in balloon angioplasty and conventional surgical intervention. Vascular surgery, such as CABG surgery, arteriovenous shunts, and the treatment of congenital anomalies of the coronary artery and pulmonary tracts, requires biologically responsive vascular substitutes. Autografts, particularly saphenous vein and internal mammary artery, are the gold-standard grafts used to treat vascular occlusions. Prosthetic grafts have been developed as alternatives to autografts, but their low patency owing to short-term and intermediate-term thrombosis still limits their clinical application. Advances in vascular tissue engineering technology-such as self-assembling cell sheets, as well as scaffold-guided and decellularized-matrix approaches-promise to produce responsive, living conduits with properties similar to those of native tissue. Over the past decade, vascular tissue engineering has become one of the fastest-growing areas of research, and is now showing some success in the clinic.
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Affiliation(s)
- Dawit G Seifu
- Laboratory for Biomaterials and Bioengineering, Department of Min-Met-Materials Engineering and Quebec University Hospital Center, Laval University, Quebec City, QC G1V 0A6, Canada
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212
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Diban N, Haimi S, Bolhuis-Versteeg L, Teixeira S, Miettinen S, Poot A, Grijpma D, Stamatialis D. Hollow fibers of poly(lactide-co-glycolide) and poly(ε-caprolactone) blends for vascular tissue engineering applications. Acta Biomater 2013; 9:6450-8. [PMID: 23318815 DOI: 10.1016/j.actbio.2013.01.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 01/04/2013] [Accepted: 01/07/2013] [Indexed: 01/06/2023]
Abstract
At present the manufacture of small-diameter blood vessels is one of the main challenges in the field of vascular tissue engineering. Currently available vascular grafts rapidly fail due to development of intimal hyperplasia and thrombus formation. Poly(lactic-co-glycolic acid) (PLGA) hollow fiber (HF) membranes have previously been proposed for this application, but as we show in the present work, they have an inhibiting effect on cell proliferation and rather poor mechanical properties. To overcome this we prepared HF membranes via phase inversion using blends of PLGA with poly(ε-caprolactone) (PCL). The influence of polymer composition on the HF physicochemical properties (topography, water transport and mechanical properties) and cell attachment and proliferation were studied. Our results show that only the ratio PCL/PLGA of 85/15 (PCL/PLGA85/15) yielded a miscible blend after processing. A higher PLGA concentration in the blend led to immiscible PCL/PLGA phase-separated HFs with an inhomogeneous morphology and variation in the cell culture results. In fact, the PCL/PLGA85/15 blend, which had the most homogeneous morphology and suitable pore structure, showed better human adipose stem cell (hASC) attachment and proliferation compared with the homopolymers. This, combined with the good mechanical and transport properties, makes them potentially useful for the development of small-caliber vascular grafts.
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213
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Liu H, Ding X, Bi Y, Gong X, Li X, Zhou G, Fan Y. In Vitro Evaluation of Combined Sulfated Silk Fibroin Scaffolds for Vascular Cell Growth. Macromol Biosci 2013; 13:755-66. [DOI: 10.1002/mabi.201200470] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 02/23/2013] [Indexed: 01/15/2023]
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214
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Tropoelastin--a multifaceted naturally smart material. Adv Drug Deliv Rev 2013; 65:421-8. [PMID: 22784558 DOI: 10.1016/j.addr.2012.06.009] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 06/09/2012] [Accepted: 06/21/2012] [Indexed: 12/18/2022]
Abstract
Tropoelastin dominates the physical performance of human elastic tissue as it is assembled to make elastin. Tropoelastin is increasingly appreciated as a protein monomer with a defined solution shape comprising modular, bridged regions that specialize in elasticity and cell attachment, which collectively participate in macromolecular assembly. This modular, multifaceted molecule is being exploited to enhance the physical performance and biological presentation of engineered constructs to augment and repair human tissues. These tissues include skin and vasculature, and emphasize how growing knowledge of tropoelastin can be powerfully adapted to add value to pre-existing devices like stents and novel, multi-featured biological implants.
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215
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Ruiz A, Flanagan CE, Masters KS. Differential support of cell adhesion and growth by copolymers of polyurethane with hyaluronic acid. J Biomed Mater Res A 2013; 101:2870-82. [DOI: 10.1002/jbm.a.34597] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 12/04/2012] [Accepted: 01/02/2012] [Indexed: 11/08/2022]
Affiliation(s)
- Amaliris Ruiz
- Materials Science Program; University of Wisconsin; Madison; Wisconsin
| | - Claire E. Flanagan
- Department of Biomedical Engineering; University of Wisconsin; Madison; Wisconsin
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216
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Brown EE, Hu D, Abu Lail N, Zhang X. Potential of nanocrystalline cellulose-fibrin nanocomposites for artificial vascular graft applications. Biomacromolecules 2013; 14:1063-71. [PMID: 23421631 DOI: 10.1021/bm3019467] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The potential of synthesizing new nanocomposites from nanocrystalline cellulose (NCC) and fibrin for small-diameter replacement vascular graft (SDRVG) application was demonstrated. Periodate oxidation of NCC can augment reactive carbonyl groups on NCC and facilitate its cross-linking with fibrin. NCC-fibrin nanocomposites were synthesized, composed of homogeneously dispersed oxidized NCC (ONCC) in a fibrin matrix, with fibrin providing elasticity and ONCC providing strength. The maximum strength and elongation of the nanocomposites were determined by Atomic Force Microscopy (AFM) and compared with a native blood vessel. The manipulation of degree of oxidation of NCC and the NCC-to-fibrin ratio resulted in the variation of strength and elongation of the nanocomposites, indicating that the nanocomposites can be tailored to conform to the diverse mechanical properties of native blood vessels. A mechanistic understanding of the molecular interactions of ONCC and fibrin was illustrated. This study established fundamental information to utilizing NCC for SDRVG applications.
