Thiol-Rich Multifunctional Macromolecular Crosslinker for Gelatin-Norbornene-Based Bioprinting

• Published in: Biomacromolecules Vol. 22; no. 6; pp. 2729 - 2739
• Main Authors: Zhao, Cailing, Wu, Zejia, Chu, Hanyu, Wang, Tao, Qiu, Shuai, Zhou, Jing, Zhu, Qingtang, Liu, Xiaolin, Quan, Daping, Bai, Ying
• Format: Journal Article
• Language: English
• Published: American Chemical Society 14.06.2021
• ISSN: 1525-7797; 1526-4602
• DOI: 10.1021/acs.biomac.1c00421

Extrusion-based bioprinting is an emerging and most frequently used technique for the fabrication of cell-laden constructs. A suitable hydrogel-based bioink for cell encapsulation and protection is critical for printability, structural stability, and post-printing cell viability. The thiol–ene chemistry-based gelatin-norbornene (GelNB) hydrogels have drawn much attention as a promising substitution of gelatin methacryloyl (GelMA), owing to the fast and controllable step-growth polymerization mechanism, as well as a significant reduction in reactive oxygen species (ROS) accumulation. Herein, thiolated heparin (HepSH) was synthesized and used as a macromolecular crosslinker for GelNB-based bioprinting, so that GelNB gelation became less sensitive to the thiol/ene ratio. The mechanical stability and moduli of GelNB/HepSH hydrogels were easily manipulated by the concentration and/or degree of thiol substitution. The GelNB/HepSH hydrogel allowed little intracellular ROS for encapsulated cells but provided vascular endothelial growth factor binding affinity for potential facilitation of neovascularization. Finally, the GelNB/HepSH bioink enabled a convenient printing process for both complex-structured bioscaffolds and cell-laden constructs, and resulted in good printability and high post-crosslinking cell viability. The crosslinker HepSH may serve as a multifunctional macromolecule that enables GelNB-based bioprinting in broad applications in regenerative medicine.