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RESEARCH ARTICLE

A Dual-sensitive Hydrogel Based on

Poly(Lactide-co-Glycolide)-Polyethylene Glycol-

Poly(Lactide-co-Glycolide) Block Copolymers for 3D

Printing

Yang Zhou , Yuecheng Cui , Li-Qun Wang *
1
1
1,2
1 MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and
Engineering, Zhejiang University, Hangzhou 310027, P. R. China
2 Hangzhou Medsun Biological Technology Co., Ltd, Hangzhou Economic and Technological Development Area, Hangzhou
310027, P. R. China

Abstract: The thermo-sensitive hydrogel formed by triblock copolymers of polyethylene glycols and aliphatic polyesters
serves as a promising candidate for bioink due to its excellent biodegradability and biocompatibility. However, the thermo-
crosslinking alone cannot achieve a robust hydrogel to support the 3D printed constructs without collapse. Herein, a photo-
crosslinkable group was introduced into the triblock copolymers to achieve a dual-sensitive hydrogel. A triblock copolymer
poly(lactide-co-glycolide)-polyethylene glycol-poly(lactide-co-glycolide) decorated with acrylate group in the chain end was
prepared. The obtained aqueous solutions of the copolymers could transform into hydrogels with excellent shear thinning
properties and rapid elastic recovery properties spontaneously on the increase of temperature. The resulted thermogels also
allowed for photo-crosslinking by exposure to ultraviolet radiation, with storage modulus dramatically increased to stable the
printed constructs. Through a two-step crosslinking strategy, complicated tissue-like constructs with high shape fidelity can be
printed using the dual-sensitive inks. Moreover, the mechanical strength, swelling ratio, and printability of the hydrogels can
be tuned by varying the substitution rate of the acrylate group without compromising the inks’ extrudability. We expect that
the dual-sensitive hydrogels may be used as bioinks to print large constructs for applications in tissue engineering.

Keywords: 3D bioprinting; Dual-sensitive hydrogels; Poly(lactide-co-glycolide)-polyethylene glycol-poly(lactide-co-
glycolide); Injectable hydrogels

*Correspondence to: Li-Qun Wang, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China;
lqwang@zju.edu.cn
Received: April 29, 2021; Accepted: June 22, 2021; Published online: June 29, 2021

Citation: Zhou Y, Cui YC, Wang LQ, 2021, A Dual-sensitive Hydrogel Based on Poly(Lactide-Co-Glycolide)-Polyethylene
Glycol-Poly(Lactide-Co-Glycolide) Block Copolymers for 3D Printing. Int J Bioprint, 7(3):389. http://doi.org/10.18063/ijb.v7i3.389

1. Introduction extrusion printing is the most widely used due to its easy
implementation and ability to print large constructs [4,7] .
Three-dimensional (3D) bioprinting is an emerging
technology in the field of tissue engineering. The ability Various biomaterials including synthetic and natural
to rapidly create complicated biomimetic structures with polymers have been reported as printing hydrogels, such
[10]
[9]
high accuracy through layer-by-layer deposition make it a as poly(ethylene glycol) (PEG) [3,8] , collagen , gelatin ,
[11]
promising tool for patient-specific treatments [1-3] . Among sodium alginate , silk fibroin [12-14] , hyaluronic acid [15-17] ,
[18]
several printing strategies, inkjet printing and laser- and decellularized extracellular matrix . Nevertheless,
[6]
assisting bioprinting have high print resolutions but can the number of compounds used as inks is still limited .
only deal with nonviscous liquid [4,5] ; stereolithography It is necessary to develop new inks to expand the inks
(STL) is fast but needs lots of ink to form a vat ; library for further applications of 3D bioprinting.
[6]
© 2021 Zhou, et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/
licenses/by/4.0/), permitting distribution, and reproduction in any medium, provided the original work is properly cited.
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