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Affiliation(s)
- Elvie E Brown
- Bioproducts, Science and Engineering Laboratory, Voiland School of Chemical Engineering and Bioengineering, Washington State University, Richland, Washington 99354, USA
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217
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He W, Hu Z, Xu A, Liu R, Yin H, Wang J, Wang S. The Preparation and Performance of a New Polyurethane Vascular Prosthesis. Cell Biochem Biophys 2013; 66:855-66. [DOI: 10.1007/s12013-013-9528-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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218
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Huang C, Wang S, Qiu L, Ke Q, Zhai W, Mo X. Heparin loading and pre-endothelialization in enhancing the patency rate of electrospun small-diameter vascular grafts in a canine model. ACS APPLIED MATERIALS & INTERFACES 2013; 5:2220-2226. [PMID: 23465348 DOI: 10.1021/am400099p] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We herein proved that the two commonly used antithrombotic methods, heparin loading and pre-endothelialization could both greatly enhance the patency rate of a small-diameter graft in a canine model. Tubular grafts having an inner diameter of 4 mm were prepared by electrospinning poly(l-lactide-co-ε-caprolactone) (P(LLA-CL)) and heparin through a coaxial electrospinning technique. Seventy-two percent of heparin was found to be released sustainably from the graft within 14 days. To prepare the pre-endothelialized grafts, we seeded endothelial cells isolated from the femoral artery and cultured then dynamically on the lumen until a cell monolayer was formed. Digital subtraction angiography (DSA) and color Doppler flow imaging (CDFI) were used to monitor the patency without sacrificing the animals. Histological analyses revealed that following the direction of blood flow, a cell monolayer was formed at the proximal end of the heparin-loaded grafts, but such a monolayer could be found in the middle or distal region of the grafts. In contrast, the whole luminal surface of the pre-endothelialized graft was covered by a cell monolayer, suggesting the in vivo survival of the preseeded cells. This demonstrated that heparin was a comparatively simple method to achieve good patency, but the pre-endothelialization had better mechanical properties and cellular compatibility.
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Affiliation(s)
- Chen Huang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620, China
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219
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In vivo regeneration of elastic lamina on fibroin biodegradable vascular scaffold. Int J Artif Organs 2013; 36:166-74. [PMID: 23404641 DOI: 10.5301/ijao.5000185] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2012] [Indexed: 11/20/2022]
Abstract
PURPOSE There is an increasing need for vascular grafts in the field of surgical revascularization. Artificial grafts offer alternative strategies to autologous tissue, however, small caliber (diameter <6 mm)
vascular prosthesis are associated with a high incidence of thrombosis and early failure. Despite promising results, vascular tissue engineering is not yet a clinical reality due to the complexity of this approach. We aimed at investigating the use of fibroin, a biodegradable protein derived from silk, as an acellular vascular graft for in vivo recellularization.
METHODS We produced small caliber fibroin matrices by electrospinning to replace small arterial segments. Electrospun fibroin scaffolds were implanted into the abdominal aorta of Lewis rats by end-
to-end anastomosis. Seven days after implantation, fibroin matrices were recovered and processed for histological and immunohistochemical analysis.
RESULTS Fibroin matrices allowed host cell infiltration, extracellular matrix remodeling, and ensured good patency of the grafts in the short term. Endothelial cells and smooth muscle cells were present in the explanted construct. Development of an elastic lamina adjacent to the lumen of the scaffold was observed with organization of intima and media layers. Vasa-vasorum were also present in the outer layer of the fibroin material.
CONCLUSIONS Our results indicate that formation of vascular tissue containing elastin occurs already
at 7 days after implantation on fibroin scaffold without in vitro cellularization. The use of an acellular electrospun silk fibroin tubular scaffold could be a promising strategy for in vivo regeneration of vascular tissue in the clinical reality.
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220
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Liu F, Grainger DW. Fluorinated Biomaterials. Biomater Sci 2013. [DOI: 10.1016/b978-0-08-087780-8.00011-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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221
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Aleksieva G, Hollweck T, Thierfelder N, Haas U, Koenig F, Fano C, Dauner M, Wintermantel E, Reichart B, Schmitz C, Akra B. Use of a special bioreactor for the cultivation of a new flexible polyurethane scaffold for aortic valve tissue engineering. Biomed Eng Online 2012. [PMID: 23206816 PMCID: PMC3538608 DOI: 10.1186/1475-925x-11-92] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Background Tissue engineering represents a promising new method for treating heart valve diseases. The aim of this study was evaluate the importance of conditioning procedures of tissue engineered polyurethane heart valve prostheses by the comparison of static and dynamic cultivation methods. Methods Human vascular endothelial cells (ECs) and fibroblasts (FBs) were obtained from saphenous vein segments. Polyurethane scaffolds (n = 10) were primarily seeded with FBs and subsequently with ECs, followed by different cultivation methods of cell layers (A: static, B: dynamic). Group A was statically cultivated for 6 days. Group B was exposed to low flow conditions (t1= 3 days at 750 ml/min, t2= 2 days at 1100 ml/min) in a newly developed conditioning bioreactor. Samples were taken after static and dynamic cultivation and were analyzed by scanning electron microscopy (SEM), immunohistochemistry (IHC), and real time polymerase chain reaction (RT-PCR). Results SEM results showed a high density of adherent cells on the surface valves from both groups. However, better cell distribution and cell behavior was detected in Group B. IHC staining against CD31 and TE-7 revealed a positive reaction in both groups. Higher expression of extracellular matrix (ICAM, Collagen IV) was observed in Group B. RT- PCR demonstrated a higher expression of inflammatory Cytokines in Group B. Conclusion While conventional cultivation method can be used for the development of tissue engineered heart valves. Better results can be obtained by performing a conditioning step that may improve the tolerance of cells to shear stress. The novel pulsatile bioreactor offers an adequate tool for in vitro improvement of mechanical properties of tissue engineered cardiovascular prostheses.
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Affiliation(s)
- Genoveva Aleksieva
- Department of Cardiac Surgery, Medical Center Munich University, Marchioninistraße 15, Munich 81377, Germany
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Hu ZJ, Li ZL, Hu LY, He W, Liu RM, Qin YS, Wang SM. The in vivo performance of small-caliber nanofibrous polyurethane vascular grafts. BMC Cardiovasc Disord 2012; 12:115. [PMID: 23206536 PMCID: PMC3523977 DOI: 10.1186/1471-2261-12-115] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 11/28/2012] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND In a previous in vitro study, we confirmed that small-caliber nanofibrous polyurethane (PU) vascular grafts have favorable mechanical properties and biocompatibility. In the present study, we examined the in vivo biocompatibility and stability of these grafts. METHODS Forty-eight adult male beagle dogs were randomly divided into two groups receiving, respectively, polyurethane (PU) or polytetrafluoroethylene (PTFE) grafts (n = 24 animals / group). Each group was studied at 4, 8, 12, and 24 weeks after graft implantation. Blood flow was analyzed by color Doppler ultrasound and computed tomography angiography. Patency rates were judged by animal survival rates. Coverage with endothelial and smooth muscle cells was characterized by hematoxylin-eosin and immunohistological staining, and scanning electron microscopy (SEM). RESULTS Patency rates were significantly higher in the PU group (p = 0.02 vs. PTFE group). During the first 8 weeks, endothelial cells gradually formed a continuous layer on the internal surface of PU grafts, whereas coverage of PTFE graft by endothelial cells was inhomogeneous. After 12 weeks, neointimal thickness remained constant in the PU group, while PTFE group showed neointimal hyperplasia. At 24 weeks, some anastomotic sites of PTFE grafts became stenotic (p = 0.013 vs. PU group). Immunohistological staining revealed a continuous coverage by endothelial cells and an orderly arrangement of smooth muscle cells on PU grafts. Further, SEM showed smooth internal surfaces in PU grafts without thrombus or obvious neointimal hyperplasia. CONCLUSIONS Small-caliber nanofibrous PU vascular grafts facilitate the endothelialization process, prevent excessive neointimal hyperplasia, and improve patency rates.
