title: Fabrication of elastomeric scaffolds with curvilinear fibrous structures for heart valve leaflet engineering.
abstract: Native semi-lunar heart valves are composed of a dense fibrous network that generally follows a curvilinear path along the width of the leaflet. Recent models of engineered valve leaflets have predicted that such curvilinear fiber orientations would homogenize the strain field and reduce stress concentrations at the commissure. In the present work, a method was developed to reproduce this curvilinear fiber alignment in electrospun scaffolds by varying the geometry of the collecting mandrel. Elastomeric poly(ester urethane)urea was electrospun onto rotating conical mandrels of varying angles to produce fibrous scaffolds where the angle of fiber alignment varied linearly over scaffold length. By matching the radius of the conical mandrel to the radius of curvature for the native pulmonary valve, the electrospun constructs exhibited a curvilinear fiber structure similar to the native leaflet. Moreover, the constructs had local mechanical properties comparable to conventional scaffolds and native heart valves. In agreement with prior modeling results, it was found under quasi-static loading that curvilinear fiber microstructures reduced strain concentrations compared to scaffolds generated on a conventional cylindrical mandrels. Thus, this simple technique offers an attractive means for fabricating scaffolds where key microstructural features of the native leaflet are imitated for heart valve tissue engineering.
authors.affiliation: Bioengineering and Surgery, McGowan Institute for Regenerative Medicine.|Department of Bioengineering.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Hobson
authors.affiliation: Bioengineering and Surgery, McGowan Institute for Regenerative Medicine.|Department of Surgery.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Amoroso
authors.affiliation: Department of Biomedical Engineering, the University of Akron, Ohio.
authors.forename: Rouzbeh
authors.initials: R
authors.lastname: Amini
authors.affiliation: Bioengineering and Surgery, McGowan Institute for Regenerative Medicine.
authors.forename: Ethan
authors.initials: E
authors.lastname: Ungchusri
authors.affiliation: Bioengineering and Surgery, McGowan Institute for Regenerative Medicine.|Department of Bioengineering, University of Texas at Arlington, Arlington, Texas, 76019.
authors.forename: Yi
authors.initials: Y
authors.lastname: Hong
authors.affiliation: Bioengineering and Surgery, McGowan Institute for Regenerative Medicine.|Department of Bioengineering.|Department of Surgery.|Foundation RiMED, Palermo, Italy.|DICGIM, University of Palermo, Palermo, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: D'Amore
authors.affiliation: Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering and the University of Texas at Austin, Austin, Texas.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Sacks
authors.affiliation: Bioengineering and Surgery, McGowan Institute for Regenerative Medicine.|Department of Bioengineering.|Department of Surgery.|Department of Chemical Engineering, University of Pittsburgh, Pennsylvania.
authors.forename: William R
authors.initials: WR
authors.lastname: Wagner
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D001696:Biomechanical Phenomena; D040761:Biomimetic Materials / Q000737:chemistry; D058385:Cardiac Valve Annuloplasty / Q000379:methods; D020724:Elastomers / Q000737:chemistry*; D006351:Heart Valves / Q000502:physiology* / Q000601:surgery*; D006801:Humans; D008422:Materials Testing; D008955:Models, Cardiovascular; D011664:Pulmonary Valve / Q000502:physiology / Q000601:surgery; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D020724:Elastomers
keywords: cardiac valve; electrospinning; microstructure; polyurethane; tissue engineering