Oxygen Transport in Bioreactors for Engineered Vascular Tissues - Computational Modeling in Tissue Engineering - page 277

Oxygen Transport in Bioreactors
for Engineered Vascular Tissues
Jason W. Bjork, Anton M. Safonov and Robert T. Tranquillo
Abstract Tissue engineered vascular grafts cultured in vitro are often done so under
static conditions, which forces a diffusion-only mass transport regime for nutrient
delivery and metabolite removal. Some bioreactor culture methods employ mechanical
stimulation to improve material strength and stiffness; however, even with mechanical
stimulation, engineered tissues are likely to operate in a diffusional transport regime for
nutrient delivery and metabolite removal. In this study, we present an analysis of
dissolved oxygen (DO) transport limitations that can arise in statically cultured vascular
grafts and highlight bioreactor designs that improve transport, particularly by perfusion
of medium through the interstitial space by transmural flow. A computational analysis is
provided in conjunction with empirical data to support the models. Our goal was to
investigate designs that would eliminate nutrient gradients that are evident using static
culture methods in order to develop more uniform engineered vascular tissues, which
could potentially improve mechanical strength and stiffness.
1 Introduction
Effective nutrient delivery and metabolite removal remain a challenge in the field
of tissue engineering. Within the body, most cells are found no more than
100-200 lm from the nearest capillary to maintain viable tissue [ 1 ]; however,
J. W. Bjork A. M. Safonov R. T. Tranquillo ( & )
Department of Biomedical Engineering,
University of Minnesota, Minneapolis, MN, USA
e-mail: [e-mail]
R. T. Tranquillo
Department of Chemical Engineering and Materials Science,
University of Minnesota, Minneapolis, MN, USA