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Affiliation(s)
- Zuo-jun Hu
- Department of Vascular Surgery, The First Affiliated Hospital of Sun Yat-Sen University, No. 58 Zhongshan 2nd Road, Guangzhou, 510080, China
| | - Zi-lun Li
- Department of Vascular Surgery, The First Affiliated Hospital of Sun Yat-Sen University, No. 58 Zhongshan 2nd Road, Guangzhou, 510080, China
| | - Ling-yu Hu
- Guangzhou Women and Children’s Medical Center, Guangzhou, 510080, China
| | - Wei He
- Guangzhou Women and Children’s Medical Center, Guangzhou, 510080, China
| | - Rui-ming Liu
- Department of Vascular Surgery, The First Affiliated Hospital of Sun Yat-Sen University, No. 58 Zhongshan 2nd Road, Guangzhou, 510080, China
| | - Yuan-sen Qin
- Department of Vascular Surgery, The First Affiliated Hospital of Sun Yat-Sen University, No. 58 Zhongshan 2nd Road, Guangzhou, 510080, China
| | - Shen-ming Wang
- Department of Vascular Surgery, The First Affiliated Hospital of Sun Yat-Sen University, No. 58 Zhongshan 2nd Road, Guangzhou, 510080, China
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223
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Madhavan K, Elliott WH, Bonani W, Monnet E, Tan W. Mechanical and biocompatible characterizations of a readily available multilayer vascular graft. J Biomed Mater Res B Appl Biomater 2012; 101:506-19. [PMID: 23165922 DOI: 10.1002/jbm.b.32851] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2012] [Revised: 07/31/2012] [Accepted: 09/25/2012] [Indexed: 01/24/2023]
Abstract
There is always a considerable clinical need for vascular grafts. Considering the availability, physical and mechanical properties, and regenerative potential, we have developed and characterized readily available, strong, and compliant multilayer grafts that support cell culture and ingrowth. The grafts were made from heterogeneous materials and structures, including a thin, dense, nanofibrous core composed of poly-ε-caprolactone (PCL), and a thick, porous, hydrogel sleeve composed of genipin-crosslinked collagen-chitosan (GCC). Because the difference in physicochemical properties between PCL and GCC caused layer separation, the layer adhesion was identified as a determinant to graft property and integrity under physiological conditions. Thus, strategies to modify the layer interface, including increasing porosity of the PCL surface, decreasing hydrophobicity, and increasing interlayer crosslinking, were developed. Results from microscopic images showed that increasing PCL porosity was characterized by improved layer adhesion. The resultant graft was characterized by high compliance (4.5%), and desired permeability (528 mL/cm(2)/min), burst strength (695 mmHg), and suture strength (2.38 N) for readily grafting. Results also showed that PCL mainly contributed to the graft mechanical properties, whereas GCC reduced the water permeability. In addition to their complementary contributions to physical and mechanical properties, the distinct graft layers also provided layer-specific structures for seeding and culture of vascular endothelial and smooth muscle cells in vitro. Acellular graft constructs were readily used to replace abdominal aorta of rabbits, resulting in rapid cell ingrowth and flow reperfusion. The multilayer constructs capable of sustaining physiological conditions and promoting cellular activities could serve as a platform for future development of regenerative vascular grafts.
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Affiliation(s)
- Krishna Madhavan
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado, USA
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224
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Marelli B, Achilli M, Alessandrino A, Freddi G, Tanzi MC, Farè S, Mantovani D. Collagen-reinforced electrospun silk fibroin tubular construct as small calibre vascular graft. Macromol Biosci 2012; 12:1566-74. [PMID: 23060093 DOI: 10.1002/mabi.201200195] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 08/05/2012] [Indexed: 11/07/2022]
Abstract
None of the replacements proposed in the literature for small-calibre blood vessels (SCBV) fully satisfies the stringent requirements that these grafts have to fulfil. Here, an electrospun silk fibroin tubular construct is hybridized with type I collagen gel to produce a biomimetic SCBV graft with physiologically relevant compliance and burst pressure and optimal cytocompatibility. The hybridization of the two polymers results in the formation of a nanofibrillar hydrated matrix, where the collagen gel enhances the mechanical properties of the SF tubular construct and improves the early response of the material to in vitro cell adhesion and proliferation.
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Affiliation(s)
- Benedetto Marelli
- BioMatLab, Bioengineering Department, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy
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225
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226
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Sivaraman B, Bashur CA, Ramamurthi A. Advances in biomimetic regeneration of elastic matrix structures. Drug Deliv Transl Res 2012; 2:323-50. [PMID: 23355960 PMCID: PMC3551595 DOI: 10.1007/s13346-012-0070-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Elastin is a vital component of the extracellular matrix, providing soft connective tissues with the property of elastic recoil following deformation and regulating the cellular response via biomechanical transduction to maintain tissue homeostasis. The limited ability of most adult cells to synthesize elastin precursors and assemble them into mature crosslinked structures has hindered the development of functional tissue-engineered constructs that exhibit the structure and biomechanics of normal native elastic tissues in the body. In diseased tissues, the chronic overexpression of proteolytic enzymes can cause significant matrix degradation, to further limit the accumulation and quality (e.g., fiber formation) of newly deposited elastic matrix. This review provides an overview of the role and importance of elastin and elastic matrix in soft tissues, the challenges to elastic matrix generation in vitro and to regenerative elastic matrix repair in vivo, current biomolecular strategies to enhance elastin deposition and matrix assembly, and the need to concurrently inhibit proteolytic matrix disruption for improving the quantity and quality of elastogenesis. The review further presents biomaterial-based options using scaffolds and nanocarriers for spatio-temporal control over the presentation and release of these biomolecules, to enable biomimetic assembly of clinically relevant native elastic matrix-like superstructures. Finally, this review provides an overview of recent advances and prospects for the application of these strategies to regenerating tissue-type specific elastic matrix structures and superstructures.
