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RESEARCH ARTICLE

Development and characterization of a photocurable

alginate bioink for three-dimensional bioprinting

H. H. Mishbak , Glen Cooper , P. J. Bartolo *
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1,2
1 Department of Biomedical Engineering, School of Engineering, University of Thi-Qar. Thi-Qar, Iraq
2 Manufacturing Group, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester,
Manchester, UK

Abstract: Alginate is a biocompatible material suitable for biomedical applications, which can be processed under mild
conditions on irradiation. This paper investigates the preparation and the rheological behavior of different pre-polymerized
and polymerized alginate methacrylate systems for three-dimensional photopolymerization bioprinting. The effect of the
functionalization time on the mechanical, morphological, swelling, and degradation characteristics of cross-linked alginate
hydrogel is also discussed. Alginate was chemically-modified with methacrylate groups and different reaction times considered.
Photocurable alginate systems were prepared by dissolving functionalized alginate with 0.5- 1.5% w/v photoinitiator solutions
and cross-linked by ultraviolet light (8 mW/cm for 8 minutes).
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Keywords: 3D bioprinting; Alginate hydrogel; Functionalization; Photopolymerization; Rheology

*Correspondence to: P. J. Bartolo, School of Mechanical, Aerospace and Civil Engineering, Manchester Biomanufacturing Centre, Manchester
Institute of Biotechnology, University of Manchester, Manchester, UK; paulojorge.dasilvabartolo@manchester.ac.uk
Received: March 4, 2019; Accepted: March 25, 2019; Published Online: July 1, 2019
Citation: Mishbak HH, Cooper G, Bartolo PJ, 2019, Development and characterization of a photocurable alginate bioink for
three dimensional bioprinting. Int J Bioprint, 5(2): 189. http://dx.doi.org/10.18063/ijb.v5i2.189

1. Introduction is a very versatile method allowing a rapid crosslinking
under biocompatible reaction conditions without the use
Three different approaches are being explored for tissue of solvents [1,6] . In addition, photocurable hydrogels are
engineering applications [1,2] . The first approach, cell particularly relevant for biomedical applications due
therapy, is based on harvesting cells, sorting, expanding, to the advantage of being able to encapsulate cells and
and implanted them. This is a simple process but presents the mild processing conditions that allow their in situ
limited outcomes as it is difficult to keep the cells in the crosslinking within a patient during a surgical procedure.
desired region for clinically relevant periods of time . Suitable hydrogels for bioprinting must be
[3]
The second approach, scaffold-based approach, is based biocompatible, biodegradable, present appropriate
on the use of three-dimensional support structures that mechanical properties, which depend on the type of
provide the necessary environment for cell attachment, tissue, good printability, and shear thinning properties
[8]
differentiation, and proliferation . In this approach, to facilitate the printing process . In the case of
[4]
[9]
scaffolds can be directly implanted after fabrication or photopolymerization bioprinting systems, the amount
seeded with cells and pre-cultured in a bioreactor before and type of photoinitiator are also critical as determines
implantation . Finally, the third approach (bioprinting) the crosslinking density, cytotoxicity, mechanical
[5]
uses bioinks (hydrogels and cells) to create cell-laden properties, and biocompatibility . The increase of
[10]
constructs. This is a highly relevant approach allowing in crosslinking density is usually associated with an increase
situ printing [6,7] . Technologies such as inkjet bioprinting, of printability and mechanical properties and a decrease
extrusion-based, and photopolymerization-based process of biocompatibility due to the reduction of free space to
are being explored. Among them, photopolymerization accommodate cell proliferation .
[11]
Development and characterization of a photocurable alginate bioink for three-dimensional bioprinting © 2019 Mishbak, et al. 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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