title: Synthesis and characterization of polycaprolactone urethane hollow fiber membranes as small diameter vascular grafts.
abstract: The design of bioresorbable synthetic small diameter (<6mm) vascular grafts (SDVGs) capable of sustaining long-term patency and endothelialization is a daunting challenge in vascular tissue engineering. Here, we synthesized a family of biocompatible and biodegradable polycaprolactone (PCL) urethane macromers to fabricate hollow fiber membranes (HFMs) as SDVG candidates, and characterized their mechanical properties, degradability, hemocompatibility, and endothelial development. The HFMs had smooth surfaces and porous internal structures. Their tensile stiffness ranged from 0.09 to 0.11N/mm and their maximum tensile force from 0.86 to 1.03N, with minimum failure strains of approximately 130%. Permeability varied from 1 to 14×10(-6)cm/s, burst pressures from 1158 to 1468mmHg, and compliance from 0.52 to 1.48%/100mmHg. The suture retention forces ranged from 0.55 to 0.81N. HFMs had slow degradation profiles, with 15 to 30% degradation after 8weeks. Human endothelial cells proliferated well on the HFMs, creating stable cell layer coverage. Hemocompatibility studies demonstrated low hemolysis (<2%), platelet activation, and protein adsorption. There were no significant differences in the hemocompatibility of HFMs in the absence and presence of endothelial layers. These encouraging results suggest great promise of our newly developed materials and biodegradable elastomeric HFMs as SDVG candidates.
authors.affiliation: Department of Orthopedic Surgery, Stanford University, Stanford, CA, USA.
authors.forename: Ángel E
authors.initials: ÁE
authors.lastname: Mercado-Pagán
authors.affiliation: Department of Orthopedic Surgery, Stanford University, Stanford, CA, USA; Department of Chemistry, Stanford University, Stanford, CA, USA.
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Stahl
authors.affiliation: Department of Orthopedic Surgery, Stanford University, Stanford, CA, USA; Department of Chemical Engineering, Stanford University, Stanford, CA, USA.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Ramseier
authors.affiliation: Department of Orthopedic Surgery, Stanford University, Stanford, CA, USA.
authors.forename: Anthony W
authors.initials: AW
authors.lastname: Behn
authors.affiliation: Department of Orthopedic Surgery, Stanford University, Stanford, CA, USA; Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA; Department of Bioengineering, Stanford University, Stanford, CA, USA. Electronic address: ypyang@stanford.edu.
authors.forename: Yunzhi
authors.initials: Y
authors.lastname: Yang
mesh_terms: D063566:Biodegradable Plastics / Q000737:chemistry*; D002448:Cell Adhesion; D049109:Cell Proliferation; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D008422:Materials Testing; D008567:Membranes, Artificial; D010539:Permeability; D011091:Polyesters / Q000737:chemistry*; D011140:Polyurethanes / Q000737:chemistry*
chemical_list: D063566:Biodegradable Plastics; D008567:Membranes, Artificial; D011091:Polyesters; D011140:Polyurethanes; C016240:polycaprolactone
keywords: Elastomers; Hollow fiber membranes; Hydroxycinnamic acid; Small diameter vascular grafts; Tyramine