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RESEARCH ARTICLE

Concentric bioprinting of alginate-based tubular

constructs using multi-nozzle extrusion-based

technique

1,2
Edgar Y. S. Tan and Wai Yee Yeong 1,2*
1 School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 637372, Singapore
2 Singapore Centre for 3D Printing, Singapore 6397798, Singapore

Abstract: Bioprinting is a layer-by-layer additive fabrication technique for making three-dimensional (3D) tissue and
organ constructs using biological products. The capability to fabricate 3D tubular structure in free-form or vertical con-
figuration is the first step towards the possibility of organ printing in three dimensions. In this study, alginate-based tu-
bular structures of varying viscosity were printed vertically using multi-nozzle extrusion-based technique. Manufactur-
ing challenges associated with the vertical printing configurations are also discussed here. We have also proposed
measurable parameters to quantify the quality of printing for systematic investigation in bioprinting. This study lays a
foundation for the successful fabrication of viable 3D tubular constructs.
Keywords: 3D printing, alginate, viscosity, rapid prototyping, additive manufacturing, extrusion

*Correspondence to: Wai Yee Yeong, Singapore Centre of 3D Printing, Singapore 6397798, Singapore; Email: wyyeong@ntu.edu.sg
Received: May 7, 2015; Accepted: June 17, 2015; Published Online: July 2, 2015
Citation: Tan E Y S and Yeong W Y, 2015, Concentric bioprinting of alginate-based tubular constructs using multi-nozzle extru-
sion-based technique. International Journal of Bioprinting, vol.1(1): 49–56. http://dx.doi.org/10.18063/IJB.2015.01.003.

1. Introduction have emerged from the use of synthetic tubular struc-
T technologies such as electrospinning [2, 6] [13, 14] . These
tures. These products have been developed using
ubular structures play an important role in mul-
, melt spin-
ticellular organisms by improving the efficien-
[10–12]
[7–9]
and extrusion
, dip coating
ning
cy of transportation of nutrients, growth factors
and specific signals into and out of different tissue methods usually use poly(ε-caprolactone) (PCL), poly-
lactic acid (PLA), poly(lactic-co-glycolic acid) (PLGA),
regions. This vast improvement in transporting mate- polyglycolic acid (PGA) and poly(ethylene-co-vinyl
rials within the organism has enabled multicellular acetate) (PEVA) to fabricate products; The product fab-
cells to develop into larger organisms. As such, the ricated can reach a resolution of approximately 7 μm [15] .
need for tubular structures in tissue engineering (TE) Although these methods have proven to be effective in
has been growing in importance as demands for re- creating tubular structures, these synthetic polymeric
placement of these structures grow. Tubular structures materials lack adhesion factors such as arginine-gly-
in TE have served a multitude of applications ranging cine-aspartic acid (RGD) which are important for cell
from micro-scaled products such as nerve guides to adhesion, proliferation and matrix production [16, 17] .
larger products such as vascular channels [1–3] and gas- Moreover, these materials usually degrade—although
trointestinal substitutes [4, 5] . only after long periods of time—and would induce
In recent years, various emerging medical products foreign body response by the host [18] which could be

Concentric bioprinting of alginate-based tubular constructs using multi-nozzle extrusion-based technique. © 2015 Edgar Y. S. Tan and Wai Yee Yeong.
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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