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PERSPECTIVE

Creation of a vascular system for organ manufacturing

*
Libiao Liu and Xiaohong Wang
Center of Organ Manufacturing, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China

Abstract: The creation of a vascular system is considered to be the main object for complex organ manufacturing. In
this short review, we demonstrate two approaches to generate a branched vascular system which can be printed using
rapid prototyping or bioprinting techniques. One approach is constructing mathematical tree models on the basis of hu-
man physiological characteristics and calculating the model using constrained constructive optimization to obtain
three-dimensional (3D) geometrical structures. The rules of the branching of the vessel tree were extracted from the
literature. Another approach is using computer-aided design models to build a multi-scale vascular network including
arteries, veins, and capillaries. A 3D vascular template with both synthetic scaffold polymer and cell/hydrogel was
created in our group, using a double-nozzle, low-temperature deposition technique. Each of the approaches holds prom-
ise in producing a vascular system.
Keywords: vascular system, three-dimensional (3D) modeling, branching rule, constrained constructive optimization,
hybrid architecture

*Correspondence to: Xiaohong Wang, Center of Organ Manufacturing, Department of Mechanical Engineering, Tsinghua University,
Beijing 100084, China; Email: wangxiaohong@tsinghua.edu.cn
Received: April 30, 2015; Accepted: June 21, 2015; Published Online: July 2, 2015
Citation: Liu L B and Wang X H, 2015, Creation of a vascular system for organ manufacturing. International Journal of Bioprinting,
vol.1(1): 77–86. http://dx.doi.org/10.18063/IJB.2015.01.009.

1. Introduction low stability, and poor efficiency [13] . Decellularized
C omplex organ failures are the first cause of types [14] . Rapid prototyping (RP) techniques, also
matrices are hard to repopulate with multiple cell
mortality all over the world despite advances
named as additive manufacturing (AM), solid

in interventional, pharmacological, and sur-
[1]
gical therapies . Clinically, orthotopic organ trans- freeform fabrication (SFF), or 3D printing (3DP)
cannot solve all the difficulties in generating a
plantation is greatly limited by the issues of donor vascular network with all the multi-scale features of
[2]
shortage and immune rejections . Over the last two large arteries, arterioles, capillaries, venules, and large
decades, the creation of branched vascular systems has veins.
attracted significant attention, both from the scientific Currently, RP (AM, or 3DP) techniques are the
and clinical areas. However, it is still a formidable prevailing tools for defining macro- or microenviron-
challenge to build a three-dimensional (3D) branched ment for cell cultures [15–20] . There is an increasing in-
vascular system, mimicking the native vascular terest in the use of RP techniques for cell-laden hy-
systems in complex organs, such as the liver, the heart, drogel or solution manipulation. However, most of the
and the kidney, with traditional or existing existing RP techniques are mainly used for the mani-
manufacturing techniques [3–11] . For example, cell sheet pulation and analysis of one or two cell types in a
techniques face problems of rescuing tissues with in- construct, which are machine dependent and signifi-
creased thicknesses above 80 µm [12] . Cell encapsula- cantly time consuming [15–20] . The least progress made
tion techniques encounter problems of capsule loss, in complex organ manufacturing is the development

Creation of a vascular system for organ manufacturing. © 2015 Libiao Liu, Xiaohong Wang. This is an Open Access article distributed under the
terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/), permitting
all non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
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