title: Functionally graded electrospun scaffolds with tunable mechanical properties for vascular tissue regeneration.
abstract: Electrospun tubular scaffolds (4 mm inner diameter) based on bio-artificial blends of polyglyconate (Maxon) and proteins such as gelatin and elastin having a spatially designed multilayer structure were prepared for use as vascular tissue scaffolds. Scanning electron microscopy analysis of scaffolds showed a random nanofibrous morphology with fiber diameter in the range of 200-400 nm for protein-blended Maxon, which mimics the nanoscale dimensions of collagen (50-500 nm). The scaffolds have a well interconnected pore structure and porosity up to 82%, with protein blending and multi-layering in contrast to electrospun Maxon scaffolds (67%). Fourier-transform infrared spectroscopy, x-ray diffraction and differential scanning calorimetry results confirmed the blended composition and crystallinity of fibers. Uniaxial tensile testing revealed a strength of 14.46 +/- 0.42 MPa and a modulus of 15.44 +/- 2.53 MPa with a failure strain of 322.5 +/- 10% for a pure Maxon scaffold. The blending of polyglyconate with biopolymers decreased the tensile properties in general, with an exception of the tensile modulus (48.38 +/- 2 MPa) of gelatin/Maxon mesh, which was higher than that of the pure Maxon scaffold. Trilayered tubular scaffolds of gelatin/elastin, gelatin/elastin/Maxon and gelatin/Maxon (GE-GEM-GM) that mimic the complex trilayer matrix structure of natural artery have been prepared by sequential electrospinning. Tensile testing under dry conditions revealed a tensile strength of 2.71 +/- 0.2 MPa and a modulus of 20.4 +/- 3 MPa with a failure strain of 140 +/- 10%. However, GE-GEM-GM scaffolds tested under wet conditions after soaking in a phosphate buffered saline medium at 37 degrees C for 24 h exhibited mechanical properties (2.5 MPa tensile strength and 9 MPa tensile modulus) comparable to those of native femoral artery.
authors.affiliation: Center for Nanoscale Materials and Biointegration, Department of Physics, University of Alabama at Birmingham, AL 35294, USA. vthomas@uab.edu
authors.forename: Vinoy
authors.initials: V
authors.lastname: Thomas
authors.forename: Xing
authors.initials: X
authors.lastname: Zhang
authors.forename: Shane A
authors.initials: SA
authors.lastname: Catledge
authors.forename: Yogesh K
authors.initials: YK
authors.lastname: Vohra
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D001705:Bioprosthesis; D001807:Blood Vessel Prosthesis; D001808:Blood Vessels / Q000166:cytology / Q000254:growth & development*; D003460:Crystallization / Q000379:methods; D004548:Elasticity; D004563:Electrochemistry / Q000379:methods; D016326:Extracellular Matrix Proteins / Q000737:chemistry*; D008422:Materials Testing; D011108:Polymers / Q000737:chemistry*; D012038:Regeneration / Q000502:physiology*; D012399:Rotation; D013314:Stress, Mechanical; D013718:Tensile Strength
chemical_list: D001672:Biocompatible Materials; D016326:Extracellular Matrix Proteins; D011108:Polymers; C046409:polyglyconate