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Affiliation(s)
- Balakrishnan Sivaraman
- Department of Biomedical Engineering, The Cleveland Clinic, 9500 Euclid Avenue, ND 20, Cleveland, OH 44195, USA
| | - Chris A. Bashur
- Department of Biomedical Engineering, The Cleveland Clinic, 9500 Euclid Avenue, ND 20, Cleveland, OH 44195, USA
| | - Anand Ramamurthi
- Department of Biomedical Engineering, The Cleveland Clinic, 9500 Euclid Avenue, ND 20, Cleveland, OH 44195, USA
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227
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Construction and characterization of an electrospun tubular scaffold for small-diameter tissue-engineered vascular grafts: A scaffold membrane approach. J Mech Behav Biomed Mater 2012; 13:140-55. [DOI: 10.1016/j.jmbbm.2012.04.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 03/22/2012] [Accepted: 04/16/2012] [Indexed: 11/18/2022]
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228
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Rizvi SB, Yildirimer L, Ghaderi S, Ramesh B, Seifalian AM, Keshtgar M. A novel POSS-coated quantum dot for biological application. Int J Nanomedicine 2012; 7:3915-27. [PMID: 22915843 PMCID: PMC3418109 DOI: 10.2147/ijn.s28577] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Quantum dots (QDs) are fluorescent semiconductor nanocrystals that have the potential for
major advancements in the field of nanomedicine through their unique photophysical
properties. They can potentially be used as fluorescent probes for various biomedical
imaging applications, including cancer localization, detection of micrometastasis, image
guided surgery, and targeted drug delivery. Their main limitation is toxicity, which
requires a biologically compatible surface coating to shield the toxic core from the
surrounding environment. However, this leads to an increase in QD size that may lead to
problems of excretion and systemic sequestration. We describe a one pot synthesis,
characterization, and in vitro cytotoxicity of a novel polyhedral oligomeric
silsesquioxane (POSS)-coated CdTe-cored QD using mercaptosuccinic acid (MSA) and
D-cysteine as stabilizing agents. Characterization was performed using transmission
electron microscopy Fourier transform infrared spectroscopy, and photoluminescence
studies. POSS-coated QDs demonstrated high colloidal stability and enhanced photostability
on high degrees of ultraviolet (UV) excitation compared to QDs coated with MSA and
D-cysteine alone (P value < 0.05). In vitro toxicity studies showed
that both POSS and MSA-QDs were significantly less toxic than ionized salts of
Cd+2 and Te−2. Confocal microscopy confirmed high
brightness of POSS-QDs in cells at both 1 and 24 hours, indicating that these QDs are
rapidly taken up by cells and remain photostable in a biological environment. We therefore
conclude that a POSS coating confers biological compatibility, photostability, and
colloidal stability while retaining the small size and unique photophysical properties of
the QDs. The amphiphilic nature of the coating allows solubility in aqueous solutions and
rapid transfer across cell membranes, enabling the use of lower concentrations of the QDs
for an overall reduced toxicity particularly for prolonged live cell and in vivo imaging
applications.
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Affiliation(s)
- Sarwat B Rizvi
- UCL Centre for Nanotechnology and Regenerative Medicine, Division of Surgery and Interventional Science, University College London, United Kingdom
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229
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Wise SG, Waterhouse A, Michael P, Ng MKC. Extracellular matrix molecules facilitating vascular biointegration. J Funct Biomater 2012; 3:569-87. [PMID: 24955633 PMCID: PMC4031001 DOI: 10.3390/jfb3030569] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 08/01/2012] [Accepted: 08/06/2012] [Indexed: 12/16/2022] Open
Abstract
All vascular implants, including stents, heart valves and graft materials exhibit suboptimal biocompatibility that significantly reduces their clinical efficacy. A range of biomolecules in the subendothelial space have been shown to play critical roles in local regulation of thrombosis, endothelial growth and smooth muscle cell proliferation, making these attractive candidates for modulation of vascular device biointegration. However, classically used biomaterial coatings, such as fibronectin and laminin, modulate only one of these components; enhancing endothelial cell attachment, but also activating platelets and triggering thrombosis. This review examines a subset of extracellular matrix molecules that have demonstrated multi-faceted vascular compatibility and accordingly are promising candidates to improve the biointegration of vascular biomaterials.
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Affiliation(s)
- Steven G Wise
- The Heart Research Institute, Eliza Street, Newtown, NSW 2042, Australia.
| | - Anna Waterhouse
- Wyss Institute for Biologically Inspired Engineering at Harvard, Boston, MA 02115, USA.
| | - Praveesuda Michael
- The Heart Research Institute, Eliza Street, Newtown, NSW 2042, Australia.
| | - Martin K C Ng
- The Heart Research Institute, Eliza Street, Newtown, NSW 2042, Australia.
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230
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McClendon MT, Stupp SI. Tubular hydrogels of circumferentially aligned nanofibers to encapsulate and orient vascular cells. Biomaterials 2012; 33:5713-22. [PMID: 22591610 PMCID: PMC3388037 DOI: 10.1016/j.biomaterials.2012.04.040] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 04/13/2012] [Indexed: 11/29/2022]
Abstract
There is a great clinical need for tissue engineered blood vessels that could be used to replace or bypass damaged arteries. The success of such grafts will depend strongly on their ability to mimic the cellular and matrix organization found in native arteries, but currently available cell scaffolds such as electrospun fibers or hydrogels lack the ability to simultaneously encapsulate and align cells. Our laboratory has recently developed liquid crystalline solutions of peptide amphiphile nanofibers that form aligned domains at exceedingly low concentrations (<1 wt%), and can be trapped as gels with macroscopic alignment using low shear rates and ionic crosslinking. We describe here the use of these systems to fabricate tubes with macroscopic circumferential alignment and demonstrate their potential as arterial cell scaffolds. The nanofibers in these tubes were circumferentially aligned by applying small amounts of shear in a custom built flow chamber prior to gelation. Small angle X-ray scattering confirmed that the direction of nanofiber alignment was the same as the direction of shear flow. We also show the encapsulation of smooth muscle cells during the fabrication process without compromising cell viability. After two days in culture the encapsulated cells oriented their long axis in the direction of nanofiber alignment thus mimicking the circumferential alignment seen in native arteries. Cell density roughly doubled after 12 days demonstrating the scaffold's ability to facilitate necessary graft maturation. Since these nanofiber gels are composed of >99% water by weight, the cells have abundant room for proliferation and remodeling. In contrast to previously reported arterial cell scaffolds, this new material can encapsulate cells and direct cellular organization without the requirement of external stimuli or gel compaction.
