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RESEARCH ARTICLE

Rheological study on 3D printability of alginate

hydrogel and effect of graphene oxide

2
1,2
Huijun Li , Sijun Liu and Lin Li 1,2,*
1 Singapore Centre for 3D Printing (SC3DP), School of Mechanical and Aerospace Engineering, Nanyang Technologi-
cal University (NTU), 50 Nanyang Avenue, Singapore 639798, Singapore
2 School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore
639798, Singapore

Abstract: In recent years, hydrogels have been used as important biomaterials for 3D printing of three dimensional tis-
sues or organs. The key issue for printing a successful scaffold is the selection of a material with a good printability.
Rheological properties of hydrogels are believed to pay an important role in 3D printability. However the relations be-
tween rheological properties of hydrogels and 3D printability have not been extensively studied. In this study, algi-
nate-based hydrogels were prepared as a model material for an extrusion-based printer and graphene oxide was added to
modify the rheological properties and 3D printability of the hydrogels. Rheological studies were performed for the hy-
drogel samples with different formulas. The range of shear rates that the hydrogels suffered during the printing process
was deduced. This range of shear rates helped us to select a proper shear rate to investigate the thixotropic properties of
the hydrogels. Furthermore, we also defined some measureable parameters to describe and discuss the quality of 3D
printing. The present study shows a new approach to analysis of 3D printability of a hydrogel and also provides some
suggestion for 3D printing of 3D scaffolds.
Keywords: printability, rheology, 3D printing, alginate hydrogel, graphene oxide

*Correspondence to: Lin Li, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue,
Singapore 639798, Singapore; Email: mlli@ntu.edu.sg

Received: April 5, 2016; Accepted: June 14, 2016; Published Online: June 24, 2016
Citation: Li H, Liu S and Li L, 2016, Rheological study on 3D printability of alginate hydrogel and effect of graphene oxide. Inter-
national Journal of Bioprinting, vol.2(2): 54–66. http://dx.doi.org/10.18063/IJB.2016.02.007.

1. Introduction the artificial tissues or organs cannot transport nutri-
D high potential and development of 3D printing tech-
ents, exchange oxygen and remove waste. Due to the
ue to the limitations of organ transplantation
such as the shortage of donors, tissue engin-
[1–3]
nologies
, fabrication of complex tissues or organs
eering was introduced in the early 1970s.
Tissue engineering aims to fabricate artificial organs may come true.
Hydrogels have attracted a great attention as bio-
or tissues to replace damaged or diseased ones in the materials for 3D printing due to their soft and wet na-
human body. The artificial substitute tissues and or- ture as well as similarities to biological tissues. There
gans can be customized, which means that a patient’s is a great success for application of hydrogels in the
own cells can be used to regenerate substitute organs area of 3D printing [4–12] for regeneration and repair of
and tissues. It has an obvious advantage that immuni- tissues or organs [4,10–12] . Alginate as one of biomate-
zation response and rejection can be overcome. How- rials is widely used in various pharmaceutical and
ever, without a three dimensional complex geometry, medical applications but displays some unsatisfactory

Rheological study on 3D printability of alginate hydrogel and effect of graphene oxide. © 2016 Huijun Li, et al. This is an Open Access article distri-
buted 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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