Electrospun polyurethane and hydrogel composite scaffolds as biomechanical mimics for aortic valve tissue engineering

Event Abstract Back to Event Electrospun polyurethane and hydrogel composite scaffolds as biomechanical mimics for aortic valve tissue engineering Daniel Puperi1, Alysha Kishan2, Tyler Touchet2, Zoe Punske1, Yan Wu3, Elizabeth Cosgriff-Hernandez2, Jennifer West3 and Jane Grande-Allen1 1 Rice University, Bioengineering, United States 2 Texas A&M University, Biomedical Engineering, United States 3 Duke University, Biomedical Engineering, United States Introduction: Most tissues are composites of several different kinds of extracellular matrix (ECM) components including collagens, elastin, and proteoglycans. Unique composition and organization of ECM allows tissues to serve the various biomechanical needs of the body. Heart valves, in particular, operate in an intense mechanical environment, opening and closing billions of times over a lifetime. The non-linear, viscoelastic, and anisotropic mechanical properties of valve tissue enable the efficient flow of blood through the heart for delivery to the rest of the body. But heart valves can become diseased, resulting in disorganized ECM and mechanical dysfunctions. Tissue engineered replacement valves must match the mechanical properties of native valves to replicate function and appropriately guide the behavior of cells seeded in the scaffold. We are using a composite scaffold of electrospun biodegradable polyurethane (BPUR) and poly(ethylene glycol) (PEG) hydrogel to mimic the heterogeneous valve ECM and mechanical properties. Materials and Methods: PEG was functionalized with an enzymatically degradable peptide sequence, GGGPQGIWGQGK (PQ), to make PEG-PQ-PEG diacrylate. RGDS was conjugated to PEG for a cell adhesion ligand. Poly(ether ester urethane) urea with 50% hard segment was electrospun and collected on a rotating mandrel to produce anisotropic mechanical behavior. The electrospun mat was encapsulated inside PEG-PQ-PEG hydrogel with 2 mM PEG-RGDS and 15x106 valve interstitial cells (VICs)/ml. Mechanical properties of the scaffold were measured in uniaxial tension, and immunohistochemistry demonstrated phenotype of encapsulated cells. Results and Discussion: The synthetic BPUR/PEG-PQ-PEG scaffold has many of the mechanical properties present in native valve tissue. The fibrous nature of the electrospun BPUR mimics ECM components collagen and elastin and the fiber alignment replicates the anisotropic behavior of valve tissue. Most synthetic materials exhibit a linear stress-strain response, which is different from the non-linear stress-strain curve of native valves (Figure 1A), especially in the 10-30% physiological strain range. Figure 1: (A) Uniaxial tensile testing of aortic valve tissue in radial direction. Stress vs. strain plot is nonlinear, with low-modulus toe region followed by transition to stiffer collagen region; (B) 1st and (C) 20th cyclic tensile loading of BPUR/PEG-PQ-PEG composite scaffold Bilinear Preconditioning the BPUR in tension altered the microphase morphology such that a bilinear stress-strain response was observed upon subsequent tensile loading of the composite scaffold (Figure 1B-C shows the 1st and 20th cycles). The PEG hydrogel component was a bioactive cell carrier in which encapsulated VICs showed healthy phenotype in 3D. Figure 2: Cross-section of top side of composite scaffold. VICs encapsulated in PEG-PQ-PEG hydrogel, which is between dashed lines; BPUR is UV auto-fluorescent (blue) in lower right corner The cells sensed the stiffness and alignment of the electrospun fibers, without strong αSMA expression which would have been indicative of a diseased state. The next step will be to assess scaffold remodeling with cell secreted ECM after long term culture under cyclic tension. Conclusion: The composite BPUR/PEG-PEG-PQ scaffold is a step towards a tissue engineered valve that mimics the structural and functional heterogeneity of native valves. Keywords: Hydrogel, Biomimetic, heart valve, 3D scaffold Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: General Session Oral Topic: Biomimetic materials Citation: Puperi D, Kishan A, Touchet T, Punske Z, Wu Y, Cosgriff-Hernandez E, West J and Grande-Allen J (2016). Electrospun polyurethane and hydrogel composite scaffolds as biomechanical mimics for aortic valve tissue engineering. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.00548 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Daniel Puperi Alysha Kishan Tyler Touchet Zoe Punske Yan Wu Elizabeth Cosgriff-Hernandez Jennifer West Jane Grande-Allen Google Daniel Puperi Alysha Kishan Tyler Touchet Zoe Punske Yan Wu Elizabeth Cosgriff-Hernandez Jennifer West Jane Grande-Allen Google Scholar Daniel Puperi Alysha Kishan Tyler Touchet Zoe Punske Yan Wu Elizabeth Cosgriff-Hernandez Jennifer West Jane Grande-Allen PubMed Daniel Puperi Alysha Kishan Tyler Touchet Zoe Punske Yan Wu Elizabeth Cosgriff-Hernandez Jennifer West Jane Grande-Allen Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.