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Affiliation(s)
- Mark T. McClendon
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208, United States
| | - Samuel I. Stupp
- Department of Chemistry, Northwestern University, Evanston, IL 60208, United States
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, United States
- Institute for BioNanotechnology in Medicine, Northwestern University, Chicago, IL 60611, United States
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States
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231
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Uzarski JS, Van De Walle AB, McFetridge PS. Preimplantation processing of ex vivo-derived vascular biomaterials: effects on peripheral cell adhesion. J Biomed Mater Res A 2012; 101:123-31. [PMID: 22825780 DOI: 10.1002/jbm.a.34308] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 04/25/2012] [Accepted: 05/25/2012] [Indexed: 01/22/2023]
Abstract
The use of ex vivo-derived scaffolds as vascular conduits has shown to be a clinically valid approach to repair or bypass occluded vessels. Implantation of allogeneic tissue grafts requires careful processing to lower immunogenicity and prevent bacterial infection. However, the mechanical/chemical treatments used to prepare biological scaffolds can result in significant alterations to the native structure and surface chemistry, which can affect in vivo performance. Of particular importance for vascular grafts are binding interactions between the implanted biomaterial and host cells from the circulation and adjacent vasculature. Here we present a comparison of four strategies used to decellularize allogeneic human umbilical vein (HUV) scaffolds: ethanol/acetone, sodium chloride, sodium dodecyl sulfate (SDS), or Triton X-100. Scanning electron microscopy revealed that all four techniques achieved removal of native cells from both the lumenal and ablumenal surfaces of HUV grafts. Platelets and promyelocytic HL-60 cells showed preferential binding on the more loosely structured ablumenal surface, although low surface coverage was observed overall by peripheral blood cells. Vascular endothelial cell adhesion was highest on HUV decellularized using ethanol/acetone, and significantly higher than on SDS-processed grafts (p = 0.016). Primary cells showed high viability on the lumenal surface regardless of decellularization technique (over 95% in all cases). These results demonstrate the critical effects of various chemical processing strategies on the adhesive properties of ex vivo-derived vascular grafts. Careful application-specific consideration is warranted when selecting a processing strategy that minimizes innate responses (e.g. thrombosis, inflammation) that are often deleterious to graft survival.
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Affiliation(s)
- Joseph S Uzarski
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611, USA
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232
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Boccafoschi F, Mosca C, Cannas M. Cardiovascular biomaterials: when the inflammatory response helps to efficiently restore tissue functionality? J Tissue Eng Regen Med 2012; 8:253-67. [DOI: 10.1002/term.1526] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 01/30/2012] [Accepted: 04/03/2012] [Indexed: 01/25/2023]
Affiliation(s)
- F. Boccafoschi
- Department of Health Sciences; University of Piemonte Orientale; “A. Avogadro” 28100 Novara Italy
| | - C. Mosca
- Department of Health Sciences; University of Piemonte Orientale; “A. Avogadro” 28100 Novara Italy
| | - M. Cannas
- Department of Health Sciences; University of Piemonte Orientale; “A. Avogadro” 28100 Novara Italy
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233
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Dudash LA, Kligman F, Sarett SM, Kottke-Marchant K, Marchant RE. Endothelial cell attachment and shear response on biomimetic polymer-coated vascular grafts. J Biomed Mater Res A 2012; 100:2204-10. [PMID: 22623267 DOI: 10.1002/jbm.a.34119] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 02/06/2012] [Accepted: 02/07/2012] [Indexed: 11/06/2022]
Abstract
Endothelial cell (EC) adhesion, shear retention, morphology, and hemostatic gene expression on fibronectin (FN) and RGD fluorosurfactant polymer (FSP)-coated expanded polytetrafluoroethylene grafts were investigated using an in vitro perfusion system. ECs were sodded on both types of grafts and exposed to 8 dyn/cm(2) of shear stress. After 24 h, the EC retention on RGD-FSP-coated grafts was 59 ± 14%, which is statistically higher than the 36 ± 11% retention measured on FN grafts (p < 0.02). Additionally, ECs on RGD-FSP exhibited a more spread morphology and oriented in the direction of shear stress, as demonstrated by actin fiber staining. This spread morphology has been observed earlier in cells that are adapting to shear stress. Real-time PCR for vascular cell adhesion molecule 1, tissue factor, tissue plasminogen activator, and inducible nitric oxide synthase indicated that the RGD-FSP material did not activate the cells and that shear stress appears to induce a more vasoprotective phenotype, as shown by a significant decrease in VCAM-1 expression, compared with sodded grafts. RGD-FSP-coating allows for a cell layer that is more resistant to physiological shear stress, as shown by the increased cell retention over FN. This shear stable EC layer is necessary for in vivo endothelialization of the graft material, which shows promise to increase the patency of synthetic small diameter vascular grafts.
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Affiliation(s)
- Lynn A Dudash
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106, USA
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234
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Zhou Y, Li K, Yang JY, Guan CX, Wang Y, Liu CJ, Zhu JH. Small-caliber vascular prosthesis prototype based on controlled release of heparin from mesochannels and its enhanced biocompatibility. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2012; 8:1373-1383. [PMID: 22378541 DOI: 10.1002/smll.201101270] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2011] [Revised: 08/21/2011] [Indexed: 05/31/2023]
Abstract
A novel small-caliber vascular prosthesis prototype is proposed on the basis of a new heparin release system, that is, the controlled delivery of heparin from mesochannels. Fabrication of mesochannels on artificial biomaterials is successfully achieved through epitaxial growth of mesoporous silica nanoparticles on expanded polytetrafluoroethylene grafts, and thus heparin can be immobilized through a space limitation effect, thereby avoiding the loss of bioactivity and enabling long-lasting release. The adsorption and release of heparin are controlled by adjusting the adsorbate-adsorbent interaction through tailoring the mesostructure. Owing to the continuous and sustained release of heparin, the performances of artificial vessels are greatly improved, thus paving a new way to prepare functional blood-contacting biomaterials with high biocompatibility.
