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International Journal of Bioprinting Optimizing inkjet bioprinting

advantages and limitations; the choice of bioprinting deformation of the print chamber, which generates
technique is dependent on the specific goals of the research pressure waves and ejects droplets from the nozzle. This
or application. cutting-edge approach facilitates DOD deposition of
living cells and biomaterials in a layer-by-layer fabrication
Inkjet-based bioprinting is one of the pioneering 3D
printing technologies that facilitate cell deposition for approach with unparalleled precision and control.
fabrication of 3D tissues or organs, whereby the printing One of the key challenges in harnessing the full potential
of collagen and fibronectin for life science applications was of inkjet bioprinting lies in optimizing cell deposition to
first demonstrated using a HP thermal inkjet printer in ensure cell homogeneity and high cell viability during
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1988. To date, it has emerged as an important technique the printing process. This review paper explores the
in the rapidly evolving landscape of biotechnology and critical importance of optimizing cell deposition in inkjet
regenerative medicine for manipulating, patterning, bioprinting, delving into various important considerations,
and assembling of biologically relevant materials (cells, such as bio-ink formulation, printing chamber design and
biomolecules, and biomaterials) in the form of ejected operation, droplet formation, droplet impact, and 3D
droplets to achieve specific biological functions in a drop- hydrogel matrix. By addressing these fundamental aspects,
on-demand (DOD) manner (Figure 1). The DOD inkjet- researchers can unlock the true potential of cell deposition
based bioprinting can be categorized as thermal inkjet for inkjet-based bioprinting.
(TIJ) or piezo inkjet (PIJ) bioprinting. TIJ bioprinting uses
thermal energy to create vapor bubbles within the print 2. Properties of cell-laden bio-inks
chamber; the generated force from the rapid expansion 2.1. Influence of cells on physical properties
of the vapor bubble expels tiny droplets of bio-ink from of bio-inks
the nozzle onto an underlying substrate. In contrast, PIJ In general, cell-laden bio-inks can be classified into three
bioprinting uses piezo actuator to induce mechanical distinct groups based on the cell volume fraction, denoted

Figure 1. Advancements in cell deposition for inkjet-based bioprinting. Pioneering studies encompass various aspects such as high-throughput cell
patterning, printing of viable cells, and pre-defined deposition of living cells. The application of inkjet printing technology for cell transfection was
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successfully demonstrated, and the effect of surfactants and agitation on cell homogeneity within the bio-ink was evaluated. Furthermore, high-speed
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imaging was employed to investigate the droplet formation process, and a separate study has demonstrated single-cell inkjet printing. High-speed
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imaging technique also played a critical role in analyzing the influence of droplet impact velocity and droplet volume on cell viability, as well as employing
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machine learning approaches to predict the number of printed cells during inkjet bioprinting process based on droplet velocity profiles.
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Volume 10 Issue 2 (2024) 183 doi: 10.36922/ijb.2135