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International Journal of Bioprinting Advancements in 3D printing

bioinks are then used in 3D printing to construct organs developmental studies. Abate’s team introduced a novel
or organ prototypes. This approach finds extensive utility microfluidic technique named high-resolution single-cell
in tissue repair, which is instrumental for unraveling tissue printing. This technique utilizes a highly miniaturized
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development mechanisms and facilitating drug screening. microfluidic sorter within Bioprine to precisely print
Hydrogels, formulated from hydrophilic polymers such as individual cells from a mixture of multiple candidates.
alginate, gelatin, and GelMA, undergo crosslinking through Achieving precision at ~10 μm and a speed of ~100 Hz,
various mechanisms, such as thermal entanglement, this approach has notable implications for bioprinting
molecular self-assembly, electrostatic interactions, ionic applications requiring single-cell precision.
bonding, and chemical reactions. Cui et al. introduced
an innovative technique employing 3D cell printing This technology overcame the limitations of traditional
technology to establish a method for addressing volumetric tissue engineering methods with low spatial resolution
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muscle loss using dECM bioink. This technique facilitated and allows for precise control of cell distribution. In the
the generation of volumetric muscle structures utilizing “cell printing” process, cells (or cell aggregates) and a sol
cell-loaded dECM bioinks with the aid of a particle- gel (precursor of hydrogel) are simultaneously placed
based printing approach. The outcomes underscore the in the printhead of a printer. The deposition positions
potential of 3D cell printing in conjunction with tissue- of cell-containing droplets are controlled by a computer,
derived bioinks for effectively generating biomimetic and printing is done point by point at specified locations.
engineered muscles, thus enhancing the treatment of After printing one layer, another layer is printed on top,
volumetric muscle loss injuries. Proposed by Ribezzi et al., and this layer-by-layer process continues to create a 3D
a groundbreaking approach termed embedded extrusion multicellular/gel system.
volume printing, which encompasses polymer extrusion Compared to traditional tissue engineering techniques like
bioprinting and layerless ultrafast volumetric bioprinting, “cell-scaffold” methods, cell printing offers several advantages:
allows for the spatial arrangement of various inks and cell (i) simultaneous construction of biologically active 2D or
types, opening up new avenues for producing biologically 3D “multi-cell/material” systems; (ii) accurate deposition of
functional regenerative grafts. Moreover, this approach different types of cells in spatiotemporal manner; and (iii)
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holds promise in developing engineered living systems and creation of a 3D microenvironment for cells.
models for metabolic diseases.
Furthermore, cell printing is a high-throughput
Ali et al. devised a kidney-specific microenvironment cell arrangement technology that is entirely computer-
for kidney tissue bioprinting using a photo-crosslinked controlled and can be developed into a technique for in
kidney ECM-derived bioink called KdECMMA. The situ operations within an organism. This technology finds
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resulting bioprinted kidney constructs exhibit both applications in tissue engineering, development of cell-
structural and functional traits akin to native kidney based sensors, modeling in drug metabolism kinetics, and
tissue. The utility of tissue-specific ECM-derived bioinks drug screening (Figure 19).
was demonstrated in cell-based bioprinting, promoting
cell maturation and eventual tissue formation. Singh et 5. Discussion
al. utilized coaxial 3D cell printing technology to craft
microfluidic hollow tubes, comprising tubular/vascular 3D bioprinting technology can meet personalized, small-
renal parenchyma composed of tubular epithelial cells batch, and large-scale medical needs. It has been widely
and endothelial cells. They developed a hybrid bioink used in the field of in vitro medical device manufacturing
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that can create the microenvironment of vascularized and is currently being extended to personalized permanent
native kidney tissue. With rapid crosslinking properties, implants, clinical prosthetics, and drug development
this hybrid bioink optimizes cell function and retains trials. However, with the expansion of the application of
the predefined hollow tube architecture, which holds 3D bioprinting technology in the field of biomedicine,
promise for applications in regenerative medicine. On the problems such as low printing throughput, standardization
other hand, Kim et al. innovatively modified the 3D cell of preparations, and specialization have become key
printing process to yield in situ uniaxial alignment and constraints restricting the application of this technology.
microtopography. Leveraging 3D printing technology, In addition to adopting the core technology of traditional
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they successfully generated cell-based dECM structures 3D printing, all manufacturing processes must be able
imbued with distinct topographical cues. This approach’s to satisfy biological and medical standards, as well as
potential extension to various musculoskeletal tissues like preserve cell activity and tissue function. This required
tendons and ligaments could lead to the development of extensive experimentations to optimize the integration of
in vitro tissue-on-a-chip models for drug screening and biomaterials, cells, and growth factors for 3D bioprinting

Volume 10 Issue 2 (2024) 68 doi: 10.36922/ijb.1752