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Affiliation(s)
- Yu Zhou
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China
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235
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Williams C, Xie AW, Emani S, Yamato M, Okano T, Emani SM, Wong JY. A Comparison of Human Smooth Muscle and Mesenchymal Stem Cells as Potential Cell Sources for Tissue-Engineered Vascular Patches. Tissue Eng Part A 2012; 18:986-98. [DOI: 10.1089/ten.tea.2011.0172] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Corin Williams
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts
| | - Angela W. Xie
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts
| | - Sirisha Emani
- Department of Cardiovascular Surgery, Children's Hospital Boston, Boston, Massachusetts
| | - Masayuki Yamato
- Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, Tokyo, Japan
| | - Teruo Okano
- Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, Tokyo, Japan
| | - Sitaram M. Emani
- Department of Cardiovascular Surgery, Children's Hospital Boston, Boston, Massachusetts
| | - Joyce Y. Wong
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts
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236
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Tzoneva R, Seifert B, Albrecht W, Richau K, Lendlein A, Groth T. Poly(ether imide) membranes: studies on the effect of surface modification and protein pre-adsorption on endothelial cell adhesion, growth and function. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2012; 19:837-52. [DOI: 10.1163/156856208784613523] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- R. Tzoneva
- a Institute of Biophysics, Bulgarian Academy of Sciences, Acad. G. Bonchev Street, Bl. 108, Sofia 1113, Bulgaria
| | - B. Seifert
- b Institute of Polymer Research, GKSS Research Centre, Kantstrasse 55, Teltow 14513, Germany
| | - W. Albrecht
- c Institute of Polymer Research, GKSS Research Centre, Kantstrasse 55, Teltow 14513, Germany
| | - K. Richau
- d Institute of Polymer Research, GKSS Research Centre, Kantstrasse 55, Teltow 14513, Germany
| | - A. Lendlein
- e Institute of Polymer Research, GKSS Research Centre, Kantstrasse 55, Teltow 14513, Germany
| | - T. Groth
- f Biomedical Materials Group, Department of Pharmaceutics and Biopharmaceutics, Institute of Pharmacy, Martin Luther University, Halle-Wittenberg, Kurt-Mothes-Strasse 1, 06120 Halle/Saale, Germany
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237
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McClure MJ, Simpson DG, Bowlin GL. Tri-layered vascular grafts composed of polycaprolactone, elastin, collagen, and silk: Optimization of graft properties. J Mech Behav Biomed Mater 2012; 10:48-61. [PMID: 22520418 DOI: 10.1016/j.jmbbm.2012.02.026] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Revised: 02/08/2012] [Accepted: 02/28/2012] [Indexed: 11/25/2022]
Abstract
The purpose of this study was to create seamless, acellular, small diameter bioresorbable arterial grafts that attempt to mimic the extracellular matrix and mechanical properties of native artery using synthetic and natural polymers. Silk fibroin, collagen, elastin, and polycaprolactone (PCL) were electrospun to create a tri-layered structure for evaluation. Dynamic compliance testing of the electrospun grafts ranged from 0.4-2.5%/100 mmHg, where saphenous vein (1.5%/100 mmHg) falls within this range. Increasing PCL content caused a gradual decrease in medial layer compliance, while changes in PCL, elastin, and silk content in the adventitial layer had varying affects. Mathematical modeling was used to further characterize these results. Burst strength results ranged from 1614-3500 mmHg, where some exceeded the capacity of the pressure regulator. Four week degradation studies demonstrated no significant changes in compliance or burst strength, indicating that these grafts could withstand the initial physiological conditions without risk of degradation. Overall, we were able to manufacture a multi-layered graft that architecturally mimics the native vascular wall and mechanically matches the gold standard of vessel replacement, saphenous vein.
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Affiliation(s)
- Michael J McClure
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284-3067, USA.
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238
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Oligonucleotide and Parylene Surface Coating of Polystyrene and ePTFE for Improved Endothelial Cell Attachment and Hemocompatibility. Int J Biomater 2012; 2012:397813. [PMID: 22481939 PMCID: PMC3312249 DOI: 10.1155/2012/397813] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 11/10/2011] [Accepted: 11/14/2011] [Indexed: 11/28/2022] Open
Abstract
In vivo self-endothelialization by endothelial cell adhesion on cardiovascular implants is highly desirable. DNA-oligonucleotides are an intriguing coating material with nonimmunogenic characteristics and the feasibility of easy and rapid chemical fabrication. The objective of this study was the creation of cell adhesive DNA-oligonucleotide coatings on vascular implant surfaces. DNA-oligonucleotides immobilized by adsorption on parylene (poly(monoaminomethyl-para-xylene)) coated polystyrene and ePTFE were resistant to high shear stress (9.5 N/m2) and human blood serum for up to 96 h. Adhesion of murine endothelial progenitor cells, HUVECs and endothelial cells from human adult saphenous veins as well as viability over a period of 14 days of HUVECs on oligonucleotide coated samples under dynamic culture conditions was significantly enhanced (P < 0.05). Oligonucleotide-coated surfaces revealed low thrombogenicity and excellent hemocompatibility after incubation with human blood. These properties suggest the suitability of immobilization of DNA-oligonucleotides for biofunctionalization of blood vessel substitutes for improved in vivo endothelialization.
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239
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Kong X, Han B, Li H, Liang Y, Shao K, Liu W. New biodegradable small-diameter artificial vascular prosthesis: A feasibility study. J Biomed Mater Res A 2012; 100:1494-504. [DOI: 10.1002/jbm.a.33298] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2011] [Revised: 07/12/2011] [Accepted: 09/26/2011] [Indexed: 11/06/2022]
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Rapoport HS, Fish J, Basu J, Campbell J, Genheimer C, Payne R, Jain D. Construction of a tubular scaffold that mimics J-shaped stress/strain mechanics using an innovative electrospinning technique. Tissue Eng Part C Methods 2012; 18:567-74. [PMID: 22250785 DOI: 10.1089/ten.tec.2011.0286] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Soft tissues such as blood vessel, lung, ureter, skin, etc., possess mechanical behavior characterized by a "J"-shaped curve on a stress-strain diagram with a low-stiffness highly elastic zone giving rise to a high-stiffness zone. This mechanical behavior may be adaptive and protective against aneurysm formation in tissues whose primary loading is pressure-based. "J"-shaped behavior arises from the synergistic interplay of two main structural proteins: collagen and elastin. An innovative electrospinning technique has been utilized to form tubular scaffold composites with structural features reminiscent of the corrugated laminae seen in blood vessels. In doing so, tubular scaffolds have been fabricated with complex "J"-shaped behavior through the use of elastic polyurethane and reinforcing poly-glycolic acid (PGA) woven mesh. In these studies, corrugated laminae were formed on the 175 μm and 1.5 mm scale. Initial moduli were 0.5±0.17 MPa (mean±standard deviation) giving rise to stiffer moduli of 36.09±6.72 MPa at a strain of 1.31±0.15. Burst pressures were physiologically relevant at 3095±1016 mmHg. The toughness of these prototypes was 6.3±1.9 MJ/m(3). The ability to employ different materials and different formation parameters utilizing this technique promises the ability to match complex stress-strain behaviors in soft tissues with a high degree of fidelity.
