Page 246 - IJB-10-4

International

Journal of Bioprinting

RESEARCH ARTICLE
Considering cell viability in 3D printing of

structured inks: A comparative and equivalent
analysis of fluid forces

Pengju Wang , Yazhou Sun *, Liwei Diao , and Haitao Liu *
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2
1 Department of Mechanical Manufacturing and Automation, School of Mechatronics Engineering,
Harbin Institute of Technology, Harbin, Heilongjiang, China
2 Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen,
Guangdong, China
(This article belongs to the Special Issue: Advanced Biomaterials for 3D Printing and Healthcare Application)

Abstract

In conventional extrusion-based three-dimensional (3D) printing (E3DP), smaller
needles reduce cell viability due to increased fluid forces like pressure and shear
stress. A novel E3DP approach has emerged, involving 3D printing with structured
inks. Fluid forces in both conventional and structured ink-based methods were
evaluated through computational fluid dynamics (CFD) simulations. By employing
18G needles, we showcased the advantages of structured inks, including
2-symmetric, 4-symmetric, vascular-like, and hepatic lobule analogue-like inks,
which demonstrated consistently lower pressures and shear stress compared with
conventional inks. Specifically, vascular-like inks with a 2:1:1 extruded fiber layer
distance showed significantly lower shear stress (average 6.595e+0 Pa, maximum
Corresponding authors: 2.069e+2 Pa) than conventional methods. Equivalent analyses explored commonly
Yazhou Sun
(sunyzh@hit.edu.cn) used symmetric and core–shell inks, examining fluid forces on cells. Particularly,
Haitao Liu (hthit@hit.edu.cn) in core–shell inks with a 2.8 mm core layer radius, cells in the flow domain of the
shell layer experienced an equivalent viscosity of 3.70 Pa·s, while in the core layer,
Citation: Wang P, Sun Y, Diao L, it was 1.72 Pa·s. The analyses revealed a positive correlation between equivalent
Liu H. Considering cell viability in
3D printing of structured inks: homogeneous ink viscosity and shear stress. The proposed workflow, emphasizing
A comparative and equivalent cell viability, offers an efficient approach for structured ink design. Also, experiments
analysis of fluid forces. that used vascular-like ink-based printing as an example indicated significantly
Int J Bioprint. 2024;10(4):2362.
doi: 10.36922/ijb.2362 higher cell viability when compared with conventional printing. This research
provides valuable insights for enhancing cell viability in 3D printing and advancing
Received: December 3, 2023
Accepted: February 5, 2024 printing material design.
Published Online: March 15, 2024
Copyright: © 2024 Author(s). Keywords: Cell viability; Extrusion-based 3D printing; Structured inks; Ink design;
This is an Open Access article Computational fluid dynamics; Fluid forces
distributed under the terms of the
Creative Commons Attribution
License, permitting distribution,
and reproduction in any medium,
provided the original work is
properly cited. 1. Introduction
Publisher’s Note: AccScience Tissue engineering is a prominent focus in both the scientific and clinical communities,
Publishing remains neutral with with extensive applications in vitro tissue construction, drug screening, and in
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regard to jurisdictional claims in 3
published maps and institutional situ tissue regeneration. This is largely attributed to the widespread availability
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affiliations. of biocompatible materials that mimic the structures and/or properties of native

Volume 10 Issue 4 (2024) 238 doi: 10.36922/ijb.2362