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RESEARCH ARTICLE

High-precision three-dimensional inkjet technology for

live cell bioprinting

Daisuke Takagi*, Waka Lin, Takahiko Matsumoto, Hidekazu Yaginuma, Natsuko Hemmi,
Shigeo Hatada, Manabu Seo

Ricoh Company Ltd., Healthcare Business Group, Biomedical Business Center, Kawasaki-city, 210-0821, Japan

Abstract: In recent years, bioprinting has emerged as a promising technology for the construction of three-dimensional (3D)
tissues to be used in regenerative medicine or in vitro screening applications. In the present study, we present the development
of an inkjet-based bioprinting system to arrange multiple cells and materials precisely into structurally organized constructs.
A novel inkjet printhead has been specially designed for live cell ejection. Droplet formation is powered by piezoelectric
membrane vibrations coupled with mixing movements to prevent cell sedimentation at the nozzle. Stable drop-on-demand
dispensing and cell viability were validated over an adequately long time to allow the fabrication of 3D tissues. Reliable
control of cell number and spatial positioning was demonstrated using two separate suspensions with different cell types
printed sequentially. Finally, a process for constructing stratified Mille-Feuille-like 3D structures is proposed by alternately
superimposing cell suspensions and hydrogel layers with a controlled vertical resolution. The results show that inkjet technology
is effective for both two-dimensional patterning and 3D multilayering and has the potential to facilitate the achievement of live
cell bioprinting with an unprecedented level of precision.

Keywords: Drop-on-demand; three-dimensional tissue engineering; drug discovery; regenerative medicine; hydrogel

*Correspondence to: Daisuke Takagi, Ricoh Company Ltd., Healthcare Business Group, Biomedical Business Center, Kawasaki-city, 210-0821,
Japan; daisuke.Takagi@jp.ricoh.com

Received: May 14, 2019; Accepted: May 27, 2019; Published Online: July 1, 2019
Citation: Takagi D, Lin W, Matsumoto T, et al., 2019, High-precision three-dimensional inkjet technology for live cell
bioprinting. Int J Bioprint, 5(2): 208. http://dx.doi.org/10.18063/ ijb.v5i2.208

1. Introduction development of novel technologies for biofabrication,
particularly bioprinting, has attracted a lot of attention
The field of tissue engineering has developed considering their potential to arrange cells and materials
considerably in recent years, along with the increasing [2]
interest in regenerative medicine globally. Advances in into structurally organized constructs .
stem cell research, particularly the discovery of induced Current bioprinting technologies are based on three
pluripotent stem cells , have provided a means to culture major approaches, including inkjet, extrusion, and laser
[1]
and manipulate cells from organs, which were once printing methods [3,4] . Extrusion-based strategies are
considered impossible to regenerate. In vitro production the most extensively developed due to their capacity
of functional tissue analogs has become a reality, and to develop 3D constructs and networks in a relatively
tissue engineering has numerous potential applications straightforward manner using high viscosity materials
in therapeutic areas including tissue repair and organ that can integrate extracellular matrix (ECM) such as
replacement, in addition to developing applications for collagen. However, the approach is not suitable since it
drug discovery, disease modeling, and alternatives for does not facilitate precise control over the deposition of a
animal testing. Today, one of the major challenges remains small number of cells. Although laser facilitates printing
how to reproduce three-dimensional (3D) structures of with a very high resolution, its productivity remains
tissues with matching complexity and functionality. The limited due to the complexity and cost of the system, in

High-precision three-dimensional inkjet technology for live cell bioprinting © 2019 Takagi, et al. This is an Open Access article distributed under the
terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/), permitting all non-
commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
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