Abstract
Objective: to define the optimal seeding conditions of a new stress free poly(carbonate-urea)urethane (CPU) graft with compliance similar to that of human artery with honeycomb structure engineered during the manufacturing process to enhance adhesion and growth of endothelial cells. Methods:111Indium-oxine radiolabeled human umbilical vein endothelial cells (HUVEC) were seeded onto CPU grafts at (a) concentrations from 2–24×105cells/cm2and (b) incubated for 0.5, 1, 2, 4 and 6 h. Following incubation, graft segments were subjected to three washing/gamma counting procedures and scanning electron microscopy (SEM). Cell viability was measured using a modified Alamar blueTMassay. To test physiological retention a pulsatile flow phantom was used to subject optimally seeded (16×105, 4 h) CPU grafts to arterial shear stress for 6 h with real time acquisition of scintigraphic images of seeded grafts using a nuclear medicine gamma camera system. Results: the seeding efficiency of 54±13% post three washes was achieved using 16×105cells/cm2. Similarly in SEM micrographs a seeding density of 16×105cells/cm2resulted in a confluent monolayer. Seeded CPU segments incubated for 4 h exhibited significantly higher resistance to wash-off than segments incubated for 30 min (p<0.05). Exposure of seeded grafts to pulsatile shear stress resulted in some cell loss with 67±3% of cells adherent following 6 h of perfusion with ongoing metabolic activity. Thus, optimal conditions were 16×105cells/cm2at 4 h. Conclusions: the optimal seeding conditions have been defined for ««tissue-engineered»» vascular graft which allow complete endothelialisation and high cell-to-substrate strength that resists hydrodynamic stress.
Published Version
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