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Affiliation(s)
- Harry Scott Rapoport
- Bioprocess Research and Assay Development, Tengion, Inc., Winston-Salem, NC 27103, USA
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241
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De Visscher G, Mesure L, Meuris B, Ivanova A, Flameng W. Improved endothelialization and reduced thrombosis by coating a synthetic vascular graft with fibronectin and stem cell homing factor SDF-1α. Acta Biomater 2012; 8:1330-8. [PMID: 21964214 DOI: 10.1016/j.actbio.2011.09.016] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 08/23/2011] [Accepted: 09/15/2011] [Indexed: 01/11/2023]
Abstract
Failure of synthetic small-diameter vascular grafts is determined mainly by the lack of endothelial cells, as these cells inhibit thrombosis and intimal hyperplasia. Coating of graft material with homing factors for circulating stem cells has the potential to improve endogenous endothelialization of these grafts and to reduce graft failure. Synthetic knitted polyester grafts (6mm diameter) were coated with FN and SDF-1α before surgical interposition in the carotid artery of sheep. Similar uncoated vascular grafts were implanted in the contralateral side as internal controls. To study the early attraction of stem cells, grafts were implanted in a first series of nine sheep and explanted after 1 or 3 days. In coated grafts, four times higher fractions of CD34(+) and three to four times higher fractions of CD117(+) cells adhering to the vessel walls were found than in control grafts (P<0.05). When such coated and non-coated grafts were implanted in 12 other sheep and explanted after 3 months, all coated grafts were patent, while one control graft was occluded. EcNOS staining revealed that FN-SDF-1α coating significantly increased coverage with endothelial cells from 27 ± 4% of the graft to 48 ± 4% compared with the controls (P=0.001). This was associated with a significant reduction of intimal hyperplasia (average thickness 1.03 ± 0.09 mm in controls vs. 0.69 ± 0.04 mm in coated grafts; P=0.009) and significantly less adhesion of thrombotic material in the middle part of the graft (P=0.029). FN-SDF-1α coating of synthetic small-caliber vascular grafts stimulated the attraction of stem cells and was associated with improved endothelialization and reduced intimal hyperplasia and thrombosis.
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242
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PLGA-based nanoparticles: an overview of biomedical applications. J Control Release 2012; 161:505-22. [PMID: 22353619 DOI: 10.1016/j.jconrel.2012.01.043] [Citation(s) in RCA: 2222] [Impact Index Per Article: 185.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 01/27/2012] [Accepted: 01/30/2012] [Indexed: 02/06/2023]
Abstract
Poly(lactic-co-glycolic acid) (PLGA) is one of the most successfully developed biodegradable polymers. Among the different polymers developed to formulate polymeric nanoparticles, PLGA has attracted considerable attention due to its attractive properties: (i) biodegradability and biocompatibility, (ii) FDA and European Medicine Agency approval in drug delivery systems for parenteral administration, (iii) well described formulations and methods of production adapted to various types of drugs e.g. hydrophilic or hydrophobic small molecules or macromolecules, (iv) protection of drug from degradation, (v) possibility of sustained release, (vi) possibility to modify surface properties to provide stealthness and/or better interaction with biological materials and (vii) possibility to target nanoparticles to specific organs or cells. This review presents why PLGA has been chosen to design nanoparticles as drug delivery systems in various biomedical applications such as vaccination, cancer, inflammation and other diseases. This review focuses on the understanding of specific characteristics exploited by PLGA-based nanoparticles to target a specific organ or tissue or specific cells.
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243
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Diban N, Stamatialis DF. Functional Polymer Scaffolds for Blood Vessel Tissue Engineering. ACTA ACUST UNITED AC 2011. [DOI: 10.1002/masy.201100038] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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244
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WANG JUNPING, ZHU YIZHOU, DU JIAN. BACTERIAL CELLULOSE: A NATURAL NANOMATERIAL FOR BIOMEDICAL APPLICATIONS. J MECH MED BIOL 2011. [DOI: 10.1142/s0219519411004058] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bacterial cellulose (BC) synthesized from Acetobacter xylinum has drawn lots of attention and interest from biomedical device field due to its unique structure and properties. Characterized by its remarkable physical strength and extremely hydrophilic surface, BC has become a favorable material for wound healing, neuron protection, and vascular grafts. Moreover, due to its homologous structure with native extracellular matrix, BC nanofibrous matrix could also be a potent candidate for tissue-engineered scaffolding materials. In this review, the characters and properties of BC, as a promising material for regenerative medicine, are summarized. The progresses made on application of BC to wound dressing, vascular grafts, meniscus and cartilage repair, bone healing, and other biomedical fields are expatiated in details. In the end, the future expectation of BC is briefly discussed. Overall, this low cost, biocompatible, and versatile nanomaterial could eventually be developed as an excellent platform for a new generation of medical device and regenerative medicine.
