Page 530 - IJB-9-5

International Journal of Bioprinting

RESEARCH ARTICLE
Enzymatic post-crosslinking of printed

hydrogels of methacrylated gelatin and
tyramine-conjugated 8-arm poly(ethylene

glycol) to prepare interpenetrating 3D network
structures

3
Jia Liang , Zhule Wang , Andreas A. Poot , Dirk W. Grijpma , Piet J. Dijkstra ,
2
2
1,2
2
Rong Wang *
2,3
1 Department of Neurosurgery, Stroke Center, Henan Provincial People’s Hospital, 450003, Henan,
China
2 Department of Biomaterials Science and Technology, University of Twente, Drienerlolaan 5, 7522
NB Enschede, The Netherlands
3 Department of Dentistry-Regenerative Biomaterials, Radboud University Medical Center, Philips
van Leydenlaan 25, 6525 EX Nijmegen, The Netherlands
(This article belongs to the Special Issue: Additive Manufacturing of Functional Biomaterials)

Abstract

Methacrylated gelatin (GelMA) has been intensively studied as a 3D printable
scaffold material in tissue regeneration fields, which can be attributed to its well-
*Corresponding author: known biological functions. However, the long-term stability of photo-crosslinked
Rong Wang
(rong.wang@radboudumc.nl) GelMA scaffolds is hampered by a combination of its fast degradation in the
presence of collagenase and the loss of physical crosslinks at higher temperatures.
Citation: Liang J, Wang Z,
Poot AA, 2023, Enzymatic post- To increase the longer-term shape stability of printed scaffolds, a mixture of
crosslinking of printed hydrogels of GelMA and tyramine-conjugated 8-arm PEG (8PEGTA) was used to create filaments
methacrylated gelatin and tyramine- composed of an interpenetrating network (IPN). Photo-crosslinking during
conjugated 8-arm poly(ethylene
glycol) to prepare interpenetrating filament deposition of the GelMA and subsequent enzymatic crosslinking of the
3D network structures. Int J 8PEGTA were applied to the printed 3D scaffolds. Although both crosslinking
Bioprint, 9(5): 750. mechanisms are radical based, they operate without interference of each other.
https://doi.org/10.18063/ijb.750 Rheological data of bulk hydrogels showed that the IPN was an elastic hydrogel,
Received: September 13, 2022 having a storage modulus of 6 kPa, independent of temperature in the range of
Accepted: November 7, 2022 10 – 40°C. Tensile and compression moduli were 110 kPa and 80 kPa, respectively.
On enzymatic degradation in the presence of collagenase, the gelatin content of
Published Online: May 11, 2023 the IPN fully degraded in 7 days, leaving a stable secondary crosslinked 8PEGTA
Copyright: © 2023 Author(s). network. Using a BioMaker bioprinter, hydrogels without and with human
This is an Open Access article osteosarcoma cells (hMG-63) were printed. On culturing for 21 days, hMG-63 in
distributed under the terms of the
Creative Commons Attribution the GelMA/8PEGTA IPN showed a high cell viability (>90%). Thus, the presence of
License, permitting distribution, the photoinitiator, incubation with H O , and mechanical forces during printing did
2
2
and reproduction in any medium, not hamper cell viability. This study shows that the GelMA/8PEGTA ink is a good
provided the original work is
properly cited. candidate to generate cell-laden bioinks for extrusion-based printing of constructs
for tissue engineering applications.
Publisher’s Note: Whioce
Publishing remains neutral with
regard to jurisdictional claims in
published maps and institutional Keywords: GelMA; 8-arm PEG; Photo-crosslinking; Enzymatic crosslinking; Bioprinting
affiliations.

Volume 9 Issue 5 (2023) 522 https://doi.org/10.18063/ijb.750