title: Physical characterization of vascular grafts cultured in a bioreactor.
abstract: Tubular scaffolds of collagen and elastin (weight ratio 1:1) with interconnected pores were prepared by freeze drying and crosslinked with N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) in the presence or absence of a Jeffamine spacer (poly(propylene glycol)-bis-(2-aminopropyl ether), J230). The crosslinked and uncrosslinked matrices had porosities of 90% and average pore sizes of 131-151 microm. Smooth muscle cells (SMC) were cultured in the crosslinked and uncrosslinked tubular scaffolds under pulsatile flow conditions (mean flow rate 9.6 ml/min, 120 beats/min, pressure 80-120 mmHg). All the constructs could withstand cyclic mechanical strain in the absence of any mechanical support without cracking or suffering permanent deformation. After 7d, SMC were homogeneously distributed throughout the uncrosslinked and EDC/NHS crosslinked constructs, whereas hardly any cell was observed on the luminal side of J230/EDC/NHS crosslinked matrices. Considering the better mechanical performance of EDC/NHS crosslinked matrices compared to non-crosslinked constructs after 7d of culture, SMC were dynamically cultured in the former scaffolds for 14d. During this period, the high strain stiffness of the constructs increased more than two-fold to 38+/-2 kPa, whereas the low strain stiffness doubled to 8+/-2 kPa. The yield stress and yield strain were 30+/-10 kPa and 120+/-20%, respectively. SMC were homogeneously distributed throughout the EDC/NHS crosslinked collagen/elastin constructs and collagen fibres tended to orient in the circumferential direction.
authors.affiliation: Department of Polymer Chemistry and Biomaterials, Faculty of Science and Technology, Institute for Biomedical Technology (BMTI), University of Twente, Enschede, P.O. Box 217, 7500 AE, The Netherlands.
authors.forename: Laura
authors.initials: L
authors.lastname: Buttafoco
authors.forename: Paula
authors.initials: P
authors.lastname: Engbers-Buijtenhuijs
authors.forename: Andre A
authors.initials: AA
authors.lastname: Poot
authors.forename: Piet J
authors.initials: PJ
authors.lastname: Dijkstra
authors.forename: Istvan
authors.initials: I
authors.lastname: Vermes
authors.forename: Jan
authors.initials: J
authors.lastname: Feijen
mesh_terms: D001672:Biocompatible Materials; D001696:Biomechanical Phenomena; D019149:Bioreactors; D001807:Blood Vessel Prosthesis; D002478:Cells, Cultured; D024042:Collagen Type I; D003432:Cross-Linking Reagents; D004549:Elastin; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D009131:Muscle, Smooth, Vascular / Q000166:cytology; D023822:Tissue Engineering
chemical_list: D001672:Biocompatible Materials; D024042:Collagen Type I; D003432:Cross-Linking Reagents; D004549:Elastin