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Affiliation(s)
- JUNPING WANG
- Xylos Corporation, 838 Town Center Drive, Langhorne, PA 19047, USA
| | - YIZHOU ZHU
- Department of Chemistry, Chemical Biology and Biomedical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA
| | - JIAN DU
- Department of Biomedical Engineering, John Hopkins University, Baltimore, MD, 21218, USA
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245
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Tan D, Zhang X, Li J, Tan H, Fu Q. Modification of poly(ether urethane) with fluorinated phosphorylcholine polyurethane for improvement of the blood compatibility. J Biomed Mater Res A 2011; 100:380-7. [DOI: 10.1002/jbm.a.33191] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 05/05/2011] [Accepted: 05/27/2011] [Indexed: 12/21/2022]
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246
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Ahmed M, Ghanbari H, Cousins BG, Hamilton G, Seifalian AM. Small calibre polyhedral oligomeric silsesquioxane nanocomposite cardiovascular grafts: influence of porosity on the structure, haemocompatibility and mechanical properties. Acta Biomater 2011; 7:3857-67. [PMID: 21763798 DOI: 10.1016/j.actbio.2011.06.051] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 06/24/2011] [Accepted: 06/24/2011] [Indexed: 01/09/2023]
Abstract
There is a significant worldwide demand for a small calibre vascular graft for use as a bypass or replacement conduit. An important feature in determining the success of a graft is the wall structure, which includes porosity, pore size and pore interconnectivity, as these play a crucial role in determining the long-term patency of a bypass graft. In this study we fabricate a small diameter (<5mm) vascular graft from polyhedral oligomeric silsesquioxane-poly(carbonate urea)urethane (POSS-PCU) via an extrusion, phase inversion method using an automated, custom built machine. Through the dispersion of a porogen, sodium bicarbonate (NaHCO(3)), in controlled concentrations (0-55%) we were able to produce grafts with well-defined pore morphologies. The impact of NaHCO(3) concentration on the structure of the graft wall and its influence on the mechanical and haemocompatibility properties are evaluated here. Scanning electron microscopy and mercury porosimetry were used to characterise graft structure. Atomic force microscopy elucidated any changes in surface morphology. The addition of NaHCO(3) improved the pore interconnectivity and increasing the concentration of NaHCO(3) led to grafts with rougher surfaces and larger pore sizes. The ultimate tensile strength and suture retention decreased with increasing concentrations of NaHCO(3), while graft compliance increased. To evaluate haemocompatibility platelets and peripheral blood mononuclear cells (PBMC) were incubated on a range of different graft samples. Platelet adhesion, PBMC surface receptor expression (CD14, CD86, CD69 and HLA-DR) and cytokine release (PF4, IL-1β, IL-6, IL-10, TNFα) were all measured. Increasing numbers of platelets adhered to grafts produced with no NaHCO(3), which exhibited a smooth surface morphology, and PBMC adherent on these grafts expressed higher levels of CD14 and CD86. Whilst the different graft samples induced varying levels of cytokine secretion in vitro, no distinct pattern suggesting a non-trivial relationship was observed.
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247
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Why Mechanical Properties of Collagen Scaffolds Should Be Tested in a Pseudo-Physiological Environment? ACTA ACUST UNITED AC 2011. [DOI: 10.4028/www.scientific.net/amr.409.158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Collagen gels constitute an adequate scaffold for supporting the adhesion, proliferation and tissue regeneration of vascular cells inside a bioreactor. However, their mechanical properties should be enhanced not only for their manipulation but also to resist the mechanical constraints applied in the bioreactor. Actually, assessing the mechanical properties of a hydrogel requires many precautions since they are very sensitive to the environmental conditions (temperature, ionic strength, aqueous environment, etc). Whereas mechanical properties are usually measured directly in the air, the aim of this work was to evaluate the effects of a pseudo-physiological environment (PPE) on the mechanical properties of collagen gels. Furthermore, reinforcement was also tested using UV treatments (λ = 254 nm, 20 J/cm2), known to induce crosslinking. Irradiated samples were more resistant to enzymatic degradation and swelling tests showed that the crosslink density was increased by a factor of 30. This increase was thereafter correlated to the mechanical properties. Results showed that the UV-treated samples were stiffer and more brittle than the non-treated ones when tested in air. However, a 20% decrease and 40% increase were respectively measured on the linear modulus and strain at rupture when the gels were tested in the PPE. In the perspective of vascular tissue regeneration, these results show that the mechanical properties of a hydrogel should be performed in PPE in order to take into account the plasticization phenomenon that will occur in a bioreactor.
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248
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Feinberg AW. Engineered tissue grafts: opportunities and challenges in regenerative medicine. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2011; 4:207-20. [PMID: 22012681 DOI: 10.1002/wsbm.164] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The human body has limited regenerative capacity in most of the major tissues and organs. This fact has spurred the field of regenerative medicine, promising to repair damage following traumatic injury or disease. Multiple therapeutic strategies are being explored including small molecules, gene delivery, and stem cells; however, tissue engineering remains a primary approach to achieving regeneration. Organ transplantation demonstrates that damaged tissues can be replaced, but technology to regenerate complex organs de novo is not yet available. Instead, tissue engineering can augment the body's own regenerative ability by replacing tissue sections and enhancing the regenerative cascade. As a consequence of these opportunities, it is timely to review the criteria and current status of engineered tissue grafts designed as patches to replace or regenerate damaged or diseased tissue and restore organ function. This topic will be explored starting from the biomaterials and cells incorporated into the engineered graft, the environment into which the graft is implanted and the integration of the engineered graft with the host. Common issues will be addressed that are relevant to regeneration in multiple tissue and organ systems. Specific examples will focus on engineered grafts for myocardial and corneal repair to illustrate the tissue-specific challenges and opportunities and highlight the innovation needed as the field moves forward.
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Affiliation(s)
- Adam W Feinberg
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
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249
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Millon LE, Padavan DT, Hamilton AM, Boughner DR, Wan W. Exploring cell compatibility of a fibronectin-functionalized physically crosslinked poly(vinyl alcohol) hydrogel. J Biomed Mater Res B Appl Biomater 2011; 100:1-10. [PMID: 21998037 DOI: 10.1002/jbm.b.31860] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 02/24/2011] [Accepted: 03/09/2011] [Indexed: 11/09/2022]
Abstract
Physically crosslinked poly(vinyl alcohol) (PVA) hydrogels prepared using a low-temperature thermally cycled process have tunable mechanical properties that fall within the range of soft tissues, including cardiovascular tissue. An approach to render it hemocompatible is by endothelization, but its hydrophilic nature is not conducive to cell adhesion and spreading. We investigated the functionalization reaction of this class of PVA hydrogel with fibronectin (FN) for adhesion and spreading of primary porcine radial artery cells and vascular endothelial cells. These are cells relevant to small-diameter vascular graft development. FN functionalization was achieved using a multistep reaction, but the activation step involving carbonyl diimidazole normally required for chemically crosslinked PVA was found to be unnecessary. The reaction resulted in an increase in the elastic modulus of the PVA hydrogel but is still well within the range of cardiovascular tissue. Confocal microscopy confirmed the adhesion and spreading of both cell types on the PVA-FN surfaces, whereas cells failed to adhere to the PVA control. This is a first step toward an alternative for the realization of a synthetic replacement small-diameter vascular graft.
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250
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Punshon G, Vara DS, Sales KM, Seifalian AM. The long-term stability in gene expression of human endothelial cells permits the production of large numbers of cells suitable for use in regenerative medicine. Biotechnol Appl Biochem 2011; 58:371-5. [DOI: 10.1002/bab.48] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2011] [Accepted: 08/12/2011] [Indexed: 02/06/2023]
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