ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

COMPUTATIONAL FLUID DYNAMICS OF COMPLEX VASCULAR
NETWORKS FUNCTIONALITY TO TISSUE ENGINEERING APPLICATIONS
1. ABSTRACT
Aura Cardona 1 , Damien Lacroix 1,2
The growth of new vessels and the posterior formation of vascular networks in tissue
engineering scaffolds are critical for a proper transport of nutrients and oxygen to the
cells. In this study a computational methodology to perform a quantitative assessment of
the functionality of micro-vascular networks from synchrotron and micro-CT data is
proposed. It is hypothesized that mechanical stimuli promote the angiogenesis process
in tissue engineering constructs and therefore drive the functionality of the tissues. The
micro-CT and synchrotron data were imported in Simpleware to obtain a three
dimensional reconstruction with a superficial and solid mesh of the vascular networks.
Once the mesh was obtained, the boundary conditions and the properties of the fluid
were defined to simulate blood movement from the superior to inferior position. The
distribution of the fluid flow in different complex networks was calculated and
differences in wall shear stress (WSS) values have been identified. Fluid velocities
around 3mm s -1 (three times the velocity inlet applied) and values of WSS in the range
of 0 and 1 Pa, allowed us to interpret the mechanical phenomenon involved in the
angiogenesis process and the importance of cellular responses to mechanical stimuli in
tissue engineering applications.
2. INTRODUCTION
The term angiogenesis is used to describe the formation of new vessels, usually at the
capillary level, by proliferation, migration, and assembly of endothelial cells from
existing capillaries or venules [1]. This new vessel formation is an structure capable to
adapt functional and architectural in response to different stimuli biochemical and
mechanical [2]. This new vascular formation process can be take place in the human
body under various conditions like embryogenesis and fetal development. In tissue
engineering purposes, angiogenesis is essential because it is necessary to be able to
predict and control capillary development in scaffolds during in vitro and in vivo tissue
development. The performance of the angiogenesis process in tissue engineering
applications is critical and is limited by an inadequate transport between the tissue and
the blood vessels [3]. The formation of large volumes of tissues will not be successful
unless a healthy blood vessel network can form rapidly enough to provide the newly
formed tissues with nutrients, oxygen, and other factors required for proper function [4].
Promoting vascular growth toward or within tissue constructs is a key element to their
success. However, the techniques used normally are not enough to induce the rapid
vascularization necessary for an adequate cellular oxygen supply. Thus, some research
has focused on the creation of µ-vascular networks within 3D tissue constructs in vitro
before implantation using in vivo models like the chicken embryo and dorsal skinfold
1
PhD Student, Institute for Bioengineering of Catalonia (IBEC), Biomechanics and Mechanobiology
group, Baldiri Reixac, 4, 08028 Barcelona, Spain.
2
Professor, Department of Mechanical Engineering, University of Sheffield, Mappin Street, S1 3JD, UK.