Abstract
Material compliance has been shown to be a predictor of vascular graft patency and as such is a critical parameter when designing new materials. Although ex vivo derived materials have been clinically successful in a number of applications their mechanical properties are a direct function of the original vessel and are not easily controllable. These investigations describe an approach to modulate the mechanical properties of an ex vivo derived scaffold by machining variable (discrete) wall thicknesses to control compliance. Human umbilical arteries (HUAs) were machine lathed directly from the umbilical cord at wall thicknesses of 250, 500, 750, and 1000 μm then decellularized using 1% sodium dodecyl sulfate. Compliance over physiological pressures, increased from 3.08 ± 1.84% to 11.47 ± 4.11% as direct function of each discrete vessel diameter. Radial stress strain analysis revealed primary and secondary failure points attributed to the discrete layers within the anisotropic scaffold. Maximum strength and suture retention were shown to increase with increasing wall thickness, by contrast stress failure decreased with increasing thickness due to increasing proportions of the mechanically weaker amorphous Wharton's jelly. Reseeded smooth muscle cells were shown to adhere, proliferate, and migrate from the scaffold surface showing the potential of the HUA as a mechanically "tunable" material with applications as an acellular implant or as a tissue engineered construct. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3189-3196, 2012.