Page 200 - IJB-9-5

International Journal of Bioprinting

REVIEW ARTICLE
Understanding droplet jetting on varying

substrate for biological applications

Jia Min Lee *, Xi Huang , Guo Liang Goh , Tuan Tran , Wai Yee Yeong 1,2
1
1,2
2
1
1 HP-NTU Digital Manufacturing Corp Lab, School of Mechanical & Aerospace Engineering, Nanyang
Technological University, Singapore
2 Singapore Centre for 3D Printing, School of Mechanical & Aerospace Engineering, Nanyang
Technological University, Singapore
(This article belongs to the Special Issue: Related to 3D printing technology and materials)

Abstract
In the inkjet printing process, the droplet experience two phases, namely the jetting
and the impacting phases. In this review article, we aim to understand the physics of
a jetted ink, which begins during the droplet formation process. Following which, we
highlight the different impacts during which the droplet lands on varying substrates
such as solid, liquid, and less commonly known viscoelastic material. Next, the
article states important process-specific considerations in determining the success
of inkjet bioprinted constructs. Techniques to reduce cell deformation throughout
the inkjet printing process are highlighted. Modifying postimpact events, such as
spreading, evaporation, and absorption, improves cell viability of printed droplet.
Last, applications that leverage on the advantage of pixelation in inkjet printing
technology have been shown for drug screening and cell–material interaction studies.
It is noteworthy that inkjet bioprinting technology has been integrated with other
processing technologies to improve the structural integrity and biofunctionality of
*Corresponding author:
Jia Min Lee bioprinted construct.
(jm.lee@ntu.edu.sg)
Citation: Lee JM, Huang X, Keywords: Inkjet printing; Material jetting; Bioprinting; Additive manufacturing;
Goh GL, et al., 2023, Understanding Hydrogel; Functional material
droplet jetting on varying substrate
for biological applications.
Int J Bioprint, 9(5): 758.
https://doi.org/10.18063/ijb.758
Received: November 22, 2022 1. Introduction
Accepted: January 04, 2023
Published Online: May 23, 2023 Three common material processing technologies have been developed for bioprinting
of engineered tissue for biological applications [1-9] . These technologies are material
Copyright: © 2023 Author(s).
This is an Open Access article extrusion, material jetting, and vat polymerization printing (VPP). Material extrusion is
distributed under the terms of the a technique that dispenses materials through a nozzle using either a pneumatic [10-21] or a
Creative Commons Attribution mechanical pump [22,23] . Material jetting, a technique which dispenses droplets of material,
License, permitting distribution,
and reproduction in any medium, has variation in the actuation module, such that material is expelled either by a vibrating
provided the original work is piezo crystal (as in piezoelectric inkjet printer) or based on vaporized volume of fluid
properly cited. (as in thermal inkjet printer) [24-29] . Alternatively, in the process of laser-induced forward
Publisher’s Note: Whioce transfer (LIFT), a pulsed laser source directs heat onto a coated quartz ribbon, which
Publishing remains neutral with causes displacement of microdroplets onto a receiving substrate [30-33] . Last, the process
regard to jurisdictional claims in
published maps and institutional of VPP is characterized by a photopolymer-filled tank that contains cell suspension. The
affiliations. cell-laden photopolymer is later selectively cured to form 3D structures [34-40] .

Volume 9 Issue 5 (2023) 192 https://doi.org/10.18063/ijb.758