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International Journal of Bioprinting 3D bioprinting of tissue with carbon nanomaterials

Figure 1. Schematic illustration of 3D bioprinting systems. (A) Droplet-assisted bioprinting (DBB) includes (a) ink-jet, (b) laser-assisted, and (c) electro-
hydrodynamic jetting. (B) Photocuring-based bioprinting (PBB) includes (d) stereolithography and (e) digital-light processing. (C) There are three types
of extrusion-based bioprinting (EBB), which are (f) pneumatic, (g) piston, and (h) screw. Images (a), (b), (d), (f), (g), and (h) were reprinted from Bioen-
gineering, 7, Jeong HJ, Nam H, Jang J, et al., 3D Bioprinting strategies for the regeneration of functional tubular tissues and organs, 32, Copyright (2020),
with permission from MDPI . Image (c) was reprinted from Micromachines, 10, Pan Y, Zeng L, Simulation and validation of droplet generation process
[23]
for revealing three design constraints in electrohydrodynamic jet printing, 94, Copyright (2019), with permission from MDPI . Image (e) was reprinted
[20]
from International Journal of Molecular Sciences, 23, Seo JW, Kim GM, Choi Y, et al., Improving printability of digital-light-processing 3D bioprinting via
photoabsorber pigment adjustment, 5428, Copyright (2022), with permission from MDPI .
[29]
(TE) and regenerative medicine. Unlike conventional bioprinting can be divided into drop-on-demand (DOD)
additive manufacturing techniques, tailored and precise and continuous inkjet (CIJ) printings. In DOD printing,
constructs can be fabricated by simply controlling the the bioprinter produces bioink droplets over the substrate
printing parameters, such as biocompatible materials, whenever required, whereas in CIJ printing, ink droplets
instrumental methods (temperature, pressure, and are continuously dispersed from a liquid stream flow.
speed), and employed cells [1-3] . 3D bioprinting primarily DOD printing is efficient for several-layered deposition of
involves layer-by-layer deposition of cell-free or cell-laden material and fine patterning, owing to its high precision
biocompatible materials in predetermined computer- and minimal waste of bioink. Thermal, electrostatic, or
designed structural constructs to fabricate functional piezoelectric forces are used in this technique to produce
tissue analogs [4-6] . Moreover, 3D bioprinting in TE has some and deposit droplets of various biological materials to
advantages in developing complex biological structures, construct a spatially heterogeneous tissue structure [11,12] .
such as high fidelity, low material loss, patient-specific Recently, Binder et al. demonstrated that the deposition
designs, and tailored fabrication within a short period of of printable bioink containing human keratinocytes and
[7]
time . fibroblasts over full-thickness skin defects of athymic
mice using DOD technology stimulated wound healing
1.1. Types of bioprinting and reduced skin contracture . However, DOD has some
[13]
3D bioprinting techniques can be classified into three types limitations, including small inkjet apertures (10–150 µm)
according to different molding principles: droplet-based and the production of nonporous tissue-engineered
bioprinting (DBB), photocuring-based bioprinting (PBB), structures, which may affect tissue perfusion and substance
and extrusion-based bioprinting (EBB) [8,9] , as shown in exchange. Hence, only low-viscosity hydrogels can be used
Figure 1. for DOD printing. In addition, the drop rate of DOD
printing is lower than that of CIJ printing .
[14]
1.1.1. Droplet-based bioprinting
Inkjet, laser-assisted, and electrohydrodynamic jetting In laser-assisted bioprinting, the system contains a
bioprinters are used in DBB technologies . Inkjet pulsed laser source, a focusing tool, a metallic ribbon film
[10]

Volume 9 Issue 1 (2023) 182 https://doi.org/10.18063/ijb.v9i1.635