Biomaterials 26 (2005) 93–99
Inkjet printing of viable mammalian cells
Tao Xu, Joyce Jin, Cassie Gregory, James J. Hickman*, Thomas Boland*
Department of Bioengineering, Clemson University, 502 Rhodes Hall, Clemson, SC 29634, USA
Received 19 December 2003; accepted 1 April 2004
Abstract
The purpose of this study was to explore the use of a commercial thermal printer to deposit Chinese Hamster Ovary (CHO) and
embryonic motoneuron cells into pre-defined patterns. These experiments were undertaken to verify the biocompatibility of thermal
inkjet printing of mammalian cells and the ability to assemble them into viable constructs. Using a modified Hewlett Packard (HP)
550C computer printer and an HP 51626a ink cartridge, CHO cells and rat embryonic motoneurons were suspended separately in a
concentrated phosphate buffered saline solution (3 Â ). The cells were subsequently printed as a kind of ‘‘ink’’ onto several ‘‘bio-
papers’’ made from soy agar and collagen gel. The appearance of the CHO cells and motoneurons on the bio-papers indicated an
healthy cell morphology. Furthermore, the analyses of the CHO cell viability showed that less than 8% of the cells were lysed during
printing. These data indicate that mammalian cells can be effectively delivered by a modified thermal inkjet printer onto biological
substrates and that they retain their ability to function. The computer-aided inkjet printing of viable mammalian cells holds
potential for creating living tissue analogs, and may eventually lead to the construction of engineered human organs.
r 2004 Elsevier Ltd. All rights reserved.
Keywords: Inkjet technology; Tissue engineering; Viable mammalian cells
1. Introduction
This work has demonstrated that viable mammalian
cells be delivered in pre-determined patterns using a
modified inkjet printer. This new ability has implications
for any application that requires spatially registered
cellular engineering, primarily in the field of tissue
engineering, which is a rapidly expanding approach to
address the shortage of organs for transplantation [1].In
the most general sense, tissue engineering seeks to
fabricate viable replacement parts for the body [2].
Although still in its infancy, much progress in tissue
engineering has been made in areas relevant to the
development of novel biomaterials [3], the design of
bioreactors for dynamic in vitro culture systems [4], and
the use of a wide variety of cell sources, including
appropriate multi-potent stem cells [5]. Advancements
in tissue engineering have permitted the creation of
functional tissue substitutes available to patients for
clinical applications, including engineered stomachs [6],
esophagus [7], spinal cord [8], and progress towards
complete tissue engineered organs [9]. To further the
construction of complex tissues, or even entire organs,
however, there are still significant technical challenges to
overcome. Among them, a very important problem is
subtly combining and orchestrating cells, growth factors
and scaffolds into an architecture that will allow their
unfettered interaction, especially where distinct cell
types are required in anatomically exact locations to
attain biological function [10]. Inkjet printing technol-
ogy offers a possible solution to this complex problem.
Inkjet printing, initially from the field of electronics
and mechanics [11], has recently been extended to
bioengineering applications [12]. With the obvious
advantages of being inexpensive as well as high
throughput, commercial thermal inkjet printers have
been modified to print biomolecules onto target
substrates with little or no reduction of their bioactiv-
ities, resulting in the creation of DNA chips [13], protein
arrays [14] and cell patterns [15]. In particular, our
recent success in printing viable bacteria directly using
an off-the-self thermal inkjet printer [16] significantly
expands the capabilities of inkjet printing in the
direction of creating living tissue substitutes. By means
ARTICLE IN PRESS
*Corresponding authors. Tel.: +1-864-656-7639; fax: +1-864-656-
4466.
E-mail address: tboland@clemson.edu(T. Boland).
0142-9612/$ - see front matter r 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.biomaterials.2004.04.011