Page 348 - IJB-9-5

International Journal of Bioprinting

RESEARCH ARTICLE
3D printing of mechanically tough and

self-healing hydrogels with carbon
nanotube fillers

Soo A Kim , Yeontaek Lee , Kijun Park , Jae Park , Soohwan An , Jinseok Oh ,
1
1
1
1
3
1,2
Minkyong Kang , Yurim Lee , Yejin Jo , Seung-Woo Cho , Jungmok Seo *
1
1
1
1,2
3
1 School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
2 LYNK Solutec Inc., Seoul 03722, Republic of Korea
3 Department of Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
(This article belongs to the Special Issue: Convergence of 3D Bioprinting and Nanotechnology)
Abstract
Hydrogels have the potential to play a crucial role in bioelectronics, as they share
many properties with human tissues. However, to effectively bridge the gap between
electronics and biological systems, hydrogels must possess multiple functionalities,
including toughness, stretchability, self-healing ability, three-dimensional (3D)
printability, and electrical conductivity. Fabricating such tough and self-healing
materials has been reported, but it still remains a challenge to fulfill all of those
features, and in particular, 3D printing of hydrogel is in the early stage of the research.
In this paper, we present a 3D printable, tough, and self-healing multi-functional
hydrogel in one platform made from a blend of poly(vinyl alcohol) (PVA), tannic acid
(TA), and poly(acrylic acid) (PAA) hydrogel ink (PVA/TA/PAA hydrogel ink). Based on
a reversible hydrogen-bond (H-bond)-based double network, the developed 3D
*Corresponding author: printable hydrogel ink showed excellent printability via shear-thinning behavior,
Jungmok Seo allowing high printing resolution (~100 μm) and successful fabrication of 3D-printed
(jungmok.seo@yonsei.ac.kr) structure by layer-by-layer printing. Moreover, the PVA/TA/PAA hydrogel ink exhibited
Citation: Kim SA, Lee Y, Park K, high toughness (tensile loading of up to ~45.6 kPa), stretchability (elongation of
et al., 2023, 3D printing of approximately 650%), tissue-like Young’s modulus (~15 kPa), and self-healing ability
mechanically tough and self-healing within 5 min. Furthermore, carbon nanotube (CNT) fillers were successfully added to
hydrogels with carbon nanotube
fillers. Int J Bioprint, 9(5): 765. enhance the electrical conductivity of the hydrogel. We confirmed the practicality
https://doi.org/10.18063/ijb.765 of the hydrogel inks for bioelectronics by demonstrating biocompatibility, tissue
Received: February 6, 2023 adhesiveness, and strain sensing ability through PVA/TA/PAA/CNT hydrogel ink.
Accepted: April 18, 2023
Published Online: May 31, 2023
Keywords: Hydrogels; 3D Printing; Toughness; Self-healing; Nanofillers;
Copyright: © 2023 Author(s).
This is an Open Access article Bioelectronics
distributed under the terms of the
Creative Commons Attribution
License, permitting distribution,
and reproduction in any medium, 1. Introduction
provided the original work is
properly cited. Bioelectronics are functional devices that integrate biomolecules and electronic
Publisher’s Note: Whioce elements to measure biosignals from various parts of the human body, including the
Publishing remains neutral with skin, heart, spinal cord, and brain [1,2] . Thus, they are at the core of emerging applications
regard to jurisdictional claims in in the medical field such as healthcare monitoring devices, drug delivery systems, and
published maps and institutional
affiliations. implantable devices [3-5] . Despite the significance of bioelectronics in advanced healthcare

Volume 9 Issue 5 (2023) 340 https://doi.org/10.18063/ijb.765